173 results on '"Marshall LF"'
Search Results
2. Multidirectional projectional rigid neuro-endoscopy: prototype and initial experience
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Marshall Lf, Henry E. Aryan, Levy Ml, and Hoeg Hd
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Models, Anatomic ,medicine.medical_specialty ,Endoscope ,Video-Assisted Surgery ,Intraventricular tumor ,Neurosurgical Procedures ,Imaging, Three-Dimensional ,Rigid endoscope ,Joystick ,medicine ,Humans ,Minimally Invasive Surgical Procedures ,Computer vision ,Map projection ,medicine.diagnostic_test ,business.industry ,Neuroendoscopes ,General Medicine ,Video image ,Surgery ,Visualization ,Endoscopy ,Neuroendoscopy ,Neurology (clinical) ,Artificial intelligence ,business - Abstract
Introduction: The role of neuro-endoscopy is emerging. Traditional endoscopy is complicated by limited 2D views that make surgical interventions difficult. We have developed a rigid endoscope with a variable direction view that provides 3D visualization. Materials and Methods: A prototype of the EndActive® endoscope was used to examine 2 brain/intraventricular models. A 360-degree view is controlled via integrated joystick. Alternatively, the computer can volumetrically capture the ventricular surface. The captured video image can be viewed later or processed to create a flat projection map. The performance of this endoscope was compared to standard endoscopy with fixed directions of view. To simulate endoscopy, the center of the first brain model had eight labeled projections. The model was inspected with the multidirectional endoscope, standard rigid endoscopes (0-, 30- and 70-degrees), and via a projection map. Ten neurosurgeons proficient in neuro-endoscopy were recruited for the experiments. The second brain model was labeled with 32 intraventricular tumors. Results: With a 0-degree endoscope, only the number directly opposite the site of entry was visualized. With increasing angles, additional numbers were visualized. The 70 -degree endoscope allowed 4 of 8 numbers to be visualized. Using the multidirectional endoscope, all 8 numbers were visualized. The multidirectional endoscope was more accurate in identifying markers compared to standard endoscopy (p = 0.031). The mean endoscopy times using the multidirectional endoscope and standard endoscopy were 143 and 117 seconds, respectively (p = 0.243). The best performance was obtained when the flat projection map was read (p < 0.01). Using the endoscope prototype, an average of 30.8 (96%) tumors was identified on the brain model. Conclusion: The EndActive® endoscope is a rigid endoscope that provides complete visualization of a 3D space by controlling an adjustable viewing direction. In our study, the multidirectional endoscope provided superior visualization compared to standard endoscopy.
- Published
- 2005
3. Patient age and outcome following severe traumatic brain injury: an analysis of 5600 patients
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Hukkelhoven, CWPM, Steyerberg, Ewout, Rampen, Anneke, Farace, E, Habbema, Dik, Marshall, LF, Murray, GD, Maas, AIR (Arne), Public Health, and Neurosurgery
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- 2003
4. Regional differences in patient characteristics, case management, and outcomes in traumatic brain injury: experience from the tirilazad trials
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Hukkelhoven, CWPM, Steyerberg, Ewout, Farace, E, Habbema, Dik, Marshall, LF, Maas, AIR (Arne), Public Health, and Neurosurgery
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- 2002
5. Intracranial hypertension and cerebral perfusion pressure: influence on neurological deterioration and outcome in severe head injury
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Juul, N, Morris, GF, Marshall, SB, Comm.int.Selfotel trial,, Marshall, LF, Maas, AIR (Arne), and Neurosurgery
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- 2000
6. Failure of the competive N-methyl-D-aspartate antagonist Selfotel (CGS 19755) in the treatment of severe head injury: results of two Phase III clinical trials
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Morris, GF, Bullock, R, Bowers marshall, S, Marmarou, A, Maas, AIR (Arne), Selfotel Investigators,, Marshall, LF, and Neurosurgery
- Published
- 1999
7. Expression of annexin and Annexin-mRNA in rat brain under influence of steroid drugs
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Voermans, PH, Go, KG, ter Horst, GJ, Ruiters, MHJ, Solito, E, Parente, L, James, HE, Marshall, LF, Reulen, HJ, Baethmann, A, Marmarou, A, Ito, U, Hoff, JT, Kuroiwa, T, Czernicki, Z, Vascular Ageing Programme (VAP), and Restoring Organ Function by Means of Regenerative Medicine (REGENERATE)
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PCR ,lipocortin ,in situ hybridization ,Annexin-1 ,steroids - Abstract
Brain tissue of rats pretreated with methylprednisolone or with the 21-aminosteroid U74389F, and that of untreated control rats, was assessed for the expression of Annexin-l (Anx-1) and the transcription of its mRNA. For this purpose Anx-1 cDNA was amplified and simultaneously a T7-RNA-polymerase promotor was incorporated into the cDNA using Polymerase Chain Reaction (PCR). Then digoxigenin-ll-UTP was incorporated into the transcribed cRNA with T7-RNA-polymerase. With this probe ill situ hybridization was carried out in sections of the brain. The probe was visualized by an immunoassay using an anti-digoxigenin antibody conjugate. Anx-1 protein was assessed by means of immunohistochemistry using a polyclonal antibody. The various brain areas of the control animals showed an appreciable amount of Anx-1 at mRNA or protein level; on the other hand, the animals which had been pretreated with either steroid, showed a more intense Anx-1 mRNA signal than the controls in many areas. In the pretreated animals Anx-1 immunostaining was unchanged in cortex, basal ganglia, amygdala and septum, but more intense in hippocampus, hypothalamus and thalamus. In ependyma, choroid plexus, meninges, and vascular walls there was no Anx-1 mRNA transcription detectable. An opposite profile was shown by the Anx-1 immunoreactivity, the protein was present in control animals as well as the steroid-pretreated animals, suggesting that here the protein was either from systemic origin, or has diffused from adjacent structures. The results indicate that Anx-1 mRNA transcription is upregulated by either steroid, and that in the untreated animals there is a resting level of Anx-1 mRNA transcription, presumably reflecting physiological influences on Anx-1 expression.
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- 1997
8. The origin of lactate in peritumoral edema as measured by proton-magnetic resonance spectroscopic imaging
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Go, Kian, Krikke, AP, Kamman, RL, Heesters, Martinus, James, HE, Marshall, LF, Reulen, HJ, Baethmann, A, Marmarou, A, Ito, U, Hoff, JT, Kuroiwa, T, and Czernicki, Z
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cerebral lactate ,proton-magnetic resonance spectroscopy ,peritumoral edema ,tissue perfusion - Abstract
Using in vivo proton-magnetic resonance spectroscopy (H-1-MRS), which allows the measurement of metabolites of adequate tissue concentration, the origin of lactate in peritumoral edema has been assessed by comparison with lactate levels in the central and marginal areas of the tumor in 18 patients with cerebral gliomas. In the majority of cases lactate content in the area of peritumoral edema was lower than that in the tumor margin or tumor center, which is consistent with the assumption that the tumor is the source of lactate, which then reaches the surrounding area of edema by diffusion. In 3 of the 18 cases the amount of lactate in the peritumoral edematous tissue was higher than in the tumor, indicating that the lactate is locally produced on account of ischemia due to regional elevation of tissue pressure in the edematous area.
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- 1997
9. A multicenter trial on the efficacy of tirilazad mesylate in head injury
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Marshall, LF, Maas, AIR, Marshall, SB, Bricolo, A, Fearnside, M, Iannotti, F, Klauber, MR, Lagarrigue, J, Persson, L, Pickard, JD, Piek, J, Servadei, F, Wellis, N, Morris, GF, Means, ED, Musch, B, Marshall, LF, Maas, AIR, Marshall, SB, Bricolo, A, Fearnside, M, Iannotti, F, Klauber, MR, Lagarrigue, J, Persson, L, Pickard, JD, Piek, J, Servadei, F, Wellis, N, Morris, GF, Means, ED, and Musch, B
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- 1998
10. Object-oriented software engineering: a use case driven approach
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Marshall, LF, primary
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- 1992
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11. Where's the manual?: preparing and producing the software user's manual
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Marshall, LF, primary
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- 1992
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12. Clinical measurement, statistical analysis, and risk-benefit: controversies from trials of spinal injury.
