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"WRIGHT, GREGORY J."
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Batman
\"In these moody 1990s tales, Batman emerges from the shadows to battle corruption in Gotham City, and face foes including Killer Croc, The Scarecrow, Mr. Freeze, Two-Face and more. These tales by the classic Batman creative team of writer Doug Moench and artist Kelley Jones include guest-appearances by Nightwing, Robin, Deadman, and Swamp Thing. Collects Batman #515-525, 527-532, and 535-536\"-- Provided by publisher.
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Tensile biomechanical properties of human temporomandibular joint disc: Effects of direction, region and sex
Approximately 30% of temporomandibular joint (TMJ) disorders include degenerative changes to the articular disc, with sex-specific differences in prevalence and severity. Limited tensile biomechanical properties of human TMJ discs have been reported. Stress relaxation tests were conducted on TMJ disc specimens harvested bilaterally from six males and six females (68.9±7.9 years), with step-strain increments of 5%, 10%, 15%, 20% and 30%, at 1% strain-per-second. Stress versus strain plots were constructed, and Young׳s Modulus, Instantaneous Modulus and Relaxed Modulus were determined. The effects of direction, region, and sex were examined. Regional effects were significant (p<0.01) for Young׳s Modulus and Instantaneous Modulus. Anteroposteriorly, the central region was significantly stiffer than medial and lateral regions. Mediolaterally, the posterior region was significantly stiffer than central and anterior regions. In the central region, anteroposteriorly directed specimens were significantly stiffer compared to mediolateral specimens (p<0.04). TMJ disc stiffness, indicated by Young׳s Modulus and Instantaneous Modulus, was higher in directions corresponding to high fiber alignment. Additionally, human TMJ discs were stiffer for females compared to males, with higher Young׳s Modulus and Instantaneous Modulus, and female TMJ discs relaxed less. However, sex effects were not statistically significant. Using second-harmonic generation microscopy, regional collagen fiber organization was identified as a potentially significant factor in determining the biomechanical properties for any combination of direction and region. These findings establish structure–function relationships between collagen fiber direction and organization with biomechanical response to tensile loading, and may provide insights into the prevalence of TMJ disorders among women.
Journal Article
Electrical Conductivity Method to Determine Sexual Dimorphisms in Human Temporomandibular Disc Fixed Charge Density
To investigate potential mechanisms associated with the increased prevalence of temporomandibular joint (TMJ) disorders among women, the study objective was to determine sex-dependent and region-dependent differences in fixed charge density (FCD) using an electrical conductivity method. Seventeen TMJ discs were harvested from nine males (77 ± 4 years) and eight females (86 ± 4 years). Specimens were prepared from the anterior band, posterior band, intermediate zone, medial disc and lateral disc. FCD was determined using an electrical conductivity method, assessing differences among disc regions and between sexes. Statistical modeling showed significant effects for donor sex (p = 0.002), with cross-region FCD for male discs 0.051 ± 0.018 milliequivalent moles per gram (mEq/g) wet tissue and 0.043 ± 0.020 mEq/g wet tissue for female discs. FCD was significantly higher for male discs compared to female discs in the posterior band, with FCD 0.063 ± 0.015 mEq/g wet tissue for male discs and 0.032 ± 0.020 mEq/g wet tissue for female discs (p = 0.050). These results indicate FCD contributes approximately 20% towards TMJ disc compressive modulus, through osmotic swelling pressure regulation. Additionally, FCD regulates critical extracellular ionic/osmotic and nutrient environments. Sexual dimorphisms in TMJ disc FCD, and resulting differences in extracellular ionic/osmotic and nutrient environments, could result in altered mechano–electro-chemical environments between males and females and requires further study.
