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  • 1.
    Appelros, Peter
    et al.
    University of Örebro, Sweden.
    Hals Berglund, Maria
    University Hospital Norrland, Sweden.
    Ström, Jakob O.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. University of Örebro, Sweden.
    Long-Term Risk of Stroke after Transient Ischemic Attack2017In: Cerebrovascular Diseases, ISSN 1015-9770, E-ISSN 1421-9786, Vol. 43, no 1-2, p. 25-30Article in journal (Refereed)
    Abstract [en]

    Background: In the absence of active management, the stroke risk after a transient ischemic attack (TIA) may be high. Almost 10 years ago, the results of the EXPRESS and SOS-TIA studies called for a more rapid management of TIA patients. The purpose of this study was to investigate the other stroke risks in the longer term, after the implementation of a more active approach to TIA. We also wanted to assess the predictive value of the ABCD2 score in this context. Methods: Riksstroke is the national stroke registry in Sweden. Data from Riksstrokes TIA module, and the national cause-of-death register, for the years 2011 and 2012 were used in this study. Stroke occurrence was monitored via Riksstroke. Coxs regression was used for risk evaluation. The predictive value of the ABCD2 score was assessed by calculating the area under the receiver operating characteristics curve. Results: A total of 15,068 TIA episodes occurred in 14,102 patients. The follow-up time varied between 0 and 819 days, with an average of 417 days. The mortality for all TIA patients during the follow-up time was 7.1%. Of the unique patients, 545 had one or more strokes (3.9%), corresponding to 34 events per 1,000 person years. Significant risk factors for stroke were: age, previous TIA, atrial fibrillation (AF), oral anticoagulant (OAC) treatment, hypertension treatment, and the ABCD2 items speech impairment, unilateral weakness, and diabetes mellitus. The ABCD2 score correlated with a subsequent stroke, but its predictive value was low. Conclusion: The risk of stroke is low after the acute phase of a TIA, probably lower than in previous studies. This may be due to better secondary prevention in recent years. Several risk factors predict stroke, notably hypertensive treatment, which may be inadequate; and AF, where OACs may be under-used. It is difficult to identify the role of the ABCD2 score in clinical practice. (C) 2016 S. Karger AG, Basel

  • 2.
    Boknäs, Niklas
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Faxälv, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob O
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Sahlgrenska Academy, University of Gothenburg, Sweden.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Response: platelets do not generate activated factor XII--how inappropriate experimental models have led to misleading conclusions2014In: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 124, no 10, p. 1692-1694Article in journal (Other academic)
  • 3.
    Faxälv, Lars
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Boknäs, Niklas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    University of Gothenburg, Gothenburg, Sweden .
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Putting polyphosphates to the test: evidence against platelet-induced activation of factor XII2013In: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 122, no 23, p. 3818-3824Article in journal (Refereed)
    Abstract [en]

    The recent claim that stimulated platelets activate the intrinsic pathway of coagulation by the release of polyphosphates has been considered a breakthrough in hemostasis research. In little more than 3 years, the original publication by Muller et al has been cited greater than100 times. However, none of the citing articles has sought to independently validate this potentially paradigm-shifting concept. To this end, we performed extensive experimentation in vitro and in vivo in an attempt to verify the claim that factor XII (FXII) is primarily activated by stimulated platelets. In contrast to the original assertion, platelet-derived polyphosphates were found to be weak activators of FXII, with a FXIIa-generating activity of less than10% compared with equivalent concentrations of kaolin. Using different coagulation assays, it was shown that platelet contribution to whole blood coagulation was unrelated to the generation of activated FXII in vitro. Additionally, key results used to verify the hypothesis in the original study in vivo were found to be irreproducible. We conclude that platelet-derived polyphosphates are not physiologically relevant activators of FXII.

  • 4.
    Hjort af Ornäs, Anders
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ström, Jakob
    Linköping University, The Tema Institute.
    Subjective views and innovative mechanisms in approaches to environmental security1999Report (Other academic)
    Abstract [en]

             

  • 5.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Orebro Univ, Sweden.
    Dock, Hua
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Ström, Jakob O.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Orebro Univ, Sweden.
    Effect of laser Doppler flowmetry and occlusion time on outcome variability and mortality in rat middle cerebral artery occlusion: inconclusive results2018In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 19, article id 24Article in journal (Refereed)
    Abstract [en]

