Search tips
Search criteria

Results 1-7 (7)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Sensitivity and Specificity of the Beck Depression Inventory-II in Persons With Traumatic Brain Injury 
Our objective was to examine the Beck Depression Inventory-II (BDI-II) in a traumatic brain injury (TBI) sample using a receiver operating characteristic (ROC) curve to determine how well the BDI-II identifies depression. An ROC curve allows for analysis of the sensitivity and specificity of a diagnostic test using various cutoff points to determine the number of true positives, true negatives, false positives, and false negatives.
This was a secondary analysis of data gathered from an observational study. We examined BDI-II scores in a sample of 52 veterans with remote histories of TBI.
This study was completed at a Veterans Affairs (VA) Medical Center.
Participants were veterans eligible to receive VA health care services.
Not applicable.
Main Outcome Measures
Outcome measures included the BDI-II and the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-IV).
We generated an ROC curve to determine how well the BDI-II identifies depression using the SCID-IV as the criterion standard for diagnosing depression, defined here as a diagnosis of major depressive disorder. Results indicated a cutoff score of at least 19 if one has a mild TBI or at least 35 if one has a moderate or severe TBI. These scores maximize sensitivity (87%) and specificity (79%).
Clinicians working with persons with TBI can use the BDI-II to determine whether depressive symptoms warrant further assessment.
PMCID: PMC5006388  PMID: 19345782
Brain injuries; Depression; Rehabilitation; Veterans
2.  Shock Wave Response of Iron-based In Situ Metallic Glass Matrix Composites 
Scientific Reports  2016;6:22568.
The response of amorphous steels to shock wave compression has been explored for the first time. Further, the effect of partial devitrification on the shock response of bulk metallic glasses is examined by conducting experiments on two iron-based in situ metallic glass matrix composites, containing varying amounts of crystalline precipitates, both with initial composition Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4. The samples, designated SAM2X5-600 and SAM2X5-630, are X-ray amorphous and partially crystalline, respectively, due to differences in sintering parameters during sample preparation. Shock response is determined by making velocity measurements using interferometry techniques at the rear free surface of the samples, which have been subjected to impact from a high-velocity projectile launched from a powder gun. Experiments have yielded results indicating a Hugoniot Elastic Limit (HEL) to be 8.58 ± 0.53 GPa for SAM2X5-600 and 11.76 ± 1.26 GPa for SAM2X5-630. The latter HEL result is higher than elastic limits for any BMG reported in the literature thus far. SAM2X5-600 catastrophically loses post-yield strength whereas SAM2X5-630, while showing some strain-softening, retains strength beyond the HEL. The presence of crystallinity within the amorphous matrix is thus seen to significantly aid in strengthening the material as well as preserving material strength beyond yielding.
PMCID: PMC4773851  PMID: 26932846
3.  3D Printing of Composite Calcium Phosphate and Collagen Scaffolds for Bone Regeneration 
Biomaterials  2014;35(13):4026-4034.
Low temperature 3D printing of calcium phosphate scaffolds holds great promise for fabricating synthetic bone graft substitutes with enhanced performance over traditional techniques. Many design parameters, such as the binder solution properties, have yet to be optimized to ensure maximal biocompatibility and osteoconductivity with sufficient mechanical properties. This study tailored the phosphoric acid-based binder solution concentration to 8.75 wt% to maximize cytocompatibility and mechanical strength, with a supplementation of Tween 80 to improve printing. To further enhance the formulation, collagen was dissolved into the binder solution to fabricate collagen-calcium phosphate composites. Reducing the viscosity and surface tension through a physiologic heat treatment and Tween 80, respectively, enabled reliable thermal inkjet printing of the collagen solutions. Supplementing the binder solution with 1–2 wt% collagen significantly improved maximum flexural strength and cell viability. To assess the bone healing performance, we implanted 3D printed scaffolds into a critically sized murine femoral defect for 9 weeks. The implants were confirmed to be osteoconductive, with new bone growth incorporating the degrading scaffold materials. In conclusion, this study demonstrates optimization of material parameters for 3D printed calcium phosphate scaffolds and enhancement of material properties by volumetric collagen incorporation via inkjet printing.