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Bracken MB, Aldrich EF, Herr DL, Hitchon PW, Holford TR, Marshall LF, Nockels RP, Pascale V, Shepard MJ, Sonntag VKH, Winn R, and Young W
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- 2000
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13. Neuroscience Critical Care
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Marshall Sb, Vos Hr, Marshall Lf, and Chestnut Rm
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business.industry ,Medicine ,Emergency Nursing ,Critical Care Nursing ,business ,Neuroscience ,Pathophysiology ,Patient management - Published
- 1991
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14. Neurogenic hypotension in patients with severe head injuries... including commentary by Barie PS.
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Chesnut RM, Gautille T, Blunt BA, Klauber MR, and Marshall LF
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- 1998
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15. Alcohol abuse and neurological outcome of the severely head injured.
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Ruff RM, Marshall LF, Klauber MR, Blunt BA, Grant I, Foulkes MA, Eisenberg H, Jane J, and Marmarou A
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- 1990
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16. Neuropsychological rehabilitation: an experimental study with head-injured patients.
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Ruff RM, Baser CA, Johnston JW, Marshall LF, Klauber SK, Klauber MR, and Minteer M
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- 1989
17. Neurobehavioral methods of assessment and the study of outcome in minor head injury.
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Ruff RM, Levin HS, and Marshall LF
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- 1986
18. ICP monitoring in severe head injury
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Eisenberg Hm and Marshall Lf
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medicine.medical_specialty ,Severe head injury ,Intracranial Pressure ,business.industry ,Brain Injuries ,Emergency medicine ,Medicine ,Humans ,business ,Icp monitoring ,Monitoring, Physiologic - Published
- 1987
19. Unix for programmers - an introduction
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Marshall, LF, primary
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- 1989
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20. The identification of a subgroup of children with traumatic subarachnoid hemorrhage at low risk of neuroworsening.
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Dalle Ore CL, Rennert RC, Schupper AJ, Gabel BC, Gonda D, Peterson B, Marshall LF, Levy M, and Meltzer HS
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- Adolescent, Child, Child, Preschool, Disease Progression, Female, Humans, Infant, Infant, Newborn, Male, Neuroimaging, Retrospective Studies, Risk Assessment, Tomography, X-Ray Computed, Brain diagnostic imaging, Subarachnoid Hemorrhage, Traumatic diagnostic imaging
- Abstract
OBJECTIVEPediatric traumatic subarachnoid hemorrhage (tSAH) often results in intensive care unit (ICU) admission, the performance of additional diagnostic studies, and ICU-level therapeutic interventions to identify and prevent episodes of neuroworsening.METHODSData prospectively collected in an institutionally specific trauma registry between 2006 and 2015 were supplemented with a retrospective chart review of children admitted with isolated traumatic subarachnoid hemorrhage (tSAH) and an admission Glasgow Coma Scale (GCS) score of 13-15. Risk of blunt cerebrovascular injury (BCVI) was calculated using the BCVI clinical prediction score.RESULTSThree hundred seventeen of 10,395 pediatric trauma patients were admitted with tSAH. Of the 317 patients with tSAH, 51 children (16%, 23 female, 28 male) were identified with isolated tSAH without midline shift on neuroimaging and a GCS score of 13-15 at presentation. The median patient age was 4 years (range 18 days to 15 years). Seven had modified Fisher grade 3 tSAH; the remainder had grade 1 tSAH. Twenty-six patients (51%) had associated skull fractures; 4 involved the petrous temporal bone and 1 the carotid canal. Thirty-nine (76.5%) were admitted to the ICU and 12 (23.5%) to the surgical ward. Four had an elevated BCVI score. Eight underwent CT angiography; no vascular injuries were identified. Nine patients received an imaging-associated general anesthetic. Five received hypertonic saline in the ICU. Patients with a modified Fisher grade 1 tSAH had a significantly shorter ICU stay as compared to modified Fisher grade 3 tSAH (1.1 vs 2.5 days, p = 0.029). Neuroworsening was not observed in any child.CONCLUSIONSChildren with isolated tSAH without midline shift and a GCS score of 13-15 at presentation appear to have minimal risk of neuroworsening despite the findings in some children of skull fractures, elevated modified Fisher grade, and elevated BCVI score. In this subgroup of children with tSAH, routine ICU-level care and additional diagnostic imaging may not be necessary for all patients. Children with modified Fisher grade 1 tSAH may be particularly unlikely to require ICU-level admission. Benefits to identifying a subgroup of children at low risk of neuroworsening include improvement in healthcare efficiency as well as decreased utilization of unnecessary and potentially morbid interventions, including exposure to ionizing radiation and general anesthesia.
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- 2018
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21. [Prevalence of Disturbed Eating Behavior in Children and Adolescents with Type 1 Diabetes: Assessment and Comparison to Healthy Peers--Results of a Multicenter Questionnaire-based Study].
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Hevelke LK, Albrecht C, Busse-Widmann P, Kranz J, Lange K, Markowitz JT, Marshall LF, Meurs S, de Soye IH, and Saßmann H
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- Adolescent, Child, Cross-Sectional Studies, Female, Germany epidemiology, Health Surveys, Humans, Male, Prevalence, Surveys and Questionnaires, Young Adult, Diabetes Mellitus, Type 1 complications, Diabetes Mellitus, Type 1 epidemiology, Feeding and Eating Disorders complications, Feeding and Eating Disorders epidemiology
- Abstract
Introduction: Published data on prevalence of disturbed eating behavior in youth with type 1 diabetes are heterogeneous. This study assesses the prevalence rate of disturbed eating behavior in a representative German sample of children and adolescents with type 1 diabetes. The prevalence rate is compared to the one published for a national sample of healthy peers. Furthermore prospects as well as limits of a generic screening tool used to identify disturbed eating behavior are compared to those of a diabetes specific screening tool., Material and Methods: A total of 246 children and adolescents (age: 11-19 years) with type 1 diabetes, from 6 pediatric diabetes centers in Germany, completed the generic SCOFF questionnaire and the diabetes specific Diabetes Eating Problem Survey-Revised (DEPS-R) to assess their eating behavior. Prevalence data were compared to representative data from a nationwide survey in Germany (KiGGS-study)., Results: A total of 16.3% of the children and adolescents with type 1 diabetes scored above the SCOFF cut-off (≥ 2) (24.2% of the girls and 8.9% of the boys). The percentages in the healthy controls were 28.9% for girls and 15.2% for boys. Compared to this the prevalence of disturbed eating behavior was lower in the diabetes group (p=0.017 and p<0.001). According to the diabetes specific DEPS-R 11.2% of the boys and 13.2% of the girls with type 1 diabetes practiced insulin-purging. The association between SCOFF-scores and the items referring to insulin-purging in DEPS-R, was stronger for girls than for boys (r=0.437 vs. r=0.144). Among the young people with type 1 diabetes DEPS-R-scores showed stronger associations to the quality of metabolic control (HbA1c) than the SCOFF (boys: r=0.357 vs. r=0.217 and girls: r=0.368 vs. r=0.131)., Discussion: Children and adolescents with type 1 diabetes are not more frequently affected by disturbed eating behavior than their healthy peers. Particularly boys with type 1 diabetes practicing insulin-purging, are not reliably detected by a generic screening tool., Conclusion: As part of long-term care a diabetes specific screening tool should be used to identify adolescents with type 1 diabetes and disturbed eating behavior more reliably., (© Georg Thieme Verlag KG Stuttgart · New York.)
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- 2016
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22. Psychometric properties of the German version of the Diabetes Eating Problem Survey-Revised: additional benefit of disease-specific screening in adolescents with Type 1 diabetes.
