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- Bidleman, TF, et al.
(författare)
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Chiral pesticides as tracers of air-surface exchange
- 1998
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Ingår i: Environmental Pollution. - 0269-7491 .- 1873-6424. ; 102:1, s. 43-49
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Tidskriftsartikel (refereegranskat)abstract
- The enantiomers of chiral pesticides are selectively broken down in soil and water to yield residues and metabolites, which are non-racemic. The distinctive enantiomer signatures of residues are preserved upon volatilization, providing site-specific tracers for air-soil and air-water exchange. Applications of enantiomeric tracers include distinguishing the atmospheric transport of freshly applied pesticides from those which are 'recycled' from lakes, oceans and soil, and investigating biotic vs abiotic degradation pathways. Examples are given of using pesticide enantiomers to follow volatilization from the Great Lakes and arctic waters and as indicators of pesticide emissions from agricultural soils.
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| 3. |
- Falconer, C, et al.
(författare)
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Changes in paraurethral connective tissue at menopause are counteracted by estrogen
- 1996
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Ingår i: Maturitas. - 0378-5122. ; 24:3, s. 197-204
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study whether the transition to menopause is accompanied by changes in the paraurethral connective tissue and if these changes are modified by estrogen replacement therapy.STUDY DESIGN: Biopsies were obtained from the paraurethral tissue from 34 women; 12 menstruating, 14 postmenopausal without estrogen treatment, and 8 with estrogen treatment. Collagen concentration and collagen extractability by pepsin digestion were measured. Proteoglycan composition and concentration were analysed using Alcian blue. The mRNA levels for collagen I and III, the small proteoglycans (PGS) decorin and biglycan, and the large proteoglycan versican, were estimated.RESULTS: The paraurethral biopsies consisted of fibrous connective tissue, with collagen fibers as dominating structure. Several proteoglycans were identified; versican, heparansulphate proteoglycans, biglycan and decorin. The small proteoglycan decorin represented 85% of all proteoglycans. The collagen concentration was almost doubled in postmenopausal biopsies compared to premenopausal. The collagen fibril organization was also changed with higher cross-linking after menopause whereas the amount and the composition of the proteoglycans were unchanged. The proteoglycan/collagen ratio was significantly decreased. Estrogen replacement therapy resulted in decreased collagen concentration, decreased cross-linking of the collagen and reversal of the PGS/collagen ratio to almost premenopausal level. The therapy resulted in increased levels of mRNA for collagen I and III which suggests that the changes are due to an increased turnover.CONCLUSION: The decrease in estrogen levels at menopause results in a connective tissue with different qualities after menopause. Estrogen replacement therapy tends to restore the metabolism of the genitourinary connective tissue to premenopausal conditions.
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| 5. |
- Falconer, C, et al.
(författare)
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Paraurethral connective tissue in stress-incontinent women after menopause
- 1998
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - 0001-6349. ; 77:1, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study whether stress urinary incontinence after menopause is correlated to changes in the paraurethral connective tissue ultrastructure and metabolism.METHODS: Transvaginal biopsies were obtained from the paraurethral connective tissue in stress urinary incontinent women after menopause with and without estrogen replacement therapy, and from comparable controls. All the stress-incontinent women underwent urodynamic investigation. In the specimens, collagen concentration, measured as hydroxyproline, and the degree of extractability by pepsin digestion, were quantified. Proteoglycan composition and concentration were analyzed using Alcian Blue precipitation, followed by electro-phoretic separation and quantification. Using Northern blots, mRNA levels for the collagens I and III, the small proteoglycans decorin and biglycan, and the large proteoglycan versican, were quantified. Collagen structure was examined with transmission electron microscopy, and the diameters of collagen fibrils were analyzed with an interactive image analysis system (IBAS, Zeiss/Kontron).RESULTS: No significant difference in paraurethral connective tissue biochemistry or ultrastructure was registered between women with stress incontinence and controls. Estrogen replacement therapy resulted in a lower collagen concentration both between the controls (p = 0.02) and between the incontinent women (0.02). In the women with stress incontinence also the extractability by pepsin digestion was higher in the group with estrogen treatment (p = 0.004), indicating a decrease in cross-linking. The proteoglycan/collagen ratio was higher in the control group with estrogen treatment compared to untreated (p = 0.02), but no difference was found between estrogen treated and untreated incontinent women. The median collagen fibril diameter was 15% larger in the incontinent group of women without estrogen therapy compared to the control group and 5% larger when comparing the incontinent group on estrogen replacement therapy to the corresponding control group.CONCLUSION: The extracellular matrix of paraurethral connective tissue in stress urinary incontinent women after menopause reacted differently to estrogen replacement therapy compared to continent controls. In contrast to incontinent women of fertile age no major changes in collagen metabolism were found in stress urinary incontinent women after menopause.
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