PMCID: PMC4065717  PMID: 24529628
4.  Loss of Consciousness: Pathophysiology and Implications in Grading and Safe Return to Play 
Journal of Athletic Training  2001;36(3):249-252.
To provide historical background and current concepts regarding the importance of loss of consciousness (LOC) in the evaluation of concussion and athletes.
Data Sources:
A MEDLINE search identified scientific and clinical articles on sport concussion management published from 1966 to present. Discussions were held with authors of selected reports. Recent research findings reported at national meetings were reviewed.
Data Synthesis:
The relative importance of LOC in the evaluation of concussion was reviewed in light of scientific and clinical evidence in the literature. Comments made by authors of concussion grading scales were considered in the development of expert consensus statements.
The observation of LOC at the time of concussion must be viewed as reflecting a potentially worrisome traumatic brain injury. LOC is followed by more severe acute mental status abnormalities and carries a greater risk of intracranial pathology than concussion without LOC. Prolonged LOC represents a neurologic emergency, which may require neurosurgical intervention. Lingering symptoms of concussion, even without LOC, should be monitored closely and managed according to established guidelines for safe return to play.
PMCID: PMC155414  PMID: 12937492
concussion; mild traumatic brain injury; sport concussion guidelines
6.  Concussion Symptom Inventory: An Empirically Derived Scale for Monitoring Resolution of Symptoms Following Sport-Related Concussion 
Self-report post-concussion symptom scales have been a key method for monitoring recovery from sport-related concussion, to assist in medical management, and return-to-play decision-making. To date, however, item selection and scaling metrics for these instruments have been based solely upon clinical judgment, and no one scale has been identified as the “gold standard”. We analyzed a large set of data from existing scales obtained from three separate case–control studies in order to derive a sensitive and efficient scale for this application by eliminating items that were found to be insensitive to concussion. Baseline data from symptom checklists including a total of 27 symptom variables were collected from a total of 16,350 high school and college athletes. Follow-up data were obtained from 641 athletes who subsequently incurred a concussion. Symptom checklists were administered at baseline (preseason), immediately post-concussion, post-game, and at 1, 3, and 5 days post-injury. Effect-size analyses resulted in the retention of only 12 of the 27 variables. Receiver-operating characteristic analyses were used to confirm that the reduction in items did not reduce sensitivity or specificity. The newly derived Concussion Symptom Inventory is presented and recommended as a research and clinical tool for monitoring recovery from sport-related concussion.
PMCID: PMC2800775  PMID: 19549721
Brain injury; Post-concussion; Scale
7.  Stimulation by Alcohols of Cyclic AMP Metabolism in Human Leukocytes 
Journal of Clinical Investigation  1977;60(2):284-294.
In this study ethanol and certain other short-chain aryl (benzyl and phenethyl) and aliphatic (methyl, propyl, butyl, and amyl) alcohols produced up to 10-fold increases in cyclic AMP (cAMP) concentrations in purified human peripheral blood lymphocytes. Ethanol concentrations as low as 80 mg/dl produced significant elevations in lymphocyte cAMP. Significant but less marked augmentation of cAMP in response to alcohols was observed in human platelets, human granulocytes, and rabbit alveolar macrophages. The mechanism of the alcohol-induced cAMP accumulation is probably secondary to membrane perturbation and consequent activation of adenylate cyclase, because ethanol directly stimulated this enzyme in lymphocyte membrane preparations but had no effect on lymphocyte phosphodiesterase activity.
Lysosomal enzyme release, by phagocytosing human leukocytes, and aminoisobutyric acid transport in mitogen-stimulated human lymphocytes were shown to be inhibited by ethanol and other alcohols at concentrations which also elevate cAMP. In general, the magnitude of the inhibition of these inflammatory processes correlated with the ability of the alcohol to elevate cAMP concentrations. Lectin-and anti-thymocyte globulin-induced lymphocyte mitogenesis was inhibited or unaffected depending upon both the concentration and type of mitogenic stimulus and the concentration and type of alcohol utilized. Inflammatory mediator release from rat mast cells also was inhibited by ethanol and certain other alcohols, but whole cell cAMP was not increased. Ethanol may alter these inflammatory responses and other biologic processes at least in part by modulating cellular levels of cAMP.
PMCID: PMC372368  PMID: 194924

Results 1-7 (7)