Head Flail Corridors From Sled Impact Acceleration Tests for Use in Occupant-Centric Vehicle Design

INTRODUCTION

In aircraft crashes, injuries to the head and upper torso are frequently reported, with head injury reported most frequently of all body regions. Because preventing flail of the head and body is of utmost importance for occupant survival, the Aircraft Crash Survival Design Guide (ACSDG), the guide to crashworthy aircraft design, published flail envelopes. However, the ACSDG flail envelopes are based on a single test with an anthropomorphic test device subjected to a frontal acceleration. In this article, human research volunteer (HRV) response data are used to calculate head flail corridors and evaluate the ACSDG flail envelopes.

MATERIALS AND METHODS

Data from HRV sled tests were obtained from the historical Naval Biodynamics Laboratory collection of the Biodynamics Data Resource. Digitized high-speed film for each test was tracked and processed to represent the head flail response in a format amenable to corridor development. Time-based and position-based head flail corridors were developed for groups of exposure-matched tests and then compared to the ACSDG flail envelopes.

RESULTS

A collection of 714 HRV sled tests conducted in six different impact directions ranging from 3 to 15 g was used to develop time-based and position-based head flail corridors for 39 match groups. The ACSDG vertical limit and anteroposterior limit and curve were not exceeded by the flail corridors, but the lateral limit and curve were exceeded by 4.6 cm to 15.8 cm.

CONCLUSIONS

The flail corridors provide a useful baseline for representing the well-restrained occupant response at lower, non-injurious exposure levels and across multiple impact directions. Under these conditions, the ACSDG lateral limit and curve are not adequate. At higher exposure levels or with modified restraints, seating, or equipment, the ACSDG vertical limit and anteroposterior limit and curves may also be inadequate.

Implementing DASH-aligned Congregate Meals and Self-Measured Blood Pressure in two senior centers: An open label study

BACKGROUND AND AIMS

Cardiovascular Disease (CVD) poses significant health risks for seniors, especially among low-income and minority communities. Senior centers offer multiple services. We tested whether implementing two evidence-based interventions- DASH-aligned meals provided through an existing congregate meal program, and support for home Self-Measured Blood Pressure (SMBP) monitoring-lowers blood pressure among participants at two senior centers serving low-income, racially diverse communities.

METHODS AND RESULTS

Open-label study, enrolling clients aged ≥60, eating ≥4 meals/week at two NYC senior centers. Participants received DASH-aligned congregate meals, and training in nutrition, BP management education, and personal SMBP device. Co-Primary outcomes: a) change in systolic BP measured by independent health professionals, and b) change in percent with "controlled BP" (Eighth Joint National Committee (JNC-8) Guidelines), at Month 1 compared to Baseline.

SECONDARY OUTCOMES

Changes in BP at Months 3 and 5/6 (last measure). We enrolled 94 participants; COVID closures interrupted implementation mid-study. Mean systolic BP at Month-1 changed by -4.41 mmHg (n = 61 p = 0.07) compared to Baseline. Participants with controlled BP increased (15.7%) at Month 1. Change in mean BP at Month 1 was significantly correlated with BMI (p = 0.02), age (p = 0.04), and baseline BP (p < 0.001). Mean systolic SMBP changed by -6.9 mmHg (p = 0.004) at Months 5/6.

CONCLUSIONS

Implementing an evidence-based multi-component BP-lowering intervention within existing congregate meal programs at senior centers serving minority and low-income communities is feasible, and early findings show promising evidence of effectiveness. This approach to cardiovascular risk reduction should be further tested for widespread adoption and impact. Registered on ClinicalTrials.gov NCT03993808 (June 21st, 2019).

Community-Academic Partnership to Improve Nutrition and Blood Pressure in Seniors: Outcomes & Impact of COVID-19

The Dietary Approaches to Stop Hypertension (“DASH diet”) has been proven in research settings to lower blood pressure, but its implementation is untested among seniors in congregate meals settings. We report the planning, implementation, impact of COVID-19, and results of an Administration of Community Living-funded study to test whether two evidence-based interventions - DASH-alignment of congregate meals, and home blood pressure self-monitoring, can lower systolic blood pressure and increase blood pressure control among community-dwelling seniors.. Congregate meal menus were aligned with the DASH eating plan, through collaboration of Bionutrition professionals on the research team, CBN food services leadership, and the NYC Department for the Aging. Seniors provided feedback on the DASH-modified meal options. The intervention began on October 15, 2019 (Site 1) and February 3, 2020 (Site 2). The study was interrupted by the COVID-19 pandemic in March 2020, when congregate meals ceased, and when approximately 75% of primary outcome data were collected. Modified implementation permitted completion of modified study outcomes. Preliminary analyses suggest that some participants were able to lower their blood pressure in this program. The DASH diet implemented in the congregate meal setting, along with programs to support BP self-efficacy through modification of existing programs, may be a valuable and scalable model to reduce cardiovascular risk among community-living seniors.

