Fig. 2.

Haematoxylin-stained lung sections from Sprague–Dawley rats. Animals had been instilled intratracheally with (a) Sephadex (SDX, 5 mg/kg), (b) SDX (5 mg/kg) and 4-thiouridine (25 mg/kg), (c) NaCl (vehicle control) and (d) 4-thiouridine only (50 mg/kg). Sections (a) and (b) show the typical granulomas that were seen associated with partially degraded Sephadex beads, indicated with arrows marked SDX. In addition to macrophages, monocytes, eosinophils and occasional lymphocytes, the Sephadex-induced lesions often displayed multi-nucleated giant cells (macrophage polykaryons) with peripheral nuclei. One example is indicated with the arrow marked MGC.