| 1. |
- Bergstrand, Jan, et al.
(författare)
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Scanning inverse fluorescence correlation spectroscopy
- 2014
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 22:11, s. 13073-13090
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Tidskriftsartikel (refereegranskat)abstract
- Scanning Inverse Fluorescence Correlation Spectroscopy (siFCS) is introduced to determine the absolute size of nanodomains on surfaces. We describe here equations for obtaining the domain size from cross-and auto-correlation functions, measurement simulations which enabled testing of these equations, and measurements on model surfaces mimicking membranes containing nanodomains. Using a confocal microscope of 270 nm resolution the size of 250 nm domains were estimated by siFCS to 257 +/- 12 nm diameter, and 40 nm domains were estimated to 65 +/- 26 nm diameter. Applications of siFCS for sizing of nanodomains and protein clusters in cell membranes are discussed.
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| 2. |
- Blom, Hans, et al.
(författare)
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Nearest neighbor analysis of dopamine D1 receptors and Na plus -K plus -ATPases in dendritic spines dissected by STED microscopy
- 2012
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Ingår i: Microscopy research and technique (Print). - : Wiley. - 1059-910X .- 1097-0029. ; 75:2, s. 220-228
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Tidskriftsartikel (refereegranskat)abstract
- Protein localization in dendritic spines is the focus of intense investigations within neuroscience. Applications of super-resolution microscopy to dissect nanoscale protein distributions, as shown in this work with dual-color STED, generate spatial correlation coefficients having quite small values. This means that colocalization analysis to some extent looses part of its correlative impact. In this study we thus introduced nearest neighbor analysis to quantify the spatial relations between two important proteins in neurons, the dopamine D1 receptor and Na+,K+-ATPase. The analysis gave new information on how dense the D1 receptor and Na+,K+-ATPase constituting nanoclusters are located both with respect to the homogenous (self to same) and the heterogeneous (same to other) topology. The STED dissected nanoscale topologies provide evidence for both a joint as well as a separated confinement of the D1 receptor and the Na+,K+-ATPase in the postsynaptic areas of dendritic spines. This confined topology may have implications for generation of local sodium gradients and for structural and functional interactions modulating slow synaptic transmission processes. Microsc. Res. Tech., 2011.
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| 3. |
- Blom, Hans, et al.
(författare)
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Spatial Distribution of DARPP-32 in Dendritic Spines
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:9, s. e75155-
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Tidskriftsartikel (refereegranskat)abstract
- The phosphoprotein DARPP-32 (dopamine and cyclic adenosine 3́, 5́-monophosphate-regulated phosphoprotein, 32 kDa) is an important component in the molecular regulation of postsynaptic signaling in neostriatum. Despite the importance of this phosphoprotein, there is as yet little known about the nanoscale distribution of DARPP-32. In this study we applied superresolution stimulated emission depletion microscopy (STED) to assess the expression and distribution of DARPP-32 in striatal neurons. Primary culture of striatal neurons were immunofluorescently labeled for DARPP-32 with Alexa-594 and for the dopamine D1 receptor (D1R) with atto-647N. Dual-color STED microscopy revealed discrete localizations of DARPP-32 and D1R in the spine structure, with clustered distributions in both head and neck. Dissected spine structures reveal that the DARPP-32 signal rarely overlapped with the D1R signal. The D1R receptor is positioned in an "aggregated" manner primarily in the spine head and to some extent in the neck, while DARPP-32 forms several neighboring small nanoclusters spanning the whole spine structure. The DARPP-32 clusters have a mean size of 52 +/- 6 nm, which is close to the resolution limit of the microscope and corresponds to the physical size of a few individual phosphoprotein immunocomplexes. Dissection of synaptic proteins using superresolution microscopy gives possibilities to reveal in better detail biologically relevant information, as compared to diffraction-limited microscopy. In this work, the dissected postsynaptic topology of the DARPP-32 phosphoprotein provides strong evidence for a compartmentalized and confined distribution in dendritic spines. The protein topology and the relatively low copy number of phosphoprotein provides a conception of DARPP-32's possibilities to fine-tune the regulation of synaptic signaling, which should have an impact on the performance of the neuronal circuits in which it is expressed.