    Background: Stroke is among the leading causes of death and disability. Although intense research efforts have provided promising treatment options in animals, most clinical trials in humans have failed and the therapeutic options are few. Several factors have been suggested to explain this translational difficulty, particularly concerning methodology and study design. Consistent infarcts and low mortality might be desirable in some, but not all, studies. Here, we aimed to investigate whether the use of laser Doppler flowmetry (LDF) and the occlusion time (60 vs. 45 min) affected outcome variability and mortality in a rat stroke model. Eighty ovariectomized female Wistar rats were subjected to ischemic stroke using intraluminal filament middle cerebral artery occlusion with or without LDF and with occlusion times of 45 or 60 min. Outcome was evaluated by triphenyl tetrazolium chloride staining of brain slices to measure infarct size and a modified sticky tape test. Results: Neither LDF nor occlusion times of 45 versus 60 min significantly affected mortality, outcome variability or outcome severity. Conclusions: Due to the unexpectedly high mortality and variability the statistical power was very low and thus the results were inconclusive.

  • 6.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Dock, Hua
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Ström, Jakob O
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Vårdvetenskapligt Forskningscentrum/Centre for Health Sciences, Örebro University Hospital, Region Örebro Län, Örebro, Sweden / School of Health and Medical Sciences, Örebro University, Örebro, Sweden..
    Method parameters’ impact on mortality and variability in mouse stroke experiments: a meta-analysis2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6Article in journal (Refereed)
    Abstract [en]

    Although hundreds of promising substances have been tested in clinical trials, thrombolysis currently remains the only specifi c pharmacological treatment for ischemic stroke. Poor quality, e.g. low statistical power, in the preclinical studies has been suggested to play an important role in these failures. Therefore, it would be attractive to use animal models optimized to minimize unnecessary mortality and outcome variability, or at least to be able to power studies more exactly by predicting variability and mortality given a certain experimental setup. The possible combinations of methodological parameters are innumerous, and an experimental comparison of them all is therefore not feasible. As an alternative approach, we extracted data from 334 experimental mouse stroke articles and, using a hypothesis-driven meta-analysis, investigated the method parameters’ impact on infarct size variability and mortality. The use of Swiss and C57BL6 mice as well as permanent occlusion of the middle cerebral artery rendered the lowest variability of the infarct size while the emboli methods increased variability. The use of Swiss mice increased mortality. Our study offers guidance for researchers striving to optimize mouse stroke models.

  • 7.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics.
    Gudjonsdottir, Johanna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. County Council Örebro, Sweden; University of Örebro, Sweden.
    Elevated body swing test after focal cerebral ischemia in rodents: methodological considerations2015In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 16, no 50Article in journal (Refereed)
    Abstract [en]

    Background: The elevated body swing test (EBST) is a behavioral test used to evaluate experimental stroke in rodents. The basic idea is that when the animal is suspended vertically by the tail, it will swing its head laterally to the left or right depending on lesion side. In a previous study from our lab using the EBST after middle cerebral artery occlusion (MCAo), rats swung contralateral to the infarct day 1 post-MCAo, but ipsilateral day 3 post-MCAo. This shift was unexpected and prompted us to perform the present study. First, the literature was systematically reviewed to elucidate whether a similar shift had been noticed before, and if consensus existed regarding swing direction. Secondly, an experiment was conducted to systematically investigate the suggested behavior. Eighty-three adult male and female Sprague-Dawley rats were subjected to MCAo or sham surgery and the EBST was performed up to 7 days after the lesion. Results: Both experimentally and through systematic literature review, the present study shows that the direction of biased swing activity in the EBST for rodents after cerebral ischemia can differ and even shift over time in some situations. The EBST curve for females was significantly different from that of males after the same occlusion time (p = 0.023). Conclusions: This study highlights the importance of adequate reporting of behavioral tests for lateralization and it is concluded that the EBST cannot be recommended as a test for motor asymmetry after MCAo in rats.

  • 8.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob O
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Methods for long-term 17β-estradiol administration to mice2012In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 175, no 1, p. 188-193Article in journal (Refereed)
    Abstract [en]

    Rodent models constitute a cornerstone in the elucidation of the effects and biological mechanisms of 17β-estradiol. However, a thorough assessment of the methods for long-term administration of 17β-estradiol to mice is lacking. The fact that 17β-estradiol has been demonstrated to exert different effects depending on dose emphasizes the need for validated administration regimens. Therefore, 169 female C57BL/6 mice were ovariectomized and administered 17β-estradiol using one of the two commonly used subcutaneous methods; slow-release pellets (0.18 mg, 60-day release pellets; 0.72 mg, 90-day release pellets) and silastic capsules (with/without convalescence period, silastic laboratory tubing, inner/outer diameter: 1.575/3.175 mm, filled with a 14 mm column of 36 μg 17β-estradiol/mL sesame oil), or a novel peroral method (56 μg 17β-estradiol/day/kg body weight in the hazelnut cream Nutella). Forty animals were used as ovariectomized and intact controls. Serum samples were obtained weekly for five weeks and 17β-estradiol concentrations were measured using radioimmunoassay. The peroral method resulted in steady concentrations within – except on one occasion – the physiological range and the silastic capsules produced predominantly physiological concentrations, although exceeding the range by maximum a factor three during the first three weeks. The 0.18 mg pellet yielded initial concentrations an order of magnitude higher than the physiological range, which then decreased drastically, and the 0.72 mg pellet produced between 18 and 40 times higher concentrations than the physiological range during the entire experiment. The peroral method and silastic capsules described in this article constitute reliable modes of administration of 17β-estradiol, superior to the widely used commercial pellets.

