Table 3.

Solutes identified by LC/MS

Solute Name or Mass (D)Colectomy/with ColonHemodialysis/ NormalDialytic Reduction Ratio
Colon-derived uremic solutes identified by analysis of chemical standards
    PCSa0.01110.25 ± 0.02
    α-N-phenylacetyl-l-glutamineb0.07910.73 ± 0.09
    ISb0.02230.31 ± 0.03
    indoxyl glucuronidec0.02e0.79 ± 0.06
    5-hydroxyindolecee0.83 ± 0.08
Colon-derived uremic solutes not identified by analysis of chemical standards
    201.0786a0.03e0.10 ± 0.26
    204.0092aee0.51 ± 0.15
    229.0043aee0.70 ± 0.07
    230.0689aee0.07 ± 0.10
    284.0813aeee
    284.0886aee0.77 ± 0.06
    301.1058aee0.32 ± 0.11
    301.1156aee0.83 ± 0.04
    306.0407aee0.81 ± 0.07
    306.0709aee0.82 ± 0.03
    325.0797aee0.81 ± 0.05
    334.1921ae230.18 ± 0.07
    376.1339a0.32e0.82 ± 0.03
    416.1321aee0.80 ± 0.04
    420.1599a0.26e0.82 ± 0.03
    474.1527ae40.62 ± 0.06
    641.3412aee0.73 ± 0.07
    169.0525bee0.42 ± 0.09
    229.0045bee0.71 ± 0.07
    244.0847bee0.26 ± 0.18
    275.0096b0.02e0.70 ± 0.06
    276.0302b0.05e0.79 ± 0.05
    101.0105c0.19e0.67 ± 0.06
    192.0552c0.21390.39 ± 0.25
    195.0529c0.02380.71 ± 0.07
    265.0949c0.06e0.79 ± 0.06
    283.0839c0.04e0.73 ± 0.20
    350.1870c0.03e0.85 ± 0.02
Colon-derived solutes that do not accumulate in uremia
    3-indolepropionic acidae1−0.07 ± 0.05
    129.0578b0.041−0.04 ± 0.08
Additional indole and phenyl compounds identified by analysis of chemical standards
    phenyl glucuronided0.15e0.80 ± 0.06
    cinnamoylglycined0.19140.22 ± 0.18
    HIPPd0.28270.60 ± 0.06
    indoleacetic acidd0.5750.48 ± 0.08
    2-hydroxybenzoic acid (salicylic acid)d0.6850.46 ± 0.24
    indolelactic acidd1.830.12 ± 0.09
    l-kynurenined2.020.44 ± 0.07
Found in higher concentration in patients without colons
    331.3233b2.920.30 ± 0.35
  • Mass values are for neutral compounds assuming monovalent ion detection by MS. Colectomy/with Colon, estimated ratio of average concentration in hemodialysis patients without colons relative to hemodialysis patients with colons; Hemodialysis/Normal, estimated ratio of average concentration in hemodialysis patients with colons relative to normal subjects; Dialytic Reduction Ratio, mean ± SD fractional reduction in plasma levels achieved by dialysis treatment in patients with colons. Levels were too low to estimate a reduction ratio for one solute.

  • Difference between patients with and without colons: asolute not detectable in patients without colons;

  • bP < 0.05;

  • cP < 0.10;

  • dP > 0.4.

  • eConcentrations were too low to be estimated in dialysis patients without colons (for Colectomy/with Colon) or in normal subjects (for Hemodialysis/Normal).