RESUMO
This study was designed to examine the fibrogenic and carcinogenic potentials of three smelter slags (primary copper slag, secondary copper slag, and nickel slag) that have been used for a number of years as substitutes for sand in abrasive blasting operations. Seven groups of 85 male Fischer 344 rats (approximately 180 g) were used. Each group was given a single 20-mg dose of one of the following test materials via intratracheal instillation: primary copper slag, secondary copper slag, nickel slag, feldspar, Min-U-Sil, novaculite, or vehicle control. Chemical, particle size, and surface area analyses were performed for each test dust. Animals were weighed monthly, and ten animals per group were necropsied at the 6-, 12-, and 18-mo interim sacrifices. The terminal sacrifice was conducted at 22 mo. Hematoxylin and eosin stained histologic sections were prepared from designated formalin-fixed tissues collected at necropsy and examined microscopically. The pulmonary fibrogenic and carcinogenic potentials of the three smelter slags were compared histopathologically with feldspar, novaculite, Min-U-Sil, and vehicle controls. Only minimal to slight alveolar wall fibrosis was seen in the two copper slag groups, while the response seen with nickel slag was consistent with a foreign body reaction with minimal fibrosis seen in only an occasional animal. The major reaction seen in both the feldspar- and the novaculite-treated rats was a granulomatous inflammation with varying degrees of fibrosis associated with the granulomas. Significant numbers of primary lung tumors, principally adenocarcinomas and adenomas, were seen in the copper slag (p = 0.005 and p = 0.022 for the primary and secondary slags, respectively), in the feldspar (p = 0.007), in the novaculite (p less than 0.001), and in the Min-U-Sil (p less than 0.001) groups when compared to the vehicle control group. In addition, the Min-U-Sil and novaculite groups had significantly elevated pulmonary tumor proportions relative to the other treatments (p less than or equal to 0.002), with the Min-U-Sil being higher than the novaculite (p = 0.012). On the basis of the tumor incidence data, one must conclude that both copper slags tested in this study are carcinogenic to rats.
Assuntos
Poluentes Ocupacionais do Ar/toxicidade , Cobre/toxicidade , Neoplasias Pulmonares/induzido quimicamente , Níquel/toxicidade , Fibrose Pulmonar/induzido quimicamente , Animais , Poeira , Exposição Ambiental , Granuloma/induzido quimicamente , Granuloma/patologia , Neoplasias Pulmonares/patologia , Tamanho da Partícula , Fibrose Pulmonar/patologia , Ratos , Ratos Endogâmicos F344 , Coloração e Rotulagem , Propriedades de SuperfícieRESUMO
An Air Force veterinarian consulted with an Air Force endodontist concerning the fractured canine in a German shepherd sentry dog. Exposure of the pulp was evident and root canal therapy was initiated; general anesthesia was used. Problems were encountered in preparation of the canal because of its length. Conventional endodontic therapy was completed at a second appointment after custom instruments and filling materials were designed and constructed to compensate for the length of the canal. Successful conventional endodontic therapy was performed on a valuable military dog. Surgical intervention was avoided by designing custom-made materials. Endodontic principles were successfully applied to serve as definitive treatment in veterinary medicine.