  • 9.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. veÖrebro University Hospital, Sweden; Unirsity of Örebro, Sweden.
    Effects of high and low 17 beta-estradiol doses on focal cerebral ischemia in rats2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, no 20228Article in journal (Refereed)
    Abstract [en]

    The majority of the numerous animal studies of the effects of estrogens on cerebral ischemia have reported neuroprotective results, but a few have shown increased damage. Differences in hormone administration methods, resulting in highly different 17 beta-estradiol levels, may explain the discrepancies in previously reported effects. The objective of the present study was to test the hypothesis that it is the delivered dose per se, and not the route and method of administration, that determines the effect, and that high doses are damaging while lower doses are protective. One hundred and twenty ovariectomized female Wistar rats (n = 40 per group) were randomized into three groups, subcutaneously administered different doses of 17 beta-estradiol and subjected to transient middle cerebral artery occlusion. The modified sticky tape test was performed after 24 h and the rats were subsequently sacrificed for infarct size measurements. In contrast to our hypothesis, a significant negative correlation between 17 beta-estradiol dose and infarct size was found (p = 0.018). Thus, no support was found for the hypothesis that 17 beta-estradiol can be both neuroprotective and neurotoxic merely depending on dose. In fact, on the contrary, the findings indicate that the higher the dose of 17 beta-estradiol, the smaller the infarct.

  • 10.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Ström, Jakob O
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Vårdvetenskapligt Forskningscentrum/Centre for Health Sciences, Örebro University Hospital, Region Örebro Län, Örebro, Sweden / School of Health and Medical Sciences, Örebro University, Örebro, Sweden..
    Effects of high and low 17β-estradiol doses on focal cerebral ischemia in rats2016Manuscript (preprint) (Other academic)
    Abstract [en]

    The majority of the numerous animal studies of the effects of estrogens on cerebral ischemia have reported neuroprotective results, but a few have shown increased damage. Differences in hormone administration methods, resulting in highly different 17β-estradiol levels, may explain the discrepancies in previously reported effects. The objective of the present study was to test the hypothesis that it is the delivered dose per se, and not the route and method of administration, that determines the effect, and that high doses are damaging while lower doses are protective. One hundred and twenty ovariectomized female Wistar rats (n=40 per group) were randomized into three groups, subcutaneously administered different doses of 17β-estradiol and subjected to transient middle cerebral artery occlusion. The modifi ed sticky tape test was performed after 24 h and the rats were subsequently sacrifi ced for infarct size measurements. In contrast to our hypothesis, a signifi cant negative correlation between 17β-estradiol dose and infarct size was found (p=0.018). Thus, no support was found for the hypothesis that 17β-estradiol can be both neuroprotective and neurotoxic merely depending on dose. In fact, on the contrary, the fi ndings indicate that the higher the dose of 17β-estradiol, the smaller the infarct.

  • 11.
    Isaksson, Ida-Maria
    et al.
    Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Methods for 17 beta-oestradiol administration to rats2011In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 71, no 7, p. 583-592Article in journal (Refereed)
    Abstract [en]

    Several studies indicate that the beneficial or harmful effects of oestrogens in stroke are dose-dependent. Rats are amongst the most frequently used animals in these studies, which calls for thoroughly validated methods for administering 17 beta-oestradiol to rats. In an earlier study we characterised three different administration methods for 17 beta-oestradiol over 42 days. The present study assesses the concentrations in a short time perspective, with the addition of a novel peroral method. Female Sprague-Dawley rats were ovariectomised and administered 17 beta-oestradiol by subcutaneous injections, silastic capsules, pellets and orally (in the nut-cream Nutella (R)), respectively. One group received 17 beta-oestradiol by silastic capsules without previous washout time. Blood samples were obtained after 30 minutes, 1, 2, 4, 8, 12, 24, 48 and 168 hours and serum 17 beta-oestradiol (and oestrone sulphate in some samples) was subsequently analysed. For long-term characterisation, one group treated perorally was blood sampled after 2, 7, 14, 21, 28, 35 and 42 days. At sacrifice, uterine horns were weighed and subcutaneous tissue samples were taken for histological assessment. The pellets, silastic capsule and injection groups produced serum 17 beta-oestradiol concentrations that were initially several orders of magnitude higher than physiological levels, while the peroral groups had 17 beta-oestradiol levels that were within the physiological range during the entire experiment. The peroral method is a promising option for administering 17 beta-oestradiol if physiological levels or similarity to womens oral hormone therapy are desired. Uterine weights were found to be a very crude measure of oestrogen exposure.