Prolonged Hya-disparate skin graft survival in ethanol-consuming mice: correlation with impaired delayed hypersensitivity

BACKGROUND

Ethanol consumption impairs cell-mediated immunity and enhances humoral immunity. Among cell-mediated immune reactions, little is known of the effect of ethanol on chronic graft rejection. Allograft responses against the male-specific minor histocompatibility antigen, Hya, are widely used to study chronic graft rejection.

METHODS

Female C57BL/6 (B6) mice were fed ethanol-containing liquid diets, were pair-fed an isocaloric liquid control diet, or were fed solid diet and water ad libitum. One week after diet initiation, the mice were grafted with split thickness, orthotopic male tail skin grafts, and the integrity of the grafts was monitored as the diet continued. Delayed hypersensitivity (DTH) was also determined in these same mice. In addition, Hya-cytolytic T-cell-deficient syngeneic major histocompatibility complex mutant B6.C-H2bm13 (bm13) and B6.C-H2bm14 (bm14) mice were assessed for skin graft rejection, DTH, and cytotoxic T-lymphocyte (CTL) activity.

RESULTS

Ethanol-consuming female B6 mice are impaired in their ability to reject syngeneic male skin grafts and to develop Hya-specific DTH responses. To address the underlying mechanism, we show that Hya graft rejection correlates with DTH and not with CTL activity. Female B6 mice clearly differ from female bm13 and bm14 mice in their ability to generate CTLs against Hya antigen. Despite their inability to make Hya-specific CTL responses, bm13 and bm14 female mice, nevertheless, make Hya-specific DTH responses and ultimately reject Hya-disparate skin grafts, indicating that Hya-specific graft rejection results from DTH. Ethanol, by impairing Hya-specific DTH, inhibits Hya-specific skin graft rejection.

CONCLUSIONS

We demonstrate that ethanol consumption impairs Hya-specific graft rejection. In addition, experiments with mice unable to generate anti-Hya CTLs support previous observations suggesting that DTH responses are sufficient to cause rejection of Hya-incompatible grafts.

Alcohol consumption alters antigen-specific Th1 responses: mechanisms of deficit and repair

Among the physiological effects associated with excessive alcohol consumption are alterations in immune function. Alcohol impairs T-helper 1 lymphocyte (Th1) regulated, cell-mediated immune responses. Antibody responses, regulated by T-helper 2 lymphocyte (Th2), are either unimpaired or enhanced. Antigen presenting cells are central to the development of both Th1 and Th2 regulated immune responses. We used both T-cell receptor transgenic and conventionally immunized mice to demonstrate that ethanol consumption directly affects antigen presenting cells that, in turn, determines whether Th1 or Th2 response patterns predominate. Ethanol consumption inhibits Th1-associated interleukin-12 and interferon-gamma cytokine production and delayed-type hypersensitivity. Administration of exogenous recombinant interleukin-12 both restores interferon-gamma levels and delayed-type hypersensitivity responses in ethanol-consuming mice.

Glutathione levels in antigen-presenting cells modulate Th1 versus Th2 response patterns

Current thinking attributes the balance between T helper 1 (Th1) and Th2 cytokine response patterns in immune responses to the nature of the antigen, the genetic composition of the host, and the cytokines involved in the early interaction between T cells and antigen-presenting cells. Here we introduce glutathione, a tripeptide that regulates intracellular redox and other aspects of cell physiology, as a key regulatory element in this process. By using three different methods to deplete glutathione from T cell receptor transgenic and conventional mice and studying in vivo and/or in vitro responses to three distinct antigens, we show that glutathione levels in antigen-presenting cells determine whether Th1 or Th2 response patterns predominate. These findings present new insights into immune response alterations in HIV and other diseases. Further, they potentially offer an explanation for the well known differences in immune responses in "Th1" and "Th2" mouse strains.

Interleukin-12 therapy restores cell-mediated immunity in ethanol-consuming mice

Previous studies from our laboratory show that ethanol consumption impairs antigen-specific, cell-mediated, but not, humoral immune responses of C57BL/6, BALB/c, and DO11.10 T-cell receptor transgenic mice. This ethanol-associated deficit is associated with decreased interleukin (IL)-12 and interferon-gamma (IFN-gamma) production, but not IL-2 or antigen-specific T-cell proliferation by explanted leukocytes from ethanol-consuming mice. IL-12 expression by macrophage/monocytes is viewed as a requirement for the production of IFN-gamma by Th1 lymphocytes that mediate cellular immunity. In this study, we restored antigen-specific, cell-mediated immunity, delayed hypersensitivity, to ethanol-consuming C57BL/6 or BALB/c mice with a single 100 ng of intravenous injection of recombinant IL-12 at the time of immunization. The addition of exogenous recombinant IL-12 to co-cultures of antigen-presenting cells derived from ethanol-consuming mice and purified T cells derived from ethanol-nonconsuming DO11.10 repairs the ability of Th1 cells to make IFN-gamma in response to antigen. Administration of recombinant IL-12 opens a potential for restoring cell-mediated immune function to ethanol-consuming individuals.