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- Lundström, Ulla, et al.
(författare)
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Advances in understanding the podzolization process resulting from a multidisciplinary study of three coniferous forest soils in the Nordic Countries
- 2000
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Ingår i: Geoderma. - 0016-7061 .- 1872-6259. ; 94:04-feb, s. 335-353
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Tidskriftsartikel (refereegranskat)abstract
- Geochemical, mineralogical, micromorphological, microbiological, hydrochemical and hpdrological joint investigations were performed at two coniferous podzolic sites in the north of Sweden and at one in the south of Finland. Mycorrhizal fungi were found to create numerous pens (3-10-mu m diameter) in many weatherable mineral grains in the eluvial (E) horizon. During the growing season, identified low molecular weight (LMW) organic acids such as citric, shikimic, oxalic and fumaric acids comprised 0.5-5% of the DOC and 0.5-15% of the total acidity in soil solutions. Between 20% and 40% of the dissolved Al was bound to the identified LMW organic acids. Mineral dissolution via complexing LMW acids, probably exuded in part by the mycorrhiza hyphae, is likely to be a major weathering process in podzols. We found no evidence for a decreasing C/metal ratio of the migrating organo-metal complexes that could explain the precipitation of secondary Fe and AL in the illuvial (B) horizon. Instead, microbial degradation of organic ligands resulting in the release of ionic,Al and Fe to the soil solution may he an important process facilitating the formation of solid Al-SI-OH and Fe-OH phases in the podzol B horizon. However, within the B horizon transport as proto-imogilite (PI) sols might be possible. In the B horizon, the extractable,Al and Fe was predominantly inorganic. The large specific surface area (SSA) removable by oxalate extraction, the high point of zero charge salt effect (PZSE), the low cation exchange capacity (CEC) and the high sulphate exchange capacity (SEC), painted to the presence of short-range ordered variable charge phases. Imogolite type material (ITM) was indeed identified in all B horizons by IR spectroscopy and crystalline imogolite was found in the deep B horizon of one profile. Mossbauer spectroscopy indicated that Fe in the form of ferrihydrite was formed by intergrowth with an Al-Si-OH phase. The high amounts of Fe and Al transported from the O to the E horizon indicate that there could be an upward transport of these elements before they are leached to the B horizon. We hypothesize that the LMW Al complexes an transported by hyphae to the mor (O) layer, partly released and subsequently complexed by high molecular weight (HMW) acids.
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| 2. |
- Nord, M., et al.
(författare)
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Decreased serum and bronchoalveolar lavage levels of Clara cell secretory protein (CC16) is associated with bronchiolitis obliterans syndrome and airway neutrophilia in lung transplant recipients
- 2002
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Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337. ; 73:8, s. 1264-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The major hinderance for long-term survival after lung transplantation is chronic rejection in the form of bronchiolitis obliterans syndrome (BOS). BOS is a fibrosing process in the small airways causing irreversible airway obstruction. BOS is associated with increased oxidative burden and activation of inflammatory and growth-stimulating mediators. The Clara cell secretory protein (CCSP or CC16) is a secreted differentiation marker for the bronchiolar epithelium with both antioxidative and antiinflammatory/immmunomodulatory properties. We asked whether this molecule could have a role in the development of BOS. METHODS: Serum and bronchoalveolar lavage (BAL) fluid samples were collected from 22 consecutive lung transplant recipients, the majority (19) was followed for 2 years. Six patients developed BOS. CCSP in serum was measured in 162 samples from 19 patients with an ELISA method, and CCSP in 191 BAL samples from 22 patients with quantitative Western blot. RESULTS: CCSP in both serum and BAL was significantly lower in BOS compared with acute rejection or no rejection. After the first postoperative month, serum and BAL CCSP levels were consistently lower in the patients who developed BOS than in those who did not. The percentage of neutrophils in BAL correlated negatively with CCSP in BAL. CONCLUSIONS: Levels of CCSP in serum and BAL is lowered in BOS. Serum CCSP could have a potential as an early marker for BOS. The correlation between decreased CCSP and increased neutrophils in BAL suggests a loss of local airway defense capacity in BOS.
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| 4. |
- Seymour, M. L., et al.
(författare)
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Leukotriene and prostanoid pathway enzymes in bronchial biopsies of seasonal allergic asthmatics
- 2001
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Ingår i: Am J Respir Crit Care Med. - 1073-449X. ; 164:11, s. 2051-6
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Tidskriftsartikel (refereegranskat)abstract
- Cysteinyl-leukotrienes and prostaglandin D2 generated by the 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways, respectively, cause bronchoconstriction, leukocyte recruitment, and bronchial hyperresponsiveness in asthma. We characterized the cellular expression of 5-LO and COX enzymes using immunohistochemistry on bronchial biopsies from 12 allergic asthmatic patients before and during seasonal exposure to birch pollen. Bronchial responsiveness (p = 0.004) and symptoms (p < 0.005) increased and peak expiratory flow (PEF; p < or = 0.02) decreased in the pollen season. In-season biopsies had 2-fold more cells immunostaining for 5-LO (p = 0.02), 5-LO-activating protein (FLAP; p = 0.04), and leukotriene (LT)A4 hydrolase (p = 0.05), and 4-fold more for the terminal enzyme for cysteinyl-leukotriene synthesis, LTC4 synthase (p = 0.02). Immunostaining for COX-1, COX-2, and PGD2 synthase was unchanged. Increased staining for LTC4 synthase was due to increased eosinophils (p = 0.035) and an increased proportion of eosinophils expressing the enzyme (p = 0.047). Macrophages also increased (p = 0.019), but mast cells and T-lymphocyte subsets were unchanged. Inverse correlations between PEF and 5-LO(+) cell counts link increased expression of 5-LO pathway enzymes in eosinophils and macrophages within the bronchial mucosa to deterioration of lung function during seasonal allergen exposure.
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