Increased [18F]Fluorodeoxyglucose Uptake in the Left Pallidum in Military Veterans with Blast-Related Mild Traumatic Brain Injury: Potential as an Imaging Biomarker and Mediation with Executive Dysfunction and Cognitive Impairment

Blast-related mild traumatic brain injury (blast-mTBI) can result in a spectrum of persistent symptoms leading to substantial functional impairment and reduced quality of life. Clinical evaluation and discernment from other conditions common to military service can be challenging and subject to patient recall bias and the limitations of available assessment measures. The need for objective biomarkers to facilitate accurate diagnosis, not just for symptom management and rehabilitation but for prognostication and disability compensation purposes is clear. Toward this end, we compared regional brain [18F]fluorodeoxyglucose-positron emission tomography ([18F]FDG-PET) intensity-scaled uptake measurements and motor, neuropsychological, and behavioral assessments in 79 combat Veterans with retrospectively recalled blast-mTBI with 41 control participants having no lifetime history of TBI. Using an agnostic and unbiased approach, we found significantly increased left pallidum [18F]FDG-uptake in Veterans with blast-mTBI versus control participants, p < 0.0001; q = 3.29 × 10-9 [Cohen's d, 1.38, 95% confidence interval (0.96, 1.79)]. The degree of left pallidum [18F]FDG-uptake correlated with the number of self-reported blast-mTBIs, r2 = 0.22; p < 0.0001. Greater [18F]FDG-uptake in the left pallidum provided excellent discrimination between Veterans with blast-mTBI and controls, with a receiver operator characteristic area under the curve of 0.859 (p < 0.0001) and likelihood ratio of 21.19 (threshold:SUVR ≥ 0.895). Deficits in executive function assessed using the Behavior Rating Inventory of Executive Function-Adult Global Executive Composite T-score were identified in Veterans with blast-mTBI compared with controls, p < 0.0001. Regression-based mediation analyses determined that in Veterans with blast-mTBI, increased [18F]FDG-uptake in the left pallidum-mediated executive function impairments, adjusted causal mediation estimate p = 0.021; total effect estimate, p = 0.039. Measures of working and prospective memory (Auditory Consonant Trigrams test and Memory for Intentions Test, respectively) were negatively correlated with left pallidum [18F]FDG-uptake, p < 0.0001, with mTBI as a covariate. Increased left pallidum [18F]FDG-uptake in Veterans with blast-mTBI compared with controls did not covary with dominant handedness or with motor activity assessed using the Unified Parkinson's Disease Rating Scale. Localized increased [18F]FDG-uptake in the left pallidum may reflect a compensatory response to functional deficits following blast-mTBI. Limited imaging resolution does not allow us to distinguish subregions of the pallidum; however, the significant correlation of our data with behavioral but not motor outcomes suggests involvement of the ventral pallidum, which is known to regulate motivation, behavior, and emotions through basal ganglia-thalamo-cortical circuits. Increased [18F]FDG-uptake in the left pallidum in blast-mTBI versus control participants was consistently identified using two different PET scanners, supporting the generalizability of this finding. Although confirmation of our results by single-subject-to-cohort analyses will be required before clinical deployment, this study provides proof of concept that [18F]FDG-PET bears promise as a readily available noninvasive biomarker for blast-mTBI. Further, our findings support a causative relationship between executive dysfunction and increased [18F]FDG-uptake in the left pallidum.

Cumulative Blast Exposure Estimate Model for Special Operations Forces Combat Soldiers

Special Operations Forces (SOF) Service members endure frequent exposures to blast and overpressure mechanisms given their high training tempo. The link between cumulative subconcussive blasts on short- and long-term neurological impairment is largely understudied. Neurodegenerative diseases such as brain dysfunction, cognitive decline, mild cognitive impairment, and dementia may develop with chronic exposures. This hypothesis remains unproven because of lack of ecologically valid occupational blast exposure surveillance among SOF Service members. The purpose of the study was to measure occupational blast exposures in a close quarter battle (CQB) training environment and to use those outcomes to develop a pragmatic cumulative blast exposure (CBE) estimate model. Four blast silhouettes equipped with a field-deployable wireless blast gauge system were positioned in breaching positions during CQB training scenarios. Silhouettes were exposed to flashbangs and three interior breaching charges (single strand roll-up interior charge, 300 grain (gr) explosive cutting tape (ECT), and Jelly charge). Mean blast measures were calculated for each silhouette for flashbangs (n = 93), single strand roll-up interior charge (n = 80), 300 gr ECT (n = 28), and Jelly charge (n = 71). Mean peak blast pressures per detonation are reported as follows: (1) flashbangs (1.97 pounds per square inch [psi]); (2) single strand roll-up interior charge (3.88 psi); (3) 300 gr ECT (2.78 psi); and (4) Jelly charge (1.89 psi). Pragmatic CBE estimates for SOF Service members suggest 36.8 psi, 184 psi, and 2760 psi may represent daily, weekly, and training cycle cumulative pressure exposures. Estimating blast exposures during routine CQB training can be determined from empirical measures taken in CQB environments. Factoring in daily, weekly, training cycle, or even career length may reasonably estimate cumulative occupational training blast exposures for SOF Service members. Future work may permit more granular exposure estimates based on operational blast exposures and those experienced by other military occupational specialties.

