Cumulative effective radiation dose received by blunt trauma patients arriving to a military level I trauma center from point of injury and interhospital transfers

Radioprotective agents against the ionizing radiation-induced hematopoietic stem and progenitor cell injury; Foundation review

Humans encounter ionizing radiation (IR) through various ways, such as medical applications, agricultural industry, and potential exposure from radioactive materials or acts of radiological terrorism. Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are crucial for maintaining the balance of blood cell lineages. The hematopoietic system, recognized as the most sensitive human tissue, is severely affected by IR, which can result in bone marrow (BM) failure, increased susceptibility to infections, hemorrhagic events, or anemia in affected individuals. Therefore, it is essential to develop radioprotective compounds to protect HSCs/HPCs. This review highlights several radioprotective agents that protect the hematopoietic system from IR-related damage to HSCs and HPCs and provides an overview of the mechanisms involved in damage and protection.

Are geriatric transfer patients with traumatic brain injury at risk for worse outcomes compared to non-geriatric? Propensity-matched study

OBJECTIVE

To compare outcomes between geriatric and non-geriatric patients with traumatic brain injury (TBI) transferred to trauma center and effects of anticoagulants/antiplatelets (AC/AP) and reversal therapy.

METHODS

A retrospective review of 1,118 patients with TBI transferred from acute care facilities to level 1 trauma center compared in groups: geriatric versus non-geriatric, geriatric with AC/AP therapy versus without, and geriatric AC/AP with AC/AP reversal therapy versus without.

RESULTS

Patients with TBI constituted 54.4% of trauma transfers. Mean transfer time was 3.9 h. Propensity matched by Injury Severity Score and Abbreviated Injury Score (AIS) head geriatric compared to non-geriatric patients had more AC/AP use (53.9% vs 8.8%), repeat head computed tomography (93.7% vs 86.1%), intensive care unit (ICU) admissions (57.4% vs 45.7%) and mortality (9.8% vs 3.2%), all p < 0.004. Patients on AC/AP versus without had more ICU admissions (69.1% vs 51.8%, p < 0.001). Patients with AC/AP reversals compared to without reversals had more AIS head 5 (32.0% vs 13.1%), brain surgeries (17.8% vs 3.5%) and ICU admissions (84.8% vs 57.1%), all p < 0.001.

CONCLUSION

TBI constituted half of trauma transfers and 10% required surgery. Based on higher ICU admissions, mortality, and prevalence of AC/AP therapy requiring reversal, geriatric patients with TBI on anticoagulants/antiplatelets should be considered for direct trauma center admission.

Cancer Incidence and Etiology in the Active Duty Population of U.S. Military

INTRODUCTION

As members of the military, all active duty service members (ADS) must meet physical fitness requirements and are provided with equal-access healthcare through the DoD. In addition, 92% of ADS are ≤40 years of age. Together, these characteristics suggest that ADS represent a healthy population that may have a low risk of cancer. Each year, however, >800 ADS are diagnosed with cancer and the resulting in time off for treatment, reassignment, or medical retirement may significantly impact force readiness.

MATERIAL AND METHODS

Relevant literature was identified by searching the PubMed database using search terms ACTIVE DUTY and CANCER. Only articles written in English were included.

RESULTS

Melanoma is the most common cancer in ADS, while testicular cancer is the most common cancer in males and breast cancer is the most common in females. Cancer incidence patterns in ADS differ from those in the general U.S. population and from military veterans. Tumor etiology in ADS may be influenced by military-enriched exposures such as prolonged use of oral contraceptives, suboptimal use of sunscreen, exposure to volatile organic compounds, or germline predisposition/family history.

CONCLUSIONS

The etiology of cancer within ADS remains largely unknown. A number of new research programs may provide the means to improve understanding of the etiology of cancer in ADS. Together, these efforts will improve prevention, early detection, and clinical management, thus improving the outcomes of ADS and preserving force readiness.

Delayed Reaction of Radiation on the Central Nervous System and Bone System in C57BL/6J Mice

The aim of this study was to provide a suitable mouse model of radiation-induced delayed reaction and identify potential targets for drug development related to the prevention and treatment of radiation injury. C57BL/6J mice were subjected to singular (109 cGy/min, 5 Gy*1) and fractional (109 cGy/min, 5 Gy*2) total body irradiation. The behavior and activity of mice were assessed 60 days after ionizing radiation (IR) exposure. After that, the pathological changes and mechanism of the mouse brain and femoral tissues were observed by HE, Nissl, Trap staining micro-CT scanning and RNA sequencing (RNA-Seq), and Western blot. The results show that singular or fractional IR exposure led to a decrease in spatial memory ability and activity in mice, and the cognitive and motor functions gradually recovered after singular 5 Gy IR in a time-dependent manner, while the fractional 10 Gy IR group could not recover. The decrease in bone density due to the increase in osteoclast number may be relative to the down-regulation of RUNX2, sclerostin, and beta-catenin. Meanwhile, the brain injury caused by IR exposure is mainly linked to the down-regulation of BNDF and Tau. IR exposure leads to memory impairment, reduced activity, and self-recovery, which are associated with time and dose. The mechanism of cognitive and activity damage was mainly related to oxidative stress and apoptosis induced by DNA damage. The damage caused by fractional 10 Gy TBI is relatively stable and can be used as a stable multi-organ injury model for radiation mechanism research and anti-radiation medicine screening.

