Publications by authors named "Susanne Karlsson"

16 Publications

  • Page 1 of 1

MR (Mineralocorticoid Receptor) Induces Adipose Tissue Senescence and Mitochondrial Dysfunction Leading to Vascular Dysfunction in Obesity.

Hypertension 2019 02;73(2):458-468

From the Department of Physiology, INSERM UMRS 1138 Team 1, Centre de Recherche des Cordeliers, Sorbonne University, Paris, France (C.L., R.P.-R., N.B., F.J., A.N.D.C.).

Adipose tissue (AT) senescence and mitochondrial dysfunction are associated with obesity. Studies in obese patients and animals demonstrate that the MR (mineralocorticoid receptor) contributes to obesity-associated cardiovascular complications through its specific role in AT. However, underlying mechanisms remain unclear. This study aims to elucidate whether MR regulates mitochondrial function in obesity, resulting in AT premature aging and vascular dysfunction. Obese (db/db) and lean (db/+) mice were treated with an MR antagonist or a specific mitochondria-targeted antioxidant. Mitochondrial and vascular functions were determined by respirometry and myography, respectively. Molecular mechanisms were probed by Western immunoblotting and real-time polymerase chain reaction in visceral AT and arteries and focused on senescence markers and redox-sensitive pathways. db/db mice displayed AT senescence with activation of the p53-p21 pathway and decreased SIRT (sirtuin) levels, as well as mitochondrial dysfunction. Furthermore, the beneficial anticontractile effects of perivascular AT were lost in db/db via ROCK (Rho kinase) activation. MR blockade prevented these effects. Thus, MR activation in obesity induces mitochondrial dysfunction and AT senescence and dysfunction, which consequently increases vascular contractility. In conclusion, our study identifies novel mechanistic insights involving MR, adipose mitochondria, and vascular function that may be of importance to develop new therapeutic strategies to limit obesity-associated cardiovascular complications.
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http://dx.doi.org/10.1161/HYPERTENSIONAHA.118.11873DOI Listing
February 2019

Evaluating gas chromatography with a halogen-specific detector for the determination of disinfection by-products in drinking water.

Environ Sci Pollut Res Int 2019 Mar 28;26(8):7305-7314. Epub 2018 Feb 28.

Department of Thematic Studies-Environmental Change, Linköping University, SE-581 83, Linköping, Sweden.

The occurrence of disinfection by-products (DBPs) in drinking water has become an issue of concern during the past decades. The DBPs pose health risks and are suspected to cause various cancer forms, be genotoxic, and have negative developmental effects. The vast chemical diversity of DBPs makes comprehensive monitoring challenging. Only few of the DBPs are regulated and included in analytical protocols. In this study, a method for simultaneous measurement of 20 DBPs from five different structural classes (both regulated and non-regulated) was investigated and further developed for 11 DBPs using solid-phase extraction and gas chromatography coupled with a halogen-specific detector (XSD). The XSD was highly selective towards halogenated DBPs, providing chromatograms with little noise. The method allowed detection down to 0.05 μg L and showed promising results for the simultaneous determination of a range of neutral DBP classes. Compounds from two classes of emerging DBPs, more cytotoxic than the "traditional" regulated DBPs, were successfully determined using this method. However, haloacetic acids (HAAs) should be analyzed separately as some HAA methyl esters may degrade giving false positives of trihalomethanes (THMs). The method was tested on real water samples from two municipal waterworks where the target DBP concentrations were found below the regulatory limits of Sweden.
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http://dx.doi.org/10.1007/s11356-018-1419-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447507PMC
March 2019

[Women strengthened by exercise. Experiences of a back muscle exercise program in vertebral fracture].

Lakartidningen 2012 Sep 12-18;109(37):1616-8

Osteoporoscentrum, Karolinska universitetssjukhuset, Huddinge.

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October 2012

Accumulative electron transfer: multiple charge separation in artificial photosynthesis.

Faraday Discuss 2012 ;155:233-52; discussion 297-308

Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.

