['SIDESTREAM', 'SMOKE', 'STUDY', 'IN’', 'RATS', 'a', 'FIG.6.', 'Low-power', 'view', 'of', 'a', 'transverse', 'section', 'of', 'ihe', 'rat:nusal', 'pussages..', 'immediutely.', 'caudil', 'woihe', 'INCISeT', 'leelh,', 'the', 'change', '‘show', 'niin', 'Figs.', '7-andia:', 'H&E:', 'original', 'magnification:', 'as,', 'There', 'were', 'no', 'significant', 'differences', 'between', 'the', 'groups', 'for', 'any.', 'clinicall', 'pathology', 'parameters', 'at', 'either', 'of', 'the', 'nec-', 'ropsies,', ',', 'THere', 'were', 'no', 'treatment-related', 'gross;', 'observations', 'at’', 'either', 'necropsy;', 'there:', 'were', 'no', 'differences', 'in', 'organ', 'Weights:,', 'He', 'istopathology', 'In', 'the', 'Nasal', 'Iisection', '(transverse.', 'immediately', 'caudal', 'to:', 'the', 'incisor', 'teeth),', 'there', 'was', 'chronic', 'active', 'ayflaammation,', 'in', 'the', 'high-exposure', 'groups', 'only.', 'This', 'change', 'mainly', 'involved', 'the', 'dorsal', 'nasal', 'conchae', '(nasoturbinates)', 'and', 'the', 'adjacent', 'wail', 'of', 'ihe', 'middie', 'meatus', '(Fig.', '6).', 'Inthis', 'lesion,', 'the', 'inflam-', 'matory', 'infiltrate', 'consisted', 'of', 'lymphohistiocytic', 'cells', 'admixedi', ' ', '137', 'The', 'arrow', 'marks', 'the', 'position', 'of', 'with', 'smalllnumbers', 'of', 'poly', 'morphonuclear', 'leukocytes.', 'Fig-', 'ure', '7', 'shows.a', 'High-power', 'view', 'of', 'the', 'tip', 'of', 'a', 'nasal', 'concha:', 'from', 'a', 'typical', 'sam', 'animal:', 'Fig.', '8', 'shows', 'a', 'similar', 'region', 'from', 'a', 'typical', 'high-exposure-group:animal.', "Figure'9", 'shows', 'the', 'distributions', 'of', 'the', 'ditlerent', 'severities', 'of', 'this.change', 'for', 'the', 'four', 'groups.', 'The', 'distribution', 'ofthe', 'change', 'in', 'the', 'high-', 'exposure', 'group:', 'was', 'signiBcantly', 'different', 'from', 'that', 'in', 'the', 'other', 'groups:', 'tHere', 'were', 'no', 'such', 'significant', 'differences', 'at', 'the', 'low', 'or', 'medium', 'exposures,', 'The', 'above', 'lesion', 'was', 'typically', 'found', 'in', 'association', 'with.', 'and', 'in', 'the', 'same', 'anatomic', 'site', 'as.', 'epithelial', 'hyperplasia.', 'Ini', 'this.', 'tauer', 'change.', 'there', 'was', 'hypercellularity', 'and', 'thickening,', 'of', 'the', 'respiratory', 'epithelium', 'of', 'the', 'dorsal', 'nasal', 'conchae', 'and', 'the', 'adjacent', 'wall', 'of', 'the', 'middle', 'meatus,', 'Figure', '10', 'shows', 'tHe', 'SPE0T', 'T6202']