Association of Low-Dose Whole-Body Computed Tomography With Missed Injury Diagnoses and Radiation Exposure in Patients With Blunt Multiple Trauma

Question

Is low-dose whole-body computed tomography with statistical image reconstruction associated with similar rates of missed injuries and accuracy but reduced radiation exposure compared with standard-dose whole-body computed tomography in the primary diagnostic workup of blunt multiple trauma?

Findings

In this quasi-experimental cohort study of 971 patients with suspected blunt multiple trauma, participants in the standard-dose and low-dose whole-body computed tomography groups had the same risk of missed injury diagnoses. Low-dose scanning markedly reduced exposure to radiation, improved the contrast-to-noise ratio, and showed similar diagnostic accuracy among the investigated anatomical areas and organs when compared with standard-dose scanning.

Meaning

These findings suggest that low-dose whole-body computed tomography may safely replace standard-dose scanning in the primary diagnostic workup of blunt multiple trauma.

Importance

Initial whole-body computed tomography (WBCT) for screening patients with suspected blunt multiple trauma remains controversial and a source of excess radiation exposure.

Objective

To determine whether low-dose WBCT scanning using an iterative reconstruction algorithm does not increase the rate of missed injury diagnoses at the point of care compared with standard-dose WBCT with the benefit of less radiation exposure.

Design, Setting, and Participants

This quasi-experimental, prospective time-series cohort study recruited 1074 consecutive patients admitted for suspected blunt multiple trauma to an academic metropolitan trauma center in Germany from September 3, 2014, through July 26, 2015, for the standard-dose protocol, and from August 7, 2015, through August 20, 2016, for the low-dose protocol. Five hundred sixty-five patients with suspected blunt multiple trauma prospectively received standard-dose WBCT, followed by 509 patients who underwent low-dose WBCT. Confounding was controlled by segmented regression analysis and a secondary multivariate logistic regression model. Data were analyzed from January 16, 2017, through October 14, 2019.

Interventions

Standard- or low-dose WBCT.

Main Outcomes and Measures

The primary outcome was the incidence of missed injury diagnoses at the point of care, using a synopsis of clinical, surgical, and radiological findings as an independent reference test. The secondary outcome was radiation exposure with either imaging strategy.

Results

Of 1074 eligible patients, 971 (mean [SD] age, 52.7 [19.5] years; 649 men [66.8%]) completed the study. A total of 114 patients (11.7%) had multiple trauma, as defined by an Injury Severity Score of 16 or greater. The proportion of patients with any missed injury diagnosis at the point of care was 109 of 468 (23.3%) in the standard-dose and 107 of 503 (21.3%) in the low-dose WBCT groups (risk difference, −2.0% [95% CI, −7.3% to 3.2%]; unadjusted odds ratio, 0.89 [95% CI, 0.66-1.20]; P = .45). Adjustments for autocorrelation and multiple confounding variables did not alter the results. Radiation exposure, measured by the volume computed tomography dose index, was lowered from a median of 11.7 (interquartile range, 11.7-17.6) mGy in the standard-dose WBCT group to 5.9 (interquartile range, 5.9-8.8) mGy in the low-dose WBCT group (P < .001).

Conclusions and Relevance

Low-dose WBCT using iterative image reconstruction does not appear to increase the risk of missed injury diagnoses at the point of care compared with standard-dose protocols while almost halving the exposure to diagnostic radiation.

The protective effects of 1,2-propanediol against radiation-induced hematopoietic injury in mice

Agents that provide protection against irradiation-induced hematopoietic injury are urgently needed for radiotherapy. We examined the effects of the small molecule, 1,2-propanediol (PPD), on total body irradiation (TBI)-induced hematopoietic injury in C57BL/6 mice. PPD administration 1 h before TBI significantly increased hematopoietic parameters such as white blood cell, platelet, red blood cell, and lymphocyte counts in vivo and enhanced the survival of mice exposed to TBI (7.0 and 7.5 Gy). PPD administration 1 h before TBI improved bone marrow (BM) and spleen recovery after TBI, with increases in both BM cellularity and spleen index. The number of colony-forming-units in bone marrow mononuclear cells (BMNCs) in vitro also increased significantly. PPD pretreatment increased the numbers of hematopoietic stem cells and hematopoietic progenitor cells in BM. Importantly, PPD also maintained endogenous antioxidant status by decreasing levels of malondialdehyde and increasing the expression of reduced glutathione, superoxide dismutase and catalase in the serum of irradiated mice. PPD alleviated the levels of apoptosis in HSCs induced by TBI, thus increasing the proportion of dividing BMNCs. These results suggest that PPD protects against TBI-induced hematopoietic injury through the increased activities of antioxidant enzymes and the inhibition of apoptosis in HSCs. PPD increased the serum levels of granulocyte-colony stimulating factor and interleukin-6 irrespective of TBI. In conclusion, these data suggest that PPD acts as a radioprotector against radiation-induced hematopoietic injury.