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Subject: cystic/sputum/iron

   
   Chest 1998 Sep;114(3):814-9
   
Increased iron and ferritin content of sputum from patients with cystic
fibrosis or chronic bronchitis.

    Stites SW, Walters B, O'Brien-Ladner AR, Bailey K, Wesselius LJ
    
   Division of Pulmonary and Critical Care Medicine, University of Kansas
   School of Medicine, Kansas City, USA.
   
   PURPOSE: Extracellular free iron, or iron bound to ferritin, may
   promote oxidative injury and bacterial growth in airways of patients
   with chronic airway inflammation due to cystic fibrosis (CF) or
   chronic bronchitis (CB). In this study, we assessed sputum content of
   total iron, ferritin, and transferrin in patients with CF or CB as
   well as sputum from normal subjects with acute airway inflammation
   caused by viral upper respiratory tract infections (URTIs). METHODS:
   Spontaneously produced sputum was obtained from 33 subjects, including
   10 subjects with CF, 18 subjects with CB (10 acute exacerbations, 8
   with stable CB), and 5 subjects with URTIs (control subjects). After
   lysing and dilution, total iron concentrations were determined by
   controlled coulometry, ferritin was measured by radioimmunoassay, and
   transferrin was measured by enzyme-linked immunosorbent assay.
   RESULTS: Iron was not present in detectable amounts in control
   sputums, but ferritin was present (6+/-2 ng/mg protein, mean+/-SE), as
   was transferrin (2.37+/-0.44 microg/mg). Compared with control
   subjects, concentrations of iron in sputum were increased in patient
   groups with higher amounts in CF patients (242+/-47 ng/mg, p<0.01)
   than CB patients with acute exacerbations or patients with stable CB
   (98+/-50 and 42+/-12 ng/mg, p<0.05 for both). Ferritin content of
   sputum was also increased in each group, with CF patients (113+/-22
   ng/mg, p<0.001) higher than CB patients (acute, 45+/-10 ng/mg; stable,
   87+/-24 ng/mg; p<0.01 for both). Compared with control subjects,
   sputum transferrin was decreased in CF patients (1.09+/-0.40
   microg/mg, p<0.05), but not CB patients. CONCLUSIONS: These findings
   indicate there are increased airway concentrations of total iron and
   ferritin-bound iron in patients with CB and, to a greater extent, in
   patients with CF. Particularly in CF patients who also demonstrated
   decreased airway concentrations of transferrin, ferritin-bound iron in
   airways may promote oxidative injury and enhance bacterial growth.
   
   PMID: 9743172, UI: 98414104
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Subject: pseudomonas/iron/cf

   
   Infect Immun 1993 Feb;61(2):656-62
   
Ability of Pseudomonas pseudomallei malleobactin to acquire transferrin-bound,
lactoferrin-bound, and cell-derived iron.

    Yang H, Kooi CD, Sokol PA
    
   Department of Microbiology and Infectious Diseases, University of
   Calgary Health Sciences Centre, Alberta, Canada.
   
   The ability of malleobactin to mobilize iron from transferrin and
   lactoferrin was examined in an equilibrium dialysis assay in the
   absence of bacteria. Malleobactin was capable of removing iron from
   both transferrin and lactoferrin at pH values of 7.4, 6.0, and 5.0.
   However, the levels of iron mobilization were greater for transferrin
   than for lactoferrin at all the pH values used in the assay. The
   ability of Pseudomonas pseudomallei to acquire iron from 30%
   iron-saturated transferrin and K562 human erythroleukemic cells was
   compared in parallel cultures as described previously (J. H. Brock, P.
   H. Williams, J. Liceaga, and K. G. Woldridge, Infect. Immun.
   59:3185-3190, 1991). P. pseudomallei U7 tended to acquire iron from
   transferrin. In contrast, P. aeruginosa PAO and P. cepacia Pc275C
   acquired iron from both sources. P. cepacia H1721, which does not
   produce detectable siderophores, but can utilize malleobactin,
   pyochelin, and azurechelin as iron sources, was used in a similar
   experiment. Addition of malleobactin resulted in iron uptake only from
   transferrin, whereas pyochelin and azurechelin promoted iron uptake
   from both sources. When the siderophores were incubated with K562
   cells alone, malleobactin was less efficient at removing iron from
   cells than pyochelin and azurechelin. It was also determined that
   malleobactin was less effective in binding to or entering cells than
   pyochelin and azurechelin. These results suggest that malleobactin can
   acquire iron more effectively from host proteins than from cellular
   sources. Pyochelin and azurechelin can acquire cell-derived iron in
   addition to iron bound to host proteins.
   
   PMID: 7678587, UI: 93138791
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