| 1. |
- Backman, Anders, et al.
(författare)
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Evaluation of an extended diagnostic PCR assay for detection and verification of the common causes of bacterial meningitis in CSF and other biological samples
- 1999
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Ingår i: Molecular and Cellular Probes. - : Elsevier BV. - 0890-8508 .- 1096-1194. ; 13:1, s. 49-60
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Tidskriftsartikel (refereegranskat)abstract
- A seminested polymerase chain reaction (PCR)-based diagnostic assay was evaluated for detection and verification of Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, Steptococcus agalactiae and Listeria monocytogenes in cerebrospinal fluid (CSF) and other biological samples. A general bacterial amplicon from the 16S rRNA gene was amplified in a first step, and species-specific regions in a second. The detection level was 4 fg DNA/reaction, corresponding to about one bacterial genome per reaction tube. Sample preparations (Dynabeads DNA DIRECT kit) were assayed from 140 bacterial strains suspended in saline. In CSF the detection level for bacteria was 103 CFU ml-1 for N. meningitidis, H. influenzae and S. pneumoniae, 104 CFU ml-1 for Escherichia coli and 105 CFU ml-1 for S. agalactiae and L. monocytogenes. The detection levels for these bacteria were the same in the other tested biological samples, like blood with or without culture media. Clinical CSF samples were evaluated from 71 patients with proven bacterial meningitis, as were 61 CSF samples from individuals without bacterial meningitis. The diagnostic sensitivity of the assay in detecting bacteria in general was 0.97, and for the specific species in the clinical CSF samples 0.87-0.94. The specificity was 1.0 for detecting bacteria in general. Some cross-reactions were noted within the streptococcus group. The PCR results were verified by banding patterns of HaeIII digested PCR products.
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| 2. |
- Taulavuori, E, et al.
(författare)
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Long-term exposure to enhanced ultraviolet-B radiation in the sub-arctic does not cause oxidative stress in Vaccinium myrtillus
- 1998
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Ingår i: New Phytologist. - : Wiley. - 1469-8137 .- 0028-646X. ; 140:4, s. 691-697
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to assess whether or not oxidative stress had developed in a dwarf shrub bilberry (Vaccinium myrtillus L.) under long-term exposure to enhanced levels of ultraviolet-B (u.v.-B) radiation. The bilberry plants were exposed to increased u.v.-B representing a 15 stratospheric ozone depletion for seven full growing seasons (19911997) at Abisko, Swedish Lapland (68N). The oxidative stress was assessed on leaves and stems by analysing ascorbate and glutathione concentrations, and activities of the closely related enzymes ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2). The affects of autumnal leaf senescence and stem cold hardening on these variables were also considered. The results showed that the treatment caused scarcely any response in the studied variables, indicating that u.v.-B flux representing a 15 ozone depletion under clear sky conditions is not sufficient to cause oxidative stress in the bilberry. It is suggested that no strain was evoked since adaptation was possible under such u.v.-B increases. The studied variables did, however, respond significantly to leaf senescence and especially to stem cold hardening.
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