| 1. |
- Silventoinen, Karri, et al.
(författare)
-
Education in twins and their parents across birth cohorts over 100 years : an individual-level pooled analysis of 42 twin cohorts
- 2017
-
Ingår i: Twin Research and Human Genetics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1832-4274 .- 1839-2628.
-
Tidskriftsartikel (refereegranskat)abstract
- Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
|
|
| 2. |
- Jelenkovic, Aline, et al.
(författare)
-
Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age : A Study of the CODATwins Project
- 2015
-
Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:5, s. 557-570
-
Tidskriftsartikel (refereegranskat)abstract
- A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m(2) in childhood and adolescence and up to 0.2 kg/m(2) in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
|
|
| 3. |
- Silventoinen, Karri, et al.
(författare)
-
The CODATwins Project : The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits
- 2015
-
Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:4
-
Tidskriftsartikel (refereegranskat)abstract
- For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
|
|
| 4. |
- Sikka, Pilleriin, et al.
(författare)
-
D-Serine metabolism in C6 glioma cells : Involvement of alanine-serine-cysteine transporter (ASCT2) and serine racemase (SRR) but not D-amino acid oxidase (DAO)
- 2010
-
Ingår i: Journal of Neuroscience Research. - : John Wiley & Sons. - 0360-4012 .- 1097-4547. ; 88:8, s. 1829-1840
-
Tidskriftsartikel (refereegranskat)abstract
- D-serine is an endogenous N-methyl-D-aspartate (NMDA) receptor coagonist. It is synthesized from L-serine by serine racemase (SRR), but many aspects of its metabolism remain unclear, especially in the forebrain, which lacks active D-amino acid oxidase (DAO), the major D-serine degradative enzyme. Candidate mechanisms include SRR operating in alpha,beta-eliminase mode (converting D-serine to pyruvate) and regulation by serine transport, in which the alanine-serine-cysteine transporter ASCT2 is implicated. Here we report studies in C6 glioma cells, which "simulate" the forebrain, in that the cells express SRR and ASCT2 but lack DAO activity. We measured D-serine, ASCT2, SRR, and DAO expression and DAO activity in two situations: after incubation of cells for 48 hr with serine isomers and after increased or decreased SRR expression by transfection and RNA interference, respectively. Incubation with serine enantiomers decreased [(3)H]D-serine uptake and ASCT2 mRNA and increased SRR immunoreactivity but did not alter DAO immunoreactivity, and DAO activity remained undetectable. SRR overexpression increased D-serine and pyruvate and decreased [(3)H]D-serine uptake and ASCT2 mRNA but did not affect DAO. SRR knockdown did not alter any of the parameters. Our data suggest that D-serine transport mediated by ASCT2 contributes prominently to D-serine homeostasis when DAO activity is absent. The factors regulating D-serine are important for understanding normal NMDA receptor function and because D-serine, along with DAO and SRR, is implicated in the pathogenesis and treatment of schizophrenia.
|
|
| 5. |
|
|
| 6. |
- Bäckstrand, Gunnar, et al.
(författare)
-
Ergonomics analysis in a virtual environment
- 2007
-
Ingår i: International Journal of Manufacturing Research. - : InderScience Publishers. - 1750-0591. ; 2:2, s. 198-208
-
Tidskriftsartikel (refereegranskat)abstract
- Simulation can support the design of an ergonomic workplace by enabling early assessment of ergonomic conditions in a virtual environment. An important feature is the possibility to study alternative solutions or the effect of improvements from an ergonomics perspective. To be able to conduct an efficient and reliable evaluation in a virtual environment, an objective analysis method is essential. Such an analysis method should be integrated in the simulation software, and support a company's everyday ergonomics work process. In order to gain from existing ergonomics knowledge within a company, the possibility to implement such wisdom in the current simulation software becomes important. This paper presents an implementation work done with the purpose of integrating an established ergonomics work process into a virtual environment. It describes the benefits of an ergonomics work process where simulation and evaluation at early stages of a design process are key factors. The paper will also describe the integration process, i.e., the technical issues as well as the change in work methods.
|
|
| 7. |
- Hardy, Matthew P., et al.
