. Author manuscript; available in PMC: 2019 Feb 26.

Published in final edited form as: Toxicology. 2018 Jul 25;409:24–32. doi: 10.1016/j.tox.2018.07.007

Table 4.

Lung histopathological findings including number of microscopically observed lung lesions at 30 weeks post-initiation with MCA or CO in A/J mice exposed to GMAW-MS fume or filtered air by whole-body inhalation.

	n	Foreign Material^{^}	Hyperplasia Severity^{^}	Hyperplasia^#	Adenoma^#	Adenocarcinoma^#	Total Lesions^#
CO/air	15	^–	0.1 ± 0.05	0.2 ± 0.11 (3)	0.07 ± 0.07 (1)	^–	0.27 ± 0.12 (4)
CO/GMAW-MS	28	0.91 ± 0.05^**	0.02 ± 0.02	0.07 ± 0.05 (2)	0.07 ± 0.05 (2)	^–	0.14 ± 0.07 (4)
MCA/air	29	0.02 ± 0.02	1.79 ± 0.18^**	2.93 ± 0.34 (85)^**	0.41 ± 0.13 (12)^ǂ	^–	3.34 ± 0.34 (97)^**
MCA/GMAW-MS	28	0.96 ± 0.02^*	2.55 ± 0.16^*	7.11 ± 0.64 (199)^*	2.67 ± 0.36 (75)^*	0.07 ± 0.05 (2)	9.86 ± 0.86 (276)^*

^–

indicates no findings.

^{^}

Severity scores are the averages of the left and right lung lobes and are presented as means ± standard error. Foreign material refers to presence of presumptive GMAW-MS fume (brown-black pigment) in the lungs. Severity was scored as 1 = minimal, 2 = mild, 3 = moderate, 4 = marked.

Hyperplasias, adenomas, and adenocarcinomas are presented as mean ± standard error with total lesion number in parenthesis.

Abbreviations: GMAW-MS – gas metal arc welding – mild steel; MCA – 3 – methylcholanthrene; CO – corn oil.

p < 0.0001 compared to MCA/air

^**

p < 0.0001 compared to CO/air

^ǂ

p < 0.02 compared to CO/air.