Journal Article
Selection of Northern Yellowstone Elk by Gray Wolves and Hunters
We compared selection of northern Yellowstone elk (Cervus elaphus) by hunters in the Gardiner Late Hunt and northern Yellowstone wolves (Canis lupus) with regard to sex, age, and impacts to recruitment. We compared harvest data from 1996–2001 with wolf-killed elk data from 1995–2001. We assessed the effects of hunting and wolf predation on reproductive female elk by constructing a life table and calculating reproductive values for females in the northern Yellowstone herd. We devised an index of total reproductive impact to measure impacts to calf production due to hunting and wolf predation. The age classes of female elk selected by wolves and hunters were significantly different. Hunters selected a large proportion of female elk with the greatest reproductive values, whereas wolves selected a large proportion of elk calves and older females with low reproductive values. The mean age of adult females killed by hunters throughout the study period was 6.5 years, whereas the mean age of adult females killed by wolves was 13.9 years. Hunting exerted a greater total reproductive impact on the herd than wolf predation. The combined effects of hunters killing prime-aged females (2–9 yr old), wolves killing calves, and predation by other predators has the potential to limit the elk population in the future. Yellowstone is unique in this regard because multiple predators that occur sympatrically, including hunters, wolves, grizzly bears (Ursus arctos), black bears (Ursus americanus), cougars (Felis concolor), and coyotes (Canis latrans), all prey on elk. Using an Adaptive Harvest Management process the known female elk harvest during the Gardiner Late Hunt has been reduced by 72% from 2,221 elk in 1997 to 620 elk in 2004. In the future, hunting harvest levels may be reduced further to partially offset elk losses to wolves, other predators, and environmental factors.
Journal Article
Effect of Mechanical Strain on Solute Diffusion in Human TMJ Discs: An Electrical Conductivity Study
This study investigated the effect of mechanical strain on solute diffusion in human TMJ discs (mean cadaver age 77.8) using the electrical conductivity method. The electrical conductivity, as well as small ion diffusivity, of male and female TMJ discs was determined under three compressive strains. In the male group, the average disc electrical conductivity (mean ± SD) at 0% strain was 5.14 ± 0.97 mS/cm, decreased to 4.50 ± 0.91 mS/cm (−12.3%) at 10% strain, and 3.93 ± 0.81 mS/cm (−23.5%) at 20% compressive strain. Correspondingly, the average disc relative ion diffusivity at 0% strain was 0.44 ± 0.08, decreased to 0.40 ± 0.08 (−8.9%) at 10% strain, and 0.36 ± 0.08 (−16.7%) at 20% compressive strain. In the female group, the average disc electrical conductivity at 0% strain was 5.84 ± 0.59 mS/cm, decreased to 5.01 ± 0.50 mS/cm (−14.2%) at 10% strain, and 4.33 ± 0.46 mS/cm (−25.8%) at 20% compressive strain. Correspondingly, the average disc relative ion diffusivity at 0% strain was 0.49 ± 0.05, decreased to 0.43 ± 0.04 (−11.3%) at 10% strain, and 0.39 ± 0.04 (−19.9%) at 20% compressive strain. The results indicated that mechanical strain significantly impeded solute diffusion through the disc. This mechanical strain effect was larger in the female than in the male human TMJ disc. This study may provide new insights into TMJ pathophysiology.
Journal Article
Impact of Storage Solution Formulation during Refrigerated Storage upon Chondrocyte Viability and Cartilage Matrix
Various preservation solutions have been evaluated for longer hypothermic cartilage storage for tissue transplantation; however, the results are mixed. This research was carried out to determine whether phosphate-buffered saline (PBS) or organ preservation solutions would preserve both the extracellular matrix and chondrocytes of articular cartilage better than culture medium during refrigerated storage in the time frame that cartilage is stored for clinical use. Porcine cartilage plugs were stored, without the underlying bone, in culture medium with and without fetal bovine serum (FBS), PBS, Belzer's and Unisol solutions for 1 month at 4°C. Metabolic activity was tested using a resazurin reduction method, and matrix permeability was evaluated by measuring electrical conductivity. Storage in culture medium with 10% FBS was shown to provide good cartilage metabolic function for 7 days, decreasing to about 36% after 1 month of storage. There was no significant difference between samples stored in culture medium with and without FBS after 1 month of storage (p = 0.5005). Refrigerated storage of cartilage in PBS and two different solutions (Belzer's and Unisol) designed for optimal refrigerated tissue and organ storage results in loss of chondrocyte function and retention of matrix permeability. In contrast, the opposite, namely significantly better retention of chondrocyte function and loss of matrix permeability, was observed with culture medium. Future research should be focused on combining retention of chondrocyte function and matrix permeability by storage solution formulation.
