| 86141. |
- Lanekoff, Ingela, 1975, et al.
(författare)
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An in situ fracture device to image lipids in single cells using ToF-SIMS
- 2011
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Ingår i: SURFACE AND INTERFACE ANALYSIS. - : Wiley. - 0142-2421 .- 1096-9918. ; 43:1-2, s. 257-260
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Tidskriftsartikel (refereegranskat)abstract
- Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) imaging yields molecule-specific images showing the spatial distribution of specific lipids with submicron resolution, making it a potentially powerful method for studying a variety of biological questions in single cells. In order to make possible the analysis of hydrated cells in vacuum, we have designed a device for in situ freeze-fracture of cell samples. PC12 cells are frozen between two silicon shards in a sandwich geometry, and the fracture is conducted under vacuum inside the analysis chamber of the instrument. After freeze-fracture, ToF-SIMS analysis was carried out using a Bi cluster ion source, providing high-resolution images of single cells. We also show that when combining freeze-fracture and cluster SIMS imaging, low abundant biologically important lipids, specifically PE, PC and non-SM PC, can be imaged in single cells. Finally, K+ ion localization was used as a diagnostic to identify fracture planes through the cell for these fractured samples.
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| 86142. |
- Lanekoff, Ingela, 1975
(författare)
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Analysis of phospholipids in cellular membranes with LC and imaging mass spectrometry
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Imaging mass spectrometry enables the creation of molecule specific images from the surface of a solid sample in vacuum. To solve the issue of bringing single cells into vacuum without altering their native distribution of molecules, a freeze fracture device that fits the time of flight secondary ion mass spectrometry (TOF-SIMS) IV instrument has been developed. This makes it possible to get a snapshot of the chemical distribution across frozen hydrated single cells that are only 10-20 µm in diameter. The cells of interest in this thesis are rat pheochromocytoma (PC12) cells. PC12 cells resemble and act like neurons in the sense that upon stimulation they release dopamine, which is a substance used for communication between neurons. In previous studies using these model cells, the rate of this release has been shown to change after the cells have been incubated with different phospholipids. To investigate the amount of phospholipids that have accumulated in the plasma membrane of PC12 cells after an overnight incubation, the combination of the freeze fracture device and the TOF-SIMS IV instrument was utilized. Relative to the endogenous phospholipid the results show that 0.5% of phosphatidylcholine (PC) and 1.3% of phosphatidylethanolamine (PE) had accumulated in the plasma membrane. Together with previous results on changes in the release of dopamine in PC12 cells, this suggests that the phospholipid composition of the plasma membrane of neurons is highly regulated. This gives a hint as to the importance of phospholipids during this highly important cellular process. The technique of liquid chromatography (LC) mass spectrometry (MS) does not provide molecular information in images but has the ability to separate similar molecules in a sample. This is of high importance when analyzing a specific molecule in a complex sample. Anaerobic ammonium oxidizing (anammox) bacteria reside in sediment on the ocean floor. These bacteria are highly important to the environment because they convert biologically available nitrogen into dinitrogen gas (N2), which is returned to the atmosphere. By denitrifying biologically available nitrogen they limit the risk of over fertilization in the ocean. They are also believed to contribute greatly to the global N2 production. By combining LCMS with an extensive sample clean up procedure a phospholipid biomarker for viable anammox bacteria has been used to detect the location of anammox bacteria in a sediment core sample.
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| 86143. |
- Lanekoff, Ingela, 1975, et al.
(författare)
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Mass spectrometry imaging of freeze-dried membrane phospholipids of dividing Tetrahymena pyriformis
- 2013
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Ingår i: Surface and Interface Analysis. - : Wiley. - 1096-9918 .- 0142-2421. ; 45:1, s. 211-214
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Tidskriftsartikel (refereegranskat)abstract
- Time of Flight secondary ion mass spectrometry (TOF-SIMS) has been used to explore the distribution of phospholipids in the plasma membrane of Tetrahymena pyriformis during cell division. The dividing cells were freeze-dried prior to analysis followed by line scan and region of interest analysis at various stages of cell division. The results showed no signs of phospholipid domain formation at the junction between the dividing cells. Instead the results showed that the sample preparation technique had a great impact on one of the examined phospholipids, namely phosphatidylcholine (PC). Phosphatidylcholine and 2-aminoethylphosphonolipid (2-AEP) have therefore been evaluated in Tetrahymena cells that have been subjected to different sample preparation techniques: freeze drying ex situ, freeze fracture, and freeze fracture with partial or total freeze drying in situ. The result suggests that freeze drying ex situ causes the celia to collapse and cover the plasma membrane.
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| 86144. |
- Lanekoff, Ingela, 1975, et al.