  • 12.
    Ivars, Katrin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Nelson Follin, Nina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping. Gothenburg University, Sweden.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Mörelius, Evalotte
    Linköping University, Department of Social and Welfare Studies, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Correction: Development of Salivary Cortisol Circadian Rhythm and Reference Intervals in Full-Term Infants2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 3, article id e0151888Article in journal (Other academic)
    Abstract [en]

    BACKGROUND:

    Cortisol concentrations in plasma display a circadian rhythm in adults and children older than one year. Earlier studies report divergent results regarding when cortisol circadian rhythm is established. The present study aims to investigate at what age infants develop a circadian rhythm, as well as the possible influences of behavioral regularity and daily life trauma on when the rhythm is established. Furthermore, we determine age-related reference intervals for cortisol concentrations in saliva during the first year of life.

    METHODS:

    130 healthy full-term infants were included in a prospective, longitudinal study with saliva sampling on two consecutive days, in the morning (07:30-09:30), noon (10:00-12:00) and evening (19:30-21:30), each month from birth until the infant was twelve months old. Information about development of behavioral regularity and potential exposure to trauma was obtained from the parents through the Baby Behavior Questionnaire and the Life Incidence of Traumatic Events checklist.

    RESULTS:

    A significant group-level circadian rhythm of salivary cortisol secretion was established at one month, and remained throughout the first year of life, although there was considerable individual variability. No correlation was found between development of cortisol circadian rhythm and the results from either the Baby Behavior Questionnaire or the Life Incidence of Traumatic Events checklist. The study presents salivary cortisol reference intervals for infants during the first twelve months of life.

    CONCLUSIONS:

    Cortisol circadian rhythm in infants is already established by one month of age, earlier than previous studies have shown. The current study also provides first year age-related reference intervals for salivary cortisol levels in healthy, full-term infants.

  • 13.
    Ivars, Katrin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Nelson Follin, Nina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping. Gothenburg University, Sweden.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Mörelius, Evalotte
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping.
    Development of Salivary Cortisol Circadian Rhythm and Reference Intervals in Full-Term Infants2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 6, article id e0129502Article in journal (Refereed)
    Abstract [en]

    Background Cortisol concentrations in plasma display a circadian rhythm in adults and children older than one year. Earlier studies report divergent results regarding when cortisol circadian rhythm is established. The present study aims to investigate at what age infants develop a circadian rhythm, as well as the possible influences of behavioral regularity and daily life trauma on when the rhythm is established. Furthermore, we determine age-related reference intervals for cortisol concentrations in saliva during the first year of life. Methods 130 healthy full-term infants were included in a prospective, longitudinal study with saliva sampling on two consecutive days, in the morning (07:30-09:30), noon (10:00-12:00) and evening (19:30-21:30), each month from birth until the infant was twelve months old. Information about development of behavioral regularity and potential exposure to trauma was obtained from the parents through the Baby Behavior Questionnaire and the Life Incidence of Traumatic Events checklist. Results A significant group-level circadian rhythm of salivary cortisol secretion was established at one month, and remained throughout the first year of life, although there was considerable individual variability. No correlation was found between development of cortisol circadian rhythm and the results from either the Baby Behavior Questionnaire or the Life Incidence of Traumatic Events checklist. The study presents salivary cortisol reference intervals for infants during the first twelve months of life. Conclusions Cortisol circadian rhythm in infants is already established by one month of age, earlier than previous studies have shown. The current study also provides first year age-related reference intervals for salivary cortisol levels in healthy, full-term infants.