To achieve artificial photosynthesis it is necessary to couple the single-electron event of photoinduced charge separation with the multi-electron reactions of fuel formation and water splitting. Therefore, several rounds of light-induced charge separation are required to accumulate enough redox equivalents at the catalytic sites for the target chemistry to occur, without any sacrificial donors or acceptors other than the catalytic substrates. Herein, we discuss the challenges of such accumulative electron transfer in molecular systems. We present a series of closely related systems base on a Ru(II)-polypyridine photosensitizer with appended triaryl-amine or oligo-triaryl-amine donors, linked to nanoporous TiO2 as the acceptor. One of the systems, based on dye 4, shows efficient accumulative electron transfer in high overall yield resulting in the formation of a two-electron charge-separated state upon successive excitation by two photons. In contrast, the other systems do not show accumulative electron transfer because of different competing reactions. This illustrates the difficulties in designing successful systems for this still largely unexplored type of reaction scheme.
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http://dx.doi.org/10.1039/c1fd00089fDOI Listing
April 2012

Organic matter chlorination rates in different boreal soils: the role of soil organic matter content.

Environ Sci Technol 2012 Feb 17;46(3):1504-10. Epub 2012 Jan 17.

Department of Thematic Studies, Water and Environmental Studies, Linköping University, 58183 Linköping, Sweden.

Transformation of chloride (Cl(-)) to organic chlorine (Cl(org)) occurs naturally in soil but it is poorly understood how and why transformation rates vary among environments. There are still few measurements of chlorination rates in soils, even though formation of Cl(org) has been known for two decades. In the present study, we compare organic matter (OM) chlorination rates, measured by (36)Cl tracer experiments, in soils from eleven different locations (coniferous forest soils, pasture soils and agricultural soils) and discuss how various environmental factors effect chlorination. Chlorination rates were highest in the forest soils and strong correlations were seen with environmental variables such as soil OM content and Cl(-) concentration. Data presented support the hypothesis that OM levels give the framework for the soil chlorine cycling and that chlorination in more organic soils over time leads to a larger Cl(org) pool and in turn to a high internal supply of Cl(-) upon dechlorination. This provides unexpected indications that pore water Cl(-) levels may be controlled by supply from dechlorination processes and can explain why soil Cl(-) locally can be more closely related to soil OM content and the amount organically bound chlorine than to Cl(-) deposition.
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http://dx.doi.org/10.1021/es203191rDOI Listing
February 2012

Ultrafast X-ray absorption studies of the structural dynamics of molecular and biological systems in solution.

Chimia (Aarau) 2011 ;65(5):303-7

Ecole Polytechnique Féderale de Lausanne, Laboratory of Ultrafast Spectroscopy, EPFL-SB-ISIC-LSU, Station 6, CH-1015 Lausanne.

We review our recent studies of excited state structures and dynamics of chemical and biological systems with pico- and femtosecond X-ray absorption spectroscopy in the liquid phase.
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http://dx.doi.org/10.2533/chimia.2011.303DOI Listing
July 2011

Decisive situations affecting partners' support to continuous positive airway pressure-treated patients with obstructive sleep apnea syndrome: a critical incident technique analysis of the initial treatment phase.

J Cardiovasc Nurs 2012 May-Jun;27(3):228-39

ENT Clinic, Ryhov County Hospital, and School of Health Sciences, Jönköping University, Sweden.

Background And Research Objective: Effective treatment of obstructive sleep apnea syndrome (OSAS) with continuous positive airway pressure (CPAP) can reduce morbidity and mortality, but adherence rates are low. The partner has an important role in supporting the patient, but this role may be adversely affected by difficulties during the early phase of the CPAP initiation. The aim of this study was to explore and describe decisive situations affecting partners' support to patients with OSAS and how the partners manage these situations during the initial phase of CPAP treatment.

Subjects And Methods: A qualitative descriptive design using critical incident technique was used. A total of 542 decisive situations affecting partners' support and 222 situations describing managing were collected by means of interviews with 25 strategically selected partners of patients with CPAP treated OSAS.

Results: Adverse effects, limited effect, practical and psychosocial problems, limited presence, and inappropriate initiation emerged as negative influences on the partners' support. A well-functioning treatment, improvements, high motivation, and receiving support from others were identified as positive influences on the partners' support. The partner managed the situations by letting the patient handle the CPAP treatment by himself/herself, by handling the treatment together with the patient, or taking over the handling of CPAP treatment.

Conclusion: Increased knowledge about the different situations that affect the partners' support negatively or positively and how these situations are managed by partners can be used in educational situations involving both patients and partners during CPAP initiation.
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http://dx.doi.org/10.1097/JCN.0b013e3182189c34DOI Listing
August 2012

A high-repetition rate scheme for synchrotron-based picosecond laser pump/x-ray probe experiments on chemical and biological systems in solution.

