1. Division of Histology and Embryology, Department of Human Morphology and Embryology, Wroclaw Medical University, 50‑368 Wroclaw, Poland
2. Department of Thoracic Surgery, Wroclaw Medical University, 53‑439 Wroclaw, Poland
3. Department of Ultrastructural Research, Wroclaw Medical University, 50‑368 Wroclaw, Poland