  • 14.
    Paues, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Eriksson, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Tuberculous meningitis with positive cell-count in lumbar puncture CSF though negative cell-count from ventricular drainage CSF2011In: Journal of Infection, ISSN 0163-4453, E-ISSN 1532-2742, Vol. 62, no 5, p. 404-405Article in journal (Other academic)
  • 15.
    Ruborg, Rebecca
    et al.
    Örebro University, Sweden.
    Gunnarsson, Karin
    Örebro University, Sweden.
    Ström, Jakob O.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry. Örebro University, Sweden; Neuro and Rehabmed Kliniken, Sweden.
    Predictors of post-stroke body temperature elevation2017In: BMC Neurology, ISSN 1471-2377, E-ISSN 1471-2377, Vol. 17, article id 218Article in journal (Refereed)
    Abstract [en]

    Background: Growing evidence indicates that elevated body temperature after stroke is associated with unfavorable outcome. The aim of the current study was to investigate which factors predict temperature elevation within 48 h of stroke onset. Specifically, we hypothesized that temperature elevation would be associated with stroke symptom severity and that hemorrhagic stroke would cause a more pronounced temperature increase compared to ischemic stroke. Methods: The medical records of 400 stroke patients were retrospectively reviewed. Multiple linear regression analysis was used to determine which factors were associated with elevated body temperature. Results: Several factors were significantly associated with peak body temperature (the highest recorded body temperature) within 48 h of stroke onset: stroke severity measured by the National Institutes of Health Stroke Scale (NIHSS) (regression coefficient; (RC) 0.022), female gender (RC 0.157), tympanic/non-rectal temperature reading (RC -0.265), swallowing difficulties (RC 0.335), intubation (RC 0.470), antipyretic treatment (RC 0.563), and C-reactive protein amp;gt; 50 or signs of infection at admission (RC 0.298). Contrary to our expectations, patients with intracerebral hemorrhage did not have higher peak body temperatures than patients with ischemic stroke. Conclusions: In conclusion, temperature elevation within the first 48 h of stroke onset is common, can be partially predicted using information at admission and is strongly associated with stroke severity. The strong association with stroke severity may, at least partly, explain the previously described association between post-stroke temperature elevation and unfavorable outcome.

  • 16.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    The dose-dependent effects of estrogens on ischemic stroke2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Estrogens are a group of female sex hormones that in addition to central roles in reproductive functions also have profound impact on for example brain development, blood vessels, bone tissue, metabolism and the immune system. The dominant endogenous production sites for estrogens in females are the ovaries and adipose tissue, while exogenous sources include combined contraceptive hormone treatments and menopausal hormone therapy. A few decades ago, the observation that females in comparison to men seemed to be protected against cerebral ischemia, and that this benefit was partially lost during menopause, sparked the hypothesis that estrogens protect against stroke. This was later confirmed by epidemiological studies and a large number of experimental animal studies, which motivated extensive clinical trials in which estrogens and/or progestagens were administered with the intent to prevent degenerative conditions rather than to ameliorate menopausal symptoms. However, the results were generally disappointing. The largest study, the Women’s Health Initiative (WHI), was discontinued due to the observation of an increased risk of breast cancer, cardiovascular disease and stroke. In parallel, a small number of animal studies in which estrogens were shown to increase damage from cerebral ischemia were published, one of these originating from our laboratory. This was, despite the WHI outcome, a surprising result, since the vast majority of previous animal studies had demonstrated protective effects.

    Therefore, in an attempt to explain the discordant results, Paper 1, and later Paper 4, of the current thesis were planned, in which four 17β-estradiol administration methods were tested. Substantial differences in serum hormone concentrations resulted from the different methods. Most importantly, the commercially available slow-release pellets used in our earlier experiments resulted in extremely high serum concentrations of 17β-estradiol. In Paper 2, 66 published studies that had investigated the effects of estrogens on stroke were meta-analyzed to pin-point the methodological reasons for the result dichotomy. Strikingly, in all six studies in which estrogens had produced damaging effects, the same type of slow-release pellets had been used, although these were used in a minority of the total number of studies. Paper 3 substantially strengthened the hypothesis that administration methods were crucial by showing that repeating the earlier experiment from our laboratory in which pellets had been used, but using a low-dose regimen instead, switched the estrogen effects from neurodamaging to neuroprotective. In Paper 5, an effort was made to challenge the assumption that the dose, and not the administration method per se, was the key factor, however this failed due to large intra-group infarct size variability.

    The current thesis adds evidence to the notion that differences in administration methods and their resulting serum concentrations of 17β-estradiol constitute a major factor responsible for the dichotomous results in studies investigating estrogens’ effects on cerebral ischemia. Even though results from animal studies are difficult to extrapolate to humans, this has a bearing on the menopausal hormone therapy debate, indicating that the risk of stroke could be reduced if serum concentrations of estrogens are minimized.

