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- Griffiths, B S, et al.
(författare)
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Ecosystem response of pasture soil communities to fumigation-induced microbial diversity reductions: an examination of the biodiversity-ecosystem function relationship
- 2000
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Ingår i: Oikos. - : Wiley. - 1600-0706 .- 0030-1299. ; 90:2, s. 279-294
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Tidskriftsartikel (refereegranskat)abstract
- A technique based on progressive fumigation was used to reduce soil microbial biodiversity, and the effects of such reductions upon the stability of key soil processes were measured. Mineral soil samples from a grassland were fumigated with chloroform for up to 24 h and then incubated for 5 months to allow recolonisation by surviving organisms. The diversity of cultivable and non-cultivable bacteria, protozoa and nematodes was progressively reduced by increasing fumigation times, as was the number of trophic groups, phyla within trophic groups, and taxa within phyla. Total microbial biomass was similar within fumigated soils, but lower than for unfumigated soil. There was no direct relationship between biodiversity and function. Some broad-scale functional parameters increased as biodiversity decreased, e.g. thymidine incorporation, growth on added nutrients, and the decomposition rate of plant residues. Other more specific parameters decreased as biodiversity decreased, e.g. nitrification, denitrification and methane oxidation. Thus specific Functional parameters may be a more sensitive indicator of environmental change than general parameters. Although fumigation reduced soil microbial biodiversity, there was evidence to suggest that it selected for organisms with particular physiological characteristics. The consequences of this for interpreting biodiversity - function relationships are discussed. The stability of the resulting communities to perturbation was further examined by imposing a transient (brief healing to 40 degrees C) or a persistent (addition of CuSO4) stress. Decomposition of grass residues was determined on three occasions after such perturbations. The soils clearly demonstrated resilience to the transient stress; decomposition rates were initially depressed by the stress and recovered over time. Resilience was reduced in the soils with decreasing biodiversity. Soils were not resilient to the persistent stress, there was no recovery in decomposition rate over time, but the soils with the highest biodiversity were more resistant to the stress than soils with impaired biodiversity. The study of functional stability under applied perturbation is a powerful means of examining the effects of biodiversity.
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| 2. |
- Bernsen, Monique R, et al.
(författare)
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Heparan sulphate epitope-expression is associated with the inflammatory response in metastatic malignant melanoma
- 2003
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Ingår i: Cancer Immunology and Immunotherapy. - : Springer Science and Business Media LLC. - 0340-7004 .- 1432-0851. ; 52:12, s. 780-783
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulphate (HS) represents a heterogeneous class of molecules on cell membranes and extracellular matrices. These molecules are involved in a variety of biological processes, including immune responses, through their binding and functional modulation of proteins. Recently a panel of HS-epitope-specific, human single chain antibodies have been generated by phage display, facilitating analysis of the structural heterogeneity of HS in relation to pathological conditions. In a pilot study a heterogeneous staining pattern in melanoma metastases was observed with one of the clones (EW4G1). Using a double-staining technique, the expression of this epitope was studied in 12 metastatic melanoma lesions in relation to the presence of a CD3 + cell infiltrate. Different staining patterns with EW4G1 were observed in the different lesions. The different staining patterns were associated with the presence and pattern of inflammation with CD3+ cells. A pronounced staining pattern of blood vessels with EW4G1 was associated with a more or less brisk presence of CD3+ cells, while a pronounced staining of tumour cells or tumour cell matrix or absence of staining with EW4G1 was associated with absence of CD3+ cells. These results suggest a dualistic role for HS in the recruitment and intratumoural migration of CD3+ cells, depending on the location of expression of its epitope recognized by EW4G1. Further characterization of the structural diversity of HS and its function in T-cell recruitment and migration is therefore warranted, since detailed understanding of this relation may provide new targets for therapeutic intervention, such that better homing and migration of T cells (in)to tumours might be achieved in immunologically based treatment strategies.
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| 3. |
- Håkansson, Annika, 1962-, et al.
(författare)
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On the effect of biochemotherapy in metastatic malignant melanoma : An immunopathological evaluation
- 2003
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Ingår i: Melanoma research. - : Ovid Technologies (Wolters Kluwer Health). - 0960-8931 .- 1473-5636. ; 13:4, s. 401-407
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Tidskriftsartikel (refereegranskat)abstract
- Although immunotherapy and biochemotherapy have shown promise, producing a subset of durable responses, for the majority of patients with metastatic melanoma the prognosis is still poor. Therefore there is a great need for predictive tests to identify patients with a high probability of responding. Furthermore, there is also a need for a better understanding of the mechanisms of action during treatment in order to be able to monitor the relevant antitumour reactivity during treatment and to optimize the efficacy of future immunotherapy and biochemotherapy. In the present study histopathological regression criteria were used to study the efficacy of biochemotherapy. Thirty-two patients with metastatic malignant melanoma (18 with regional disease and 14 with systemic disease) were treated with biochemotherapy (cisplatin 30 mg/m2 intravenously on days 1-3, dacarbazine 250 mg/m2 intravenously on days 1-3 and interferon-a2b 10 million IU subcutaneously 3 days a week, every 28 days). Pre-treatment fine needle aspirates were obtained from metastases to analyse the number of tumour-infiltrating CD4+ lymphocytes. Therapeutic efficacy was evaluated in metastases resected after treatment using histopathological criteria of tumour regression. Comparisons were also made with metastases from 17 untreated patients, all with regional disease. Regressive changes of 25% or more (of the section area) were found in two of the 17 untreated patients with regional disease compared with 13 of the 18 patients with regional disease and 10 of the 14 patients with systemic disease after biochemotherapy. Fifty per cent of the patients with regional disease showed a high degree of regressive changes (75-100% of the section area) after biochemotherapy. These results demonstrate the occurrence of an antitumour reactivity in the majority of patients. Patients with extensive regressive changes in 75-100% of the analysed biopsies were also found to have a longer overall survival (P = 0.019). In patients with regional disease there was a close correlation between a larger number of CD4+ lymphocytes pre-treatment and a higher degree of regressive changes post-treatment (P < 0.05). Thus, immunohistochemical analysis of tumour biopsies shortly after treatment seems to be a good surrogate endpoint This technique also allows detailed analysis of antitumour reactivity and escape mechanisms. ⌐ 2003 Lippincott Williams & Wilkins.
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