Rev Sci Instrum 2011 Jun;82(6):063111

Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, 1015 Lausanne, Switzerland.

We present the extension of time-resolved optical pump/x-ray absorption spectroscopy (XAS) probe experiments towards data collection at MHz repetition rates. The use of a high-power picosecond laser operating at an integer fraction of the repetition rate of the storage ring allows exploitation of up to two orders of magnitude more x-ray photons than in previous schemes based on the use of kHz lasers. Consequently, we demonstrate an order of magnitude increase in the signal-to-noise of time-resolved XAS of molecular systems in solution. This makes it possible to investigate highly dilute samples at concentrations approaching physiological conditions for biological systems. The simplicity and compactness of the scheme allows for straightforward implementation at any synchrotron beamline and for a wide range of x-ray probe techniques, such as time-resolved diffraction or x-ray emission studies.
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http://dx.doi.org/10.1063/1.3600616DOI Listing
June 2011

Accumulative charge separation inspired by photosynthesis.

J Am Chem Soc 2010 Dec 7;132(51):17977-9. Epub 2010 Dec 7.

Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.

Molecular systems that follow the functional principles of photosynthesis have attracted increasing attention as a method for the direct production of solar fuels. This could give a major carbon-neutral energy contribution to our future society. An outstanding challenge in this research is to couple the light-induced charge separation (which generates a single electron-hole pair) to the multielectron processes of water oxidation and fuel generation. New design considerations are needed to allow for several cycles of photon absorption and charge separation of a single artificial photosystem. Here we demonstrate a molecular system with a regenerative photosensitizer that shows two successive events of light-induced charge separation, leading to high-yield accumulation of redox equivalents on single components without sacrificial agents.
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http://dx.doi.org/10.1021/ja104809xDOI Listing
December 2010

Posttraumatic stress, anxiety and depression symptoms in patients during the first year post intensive care unit discharge.

Crit Care 2010 8;14(1):R14. Epub 2010 Feb 8.

Intensive Care Unit, Ulleval, Oslo University Hospital, Kirkeveien 177, 0407 Oslo, Norway.

Introduction: To study the level and predictors of posttraumatic stress, anxiety and depression symptoms in medical, surgical and trauma patients during the first year post intensive care unit (ICU) discharge.

Methods: Of 255 patients included, 194 participated at 12 months. Patients completed the Impact of Event Scale (IES), Hospital Anxiety and Depression Scale (HADS), Life Orientation Test (LOT) at 4 to 6 weeks, 3 and 12 months and ICU memory tool at the first assessment (baseline). Case level for posttraumatic stress symptoms with high probability of a posttraumatic stress disorder (PTSD) was > or = 35. Case level of HADS-Anxiety or Depression was > or = 11. Memory of pain during ICU stay was measured at baseline on a five-point Likert-scale (0-low to 4-high). Patient demographics and clinical variables were controlled for in logistic regression analyses.

Results: Mean IES score one year after ICU treatment was 22.5 (95%CI 20.0 to 25.1) and 27% (48/180) were above case level, IES > or = 35. No significant differences in the IES mean scores across the three time points were found (P = 0.388). In a subgroup, 27/170 (16%), patients IES score increased from 11 to 32, P < 0.001. No differences in posttraumatic stress, anxiety or depression between medical, surgical and trauma patients were found. High educational level (OR 0.4, 95%CI 0.2 to 1.0), personality trait (optimism) OR 0.9, 95%CI 0.8 to 1.0), factual recall (OR 6.6, 95%CI 1.4 to 31.0) and memory of pain (OR 1.5, 95%CI 1.1 to 2.0) were independent predictors of posttraumatic stress symptoms at one year. Optimism was a strong predictor for less anxiety (OR 0.8, 0.8 to 0.9) and depression symptoms (OR 0.8, 0.8 to 0.9) after one year.

Conclusions: The mean level of posttraumatic stress symptoms in patients one year following ICU treatment was high and one of four were above case level Predictors of posttraumatic stress symptoms were mainly demographics and experiences during hospital stay whereas clinical injury related variables were insignificant. Pessimism was a predictor of posttraumatic stress, anxiety and depression symptoms. A subgroup of patients developed clinically significant distress symptoms during the follow-up period.
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http://dx.doi.org/10.1186/cc8870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875529PMC
September 2010

Vectorial electron transfer in donor-photosensitizer-acceptor triads based on novel bis-tridentate ruthenium polypyridyl complexes.