(författare)
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Relative quantification of phospholipid accumulation in the PC12 cell plasma membrane following phospholipid incubation using TOF-SIMS Imaging.
- 2011
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 83:13, s. 5337-5343
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Tidskriftsartikel (refereegranskat)abstract
- Time of flight secondary ion mass spectrometry (TOF-SIMS) imaging has been used to investigate the incorporation of phospholipids into the plasma membrane of PC12 cells after incubation with phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The incubations were done at concentrations previously shown to change the rate of exocytosis in model cell lines. The use of TOF-SIMS in combination with an in situ freeze fracture device enables the acquisition of ion images from the plasma membrane in single PC12 cells. By incubating cells with deuterated phospholipids and acquiring ion images at high mass resolution, specific deuterated fragment ions were used to monitor the incorporation of lipids into the plasma membrane. The concentration of incorporated phospholipids relative to the original concentration of PC was thus determined. The observed relative amounts of phospholipid accumulation in the membrane ranges from 0.5 to 2 percent following 19 hours of incubation with PC at 100 to 300 μM and from 1 to 9 percent following incubation with PE at the same concentrations. Phospholipid accumulation is therefore shown to be dependent on the concentration in the surrounding media. In combination with previous exocytosis results, the present data suggests that very small changes in the plasma membrane phospholipid concentration are sufficient to produce significant effects on important cellular processes, such as exocytosis in PC12 cells.
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| 86145. |
- Lanekoff, Ingela, 1975, et al.
(författare)
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Time of Flight Mass Spectrometry Imaging of Samples Fractured In Situ with a Spring-Loaded Trap System.
- 2010
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Ingår i: Analytical chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 82:15, s. 6652-6659
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Tidskriftsartikel (refereegranskat)abstract
- An in situ freeze fracture device featuring a spring-loaded trap system has been designed and characterized for time of flight secondary ion mass spectrometry (TOF SIMS) analysis of single cells. The device employs the sandwich assembly, which is typically used in freeze fracture TOF SIMS experiments to prepare frozen, hydrated cells for high-resolution SIMS imaging. The addition of the spring-loaded trap system to the sandwich assembly offers two advances to this sample preparation method. First, mechanizing the fracture by adding a spring standardizes each fracture by removing the need to manually remove the top of the sandwich assembly with a cryogenically cooled knife. A second advance is brought about because the top of the sandwich is not discarded after the sandwich assembly has been fractured. This results in two imaging surfaces effectively doubling the sample size and providing the unique ability to image both sections of a cell bifurcated by the fracture. Here, we report TOF SIMS analysis of freeze fractured rat pheochromocytoma (PC12) cells using a Bi cluster ion source. This work exhibits the ability to obtain single cell chemical images with subcellular lateral resolution from cells preserved in an ice matrix. In addition to preserving the cells, the signal from lipid fragment ions rarely identified in single cells are better observed in the freeze-fractured samples for these experiments. Furthermore, using the accepted argument that K(+) signal indicates a cell that has been fractured though the cytoplasm, we have also identified different fracture planes of cells over the surface. Coupling a mechanized freeze fracture device to high-resolution cluster SIMS imaging will provide the sensitivity and resolution as well as the number of trials required to carry out biologically relevant SIMS experiments.
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| 86146. |
- Lanemo, Emy, et al.
(författare)
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Kunskap och underlag i planeringen – exemplet kulturmiljö.
- 2015
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Ingår i: Plan. ; 2015:4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- En rimlig förväntan på samhällsplaneringen är att den ska bygga på en adekvat kunskapsgrund. Men vad är det egentligen för kunskap som behövs i planeringen? Och vilka verktyg har planeringen för att hantera de allt större kraven på att föra kvalitativa medborgardialoger? I den här artikeln diskuterar Emy Lanemo och Krister Olsson kunskap, underlag och relationen mellan experter och lekmän i planeringen. Deras utgångspunkt är att föra ett resonemang som är allmängiltigt, men de gör det med kulturmiljöplanering som ett belysande exempel.
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| 86147. |
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| 86148. |
- Lanfer, Anne, et al.
(författare)
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Does change in hip circumference predict cardiovascular disease and overall mortality in Danish and Swedish women?
