Wounding patterns in pediatric firearm fatalities.

INTRODUCTION: Pediatric firearm injury became the leading cause of death among U.S. children in 2020. Studies evaluating wounding patterns in military and mass casualty shootings have provided insights into treatment and potential salvageability in adults, however, similar studies in the pediatric population do not exist. Hence, our study aimed to analyze wounding patterns of pediatric firearm fatalities and associated demographics and characteristics, such as place of death, to better understand pediatric firearm injuries, potential salvageability, and opportunities to reduce firearm deaths among vulnerable pediatric populations. METHODS: A retrospective review of the National Violent Death Reporting System from 2005-2017 was performed on patients 18 and younger. Mortalities were stratified by patient age: <12 years and 13-18 years and by intent- homicide, suicide, and unintentional. Comparative and exploratory analyses of demographics, location of death and anatomic location of wounds were performed. RESULTS: Of 8,527 pediatric firearm mortalities identified, 4,728 were homicides, 3,180 were suicides and 619 were unintentional injuries. Suicide victims were most likely to be dead on scene and >90% of suicide victims suffered head/neck injuries. For victims of homicide, younger children were more likely to die on scene (61% vs 44% p < 0.001). The pattern of injury in homicides differed for younger children compared to adolescents, with younger children with more head/neck injuries and older children more thoracic, thoracoabdominal, abdominal, and junctional injuries. In both age groups, children with extremity, abdominal and thoracoabdominal injuries were more likely to die later in the emergency department or inpatient setting. CONCLUSIONS: Wounding patterns across pediatric firearm mortalities in the U.S. vary by age and intent. The majority of pediatric firearm deaths were due to head/neck injuries. Children with homicide and unintentional deaths had more wounding pattern variation, including more injuries to the thorax and abdomen, and a much lower rate of dead-on scene than suicide victims. Our study of wounding patterns among U.S. children killed by firearms highlights the complexity of these injuries and offers opportunities for tailored public health strategies across varying vulnerable pediatric populations.

Altered baseline and amphetamine-mediated behavioral profiles in dopamine transporter Cre (DAT-Ires-Cre) mice compared to tyrosine hydroxylase Cre (TH-Cre) mice.

RATIONALE: Transgenic mouse lines expressing Cre-recombinase under the regulation of either dopamine transporter (DAT) or tyrosine hydroxylase (TH) promoters are commonly used to study the dopamine (DA) system. While use of the TH promoter appears to have less liability to changes in native gene expression, transgene insertion in the DAT locus results in reduced DAT expression and function. This confound is sometimes overlooked in genetically targeted behavioral experiments. OBJECTIVES: We sought to evaluate the suitability of DAT-Ires-Cre and TH-Cre transgenic lines for behavioral pharmacology experiments with DA agonists. We hypothesized that DAT-Ires-Cre expression would impact DAT-mediated behaviors, but no impact of TH-Cre expression would be observed. METHODS: DAT-Ires-Cre and TH-Cre mice bred on mixed 129S6/C57BL/6 and pure C57BL/6 backgrounds were evaluated for novelty-induced, baseline, and amphetamine (AMPH)-induced locomotion, and for AMPH and D1 agonist (SKF-38393)-induced preservative behaviors. RESULTS: DAT-Ires-Cre mice on both mixed 129S6/C57BL/6 and pure C57BL/6 backgrounds displayed increased novelty-induced activity and decreased AMPH-induced locomotion, with mixed results for AMPH-induced stereotypy. TH-Cre mice on both backgrounds showed typical baseline activity and AMPH-induced stereotypy, with a difference in AMPH-induced locomotion observed only on the mixed background. Both transgenic lines displayed unaltered SKF-38393-induced grooming behavior. CONCLUSIONS: Our findings indicate that the DAT-Ires-Cre transgenic line may lead to confounds for experiments that are dependent on DAT expression. The TH-Cre transgenic line studied here may be a more useful option, depending on background strain, because of its lack of baseline and drug-induced phenotypes. These data highlight the importance of appropriate controls in studies employing transgenic mice.