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Saßmann H, Albrecht C, Busse-Widmann P, Hevelke LK, Kranz J, Markowitz JT, Marshall LF, Meurs S, de Soye IH, and Lange K
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- Adolescent, Adolescent Medicine trends, Adult, Child, Cohort Studies, Cross-Sectional Studies, Diabetes Mellitus, Type 1 blood, Diabetes Mellitus, Type 1 complications, Early Diagnosis, Feeding and Eating Disorders complications, Feeding and Eating Disorders epidemiology, Female, Germany epidemiology, Glycated Hemoglobin analysis, Humans, Male, Prevalence, Psychiatric Status Rating Scales, Psychometrics trends, Risk, Self Report, Sensitivity and Specificity, Young Adult, Adolescent Medicine methods, Diabetes Mellitus, Type 1 psychology, Feeding and Eating Disorders diagnosis, Mass Screening, Psychometrics methods
- Abstract
Aim: To examine the psychometric properties of the German version of the abbreviated 16-item Diabetes Eating Problem Survey-Revised in a sample of young people with Type 1 diabetes., Methods: A total of 246 young people, aged 11-19 years, with Type 1 diabetes from six pediatric diabetes centres in Germany were assessed using the Diabetes Eating Problem Survey-Revised. In addition, they underwent screening with two generic tools as well as the WHO five-question well-being index. A clinician's report was also obtained., Results: The Diabetes Eating Problem Survey-Revised was found to have good internal consistency (Cronbach's α = 0.84). The Diabetes Eating Problem Survey-Revised scores significantly correlated with those provided by the non-specific screening tools (r = 0.37, P ≤ 0.000 and r = 0.50, P ≤ 0.000 for boys and r = 0.62, P ≤ 0.000 and r = 0.79, P ≤ 0.000 for girls), indicating convergent validity. The mean (sd) total of the scores was 12.0 (9.6). Criterion validity was confirmed against HbA1c value, BMI standard deviation score and expert (clinician) report. Of the boys included in the study, 11 scored higher than the threshold score on the Diabetes Eating Problem Survey-Revised, of whom only three (27%) were classified as 'suspected to have a disordered eating behaviour' by their clinicians., Conclusions: The Diabetes Eating Problem Survey-Revised delivered more specific information than generic screening instruments and identified more young people with eating disorders than did clinician report, especially regarding the detection of boys at risk. The results of this study support the utility of the German version of the Diabetes Eating Problem Survey-Revised to identify eating disorders in young people with Type 1 diabetes at an early stage. (German Clinical Trials Registry no.: DRKS00004699)., (© 2015 The Authors. Diabetic Medicine © 2015 Diabetes UK.)
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- 2015
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23. Direct observation of rapid discrete spectral dynamics in single colloidal CdSe-CdS core-shell quantum dots.
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Beyler AP, Marshall LF, Cui J, Brokmann X, and Bawendi MG
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- Diffusion, Fourier Analysis, Spectrum Analysis methods, Cadmium Compounds chemistry, Colloids chemistry, Models, Chemical, Quantum Dots, Selenium Compounds chemistry, Sulfides chemistry
- Abstract
We measure the anomalous spectral diffusion of single colloidal quantum dots over eight temporal decades simultaneously by combining single-molecule spectroscopy and photon-correlation Fourier spectroscopy. Our technique distinguishes between discrete and continuous dynamics and directly reveals that the quasicontinuous spectral diffusion observed using conventional spectroscopy is composed of rapid, discrete spectral jumps. Despite their multiple time scales, these dynamics can be captured by a single mechanism whose parameters vary widely between dots and over time in individual dots.
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- 2013
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24. Direct probe of spectral inhomogeneity reveals synthetic tunability of single-nanocrystal spectral linewidths.
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Cui J, Beyler AP, Marshall LF, Chen O, Harris DK, Wanger DD, Brokmann X, and Bawendi MG
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- Cadmium Compounds chemistry, Selenium Compounds chemistry, Spectrometry, Fluorescence, Sulfides chemistry, Nanoparticles
- Abstract
The spectral linewidth of an ensemble of fluorescent emitters is dictated by the combination of single-emitter linewidths and sample inhomogeneity. For semiconductor nanocrystals, efforts to tune ensemble linewidths for optical applications have focused primarily on eliminating sample inhomogeneities, because conventional single-molecule methods cannot reliably build accurate ensemble-level statistics for single-particle linewidths. Photon-correlation Fourier spectroscopy in solution (S-PCFS) offers a unique approach to investigating single-nanocrystal spectra with large sample statistics and high signal-to-noise ratios, without user selection bias and at fast timescales. With S-PCFS, we directly and quantitatively deconstruct the ensemble linewidth into contributions from the average single-particle linewidth and from sample inhomogeneity. We demonstrate that single-particle linewidths vary significantly from batch to batch and can be synthetically controlled. These findings delineate the synthetic challenges facing underdeveloped nanomaterials such as InP and InAs core-shell particles and introduce new avenues for the synthetic optimization of fluorescent nanoparticles.
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- 2013
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25. Intraoperative detection and removal of microscopic residual sarcoma using wide-field imaging.
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Mito JK, Ferrer JM, Brigman BE, Lee CL, Dodd RD, Eward WC, Marshall LF, Cuneo KC, Carter JE, Ramasunder S, Kim Y, Lee WD, Griffith LG, Bawendi MG, and Kirsch DG
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- Animals, Fluorescent Dyes, Infrared Rays, Intraoperative Period, Mice, Sarcoma, Experimental surgery, Surgery, Computer-Assisted, Neoplasm, Residual surgery, Sarcoma surgery, Soft Tissue Neoplasms surgery
- Abstract
Background: The goal of limb-sparing surgery for a soft tissue sarcoma of the extremity is to remove all malignant cells while preserving limb function. After initial surgery, microscopic residual disease in the tumor bed will cause a local recurrence in approximately 33% of patients with sarcoma. To help identify these patients, the authors developed an in vivo imaging system to investigate the suitability of molecular imaging for intraoperative visualization., Methods: A primary mouse model of soft tissue sarcoma and a wide field-of-view imaging device were used to investigate a series of exogenously administered, near-infrared (NIR) fluorescent probes activated by cathepsin proteases for real-time intraoperative imaging., Results: The authors demonstrated that exogenously administered cathepsin-activated probes can be used for image-guided surgery to identify microscopic residual NIR fluorescence in the tumor beds of mice. The presence of residual NIR fluorescence was correlated with microscopic residual sarcoma and local recurrence. The removal of residual NIR fluorescence improved local control., Conclusions: The authors concluded that their technique has the potential to be used for intraoperative image-guided surgery to identify microscopic residual disease in patients with cancer., (Copyright © 2012 American Cancer Society.)
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- 2012
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26. Extracting spectral dynamics from single chromophores in solution.
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Marshall LF, Cui J, Brokmann X, and Bawendi MG
- Abstract
Fluorescence spectroscopy of single chromophores immobilized on a substrate has provided much fundamental insight, yet the spectral line shapes and dynamics of single chromophores freely diffusing in solution have remained difficult or impossible to measure with conventional linear spectroscopies. Here, we demonstrate an interferometric technique for extracting time dependent single chromophore spectral correlations from intensity correlations in the interference pattern of an ensemble fluorescence spectrum. We apply our technique to solutions of colloidal quantum dots and explore the spectrum of single particles on short time scales not feasible with conventional fluorescence measurements.
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- 2010
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27. Compact biocompatible quantum dots via RAFT-mediated synthesis of imidazole-based random copolymer ligand.
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Liu W, Greytak AB, Lee J, Wong CR, Park J, Marshall LF, Jiang W, Curtin PN, Ting AY, Nocera DG, Fukumura D, Jain RK, and Bawendi MG
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- Animals, HeLa Cells, Humans, Hydrogen-Ion Concentration, Ligands, Mice, Molecular Imaging methods, Molecular Structure, Particle Size, Polyethylene Glycols chemistry, Surface Properties, Biocompatible Materials chemistry, Imidazoles chemistry, Polyethylene Glycols chemical synthesis, Quantum Dots
- Abstract
We present a new class of polymeric ligands for quantum dot (QD) water solubilization to yield biocompatible and derivatizable QDs with compact size (approximately 10-12 nm diameter), high quantum yields (>50%), excellent stability across a large pH range (pH 5-10.5), and low nonspecific binding. To address the fundamental problem of thiol instability in traditional ligand exchange systems, the polymers here employ a stable multidentate imidazole binding motif to the QD surface. The polymers are synthesized via reversible addition-fragmentation chain transfer-mediated polymerization to produce molecular weight controlled monodisperse random copolymers from three types of monomers that feature imidazole groups for QD binding, polyethylene glycol (PEG) groups for water solubilization, and either primary amines or biotin groups for derivatization. The polymer architecture can be tuned by the monomer ratios to yield aqueous QDs with targeted surface functionalities. By incorporating amino-PEG monomers, we demonstrate covalent conjugation of a dye to form a highly efficient QD-dye energy transfer pair as well as covalent conjugation to streptavidin for high-affinity single molecule imaging of biotinylated receptors on live cells with minimal nonspecific binding. The small size and low serum binding of these polymer-coated QDs also allow us to demonstrate their utility for in vivo imaging of the tumor microenvironment in live mice.