    List of papers
    1. Order of magnitude differences between methods for maintaining physiological 17β-estradiol concentrations in ovariectomized rats
    Open this publication in new window or tab >>Order of magnitude differences between methods for maintaining physiological 17β-estradiol concentrations in ovariectomized rats
    2008 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 68, no 8, p. 814-822Article in journal (Refereed) Published
    Abstract [en]

    The use of animal, especially rat, models, is crucial for elucidating the biological effects and mechanisms of the widely used hormone 17β-estradiol. Unfortunately there is a lack of consensus on optimal means of obtaining and maintaining physiological 17β-estradiol concentrations in plasma. This may be the reason for varying results in several studies including the disagreement on whether 17β-estradiol is neuroprotective or not. Very few studies have been devoted to investigating the characteristics and biological relevance of different methods of 17β-estradiol administration. We therefore ovariectomized 75 Sprague-Dawley rats and, following a 2 weeks wash-out period, administered 17β-estradiol using three different methods; daily injections (10 µg 17β-estradiol/kg), slow-release pellets (0.25 mg 60 day-release pellets, 0.10 mg 90 day-release pellets) and silastic capsules (with/without wash-out periods) (silastic laboratory tubing, inner/outer diameter: 1.575/3.175 mm, filled with 20 mm columns of 180 µg 17β-estradiol/mL sesame oil). Further 45 animals were used as ovariectomized and native controls, studied in different parts of the estrous cycle. Silastic capsules produced concentrations of 17β-estradiol within the physiological range for 4-5 weeks independent of whether a prior wash-out period was included or not. The slow-release pellets, irrespective of dose or release period, resulted in initial concentrations which were an order of magnitude above physiological concentrations during the first two weeks followed by a substantial decrease. Daily injections resulted in increasing 17β-estradiol concentrations, however within physiological levels. Silastic capsules are conveniently manufactured and used, and are superior to pellets and injections in reliably producing long-term 17β-estradiol concentrations within the physiological range.

    Keywords
    Estrogens, Injections, Pharmacokinetics, Silastic capsules, Slow-release pellets, Wash-out
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-15389 (URN)10.1080/00365510802409703 (DOI)
    Note
    Original publication: Jakob O. Ström, Elvar Theodorsson and Annette Theodorsson, Order of magnitude differences between methods for maintaining physiological 17β-estradiol concentrations in ovariectomized rats, 2008, Scandinavian Journal of Clinical and Laboratory Investigation.http://dx.doi.org/10.1080/00365510802409703. Copyright © Taylor & Francis Group, an informa businessAvailable from: 2008-11-05 Created: 2008-11-05 Last updated: 2017-12-14Bibliographically approved
    2. Dose-related neuroprotective versus neurodamaging effects of estrogens in rat cerebral ischemia: a systematic analysis
    Open this publication in new window or tab >>Dose-related neuroprotective versus neurodamaging effects of estrogens in rat cerebral ischemia: a systematic analysis
    2009 (English)In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 29, no 8, p. 1359-1372Article, review/survey (Refereed) Published
    Abstract [en]

    Numerous studies of the effects of estrogens for stroke prevention have yielded conflicting results in human and animal studies alike. We present a systematical analysis of study design and methodological differences between 66 studies where estrogens impact on ischemic brain damage in rat models has been investigated, providing evidence that the differences in results may be explained by high estrogen doses produced by slow-release pellets. These pellets have been used in all studies showing increased neurologic damage because of estrogens. Our data indicate that the increased neurologic damage is related to the pellets plasma concentration profile with an early, prolonged, supraphysiological peak. Neither the method of inducing the ischemic brain lesions, the choice of variables for measuring outcome, the measured plasma concentrations of estrogens at the time of ischemia nor rat population attributes (sex, strain, age, and diseases) are factors contributing to the discrepancies in results. This suggests that the effects of estrogens for stroke prevention are concentration related with a complex dose-response curve, and underscores the importance of carefully validating the experimental methods used. Future studies of hormone-replacement therapy in women may have to take dosage and administration regimens into account.

    Keywords
    ischemia, estrogen, hormone administration, methodology, rat
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-19897 (URN)10.1038/jcbfm.2009.66 (DOI)
    Available from: 2009-08-14 Created: 2009-08-14 Last updated: 2017-12-13Bibliographically approved
    3. Different methods for administering 17 beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage
    Open this publication in new window or tab >>Different methods for administering 17 beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage
    2010 (English)In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 11, p. 39-Article in journal (Refereed) Published
    Abstract [en]

    Background: Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17 beta-estradiol administration; home-made silastic capsules instead of commercial slow-release 17 beta-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17 beta-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later.

    Results: In contrast to our earlier results using the commercial pellets, the group receiving 17 beta-estradiol during the entire experiment had significantly smaller lesions than the group receiving placebo (mean +/- SEM: 3.85 +/- 0.70% versus 7.15 +/- 0.27% of total slice area, respectively; p = 0.015). No significant neuroprotection was found when the 17 beta-estradiol was administered only during the two weeks before or the three days immediately after MCAo.