(författare)
-
Characterization of the type I interferon locus and identification of novel genes
- 2004
-
Ingår i: Genomics. - : Elsevier. - 0888-7543 .- 1089-8646. ; 84:2, s. 331-345
-
Tidskriftsartikel (refereegranskat)abstract
- The human type I interferon (IFN) genes are clustered on human chromosome 9p21 and the mouse genes are located in the region of conserved synteny on mouse chromosome 4. We have identified two novel mouse Ifna genes (Ifna12, Ifna13) and Ifnl2 (IFN-like 2, a homologue of Limitin/IFN-like 1). Another type I IFN gene was designated Ifne1. Mouse Ifne1 was expressed in ovaries and uterus but not in tissues of hematopoietic origin. IFN-epsilon1 has general structural characteristics of a type I IFN. These studies represent the first detailed annotation of the mouse type I IFN locus, and the products of these novel genes may have important functions in reproduction and host defense.
|
|
| 8. |
- Hemeren, Paul, et al.
(författare)
-
A Framework for Representing Action Meaning in Artificial Systems via Force Dimensions
- 2012
-
Ingår i: Artificial General Intelligence. - Heidelberg, Dordrecht, London, New York : Springer Berlin/Heidelberg. - 9783642355059 - 9783642355066 ; , s. 99-106, s. 99-99
-
Konferensbidrag (refereegranskat)abstract
- General (human) intelligence critically includes understanding human action, both action production and action recognition. Human actions also convey social signals that allow us to predict the actions of others (intent) as well as the physical and social consequences of our actions. What's more, we are able to talk about what we (and others) are doing. We present a framework for action recognition and communication that is based on access to the force dimensions that constrain human actions. The central idea here is that forces and force patterns constitute vectors in conceptual spaces that can represent actions and events. We conclude by pointing to the consequences of this view for how artificial systms could be made to understand and communicate bout actions.
|
|
| 9. |
- James, John R., et al.
(författare)
-
The T Cell Receptor Triggering Apparatus Is Composed of Monovalent or Monomeric Proteins
- 2011
-
Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology, Inc.. - 0021-9258 .- 1083-351X. ; 286:37, s. 31993-32001
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the component stoichiometry of the T cell antigen receptor (TCR) triggering apparatus is essential for building realistic models of signal initiation. Recent studies suggesting that the TCR and other signaling-associated proteins are preclustered on resting T cells relied on measurements of the behavior of membrane proteins at interfaces with functionalized glass surfaces. Using fluorescence recovery after photo-bleaching, we show that, compared with the apical surface, the mobility of TCRs is significantly reduced at Jurkat T cell/glass interfaces, in a signaling-sensitive manner. Using two biophysical approaches that mitigate these effects, bioluminescence resonance energy transfer and two-color coincidence detection microscopy, we show that, within the uncertainty of the methods, the membrane components of the TCR triggering apparatus, i.e. the TCR complex, MHC molecules, CD4/Lck and CD45, are exclusively monovalent or monomeric in human T cell lines, implying that TCR triggering depends only on the kinetics of TCR/pMHC interactions. These analyses also showed that constraining proteins to two dimensions at the cell surface greatly enhances random interactions versus those between the membrane and the cytoplasm. Simulations of TCR-pMHC complex formation based on these findings suggest how unclustered TCR triggering-associated proteins might nevertheless be capable of generating complex signaling outputs via the differential recruitment of cytosolic effectors to the cell membrane.
|
|
| 10. |
- Jansson, Andreas, et al.
(författare)
-
A Theoretical Framework for Quantitative Analysis of the Molecular Basis of Costimulation
- 2005
-
Ingår i: Journal of Immunology. - : American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 175:3, s. 1575-1585
-
Tidskriftsartikel (refereegranskat)abstract
- We present a theoretical framework for simulating the synaptic accumulation of the costimulatory molecules CD28, CTLA-4, B7-1, and B7-2, based on a system of mean-field, ordinary differential equations, and rigorous biophysical and expression data. The simulations show that binding affinity, stoichiometric properties, expression levels, and, in particular, competition effects all profoundly influence complex formation at cellular interfaces. B7-2 engages 33-fold more CD28 than CTLA-4 at the synapse in contrast to B7-1, which ligates ~7-fold more CTLA-4 than CD28. Although B7-1 completely dominates interactions with CTLA-4, forming linear arrays of 7-18 receptor-ligand pairs, CTLA-4 is fully engaged by B7-2 when B7-1 is absent. Additional simulations reveal the sensitivity of CD28 interactions to modeled transport processes. The results support the concept that B7-2 and B7-1 are the dominant ligands of CD28 and CTLA-4, respectively, and indicate that the inability of B7-2 to recruit CTLA-4 to the synapse cannot be due to the differential binding properties of B7-1 and B7-2 only. We discuss the apparent redundancy of B7-1 in the context of a potentially dynamic synaptic microenvironment, and in light of functions other than the direct enhancement of T cell inhibition by CTLA-4.
|
|