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| 4. |
- Chen, Xingqi, et al.
(författare)
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Chromatin in situ proximity (ChrISP) : Single-cell analysis of chromatin proximities at a high resolution
- 2014
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Ingår i: BioTechniques. - : Future Science Ltd. - 0736-6205 .- 1940-9818. ; 56:3, s. 117-124
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Tidskriftsartikel (refereegranskat)abstract
- Current techniques for analyzing chromatin structures are hampered by either poor resolution at the individual cell level or the need for a large number of cells to obtain higher resolution. This is a major problem as it hampers our understanding of chromatin conformation in single cells and how these respond to environmental cues. Here we describe a new method, chromatin in situ proximity (ChrISP), which reproducibly scores for proximities between two different chromatin fibers in 3-D with a resolution of similar to 170 angstrom in single cells. The technique is based on the in situ proximity ligation assay (ISPLA), but ChrISP omits the rolling circle amplification step (RCA). Instead, the proximities between chromatin fibers are visualized by a fluorescent connector oligonucleotide DNA, here termed splinter, forming a circular DNA.with another circle-forming oligonucleotide, here termed backbone, upon ligation. In contrast to the regular ISPLA technique, our modification enables detection of chromatin fiber proximities independent of steric hindrances from nuclear structures. We use this method to identify higher order structures of individual chromosomes in relation to structural hallmarks of interphase nuclei and beyond the resolution of the light microscope.
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| 5. |
- Eriksson, Daniel, et al.
(författare)
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Effects of perceived long-term stress on health and memory functioning
- 2010
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Ingår i: Abstracts of the Psychonomic Society. ; , s. 78-78
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Konferensbidrag (refereegranskat)abstract
- The study examined effects of perceived long-term stress on health and memory functioning in middle-aged individuals (40–60 years). Participants in the Betula study (Nilsson et al., 1997) describing themselves as being stressed in general over three measurement occasions (10 years in total) were compared with a matched (sex and education) group (n = 98) reporting no stress. The results revealed a higher incidence of depressive symptoms, flus, and not-healthy-ratings over time for the stress group. In addition, the stress group provided more negative subjective memory ratings, whereas time-related change in memory performance, indicative of a high degree of cognitive stability, did not differ from that of controls. Degree of perceived stress is discussed as a factor underlying variations in regard to the outcome of studies of perceived stress.
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| 6. |
- Eriksson Sörman, Daniel, et al.
(författare)
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Blood Pressure Levels and Longitudinal Changes in Relation to Social Network Factors
- 2016
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Ingår i: Psychological Topics. - 1332-0742. ; 25:1, s. 59-73
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine the relationship between social network variables and levels of and longitudinal changes in blood pressure in a middle-aged/older sample. The participants (50-75 years at baseline; n=1097) responded to questions concerning social relationships at baseline and their blood pressure (diastolic, systolic) was measured. Blood pressure levels were reassessed 5, 10, and 15 years later. Latent growth models with responses to questions concerning social relationships as predictors and basic demographic factors (age, sex) as covariates, unexpectedly indicated that a more limited social network (no close friend, few visits, little contact with friends in other ways, not living with someone, and a composite index based on all questions) was associated with significantly lower diastolic blood pressure levels. For systolic blood pressure a similar result was observed for one of the variables (lack of a close friend). In general, these effects diminished over time, as indexed by the positive relationship between several of the social variables and slope. The results were little affected by inclusion of additional covariates (e.g. measures of psychological distress, smoking/alcohol habits, and BMI) suggesting that the origins of this unexpected pattern of findings must probably be sought for in other subjectrelated factors, such as, for example, increased help seeking. Future studies should consider qualitative aspects (e.g. feelings of loneliness, quality of social relationships) in addition to structural aspects to provide a better understanding of these associations.
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| 7. |
- Eriksson Sörman, Daniel, et al.
(författare)
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Ger en aktiv livsstil bättre minne?
- 2011
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Ingår i: Svensk Idrottsforskning. - Stockholm : Centrum för idrottsforskning. - 1103-4629. ; 20:1, s. 43-45
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Det sägs ibland att aktivteter som stimulerar hjärnan förbättrar minnet. En rad studier indikerar också att olika typer av livsstilsfaktorer hänger samman med prestation i kognitiva test. De visar att dålig minnesförmåga är överrepresenterad hos dem som inte ägnar sig åt fritidsaktiviteter såsom att läsa, idrotta och lägga pussel.