Journal Article
Comparison and evaluation of biomechanical, electrical, and biological methods for assessment of damage to tissue collagen
In regard to evaluating tissue banking methods used to preserve or otherwise treat (process) soft allograft tissue, current tests may not be sufficiently sensitive to detect potential damage inflicted before, during, and after processing. Using controlled parameters, we aim to examine the sensitivity of specific biomechanical, electrical, and biological tests in detecting mild damage to collagen. Fresh porcine pulmonary heart valves were treated with an enzyme, collagenase, and incubated using various times. Controls received no incubation. All valves were cryopreserved and stored at −135 °C until being rewarmed for evaluation using biomechanical, permeability, and cell viability tests. Statistically significant time dependent changes in leaflet ultimate stress, (
p
= 0.006), permeability (
p
= 0.01), and viability (
p
≤ 0.02, four different days of culture) were found between heart valves subjected to 0–15 min of collagenase treatment (ANOVA). However, no statistical significance was found between the tensile modulus of treated and untreated valves (
p
= 0.07). Furthermore, the trends of decreasing and increasing ultimate stress and viability, respectively, were somewhat inconsistent across treatment times. These results suggest that permeability tests may offer a sensitive, quantitative assay to complement traditional biomechanical and viability tests in evaluating processing methods used for soft tissue allografts, or when making changes to current validated methods. Multiple test evaluation may also offer insight into the mechanism of potential tissue damage such as, as is the case here, reduced collagen content and increased tissue porosity.
Journal Article
Guidelines for the Management of Severe Traumatic Brain Injury: 2020 Update of the Decompressive Craniectomy Recommendations
Abstract
When the fourth edition of the Brain Trauma Foundation's Guidelines for the Management of Severe Traumatic Brain Injury were finalized in late 2016, it was known that the results of the RESCUEicp (Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension) randomized controlled trial of decompressive craniectomy would be public after the guidelines were released. The guideline authors decided to proceed with publication but to update the decompressive craniectomy recommendations later in the spirit of “living guidelines,” whereby topics are updated more frequently, and between new editions, when important new evidence is published. The update to the decompressive craniectomy chapter presented here integrates the findings of the RESCUEicp study as well as the recently published 12-mo outcome data from the DECRA (Decompressive Craniectomy in Patients With Severe Traumatic Brain Injury) trial. Incorporation of these publications into the body of evidence led to the generation of 3 new level-IIA recommendations; a fourth previously presented level-IIA recommendation remains valid and has been restated. To increase the utility of the recommendations, we added a new section entitled Incorporating the Evidence into Practice. This summary of expert opinion provides important context and addresses key issues for practitioners, which are intended to help the clinician utilize the available evidence and these recommendations.
The full guideline can be found at: https://braintrauma.org/guidelines/guidelines-for-the-management-of-severe-tbi-4th-ed#/.
Journal Article
Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition
Abstract
The scope and purpose of this work is 2-fold: to synthesize the available evidence and to translate it into recommendations. This document provides recommendations only when there is evidence to support them. As such, they do not constitute a complete protocol for clinical use. Our intention is that these recommendations be used by others to develop treatment protocols, which necessarily need to incorporate consensus and clinical judgment in areas where current evidence is lacking or insufficient. We think it is important to have evidence-based recommendations to clarify what aspects of practice currently can and cannot be supported by evidence, to encourage use of evidence-based treatments that exist, and to encourage creativity in treatment and research in areas where evidence does not exist. The communities of neurosurgery and neuro-intensive care have been early pioneers and supporters of evidence-based medicine and plan to continue in this endeavor. The complete guideline document, which summarizes and evaluates the literature for each topic, and supplemental appendices (A-I) are available online at https://www.braintrauma.org/coma/guidelines.
Journal Article