- Published
- 2010
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28. Narrow-band absorption-enhanced quantum dot/J-aggregate conjugates.
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Walker BJ, Nair GP, Marshall LF, Bulović V, and Bawendi MG
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- Adsorption, Carbocyanines chemistry, Colloids, Fluorescence Resonance Energy Transfer, Ligands, Nanoparticles, Semiconductors, Static Electricity, Time Factors, Quantum Dots
- Abstract
We report narrow-band absorption enhancement of semiconductor nanocrystals via Förster resonance energy transfer from cyanine J-aggregates. These J-aggregated dyes associate electrostatically with short quantum-dot (QD) surface ligands in solution. Energy transfer efficiencies approach unity for this light sensitization and result in a 5-fold enhancement in the QD excitation near the J-aggregate absorption maximum. Because a thin layer of J-aggregates attenuates the same amount of light (at peak absorbance) as a far thicker film of monomer dye, these absorption-enhanced materials may have applications in light-sensitizing applications such as photodetection and optical down-conversion.
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- 2009
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29. Pediatric traumatic brain injury and elevated intracranial pressure.
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Marshall LF
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- Cerebrovascular Circulation physiology, Child, Follow-Up Studies, Humans, Brain Injuries physiopathology, Intracranial Pressure
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- 2008
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30. Progression of traumatic intracerebral hemorrhage: a prospective observational study.
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Narayan RK, Maas AI, Servadei F, Skolnick BE, Tillinger MN, and Marshall LF
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- Adolescent, Adult, Aged, Aged, 80 and over, Brain blood supply, Brain Hemorrhage, Traumatic complications, Brain Injuries complications, Disease Progression, Female, Glasgow Coma Scale, Hematoma diagnostic imaging, Hematoma etiology, Hematoma physiopathology, Humans, Male, Middle Aged, Predictive Value of Tests, Prognosis, Prospective Studies, Thromboembolism diagnostic imaging, Thromboembolism etiology, Thromboembolism physiopathology, Time Factors, Tomography, X-Ray Computed methods, Brain diagnostic imaging, Brain physiopathology, Brain Hemorrhage, Traumatic diagnostic imaging, Brain Hemorrhage, Traumatic physiopathology, Brain Injuries diagnostic imaging, Brain Injuries physiopathology
- Abstract
ABSTRACT Preliminary evidence has shown that intracerebral hemorrhages, either spontaneous (sICH) or traumatic (tICH) often expand over time. An association between hemorrhage expansion and clinical outcomes has been described for sICH. The intent of this prospective, observational study was to characterize the temporal profile of hemorrhage progression, as measured by serial computed tomography (CT) scanning, with the aim of better understanding the natural course of hemorrhage progression in tICH. There was also a desire to document the baseline adverse event (AE) profile in this patient group. An important motive for performing this study was to set the stage for subsequent studies that will examine the role of a new systemic hemostatic agent in tICH. Subjects were enrolled if they had tICH lesions of at least 2 mL on a baseline CT scan obtained within 6 h of a head injury. CT scans were repeated at 24 and 72 h. Clinical outcomes and pre-defined AEs were documented. The data showed that 51% of the subjects demonstrated an increase in tICH volume, and that most of the increase occurred early. In addition, larger hematomas exhibited the greatest expansion. Thromboembolic complications were identified in 13% of subjects. This study demonstrates that tICH expansion between the baseline and 24-h CT scans occurred in approximately half of the subjects. The earlier after injury that the initial CT scan is obtained, the greater is the likelihood that the hematoma will expand on subsequent scans. The time frame during which hemorrhagic expansion occurs provides an opportunity for early intervention to limit a process with adverse prognostic implications.
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- 2008
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31. Monovalent, reduced-size quantum dots for imaging receptors on living cells.
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Howarth M, Liu W, Puthenveetil S, Zheng Y, Marshall LF, Schmidt MM, Wittrup KD, Bawendi MG, and Ting AY
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- Animals, Carcinoembryonic Antigen, Cell Survival, Cells, Cultured, Electrophoresis, Agar Gel, Fluorescent Dyes, Image Processing, Computer-Assisted, Ligands, Nanotechnology methods, Polyethylene Glycols, Rats, Receptors, Glutamate metabolism, Staining and Labeling methods, Streptavidin, Synapses metabolism, Cells cytology, Cells metabolism, Quantum Dots, Receptors, Cell Surface analysis
- Abstract
We describe a method to generate monovalent quantum dots (QDs) using agarose gel electrophoresis. We passivated QDs with a carboxy-terminated polyethylene-glycol ligand, yielding particles with half the diameter of commercial QDs, which we conjugated to a single copy of a high-affinity targeting moiety (monovalent streptavidin or antibody to carcinoembryonic antigen) to label cell-surface proteins. The small size improved access of QD-labeled glutamate receptors to neuronal synapses, and monovalency prevented EphA3 tyrosine kinase activation.
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- 2008
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32. Recombinant factor VIIA in traumatic intracerebral hemorrhage: results of a dose-escalation clinical trial.
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Narayan RK, Maas AI, Marshall LF, Servadei F, Skolnick BE, and Tillinger MN
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- Adolescent, Adult, Aged, Aged, 80 and over, Cerebral Hemorrhage, Traumatic complications, Cerebral Hemorrhage, Traumatic diagnosis, Dose-Response Relationship, Drug, Double-Blind Method, Female, Humans, Internationality, Intracranial Thrombosis diagnosis, Male, Maximum Tolerated Dose, Middle Aged, Placebo Effect, Recombinant Proteins administration & dosage, Recombinant Proteins adverse effects, Treatment Outcome, Cerebral Hemorrhage, Traumatic drug therapy, Factor VIIa administration & dosage, Factor VIIa adverse effects, Intracranial Thrombosis chemically induced
- Abstract
Objective: Intracerebral hemorrhages, whether spontaneous or traumatic (tICH), often expand, and an association has been described between hemorrhage expansion and worse clinical outcomes. Recombinant factor VIIa (rFVIIa) is a hemostatic agent that has been shown to limit hemorrhage expansion and which, therefore, could potentially reduce morbidity and mortality in tICH. This first prospective, randomized, placebo-controlled, dose-escalation study evaluated the safety and preliminary effectiveness of rFVIIa to limit tICH progression., Methods: Patients were enrolled if they had tICH lesions of at least 2 ml on a baseline computed tomographic scan obtained within 6 hours of injury. rFVIIa or placebo was administered within 2.5 hours of the baseline computed tomographic scan but no later than 7 hours after injury. Computed tomographic scans were repeated at 24 and 72 hours. Five escalating dose tiers were evaluated (40, 80, 120, 160, and 200 microg/kg rFVIIa). Clinical evaluations and adverse events were recorded until Day 15., Results: No significant differences were detected in mortality rate or number and type of adverse events among treatment groups. Asymptomatic deep vein thrombosis, detected on routinely performed ultrasound at Day 3, was observed more frequently in the combined rFVIIa treatment group (placebo, 3%; rFVIIa, 8%; not significant). A nonsignificant trend for rFVIIa dose-response to limit tICH volume increase was observed (placebo, 21.0 ml; rFVIIa, 10.1 ml)., Conclusion: In this first prospective study of rFVIIa in tICH, there appeared to be less hematoma progression in rFVIIa-treated patients (80-200 microg/kg) compared with that seen in placebo treated patients. The potential significance of this biological effect on clinical outcomes and the significance of the somewhat higher incidence of ultrasound-detected deep vein thromboses in the rFVIIa-treated group need to be examined in a larger prospective randomized clinical trial.
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- 2008
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33. Development of spontaneous intracranial hypotension concurrent with grade IV mobilization of the cervical and thoracic spine: a case report.
