https://ntp.niehs.nih.gov/go/19298

Lesion counts and average severity grades for Male Rats

  3/16/2005  Lesion counts and average serverity grades for Male Rats in 
                          METHYL ISOBUTYL KETONE
  Dose                         CONTROL      450 PPM      900 PPM      1800 PPM 
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  Kidney Renal        counts    0/50          3/50        4/50         6/50
  Tubule Hyperplasia
  (Step Sections)     average
                      severity  NA            2.0         2.0          2.3
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  Kidney Renal 
  Tubule Hyperplasia  counts   1/50           14/50      7/50          21/50
  (Step Sections and 
  Original Sections)
                      average
                      severity  2.0            2.9        2.0           2.5