Detection and analysis of tracers in experimental drowning

Area of Science:

• Forensic Pathology
• Toxicology
• Cell Biology

Background:

• Drowning is a significant cause of accidental death, but its precise cellular and physiological mechanisms remain incompletely understood.
• Investigating the passage of immersion fluid components across biological barriers is crucial for elucidating drowning pathophysiology.

Purpose of the Study:

• To elucidate the mechanisms by which immersion fluid components traverse the air-blood barrier during drowning.
• To evaluate the utility of tracer particles in understanding the systemic dissemination of immersion fluid in drowning.

Main Methods:

• Animal models were utilized with latex and gold tracers of specific sizes and concentrations.
• Tracers were detected using fluorescence and electron microscopy in various organs (lungs, kidneys, lymph nodes).
• X-ray microanalysis with a transmission scanning electron microscope was employed for further tracer analysis.

Main Results:

• Small diameter tracers were observed to penetrate intercellular gaps in the alveolar epithelium.
• Larger tracers were internalized by epithelial and endothelial cells via active pinocytosis, crossing the air-blood barrier.
• Tracers were detected in organs of the systemic circulation, originating from the immersion fluid.

Conclusions:

• The study demonstrates that tracers from immersion fluid can cross the air-blood barrier through both paracellular and transcellular pathways.
• Detection of these tracers in systemic organs provides insights into drowning pathophysiology.
• This method shows potential for aiding in the diagnosis of drowning in specific cases.