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| 8. |
- Eriksson Sörman, Daniel, et al.
(författare)
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Leisure Activity in Old Age and Risk of Dementia : a 15-Year Prospective Study
- 2014
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Ingår i: The journals of gerontology. Series B, Psychological sciences and social sciences. - : Oxford University Press. - 1079-5014 .- 1758-5368. ; 69:4, s. 493-501
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. The aim of this study was to investigate whether leisure activity is associated with incident dementia in an older sample.Method. We examined a sample of 1,475 elderly (>= 65 years) who were dementia free at baseline over a follow-up period of up to 15 years. In addition to analyses involving the total time period, separate analyses of three time periods were performed, 1-5, 6-10, and 11-15 years, following baseline measurement of leisure activity.Results. After controlling for a variety of potential confounders, analyses of data for the total time period revealed that higher levels of "Total activity" and "Social activity," but not "Mental activity," were associated with decreased risk of dementia. However, analyses of the separate time periods showed that this association was only significant in the first time period, 1-5 years after baseline.Discussion. The results from this study provide little support for the hypothesis that frequent engagement in leisure activities among elderly serve to protect against dementia diseases across a longer time frame. The finding of a relationship for the first time period, 1-5 years after baseline, could indicate short-term protective effects but could also reflect reverse causality.
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| 9. |
- Eriksson Sörman, Daniel, et al.
(författare)
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Leisure-time activity in old age as predictors of impending dementia: A 15-year prospective study
- 2012
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Konferensbidrag (refereegranskat)abstract
- This study examined the relationship between leisure activities and risk of dementia in a sample of healthy older individuals, dementia free at the beginning of the project. Data were drawn from a population-based longitudinal study (the Betula project) and the participants were followed up for 15 years. At baseline, participants were asked about their frequency of participation in 15 selected leisure activities. When age, gender, education, APOE and other potential confounders were controlled for, results revealed quite moderate effects on dementia after analysis of the activities separately. However, by weighting each activity into a mental, social and physical dimension (based on valuation by the participants), and then summarizing into a score for each dimension, we further investigated if level of engagement could predict impending dementia. Preliminary results indicate that the dimensions may have influence on the risk of dementia for certain age groups. The study also showed that the strongest predictor of dementia is being a carrier of the APOE ɛ4 allele. The outcomes are discussed in terms of important methodological difference between studies concerning the effects of leisure activities in preventing dementia diseases.
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| 10. |
- Eriksson Sörman, Daniel, 1974-, et al.
(författare)
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Occupational cognitive complexity and episodic memory in old age
- 2021
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Ingår i: Intelligence. - : Elsevier. - 0160-2896 .- 1873-7935. ; 89
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate occupational cognitive complexity of main lifetime occupation in relation to level and 15-year change in episodic memory recall in a sample of older adults (≥ 65 years, n = 780). We used latent growth curve modelling with occupational cognitive complexity (O*NET indicators) as independent variable. Subgroup analyses in a sample of middle-aged (mean: 49.9 years) men (n = 260) were additionally performed to investigate if a general cognitive ability (g) factor at age 18 was predictive of future occupational cognitive complexity and cognitive performance in midlife. For the older sample, a higher level of occupational cognitive complexity was related to a higher level of episodic recall (β = 0.15, p < .001), but the association with rate of change (β = 0.03, p = .64) was not statistically significant. In the middle-aged sample, g at age 18 was both directly (β = 0.19, p = .01) and indirectly (via years of education after age 18, ab = 0.19) predictive of midlife levels of occupational cognitive complexity. Cognitive ability at age 18 was also a direct predictor of midlife episodic recall (β = 0.60, p ≤ 0.001). Critically, entry of the early adult g factor attenuated the association between occupational complexity and cognitive level (from β = 0.21, p = .01 to β = 0.12, p = .14). Overall, our results support a pattern of preserved differentiation from early to late adulthood for individuals with different histories of occupational complexity.
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