Publications by authors named "Kaja K Aas"

4 Publications

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Comparison of blood RNA isolation methods from samples stabilized in Tempus tubes and stored at a large human biobank.

BMC Res Notes 2016 Sep 1;9(1):430. Epub 2016 Sep 1.

Norwegian Institute of Public Health, P.O Box 4404, 0403, Nydalen, Oslo, Norway.

Background: More than 50,000 adult and cord blood samples were collected in Tempus tubes and stored at the Norwegian Institute of Public Health Biobank for future use. In this study, we systematically evaluated and compared five blood-RNA isolation protocols: three blood-RNA isolation protocols optimized for simultaneous isolation of all blood-RNA species (MagMAX RNA Isolation Kit, both manual and semi-automated protocols; and Norgen Preserved Blood RNA kit I); and two protocols optimized for large RNAs only (Tempus Spin RNA, and Tempus 6-port isolation kit). We estimated the following parameters: RNA quality, RNA yield, processing time, cost per sample, and RNA transcript stability of six selected mRNAs and 13 miRNAs using real-time qPCR.

Findings: Whole blood samples from adults (n = 59 tubes) and umbilical cord blood (n = 18 tubes) samples collected in Tempus tubes were analyzed. High-quality blood-RNAs with average RIN-values above seven were extracted using all five RNA isolation protocols. The transcript levels of the six selected genes showed minimal variation between the five protocols. Unexplained differences within the transcript levels of the 13 miRNA were observed; however, the 13 miRNAs had similar expression direction and they were within the same order of magnitude. Some differences in the RNA processing time and cost were noted.

Conclusions: Sufficient amounts of high-quality RNA were obtained using all five protocols, and the Tempus blood RNA system therefore seems not to be dependent on one specific RNA isolation method.
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http://dx.doi.org/10.1186/s13104-016-2224-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009671PMC
September 2016

Long-term storage of blood RNA collected in RNA stabilizing Tempus tubes in a large biobank--evaluation of RNA quality and stability.

BMC Res Notes 2014 Sep 12;7:633. Epub 2014 Sep 12.

The Norwegian Institute of Public Health, PO Box 4404, Nydalen, NO-0403, Oslo, Norway.

Background: Establishing methods for secure long term storage of RNA is critical to realizing the promise of biobanks in biomedical research. Here, we describe the results of yearly analyses of the same set of umbilical cord and adult whole blood RNA collected in Tempus Blood RNA tubes and stored at -80 °C, over a period of up to six years. We systematically investigated the effects of long-term storage of samples (75 Tempus tubes form three adult donors and 30 Tempus tubes from three cord blood donors) on the RNA quality and transcript stability of six selected genes (CDKN1A, FOS, IL1B, IL8, MYC and TP53). This is the first systematic study of both cord and adult blood samples stored for many years.

Findings: The RNA purity and integrity, expressed as RIN-values, were stable up to six years of storage, and there were no storage-related deleterious effects on RNA purity. There were limited intra- and inter-individual variations in RNA yields; however, no consistent trend of decreasing RNA yield was observed with the duration of storage. Some long-term storage effects were found on the relative transcript levels of the six genes when compared to the year 0 samples. However, these changes were within ± 2-fold for both types of blood samples, except for two genes. Our results show that storage of these samples for up to six years did not have significant effects on the RNA quality and transcript stability of the six genes.

Conclusions: Blood RNA is stable in Tempus tubes stored at -80 °C over a period of six years. Intact and good-quality RNA suitable for transcript profiling analyses in epidemiological studies was obtained from blood samples stored in Tempus tubes. This suggests that blood samples collected in large biobanks-such as the Mother and Child (MoBa) Cohort at Norwegian Institute of Public Health (NIPH) and frozen in suitable collection tubes for total RNA stabilization, can be used for quantitative studies after at least six years of storage.
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http://dx.doi.org/10.1186/1756-0500-7-633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4168124PMC
September 2014

Human blood RNA stabilization in samples collected and transported for a large biobank.