    Conclusions: The results indicate that different estrogen treatment regimens result in diametrically different effects on cerebral ischemia. Thus the effects of estrogens on ischemic damage seem to be concentration-related, with a biphasic, or even more complex, dose-response relation. These findings have implications for the design of animal experiments and also have a bearing on the estrogen doses used for peri-menopausal hormone replacement therapy.

    Place, publisher, year, edition, pages
    BioMed Central, 2010
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-55058 (URN)10.1186/1471-2202-11-39 (DOI)000276444500001 ()20236508 (PubMedID)
    Note

    Original Publication: Jakob O Ström, Elvar Theodorsson, Lovisa Holm and Annette Theodorsson, Different methods for administering 17 beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage, 2010, BMC NEUROSCIENCE, (11), 39. http://dx.doi.org/10.1186/1471-2202-11-39 Licensee: BioMed Central http://www.biomedcentral.com/

    Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2017-12-12Bibliographically approved
    4. Methods for 17 beta-oestradiol administration to rats
    Open this publication in new window or tab >>Methods for 17 beta-oestradiol administration to rats
    2011 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 71, no 7, p. 583-592Article in journal (Refereed) Published
    Abstract [en]

    Several studies indicate that the beneficial or harmful effects of oestrogens in stroke are dose-dependent. Rats are amongst the most frequently used animals in these studies, which calls for thoroughly validated methods for administering 17 beta-oestradiol to rats. In an earlier study we characterised three different administration methods for 17 beta-oestradiol over 42 days. The present study assesses the concentrations in a short time perspective, with the addition of a novel peroral method. Female Sprague-Dawley rats were ovariectomised and administered 17 beta-oestradiol by subcutaneous injections, silastic capsules, pellets and orally (in the nut-cream Nutella (R)), respectively. One group received 17 beta-oestradiol by silastic capsules without previous washout time. Blood samples were obtained after 30 minutes, 1, 2, 4, 8, 12, 24, 48 and 168 hours and serum 17 beta-oestradiol (and oestrone sulphate in some samples) was subsequently analysed. For long-term characterisation, one group treated perorally was blood sampled after 2, 7, 14, 21, 28, 35 and 42 days. At sacrifice, uterine horns were weighed and subcutaneous tissue samples were taken for histological assessment. The pellets, silastic capsule and injection groups produced serum 17 beta-oestradiol concentrations that were initially several orders of magnitude higher than physiological levels, while the peroral groups had 17 beta-oestradiol levels that were within the physiological range during the entire experiment. The peroral method is a promising option for administering 17 beta-oestradiol if physiological levels or similarity to womens oral hormone therapy are desired. Uterine weights were found to be a very crude measure of oestrogen exposure.

    Place, publisher, year, edition, pages
    Informa Healthcare, 2011
    Keywords
    Dosage, drug administration routes, injection, oestradiol, per os, rat, silastic capsule, slow-release pellet, uterine weight, washout
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-71772 (URN)10.3109/00365513.2011.596944 (DOI)000295799300009 ()
    Available from: 2011-11-04 Created: 2011-11-04 Last updated: 2017-12-08Bibliographically approved
    5. Effects of high and low 17β-estradiol doses on cerebral ischemia
    Open this publication in new window or tab >>Effects of high and low 17β-estradiol doses on cerebral ischemia
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    INTRODUCTION: Estrogens’ effects on cerebral ischemia have during the last two decades been the subject of intense research efforts. Notwithstanding this, the reasons that some studies indicate that estrogens are damaging while others show estrogen-induced neuroprotection has hitherto not been fully elucidated. Recent evidence indicates that discrepancies in hormone administration paradigms, resulting in highly different serum hormone concentrations, may account for this dichotomy. The current study was designed to test this  ypothesis.

    METHODS: Sixty ovariectomized female rats were randomized into three groups differing in subsequent 17β-estradiol regimen (vehicle, low dose and high dose respectively). Following two weeks of treatment, focal cerebral ischemia was induced via an intraluminal filament middle cerebral artery occlusion (MCAo) method. All animals were subjected to a small functional testing battery, and three days after MCAo they were sacrificed for infarct size assessment.

    RESULTS AND DISCUSSION: The hormone administration regimens significantly affected animal weights and feeding behavior, but infarct sizes did not differ between groups. Further, random intra-group variations in infarct size were too large to allow negative conclusions to be drawn. The large variation was possibly a consequence of too large occluding filament diameter in combination with that the animals were allowed to wake up during ongoing MCAo. After correcting the large variation, the hypothesis needs to be addressed anew.