Acceptability of technological solutions for overdose monitoring: Perspectives of people who use drugs

INTRODUCTION

Rising overdose deaths are a devastating problem across the United States and Canada. Despite the availability of observed consumption sites in British Columbia (BC), data suggest people who use drugs (PWUD) alone in private residences are most at risk of overdose death. These individuals may not use consumption sites due to fear of stigmatization, lack of privacy, or personal preference. It is this population that would benefit from overdose monitoring alternatives.

METHODS

This 2018 study employed two sources of data. (1) A provincial harm reduction distribution site client survey administered at 27 sites across BC asked about cell phone possession and functionality. (2) Structured interviews with PWUD in Vancouver gathered perspectives regarding monitoring devices and alerting systems. Results: The client survey was administered to 486 individuals. Among 443 respondents, 48% (n = 212) owned a cellphone and 68% (n = 115) of individuals with a cellphone with access to internet (n = 168) would use an application to mitigate opioid-related overdose deaths. Thirty qualitative interviews were performed; thematic analysis of the responses identified three major themes - safety, public versus private drug use, and technological monitoring and function. The relevance of technological devices was affected by the inconsistent availability of cellphones, concerns about anonymity, as well as personal comfort while using drugs. Conclusions: Technological applications may not be suitable for clients with transient lifestyles, no permanent home, and lack of consistent access to a mobile device. Thorough needs assessments, considerations of lifestyle limitations, and understanding perceptions around cellphone and overdose monitoring can increase the potential that devices will be used.Highlights45% (n = 219) of client survey respondents owned a cellphoneOut of cellphone owners, 59% (n = 102) of client survey respondents had access to internetOf 168 with internet access, 68% willing to use any applications for overdose responseApplications not suitable for transient lifestyles, no permanent home, and lack of consistent access to cellphone.

1784: The Marquis de Puységur and the psychological turn in the west

In 1970 Henri Ellenberger called attention to the previously unrecognized importance of Franz Anton Mesmer's "animal magnetism" in the rise of psychodynamic psychology in the West. This article takes the next step of tracing the course of events that led to Puységur's discovery of magnetic somnambulism and describing the tumultuous social and political climate into which it was introduced in 1784. Beginning from the secret and private publication of his first Mémoires, only a few copies of which remain today, the original core of his discovery is identified and the subsequent development of its implications are examined. Puysègur was initiated into his investigations by Mesmer's system of physical healing, which bears some resemblance to the traditional healing approaches of the East. But Puységur took Mesmer's ideas in an unexpected direction. In doing so, he accomplished a turn toward the psychological that remains one of the distinguishing features of Western culture.

"Automatism" and the emergence of dynamic psychiatry

This article is about the clash of two explanatory paradigms, each attempting to account for the same data of human experience. In the first half of the nineteenth century, physiologists investigated reflex actions and applied a recently coined word, "automatism," to describe actions which, although seeming to arise from higher centers, actually result from automatic reaction to sensory stimuli. Experiments with spinal reflexes led to the investigation of the reflex action of the brain or "cerebral automatisms." Reflex actions of this kind were used to explain everything from acting compulsively to composing symphonies. Physiological explanations of phenomena of this kind seemed insufficient to some and, in the 1880s, Frederic Myers and Pierre Janet developed psychological frameworks for understanding these phenomena, positing hidden centers of intelligence at work in the individual, outside ordinary awareness, which produce what came to be called "psychological automatisms." Their attempts to unify this psychological framework with the existing physiological one failed. Nevertheless, their work played a crucial role in paving the way for what Ellenberger called dynamic psychiatry, which accepts the reality of an unconscious dynamic of the psyche.

Transcriptional induction of the urokinase receptor gene by a constitutively active Src. Requirement of an upstream motif (-152/-135) bound with Sp1

Since c-src overexpression increases colonic cell invasiveness and because both Src activity and urokinase receptor protein are elevated in invasive colon cancers, the present study was undertaken: 1) to determine if a constitutively active Src regulates urokinase receptor expression and 2) to identify required cis-elements and trans-acting factors. SW480 colon cancer cells transfected with an expression plasmid (c-srcY527F) encoding a constitutively active Src protein manifested increased urokinase receptor gene expression and Src activity. Treatment of the src transfectants with a Src-inhibitor (PD173955) reduced urokinase receptor protein levels and laminin degradation. Inasmuch as we recently implicated an upstream region of the urokinase receptor promoter (-152/-135) in constitutive urokinase receptor expression, we determined its role for the induction by src. Whereas the activity of a CAT reporter driven by this region was stimulated by c-srcY527F, the u-PAR promoter mutated at the Sp1-binding motif in the -152/-135 region was not. Nuclear extracts from the src transfectants demonstrated increased Sp1 binding to region -152/-135 compared with those from SW480 cells. Finally, endogenous urokinase receptor protein amounts in 10 colon cancers and corresponding normal colon correlated with Src specific activity. These data suggest that urokinase receptor gene expression is regulated by Src partly via increased Sp1 binding.

The calibre changes of retinal vessels subject to prolonged hyperoxia

The constriction of retinal vessels occurring in response to breathing 100% oxygen was studied in 10 normal subjects over a period of 30 min. Brachial blood pressure, radial pulse and end tidal CO2 were recorded throughout. The mean arteriolar constriction was 15.3% +/- 4.6 and venous constriction 21.8% +/- 4.3. Time constants (the time for 95% of the maximal response to have occurred) were 2.25 min +/- 0.75 and 2.37 min +/- 0.57 for arterioles and veins respectively. A highly variable late vascular response was recorded. A small proportion of arterial vessels showing a response were nonuniform while a larger proportion of veins showed a significant dilatation.