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Donovan JS, Kerber CW, Donovan WH, and Marshall LF
- Subjects
- Adult, Aminocaproic Acid administration & dosage, Antifibrinolytic Agents administration & dosage, Blood Patch, Epidural, Cervical Vertebrae pathology, Combined Modality Therapy, Dura Mater pathology, Extravasation of Diagnostic and Therapeutic Materials etiology, Female, Humans, Intracranial Hypotension therapy, Magnetic Resonance Imaging, Myelography, Neurologic Examination, Subdural Effusion therapy, Thoracic Vertebrae pathology, Tomography, X-Ray Computed, Dura Mater injuries, Intracranial Hypotension etiology, Manipulation, Spinal adverse effects, Physical Therapy Modalities adverse effects, Subdural Effusion etiology
- Abstract
Spontaneous intracranial hypotension (SIH) has been clinically defined as the development of severe orthostatic headaches caused by an acute cerebrospinal fluid (CSF) leak. Typically, intracranial hypotension occurs as a complication of lumbar puncture, but recent reports have identified cases caused by minor trauma. We report a case of SIH secondary to a dural tear caused by a cervical and thoracic spine mobilization. A 32-year-old woman with SIH presented with severe positional headaches with associated hearing loss and C6-8 nerve root distribution weakness. CSF opening pressure was less than 5cmH(2)O and showed no abnormalities in white blood cell count. Cranial, cervical, and thoracic magnetic resonance imaging revealed epidural and subdural collections of CSF with associated meningeal enhancement. Repeated computed tomography myelograms localized the leak to multiple levels of the lower cervical and upper thoracic spine. A conservative management approach of bedrest and increased caffeine intake had no effect on the dural tear. The headache, hearing loss, and arm symptoms resolved completely after 2 epidural blood patches were performed. Practitioners performing manual therapy should be aware of this rare, yet potential complication of spinal mobilizations and manipulations.
- Published
- 2007
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34. Some prognostic models for traumatic brain injury were not valid.
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Hukkelhoven CW, Rampen AJ, Maas AI, Farace E, Habbema JD, Marmarou A, Marshall LF, Murray GD, and Steyerberg EW
- Subjects
- Area Under Curve, Brain Injuries mortality, Clinical Trials as Topic, Humans, Logistic Models, Prognosis, Treatment Outcome, Brain Injuries therapy
- Abstract
Objective: Various prognostic models have been developed to predict outcome after traumatic brain injury (TBI). We aimed to determine the validity of six models that used baseline clinical and computed tomographic characteristics to predict mortality or unfavorable outcome at 6 months or later after severe or moderate TBI., Study Design and Setting: The validity was studied in two selected series of TBI patients enrolled in clinical trials (Tirilazad trials; n = 2,269; International Selfotel Trial; n = 409) and in two unselected series of patients consecutively admitted to participating centers (European Brain Injury Consortium [EBIC] survey; n = 796; Traumatic Coma Data Bank; n = 746). Validity was indicated by discriminative ability (AUC) and calibration (Hosmer-Lemeshow goodness-of-fit test)., Results: The models varied in number of predictors (four to seven) and in development technique (two prediction trees and four logistic regression models). Discriminative ability varied widely (AUC: .61-.89), but calibration was poor for most models. Better discrimination was observed for logistic regression models compared with trees, and for models including more predictors. Further, discrimination was better when tested on unselected series that contained more heterogeneous populations., Conclusion: Our findings emphasize the need for external validation of prognostic models. The satisfactory discrimination indicates that logistic regression models, developed on large samples, can be used for classifying TBI patients according to prognostic risk.
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- 2006
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35. Prediction of outcome in traumatic brain injury with computed tomographic characteristics: a comparison between the computed tomographic classification and combinations of computed tomographic predictors.
- Author
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Maas AI, Hukkelhoven CW, Marshall LF, and Steyerberg EW
- Subjects
- Adolescent, Adult, Brain diagnostic imaging, Brain Injuries complications, Brain Injuries mortality, Humans, Logistic Models, Middle Aged, Multivariate Analysis, Prognosis, Subarachnoid Hemorrhage etiology, Brain Injuries classification, Brain Injuries diagnostic imaging, Tomography, X-Ray Computed, Trauma Severity Indices
- Abstract
Background and Objective: The Marshall computed tomographic (CT) classification identifies six groups of patients with traumatic brain injury (TBI), based on morphological abnormalities on the CT scan. This classification is increasingly used as a predictor of outcome. We aimed to examine the predictive value of the Marshall CT classification in comparison with alternative CT models., Methods: The predictive value was investigated in the Tirilazad trials (n = 2269). Alternative models were developed with logistic regression analysis and recursive partitioning. Six month mortality was used as outcome measure. Internal validity was assessed with bootstrapping techniques and expressed as the area under the receiver operating curve (AUC)., Results: The Marshall CT classification indicated reasonable discrimination (AUC = 0.67), which could be improved by rearranging the underlying individual CT characteristics (AUC = 0.71). Performance could be further increased by adding intraventricular and traumatic subarachnoid hemorrhage and by a more detailed differentiation of mass lesions and basal cisterns (AUC = 0.77). Models developed with logistic regression analysis and recursive partitioning showed similar performance. For clinical application we propose a simple CT score, which permits a more clear differentiation of prognostic risk, particularly in patients with mass lesions., Conclusion: It is preferable to use combinations of individual CT predictors rather than the Marshall CT classification for prognostic purposes in TBI. Such models should include at least the following parameters: status of basal cisterns, shift, traumatic subarachnoid or intraventricular hemorrhage, and presence of different types of mass lesions.
- Published
- 2005
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36. The effect of the selective NMDA receptor antagonist traxoprodil in the treatment of traumatic brain injury.
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Yurkewicz L, Weaver J, Bullock MR, and Marshall LF
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- Adolescent, Adult, Aged, Brain Injuries mortality, Excitatory Amino Acid Antagonists blood, Female, Glasgow Outcome Scale, Humans, Male, Middle Aged, Neuroprotective Agents blood, Piperidines blood, Recovery of Function, Survival Analysis, Survival Rate, Treatment Outcome, Brain Injuries drug therapy, Excitatory Amino Acid Antagonists therapeutic use, Neuroprotective Agents therapeutic use, Piperidines therapeutic use, Receptors, N-Methyl-D-Aspartate antagonists & inhibitors
- Abstract
Traumatic brain injury (TBI) remains a major public health problem, and there is a great medical need for a pharmacological treatment that could improve long-term outcome. The excitatory neurotransmitter, glutamate, has been implicated in processes leading to neurodegeneration. Traxoprodil (CP-101,606) is a novel and potent glutamate receptor antagonist that is highly selective for the NR2B subunit of the NMDA receptor; it has been shown to be neuroprotective in animal models of brain injury and ischemia. A randomized, double-blind, placebo-controlled study was therefore conducted to assess the efficacy and safety of a 72-h infusion of traxoprodil compared to placebo in subjects with computed tomography scan evidence of severe TBI (GCS 4-8). A total of 404 males and non-pregnant females, aged 16-70, were treated within 8 h of injury. At baseline, subjects were stratified by motor score severity. The results showed that a greater proportion of the traxoprodil-treated subjects had a favorable outcome on the dichotomized Glasgow Outcome Scale (dGOS) at 6 months (delta 5.5%, OR 1.3, p = 0.21, 95% CI:[0.85, 2.06]) and at last visit (delta 7.5%, OR 1.47, p = 0.07, 95% CI:[0.97, 2.25]). The mortality rate with traxoprodil treatment was 7% less than with placebo treatment (OR 1.45, p = 0.08, 95% CI:[0.96, 2.18]). Differences between treatment groups were more pronounced in the severest subset (delta 11.8% for the dGOS at last visit and delta 16.6% for mortality). Traxoprodil was well tolerated. Although these results are intriguing, no definitive claim of efficacy can be made for traxoprodil for the treatment of severe TBI.
- Published
- 2005
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37. Predicting outcome after traumatic brain injury: development and validation of a prognostic score based on admission characteristics.