Chemistry 2010 Mar;16(9):2830-42

Department of Photochemistry and Molecular Science, Uppsala University, Box 523, 751 20 Uppsala, Sweden.

The first examples of rodlike donor-photosensitizer-acceptor arrays based on bis-2,6-di(quinolin-8-yl)pyridine Ru(II) complexes 1a and 3a for photoinduced electron transfer have been synthesized and investigated. The complexes are synthesized in a convergent manner and are isolated as linear, single isomers. Time-resolved absorption spectroscopy reveals long-lived, photoinduced charge-separated states (tau(CSS) (1a)=140 ns, tau(CSS) (3a)=200 ns) formed by stepwise electron transfer. The overall yields of charge separation (> or = 50% for complex 1a and > or = 95% for complex 3a) are unprecedented for bis-tridentate Ru(II) polypyridyl complexes. This is attributed to the long-lived excited state of the [Ru(dqp)(2)](2+) complex combined with fast electron transfer from the donor moiety following the initial charge separation. The rodlike arrangement of donor and acceptor gives controlled, vectorial electron transfer, free from the complications of stereoisomeric diversity. Thus, such arrays provide an excellent system for the study of photoinduced electron transfer and, ultimately, the harvesting of solar energy.
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http://dx.doi.org/10.1002/chem.200902716DOI Listing
March 2010

Patients' memory and psychological distress after ICU stay compared with expectations of the relatives.

Intensive Care Med 2009 Dec 15;35(12):2078-86. Epub 2009 Sep 15.

Intensive Care Unit, Oslo University Hospital, Ulleval, Oslo, Norway.

Purpose: To compare patients' psychological distress and memories from intensive care unit (ICU) treatment 4-6 weeks after ICU discharge with expectations of their relatives. Further, to explore the relationship between personality traits and ICU memories with psychological distress.

Methods: A cross-sectional study of 255 patients and 298 relatives. The questionnaire included: hospital anxiety and depression scale (HADS), impact of event scale (IES), life orientation test, ICU memory tool and memory of ICU; technical procedures, pain, lack of control and inability to express needs. Relatives were assessed for their expectations of the patients' memories and psychological distress.

Results: Twenty-five percent of the patients reported severe posttraumatic stress symptoms, IES-total >or= 35. The levels of anxiety and depression were significantly higher than in the general population, mean anxiety was 5.6 versus 4.2 (p < 0.001), and mean depression was 4.8 versus 3.5 (p < 0.001). Relatives expected more psychological distress and the relatives thought the patient was less able to express needs than the patients reported (p < 0.001). Higher age, unemployment, respirator treatment, pessimism, memory of pain, lack of control and inability to express needs were independent predictors of posttraumatic stress symptoms (p < 0.01).

Conclusions: Psychological distress symptoms were frequent among ICU survivors. Relatives expected the patients to be more distressed after ICU treatment than the patients reported. The strongest predictors of posttraumatic stress symptoms from the ICU were memoris about pain, lack of control and inability to express needs. Pessimism may be a reason for psychological distress and should be addressed during follow up, as pessimistic patients may need more motivation and support.
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http://dx.doi.org/10.1007/s00134-009-1614-1DOI Listing
December 2009

Temperature sensitivity indicates that chlorination of organic matter in forest soil is primarily biotic.

Environ Sci Technol 2009 May;43(10):3569-73

Department of Geology and Geochemistry, Stockholm University, SE-106 91 Stockholm, Sweden.