BMC Res Notes 2012 Sep 18;5:510. Epub 2012 Sep 18.

The Norwegian Institute of Public Health, Oslo, Norway.

Background: The Norwegian Mother and Child Cohort Study (MoBa) is a nation-wide population-based pregnancy cohort initiated in 1999, comprising more than 108.000 pregnancies recruited between 1999 and 2008. In this study we evaluated the feasibility of integrating RNA analyses into existing MoBa protocols. We compared two different blood RNA collection tube systems - the PAXgene™ Blood RNA system and the Tempus™ Blood RNA system - and assessed the effects of suboptimal blood volumes in collection tubes and of transportation of blood samples by standard mail. Endpoints to characterize the samples were RNA quality and yield, and the RNA transcript stability of selected genes.

Findings: High-quality RNA could be extracted from blood samples stabilized with both PAXgene and Tempus tubes. The RNA yields obtained from the blood samples collected in Tempus tubes were consistently higher than from PAXgene tubes. Higher RNA yields were obtained from cord blood (3 - 4 times) compared to adult blood with both types of tubes. Transportation of samples by standard mail had moderate effects on RNA quality and RNA transcript stability; the overall RNA quality of the transported samples was high. Some unexplained changes in gene expression were noted, which seemed to correlate with suboptimal blood volumes collected in the tubes. Temperature variations during transportation may also be of some importance.

Conclusions: Our results strongly suggest that special collection tubes are necessary for RNA stabilization and they should be used for establishing new biobanks. We also show that the 50,000 samples collected in the MoBa biobank provide RNA of high quality and in sufficient amounts to allow gene expression analyses for studying the association of disease with altered patterns of gene expression.
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http://dx.doi.org/10.1186/1756-0500-5-510DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3503553PMC
September 2012

Genetic testing of newborns for type 1 diabetes susceptibility: a prospective cohort study on effects on maternal mental health.

BMC Med Genet 2010 Jul 15;11:112. Epub 2010 Jul 15.

Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.

Background: Concerns about the general psychological impact of genetic testing have been raised. In the Environmental Triggers of Type 1 Diabetes (MIDIA) study, genetic testing was performed for HLA-conferred type 1 diabetes susceptibility among Norwegian newborns. The present study assessed whether mothers of children who test positively suffer from poorer mental health and well-being after receiving genetic risk information about their children.

Methods: The study was based on questionnaire data from the Norwegian Mother and Child Cohort (MoBa) study conducted by the Norwegian Institute of Public Health. Many of the mothers in the MoBa study also took part in the MIDIA study, in which their newborn children were tested for HLA-conferred genetic susceptibility for type 1 diabetes. We used MoBa questionnaire data from the 30th week of pregnancy (baseline) and 6 months post-partum (3-3.5 months after disclosure of test results). We measured maternal symptoms of anxiety and depression (SCL-8), maternal self-esteem (RSES), and satisfaction with life (SWLS). The mothers also reported whether they were seriously worried about their child 6 months post-partum. We compared questionnaire data from mothers who had received information about having a newborn with high genetic risk for type 1 diabetes (N = 166) with data from mothers who were informed that their baby did not have a high-risk genotype (N = 7224). The association between genetic risk information and maternal mental health was analysed using multiple linear regression analysis, controlling for baseline mental health scores.

Results: Information on genetic risk in newborns was found to have no significant impact on maternal symptoms of anxiety and depression (p = 0.9), self-esteem (p = 0.2), satisfaction with life (p = 0.2), or serious worry about their child (OR = 0.98, 95% CI 0.64-1.48). Mental health before birth was strongly associated with mental health after birth. In addition, an increased risk of maternal worry was found if the mother herself had type 1 diabetes (OR = 2.39, 95% CI 1.2-4.78).

Conclusions: This study did not find evidence supporting the notion that genetic risk information about newborns has a negative impact on the mental health of Norwegian mothers.
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http://dx.doi.org/10.1186/1471-2350-11-112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152763PMC
July 2010
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