| 1. |
- Baldetorp, Bo, et al.
(författare)
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Reproducibility in DNA flow cytometric analysis of breast cancer: comparison of 12 laboratories' results for 67 sample homogenates
- 1995
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Ingår i: Cytometry. - : Wiley. - 0196-4763 .- 1097-0320. ; 22:2, s. 115-127
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Tidskriftsartikel (refereegranskat)abstract
- Flow cytometric (FCM) DNA analysis yields information on ploidy status and the S-phase fraction (SPF), variables of prognostic importance in breast cancer. The clinical value of the SPF is currently being evaluated in prospective randomized trials. The widespread use of FCM DNA analysis emphasizes the importance of reproducibility (both intra- and interlaboratory). In this study, 67 nuclear suspensions of breast cancer samples were analyzed by 12 laboratories routinely performing FCM DNA analysis in breast cancer. No general guidelines were imposed; each laboratory used its own standard protocols. For DNA ploidy status (diploid vs. non-diploid), agreement was complete for 79% (53/67) of the samples, compared with 64% (43/67) of samples when tetraploidy was considered [i.e., euploid (diploid+tetraploid) vs. aneuploid (the remaining non-diploid)]. For the SPF, pairwise comparison of the results of all 12 laboratories yielded a mean Spearman's rank correlation of 0.78 (range: 0.54-0.93). For those 39 samples being categorized in low or high SPF by all laboratories, all agreed in 14 samples (36%). Similar patterns were obtained with kappa measures, agreement being good for ploidy status (diploid vs. non-diploid; overall kappa = 0.87 and 0.74 for euploid vs. aneuploid), but moderate for the SPF [overall kappa = 0.47 (for low SPF vs. high SPF vs. "no SPF reported")]. Discrepancies were chiefly attributable to differences in the categorization of the S-phase values, rather than in FCM procedures, other critical differences being in the detection and interpretation of near-diploid and small non-diploid cell populations, the definition of tetraploidy, and the choice and execution of the method used for S-phase estimation. Based on the observations of this study, detailed guidelines for FCM analysis and interpretation of data are proposed in the Appendix. Some issues remain, however, e.g., to standardize a method for S-phase calculation and tetraploid definition.
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| 4. |
- Sandström, Monica, 1946-, et al.
(författare)
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Skin symptoms among VDT workers and electromagnetic-fields : a case-referent study
- 1995
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Ingår i: Indoor Air. - : John Wiley & Sons. - 0905-6947 .- 1600-0668. ; 5:1, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Th is case referent study is a part of the Office illness Project in Northern Sweden. From a questionnaire study among 5986 office workers, 75 VDT workers with self-reported facial skin symptoms and the same number of referents were selected for this study. The environmental electric and magnetic fields in the office as well as electromagnetic fields associated with the VDT at the workplace were measured, The aim of this part of the project was to explore the role of the measured electromagnetic parameters in relation to skin symptoms. For most of the measured parameters there was no difference between cases and referents. However, more cases than referents were found in the highest exposure group for two of the measured parameters. Fm the background electric field in the mom the relative risk in terms of crude odds ratio (OR) was 3.0 (95% CI: 1.2-7.2) for the high exposed group (greater than or equal to 31 V/m) compared with the lowest group (less than or equal to 10 V/m). The same comparison for the magnetic field in the ELF-range (greater than or equal to 0.30 mu T vs less than or equal to 0.145 mu T) in front of the VDT gave an OR of 2.7(95% CI: 1.0-6.9).
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