Old assumptions that chloride is inert and that most chlorinated organic matter in soils is anthropogenic have been challenged by findings of naturally formed organochlorines. Such natural chlorination has been recognized for several decades, but there are still very few measurements of chlorination rates or estimates of the quantitative importance of terrestrial chlorine transformations. While much is known about the formation of specific compounds, bulk chlorination remains poorly understood in terms of mechanisms and effects of environmental factors. We quantified bulk chlorination rates in coniferous forest soil using 36Cl-chloride in tracer experiments at different temperatures and with and without molecular oxygen (O2). Chlorination was enhanced by the presence of O2 and had a temperature optimum at 20 degrees C. Minimum rates were found at high temperatures (50 degrees C) or under anoxic conditions. The results indicate (1) that most of the chlorination between 4 and 40 degrees C was biotic and driven by O2 dependent enzymes, and (2) that there is also slower background chlorination occurring under anoxic conditions at 20 degrees C and under oxic conditions at 50 degrees C. Hence, while oxic and biotic chlorination clearly dominated, chlorination by other processes including possible abiotic reactions was also detected.
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http://dx.doi.org/10.1021/es8035779DOI Listing
May 2009

Patients on the waiting list for total hip replacement: a 1-year follow-up study.

Scand J Caring Sci 2008 Dec;22(4):536-42

Division of Nursing Science, Department of Medicine and Care, Faculty of Health Sciences, University of Linköping, Linköping, Sweden.

Untreated osteoarthritis (OA) in the hip causes pain and reduced physical and social functioning. The aim of this study was to evaluate the effect of waiting time on health-related quality of life (HRQOL), functional condition and dependence on help at the time of surgery and during follow-up 1 year after surgery. A further aim was to elucidate possible differences between men and women. Two hundred and twenty-nine consecutively included patients with OA in the hip were interviewed when assigned to the waiting list, again 1 week prior to surgery with unilateral total hip replacement (THR), and 1 year after surgery. Health-related quality of life and function were measured using the Nottingham Health Profile, EuroQoL and the Western Ontario and McMaster Universities Osteoarthritis Index. The result showed that the average waiting time was 239 days, that 15% of the patients were operated on within 3 months, and that 21% had to wait more than 6 months. At the time of surgery, HRQOL had deteriorated significantly (p < 0.05) and the number of patients receiving support from relatives had increased from 31% to 58% during the wait. At the 1-year follow-up, both HRQOL and functional condition had improved significantly despite the wait, and the need for support from relatives had decreased to 11% (p < 0.001). In conclusion, long waiting time for THR is detrimental to patients' HRQOL causing reduced functional condition, pain and increased need for support from relatives, which limit the independence in daily life.
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http://dx.doi.org/10.1111/j.1471-6712.2007.00567.xDOI Listing
December 2008

How close can you get? Studies of ultrafast light-induced processes in ruthenium-[60] fullerene dyads with short pyrazolino and pyrrolidino links.

Inorg Chem 2008 Aug 18;47(16):7286-94. Epub 2008 Jul 18.

Department of Biochemistry and Organic Chemistry, Uppsala University, Box 576, SE- 751 24 Uppsala, Sweden.

Two pyrazoline- and one pyrrolidine-bridged Ru(II)bipyridine-[60]fullerene dyads have been prepared and studied by ultrafast time-resolved spectroscopy. A silver-assisted synthesis route, in which Ag(I) removes the chlorides from the precursor complex Ru(bpy) 2Cl 2 facilitates successful coordination of the [60]fullerene-substituted third ligand. Upon light excitation of the ruthenium moiety, the emission was strongly quenched by the fullerene. The main quenching mechanism is an exceptionally fast direct energy transfer ( k obs > 1 x 10 (12) s (-1) in the pyrazoline-bridged dyads), resulting in population of the lowest excited triplet state of fullerene. No evidence for electron transfer was found, despite the extraordinarily short donor-acceptor distance that could kinetically favor that process. The observations have implications on the ongoing development of devices built from Ru-polypyridyl complexes and nanostructured carbon, such as C 60 or nanotubes.
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http://dx.doi.org/10.1021/ic800168dDOI Listing
August 2008

Very large acceleration of the photoinduced electron transfer in a Ru(bpy)3-naphthalene bisimide dyad bridged on the naphthyl core.

Chem Commun (Camb) 2007 Jan 22(1):64-6. Epub 2006 Nov 22.

Laboratoire de Synthèse Organique, UMR 6513 CNRS & FR CNRS 2465, Université de Nantes, Faculté des Sciences et des Techniques de Nantes, BP 92208, Nantes Cedex 03, France.

By linking a naphthalenebisimide (NBI) unit to [Ru(bpy)3]2+ on the naphthyl core the rate of photoinduced Ru-to-NBI electron transfer was 1000-fold increased compared to the case with a conventional linking on the nitrogen.
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http://dx.doi.org/10.1039/b615085cDOI Listing
January 2007