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Hukkelhoven CW, Steyerberg EW, Habbema JD, Farace E, Marmarou A, Murray GD, Marshall LF, and Maas AI
- Subjects
- Adolescent, Adult, Age Factors, Aged, Brain Injuries mortality, Clinical Trials as Topic, Female, Glasgow Outcome Scale, Humans, Hypotension etiology, Hypotension physiopathology, Hypoxia etiology, Hypoxia physiopathology, Male, Middle Aged, Predictive Value of Tests, Prognosis, Reflex, Pupillary, Treatment Outcome, Brain Injuries complications, Brain Injuries physiopathology, Models, Statistical
- Abstract
The early prediction of outcome after traumatic brain injury (TBI) is important for several purposes, but no prognostic models have yet been developed with proven generalizability across different settings. The objective of this study was to develop and validate prognostic models that use information available at admission to estimate 6-month outcome after severe or moderate TBI. To this end, this study evaluated mortality and unfavorable outcome, that is, death, and vegetative or severe disability on the Glasgow Outcome Scale (GOS), at 6 months post-injury. Prospectively collected data on 2269 patients from two multi-center clinical trials were used to develop prognostic models for each outcome with logistic regression analysis. We included seven predictive characteristics-age, motor score, pupillary reactivity, hypoxia, hypotension, computed tomography classification, and traumatic subarachnoid hemorrhage. The models were validated internally with bootstrapping techniques. External validity was determined in prospectively collected data from two relatively unselected surveys in Europe (n = 796) and in North America (n = 746). We evaluated the discriminative ability, that is, the ability to distinguish patients with different outcomes, with the area under the receiver operating characteristic curve (AUC). Further, we determined calibration, that is, agreement between predicted and observed outcome, with the Hosmer-Lemeshow goodness-of-fit test. The models discriminated well in the development population (AUC 0.78-0.80). External validity was even better (AUC 0.83-0.89). Calibration was less satisfactory, with poor external validity in the North American survey (p < 0.001). Especially, observed risks were higher than predicted for poor prognosis patients. A score chart was derived from the regression models to facilitate clinical application. Relatively simple prognostic models using baseline characteristics can accurately predict 6-month outcome in patients with severe or moderate TBI. The high discriminative ability indicates the potential of this model for classifying patients according to prognostic risk.
- Published
- 2005
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38. Multidirectional projectional rigid neuro-endoscopy: prototype and initial experience.
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Aryan HE, Hoeg HD, Marshall LF, and Levy ML
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- Humans, Imaging, Three-Dimensional instrumentation, Imaging, Three-Dimensional methods, Minimally Invasive Surgical Procedures methods, Models, Anatomic, Neurosurgical Procedures methods, Video-Assisted Surgery instrumentation, Video-Assisted Surgery methods, Minimally Invasive Surgical Procedures instrumentation, Neuroendoscopes, Neuroendoscopy methods, Neurosurgical Procedures instrumentation
- Abstract
Introduction: The role of neuro-endoscopy is emerging. Traditional endoscopy is complicated by limited 2D views that make surgical interventions difficult. We have developed a rigid endoscope with a variable direction view that provides 3D visualization., Materials and Methods: A prototype of the EndActive endoscope was used to examine 2 brain/intraventricular models. A 360-degree view is controlled via integrated joystick. Alternatively, the computer can volumetrically capture the ventricular surface. The captured video image can be viewed later or processed to create a flat projection map. The performance of this endoscope was compared to standard endoscopy with fixed directions of view. To simulate endoscopy, the center of the first brain model had eight labeled projections. The model was inspected with the multidirectional endoscope, standard rigid endoscopes (0-, 30- and 70-degree), and via a projection map. Ten neurosurgeons proficient in neuro-endoscopy were recruited for the experiments. The second brain model was labeled with 32 intraventricular tumors., Results: With a 0-degree endoscope, only the number directly opposite the site of entry was visualized. With increasing angles, additional numbers were visualized. The 70-degree endoscope allowed 4 of 8 numbers to be visualized. Using the multidirectional endoscope, all 8 numbers were visualized. The multidirectional endoscope was more accurate in identifying markers compared to standard endoscopy (p = 0.031). The mean endoscopy times using the multidirectional endoscope and standard endoscopy were 143 and 117 seconds, respectively (p = 0.243). The best performance was obtained when the flat projection map was read (p < 0.01). Using the endoscope prototype, an average of 30.8 (96%) tumors was identified on the brain model., Conclusion: The EndActive endoscope is a rigid endoscope that provides complete visualization of a 3D space by controlling an adjustable viewing direction. In our study, the multidirectional endoscope provided superior visualization compared to standard endoscopy.
- Published
- 2005
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39. The science of shrinking human heads: tribal warfare and revenge among the South American Jivaro-Shuar.
- Author
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Jandial R, Hughes SA, Aryan HE, Marshall LF, and Levy ML
- Subjects
- Ecuador ethnology, Humans, Indians, South American ethnology, Anthropology, Cultural, Embalming methods, Ethnicity, Head, Warfare
- Abstract
THE PRACTICE OF "head-shrinking" has been the proper domain not of Africa but rather of the denizens of South America. Specifically, in the post-Columbian period, it has been most famously the practice of a tribe of indigenous people commonly called the Jivaro or Jivaro-Shuar. The evidence suggests that the Jivaro-Shuar are merely the last group to retain a custom widespread in northwestern South America. In both ceramic and textile art of the pre-Columbian residents of Peru, the motif of trophy heads smaller than normal life-size heads commonly recurs; the motif is seen even in surviving carvings in stone and shell. Moreover, although not true shrunken heads, trophy heads found in late pre-Columbian and even post-Columbian graves of the region demonstrate techniques of display very similar to those used by the Jivaro-Shuar, at least some of which are best understood in the context of head-shrinking. Regardless, the Jivaro-Shuar and their practices provide an illustrative counterexample to popular myth regarding the culture and science of the shrinking of human heads.
- Published
- 2004
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40. Syringocephaly.
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Aryan HE, Yanni DS, Nakaji P, Jandial R, Marshall LF, and Taylor WR
- Subjects
- Cerebellum surgery, Craniotomy methods, Humans, Hydrocephalus pathology, Hydrocephalus surgery, Laminectomy methods, Magnetic Resonance Imaging methods, Male, Middle Aged, Syringomyelia pathology, Syringomyelia surgery, Tegmentum Mesencephali surgery, Tomography, X-Ray Computed methods, Hydrocephalus complications, Syringomyelia complications
- Abstract
Syringomyelia is associated with Arnold-Chiari Type I malformations. Syringobulbia describes the phenomenon of syrinx extension into the brain stem. Syringocephaly is the further dissection of the fluid-filled cavity into the cerebral peduncles and cerebrum. In this case report, we describe a patient who presented with bulbar, sensory, motor, and coordination deficits both ipsilateral and contralateral to the lesion. This is most likely attributable to the wandering course the syrinx takes as it dissects through the spinal cord and into the internal capsule. This ill-defined syrinx disrupts various nuclei and fasciculi, both pre- and post-decussation, thus explaining the multiple deficits on each side. We initially treated this patient with a suboccipital craniectomy, C1 laminectomy, and duraplasty, which mildly improved his deficits. During follow-up, the patient was then found to have an exacerbation of his symptoms, at which time we performed a VP shunt revision (the patient had a history of hydrocephalus treated by a functioning VP shunt). Approximately 2 weeks after revision of the VP shunt, the patient had worsening of his symptoms, which we treated with a syringopleural shunt. This proved to be the most effective treatment with the greatest clinical improvement. Several months later, however, the patient died secondary to pulmonary disease exacerbated by VP shunt infection. In this paper, we also review the literature regarding the formation and treatment of syringocephaly, a rare and poorly understood entity.
- Published
- 2004
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41. High-dose mannitol.
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Marshall LF
- Subjects
- Carbon Dioxide blood, Diuretics, Osmotic administration & dosage, Dose-Response Relationship, Drug, Drug Administration Schedule, Humans, Hyperventilation physiopathology, Hypocapnia physiopathology, Mannitol administration & dosage, Brain Edema drug therapy, Brain Edema etiology, Brain Injuries complications, Diuretics, Osmotic therapeutic use, Mannitol therapeutic use
- Published
- 2004
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42. Lessons from epidemiologic studies in clinical trials of traumatic brain injury.
