The papers of Drs. Lenz and Germann have broadened the spectrum of lesions of laboratory animals with interesting aspects that are valuable for routine work.

With her paper on the atrophy of chief and parietal cells of the gastric mucosa induced by retinoids, Dr. Lenz has drawn our attention to a previously unknown target organ of this substance group (1). Special emphasis should be given to the exemplary care with which she verified her statements and the special value she placed on carrying out all of her work with technical perfection. This led to a modification of the staining according to Schiebler and Behr (2). She describes a pattern of damage to the gastric mucosa which was previously unknown, even for other substance classes.

With his investigations on oropharyngeal granulomas and cartilage changes in the laryngeal area, Dr Germann has indicated spontaneous changes which previously received little attention. He identified these changes as the cause of unexpectedly high mortality rates in long-term studies with Fischer rats treated by gavage (3). In a comparison of 6 different rat strains, he also identified the Fischer rat as having a predisposition for these lesions (4). These results are of great importance for the planning and interpretation of long-term studies, which play an essential role in toxicologic pathology.

References:

1. Lenz B, Kuhn H, Niederhausen UB (1998) Gastric chief and parietal cell atrophy induced by a new synthetic retinoid in rats and dogs. Exp Toxic Pathol 50: 35-39
   
   
2. Lenz B, Frossard M. Modified Schiebler-Behr-Färbung zur besseren Differenzierung der Magenschleimhautzellen. F. Hoffmann-La Roche Ltd., Abteilung Toxikologie, CH-4070 Basel
   
   
3. Germann PG, Ockert D, Heinrichs M (1998) Pathology of the oropharyngeal cavity in six strains of rats: Predisposition of Fischer 344 rats for inflammatory and degenerative changes. Toxicol Pathol 26: 283-289
   
   
4. Germann PG, Ockert D, Tuch K (1995) Oropharyngeal granulomas and tracheal cartilage degeneration in Fischer-344 rats. Toxicol Pathol 23: 349-355

Zurich, October 10, 1998