- 2014
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Ingår i: Obesity. - : Wiley. - 1930-7381 .- 1930-739X. ; 22:3, s. 957-963
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Tidskriftsartikel (refereegranskat)abstract
- Abstract OBJECTIVE: Accumulating evidence consistently shows that small hip circumference (HC) is related to increased risk of cardiovascular disease (CVD), coronary heart disease, diabetes, and premature death in women. This study aims to clarify whether this inverse association can be found in both normal- and overweight individuals and if change in HC over time relates to morbidity and mortality risk. DESIGN AND METHODS: HC and 6-year change in HC in relation to the risk for all-cause mortality and CVD morbidity and mortality was investigated in a pooled sample of 2,867 women from the DANISH MONICA study and the Prospective Population Study of Women in Gothenburg with a total of 66,627 person-years of follow-up. RESULTS: Baseline HC was significantly and inversely associated with all-cause and CVD-specific mortality after adjustment for BMI, waist circumference (WC), and other covariates. In stratified analyses, the inverse association was weaker in women with a BMI of more than 25 kg/m2 . Six-year change in hip size was not associated with mortality or morbidity endpoints. CONCLUSIONS: Our results imply the existence of a basal risk associated with small hip size, which is, however, independent from changes in gluteofemoral body mass and therefore unlikely to be modifiable.
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| 86149. |
- Lanfer, A., et al.
(författare)
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Predictors and correlates of taste preferences in European children: The IDEFICS study
- 2013
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Ingår i: Food Quality and Preference. - : Elsevier BV. - 0950-3293. ; 27:2, s. 128-136
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigated taste preferences in a sample of 1705 children aged 6 to 9 years from survey centres in Italy, Estonia, Cyprus, Belgium, Sweden, Germany, Hungary, and Spain and aimed to identify factors correlated with taste preference. Children's preferences for varying levels of sucrose (sweet) in apple juice and fat, sodium chloride (salt) and monosodium glutamate (umami) in crackers were assessed using paired-comparison tests. Socio-demographics (age, sex, parental education), early feeding practises (breastfeeding, introduction of fruits), parenting behaviour (TV viewing, using food as a reward) and taste threshold sensitivity for sucrose (sweet), sodium chloride (salt), caffeine (bitter) and monosodium glutamate (umami) were investigated as possible correlates of taste preferences. Parents reported on socio-demographics, early feeding and parenting behaviour. Taste thresholds were determined via a paired-comparison staircase method. Country of residence was the strongest factor related to preferences for all four tastes. Taste preferences also differed by age. Preference for sugar and salt increased between 6 and 9 years of age while preference for monosodium glutamate decreased. The age differences remained significant even after adjustment for sex, country of residence, parental education and early feeding habits. Sex, parental education, early feeding habits, TV viewing, using food as a reward and taste thresholds were not consistently related to taste preferences among the survey centres. In summary, the results highlight the importance of culture and age in taste preferences in children younger than 10 years of age. (C) 2012 Elsevier Ltd. All rights reserved.
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| 86150. |
- Lanfer, A., et al.
(författare)
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Reproducibility of food consumption frequencies derived from the Children's Eating Habits Questionnaire used in the IDEFICS study
- 2011
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Ingår i: International Journal of Obesity. - : Nature Publishing Group. - 0307-0565 .- 1476-5497. ; 35, s. S61-S68
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the reproducibility of food consumption frequencies derived from the food frequency section of the Children's Eating Habits Questionnaire (CEHQ-FFQ) that was developed and used in the IDEFICS (Identification and prevention of dietary-and lifestyle-induced health effects in children and infants) project to assess food habits in 2- to 9-year-old European children. Design and methods: From a subsample of 258 children who participated in the IDEFICS baseline examination, parental questionnaires of the CEHQ were collected twice to assess reproducibility of questionnaire results from 0 to 354 days after the first examination. Weighted Cohen's kappa coefficients (kappa) and Spearman's correlation coefficients (r) were calculated to assess agreement between the first and second questionnaires for each food item of the CEHQ-FFQ. Stratification was performed for sex, age group, geographical region and length of period between the first and second administrations. Fisher's Z transformation was applied to test correlation coefficients for significant differences between strata. Results: For all food items analysed, weighted Cohen's kappa coefficients (kappa) and Spearman's correlation coefficients (r) were significant and positive (P < 0.001). Reproducibility was lowest for diet soft drinks (kappa = 0.23, r = 0.32) and highest for sweetened milk (kappa = 0.68, r = 0.76). Correlation coefficients were comparable to those of previous studies on FFQ reproducibility in children and adults. Stratification did not reveal systematic differences in reproducibility by sex and age group. Spearman's correlation coefficients differed significantly between northern and southern European countries for 10 food items. In nine of them, the lower respective coefficient was still high enough to conclude acceptable reproducibility. As expected, longer time (> 128 days) between the first and second administrations resulted in a generally lower, yet still acceptable, reproducibility. Conclusion: Results indicate that the CEHQ-FFQ gives reproducible estimates of the consumption frequency of 43 food items from 14 food groups in European children. International Journal of Obesity (2011) 35, S61-S68; doi:10.1038/ijo.2011.36
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