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Farin A and Marshall LF
- Subjects
- Databases, Factual, Humans, Medical Records Systems, Computerized, Patient Selection, Pipecolic Acids therapeutic use, Pregnatrienes therapeutic use, Prognosis, Risk Factors, Treatment Outcome, United States, Brain Injuries drug therapy, Brain Injuries mortality, Clinical Trials as Topic methods, Epidemiologic Methods, Neuroprotective Agents therapeutic use, Quality Assurance, Health Care methods, Risk Assessment methods
- Abstract
Lessions from epidemiological studies. The Clinical Trial Group for Neurosurgery of the University of California San Diego (UCSD) is involved in epidemiological studies and trials of new pharmacological agents in traumatic brain injury. A great number (> 10,000) of patients has been prospectively analyzed forming an integrated database for further purposes. The development of these databases is based on earlier work by the European Neurosurgeons Jennett and Braakmann and the US-Traumatic Coma Data Bank Study. These studies allowed for the development of sophisticated data collection instruments which were used in the international Tirilizad Trials which enrolled over 1,100 patients. A major observation from that trial was that pretreatment hypotension or hypoxia could be unbalanced even in a large two arm blinded study. Another issue of the tirilazad trial was the influence of gender affecting not only outcome but also drug metabolism. Similar experiences were gathered with the phase-III trial on the competitive NMDA-receptor antagonist selfotel, which interferes with the excitotoxic amino acid glutamate as mediator of secondary brain damage, as ischemia-induced neuronal degeneration. Unfortunately, the trial, already underway, had to be prematurely aborted, since concurrent stroke studies with enrollment of nonintubated patients on low-dose selfotel revealed an increased number of deaths and other adverse events. A retrospective analysis did not confirm that Selfotel was associated with an increased mortality in TBI, but there was also no evidence that the drug was efficacious. A problem here was that a major portion of patients did not have intracranial mass lesions (contusion, subdural haematoma) on CT, questioning whether these had a treatment responsive brain injury. Both studies on tirilazad or selfotel underscore the significance of well designed and conducted phase-I and -II trials to characterize the pharmacokinetics of the agent, to confirm availability of drug in the brain, and to identify a sufficient number of patients with lesions responding to the drug. A major issue is the blood-brain barrier permeability of the agent under study. Further, the phenomenon of secondary deterioration - neurological worsening - turned out as a powerful predictor of poor outcome. The findings and conclusions of both clinical trials (tirilazad, selfotel) were utilized for a subsequent patient study on CP101-606 in consultation with the Pfizer company, the US Brain Injury Consortium, and the San Diego Clinical Trial Group. The patient population was a priori selected towards responsiveness of the brain lesions to the treatment. The major conclusions are: I Development of therapeutic regimens targeted towards the mechanisms of brain injury. II Availability of adequate preclinical data. III Directing treatment towards an appropriate patient population. IV Central gathering and interpretation of the neuroradiological findings. V Monitoring of trial center performance. VI Stratification and pre-trial prognostic analysis for identification of subgroups.
- Published
- 2004
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43. Quality of life in acoustics.
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Farace E and Marshall LF
- Subjects
- Humans, Neuroma, Acoustic psychology, Neuroma, Acoustic surgery, Outcome Assessment, Health Care, Quality of Life
- Published
- 2003
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44. Patient age and outcome following severe traumatic brain injury: an analysis of 5600 patients.
- Author
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Hukkelhoven CW, Steyerberg EW, Rampen AJ, Farace E, Habbema JD, Marshall LF, Murray GD, and Maas AI
- Subjects
- Adult, Age Factors, Aged, Brain Injuries pathology, Female, Glasgow Coma Scale, Humans, Logistic Models, Magnetic Resonance Imaging, Male, Middle Aged, Multivariate Analysis, Prospective Studies, Survival Rate, Brain Injuries mortality
- Abstract
Object: Increasing age is associated with poorer outcome in patients with closed traumatic brain injury (TBI). It is uncertain whether critical age thresholds exist, however, and the strength of the association has yet to be investigated across large series. The authors studied the shape and strength of the relationship between age and outcome, that is, the 6-month mortality rate and unfavorable outcome based on the Glasgow Outcome Scale., Methods: The shape of the association was examined in four prospective series with individual patient data (2664 cases). All patients had a closed TBI and were of adult age (96% < 65 years of age). The strength of the association was investigated in a metaanalysis of the aforementioned individual patient data (2664 cases) and aggregate data (2948 cases) from TBI studies published between 1980 and 2001 (total 5612 cases). Analyses were performed with univariable and multivariable logistic regression. Proportions of mortality and unfavorable outcome increased with age: 21 and 39%, respectively, for patients younger than 35 years and 52 and 74%, respectively, for patients older than 55 years. The association between age and both mortality and unfavorable outcome was continuous and could be adequately described by a linear term and expressed even better statistically by a linear and a quadratic term. The use of age thresholds (best fitting threshold 39 years) in the analysis resulted in a considerable loss of information. The strength of the association, expressed as an odds ratio per 10 years of age, was 1.47 (95% confidence interval [CI] 1.34-1.63) for death and 1.49 (95% CI 1.43-1.56) for unfavorable outcome in univariable analyses, and 1.39 (95% CI 1.3-1.5) and 1.46 (95% CI 1.36-1.56), respectively, in multivariable analyses. Thus, the odds for a poor outcome increased by 40 to 50% per 10 years of age., Conclusions: An older age is continuously associated with a worsening outcome after TBI; hence, it is disadvantageous to define the effect of age on outcome in a discrete manner when we aim to estimate prognosis or adjust for confounding variables.
- Published
- 2003
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45. Atypical presentation of C-7 radiculopathy.
- Author
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Ozgur BM and Marshall LF
- Subjects
- Diskectomy, Fibula transplantation, Humans, Magnetic Resonance Imaging, Nerve Compression Syndromes etiology, Nerve Compression Syndromes surgery, Radiculopathy etiology, Radiculopathy surgery, Retrospective Studies, Spinal Diseases surgery, Spinal Fusion, Cervical Vertebrae, Nerve Compression Syndromes diagnosis, Radiculopathy diagnosis, Spinal Diseases complications, Spinal Diseases diagnosis
- Abstract
Object: The authors retrospectively reviewed the presenting symptomatology and 6-month outcome in 241 consecutive patients who underwent C6-7 anterior cervical discectomy (ACD) from an overall series of 1008 patients in whom the senior author performed one-level procedures., Methods: In 28 (12%) of the 241 patients, the sole complaint was subscapular pain on the side ipsilateral to nerve root compression. In 11 patients (5%), the primary complaint was unilateral deep breast or chest pain. No patient experienced any of the traditional radicular signs involving C-7 such as numbness of the second or third digits, pain in the triceps, and/or atrophy or weakness of the triceps or pronator muscles. Of the 28 patients presenting with subscapular pain 238 (93%) of 241 experienced complete symptom relief within 6 months, and of the 11 who presented with chest pain complete relief or relief to the point of requiring nonnarcotic analgesic agents occurred in nine cases., Conclusions: Approximately 15% of patients with a C-7 radiculopathy are likely to present with atypical symptoms that, if persisting after nonsurgical therapy, will often resolve after ACD and fusion.
- Published
- 2003
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46. Sex-related differences in patients with severe head injury: greater susceptibility to brain swelling in female patients 50 years of age and younger.
- Author
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Farin A, Deutsch R, Biegon A, and Marshall LF
- Subjects
- Adolescent, Adult, Age Factors, Aged, Brain Edema diagnostic imaging, Brain Injuries diagnostic imaging, Female, Glasgow Outcome Scale, Humans, Intracranial Hypertension diagnostic imaging, Male, Middle Aged, Retrospective Studies, Sex Factors, Tomography, X-Ray Computed, Trauma Severity Indices, Brain Edema etiology, Brain Edema surgery, Brain Injuries complications, Brain Injuries surgery, Intracranial Hypertension etiology, Intracranial Hypertension surgery, Outcome Assessment, Health Care
- Abstract
Object: The goal of this study was to study the influence of sex and age on factors affecting patient outcome in severe head injury., Methods: Data from the prospectively conducted international trial of tirilazad mesylate in patients with head injury were analyzed retrospectively. Included were 957 patients, 23% of whom were female and all of whom were between the ages of 15 and 79 years. All patients presented with Glasgow Coma Scale (GCS) scores between 3 and 8 and evidence of structural brain damage and/or subarachnoid hemorrhage (SAH) on the initial CT scan. Frequencies of recognized risk factors, including brain swelling, intracranial hypertension, systemic hypotension, advanced age, SAH, and injury severity (based on GCS scores), as well as dichotomized Glasgow Outcome Scale (GOS) scores (good recovery or moderate disability compared with severe disability, persistent vegetative state, or death) obtained 6 months postinjury were compared between male and female patients., Conclusions: Overall significantly greater frequencies of brain swelling and intracranial hypertension were found in female compared with male patients (35% compared with 24% [p < 0.0008] and 39 compared with 31% [p < 0.03], respectively). The highest rates were found in female patients younger than 51 years old (38% compared with 24% [p < 0.002] and 40% compared with 30% [p < 0.02], respectively, in male patients younger than 51 years of age). This effect was independent of injury severity (GCS) scores, which were not different in male and female patients. Female patients younger than 50 years tended to have worse outcomes, but the difference was not statistically significant. Thus, female patients who sustain severe head injury, especially (presumably) premenopausal ones aged 50 years and younger, are significantly more likely to experience brain swelling and intracranial hypertension than male patients with a comparable injury severity, suggesting that younger women may benefit from more aggressive monitoring and treatment of intracranial hypertension.
- Published
- 2003
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47. Quantitative pupillometry, a new technology: normative data and preliminary observations in patients with acute head injury. Technical note.
- Author
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Taylor WR, Chen JW, Meltzer H, Gennarelli TA, Kelbch C, Knowlton S, Richardson J, Lutch MJ, Farin A, Hults KN, and Marshall LF
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, Equipment Design, Humans, Infant, Intracranial Pressure physiology, Middle Aged, Reference Values, Reproducibility of Results, Brain Injuries complications, Brain Injuries physiopathology, Diagnostic Techniques, Ophthalmological instrumentation, Pupil Disorders etiology, Pupil Disorders physiopathology, Reflex, Pupillary physiology, Subarachnoid Hemorrhage complications, Subarachnoid Hemorrhage physiopathology
- Abstract
The authors prospectively used a new hand-held point-and-shoot pupillometer to assess pupillary function quantitatively. Repetitive measurements were initially made in more than 300 healthy volunteers ranging in age from 1 to 87 years, providing a total of 2,432 paired (alternative right eye, left eye) measurements under varying light conditions. The authors studied 17 patients undergoing a variety of nonintracranial, nonophthalmological, endoscopic, or surgical procedures and 20 seniors in a cardiology clinic to learn more about the effects of a variety of drugs. Additionally, the authors carried out detailed studies in 26 adults with acute severe head injury in whom intracranial pressure (ICP) was continuously monitored. Finally, five patients suffering from subarachnoid hemorrhage were also studied. Quantitative pupillary measurements could be reliably replicated in the study participants. In healthy volunteers the resting pupillary aperture averaged 4.1 mm and the minimal aperture after stimulation was 2.7 mm, resulting in a 34% change in pupil size. Constriction velocity averaged 1.48 +/- 0.33 mm/second. Pupillary symmetry was striking in both healthy volunteers and patients without intracranial or uncorrected visual acuity disorders. In the 2,432 paired measurements in healthy volunteers, constriction velocity was noted to fall below 0.85 mm/second on only 33 occasions and below 0.6 mm/second on eight occasions (< one in 310 observations). In outpatients, the reduction in constriction velocity was observed when either oral or intravenous narcotic agents and diazepam analogs were administered. These effects were transient and always symmetrical. Among the 26 patients with head injuries, eight were found to have elevations of ICP above 20 mm Hg and pupillary dynamics in each of these patients remained normal. In 13 patients with a midline shift greater than 3 mm, elevations of ICP above 20 mm Hg, when present for 15 minutes, were frequently associated with a reduction in constriction velocity on the side of the mass effect to below 0.6 mm/second (51% of 156 paired observations). In five patients with diffuse brain swelling but no midline shift, a reduction in constriction velocities did not generally occur until the ICP exceeded 30 mm Hg. Changes in the percentage of reduction from the resting state following stimulation were always greater than 10%, even in patients receiving large doses of morphine and propofol in whom the ICP was lower than 20 mm Hg. Asymmetry of pupillary size greater than 0.5 mm was observed infrequently (< 1%) in healthy volunteers and was rarely seen in head-injured patients unless the ICP exceeded 20 mm Hg. Pupillometry is a reliable technology capable of providing repetitive data on quantitative pupillary function in states of health and disease.
- Published
- 2003
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48. Regional differences in patient characteristics, case management, and outcomes in traumatic brain injury: experience from the tirilazad trials.
- Author
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Hukkelhoven CW, Steyerberg EW, Farace E, Habbema JD, Marshall LF, and Maas AI
- Subjects
- Adolescent, Adult, Aged, Canada epidemiology, Europe epidemiology, Female, Glasgow Coma Scale, Humans, Male, Middle Aged, Randomized Controlled Trials as Topic, Referral and Consultation, Treatment Outcome, United States epidemiology, Brain Injuries drug therapy, Brain Injuries mortality, Case Management, Neuroprotective Agents administration & dosage, Pregnatrienes administration & dosage
- Abstract
Object: Regional differences have been shown in patient characteristics and case management within multiple unselected series of patients suffering from traumatic brain injury (TBI). One might expect that such regional heterogeneity would be small in a more selected population of a randomized clinical trial. The goal of this study was to examine what regional differences in patient characteristics, case management, and outcomes exist between continents and among countries within a patient population included in a randomized clinical trial., Methods: Data were extracted from two concurrently conducted randomized clinical trials of the drug tirilazad; the designs of these studies were similar. The studies included 1701 patients with severe and 476 patients with moderate TBI. Differences were primarily investigated between studies performed in Europe and North America, but also among European regions and between Canada and the United States. Associations among regions and outcomes (6-month mortality rate and Glasgow Outcome Scale scores) were studied using multivariable logistic regression analysis. Comparisons between continents and among regions within Europe showed differences in the distribution of patient ages, causes of injury, and several clinical characteristics (motor score, pupillary reactivity, hypoxia, hypotension, intracranial pressure [ICP]). and findings on computerized tomography scans. Secondary referrals occurred 2.5 times more frequently in Europe. Within Europe secondary referral was mainly associated with an increased proportion of patients with mass lesions (46% in the European Study compared with 40% in the North American Study). Therapy for lowering ICP was more frequently applied in North America. After adjustments for case mix and management, mortality and unfavorable outcomes were significantly higher in Europe (odds ratios = 1.58 and 1.46, respectively). Significant differences in outcome between regions within Europe or within North America were not observed., Conclusions: Despite the use of a strict study protocol, considerable differences in patient characteristics and case management exist between continents and among countries, reflecting variations in social, cultural, and organizational aspects. Outcomes of TBI may be worse in Europe compared with North America, but this finding requires further study.
- Published
- 2002
- Full Text
- View/download PDF
49. Clinical trials in head injury.
- Author
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Narayan RK, Michel ME, Ansell B, Baethmann A, Biegon A, Bracken MB, Bullock MR, Choi SC, Clifton GL, Contant CF, Coplin WM, Dietrich WD, Ghajar J, Grady SM, Grossman RG, Hall ED, Heetderks W, Hovda DA, Jallo J, Katz RL, Knoller N, Kochanek PM, Maas AI, Majde J, Marion DW, Marmarou A, Marshall LF, McIntosh TK, Miller E, Mohberg N, Muizelaar JP, Pitts LH, Quinn P, Riesenfeld G, Robertson CS, Strauss KI, Teasdale G, Temkin N, Tuma R, Wade C, Walker MD, Weinrich M, Whyte J, Wilberger J, Young AB, and Yurkewicz L
- Subjects
- Humans, Brain Injuries therapy, Clinical Trials as Topic methods
- Abstract
Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate significant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.
- Published
- 2002
- Full Text
- View/download PDF
50. Intercenter variance.
- Author
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Marshall LF
- Subjects
- Craniocerebral Trauma therapy, Humans, Clinical Trials as Topic, Multicenter Studies as Topic standards
- Published
- 2001
- Full Text
- View/download PDF
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