    Keywords
    Administration methods, Cerebral ischemia, Elevated body swing test, Estrogens, Hormesis, Silastic capsules, Slow-release pellets
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-77192 (URN)
    Available from: 2012-05-08 Created: 2012-05-08 Last updated: 2016-02-29Bibliographically approved
  • 17.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Boström, Sverre
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Bobinski, L.
    Umeå University, Sweden.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Low-grade infection complicating silastic dural substitute 32 years post-operatively2011In: Brain Injury, ISSN 0269-9052, E-ISSN 1362-301X, Vol. 25, no 2, p. 250-254Article in journal (Refereed)
    Abstract [en]

    Background: A complication of a silastic dural substitute is described, which appeared after 32 years-by far the longest latency period reported in the literature. Methods: Case report and literature review. Results: In 1971, a 20-year old woman suffered from an acute subdural haematoma and a temporal cerebral contusion due to a motorbike accident. She underwent an operation with evacuation of these and the dura was mended with a silastic duraplasty. Thirty-two years later she deteriorated with increased memory problems and dysphasia. CT revealed an expanding haemorrhagic mass around the previous duraplasty, which demanded surgery with removal of the silastic dural implant and evacuation of the haemorrhagic mass. Although the haemorrhagic mass enveloped the silastic implant, a contribution of the acrylate flap cannot be ruled out. Bacteriological cultures revealed Acinetobacter spp. in the CSF. Adequate post-operative antibiotic treatment was administered. The patient slowly improved, but the complication represented a major setback in her long-term cognitive and communicative functions. Conclusions: This case widens the previously reported time-frame of late complications by 60%, from 20 to 32 years, and will hopefully serve to increase the awareness of late infections and haemorrhages induced by silastic dural implants, thereby improving diagnosis and treatment in future cases.

  • 18.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Örebro University Hospital, Sweden.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Impact of methodology on estrogens’ effects on cerebral ischemia in rats: an updated meta-analysis2014In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 15, no 22Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Although most animal stroke studies have demonstrated potent neuroprotective effects of estrogens, there are a number of articles reporting the opposite. In 2009, we made the case that this dichotomy was related to administered estrogen dose. Several other suggestions for the discordant results have also been propagated, including the age of the experimental animals and the length of hypoestrogenicity prior to estrogen administration. These two suggestions have gained much popularity, probably because of their kinship with the window of opportunity hypothesis, which is commonly used to explain the analogous dichotomy among human studies. We were therefore encouraged to perform an updated meta-analysis, and to improve it by including all relevant variables in a large multiple regression model, where the impact of confounders could be controlled for.

    RESULTS:

    The multiple regression model revealed an indisputable impact of estrogen administration mode on the effects of estrogens in ischemic stroke. Subcutaneous slow-release pellets differed from the injection and silastic capsule treatments in terms of impact of estrogens on ischemic stroke, showing that the first mentioned were more prone to render estrogens damaging. Neither the use of elderly animals nor the adoption of longer wash-out periods influenced estrogens' effects on experimental ischemic stroke in rats.

    CONCLUSIONS:

    We conclude that the discordant results regarding estrogens' effects in rat models of ischemic stroke are a consequence of differences in estrogen administration modes. These results are not only of importance for the ongoing debate regarding menopausal hormone therapy, but also have an important bearing on experimental stroke methodology and the apparent translational roadblock for suggested stroke interventions.

  • 19.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Method parameters’ impact on mortality and variability in rat stroke experiments: a meta-analysis2013In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 14, no 41Article in journal (Refereed)
    Abstract [en]

    Background

    Even though more than 600 stroke treatments have been shown effective in preclinical studies, clinically proven treatment alternatives for cerebral infarction remain scarce. Amongst the reasons for the discrepancy may be methodological shortcomings, such as high mortality and outcome variability, in the preclinical studies. A common approach in animal stroke experiments is that A) focal cerebral ischemia is inflicted, B) some type of treatment is administered and C) the infarct sizes are assessed. However, within this paradigm, the researcher has to make numerous methodological decisions, including choosing rat strain and type of surgical procedure. Even though a few studies have attempted to address the questions experimentally, a lack of consensus regarding the optimal methodology remains.

    Methods

    We therefore meta-analyzed data from 502 control groups described in 346 articles to find out how rat strain, procedure for causing focal cerebral ischemia and the type of filament coating affected mortality and infarct size variability.

    Results

    The Wistar strain and intraluminal filament procedure using a silicone coated filament was found optimal in lowering infarct size variability. The direct and endothelin methods rendered lower mortality rate, whereas the embolus method increased it compared to the filament method.

    Conclusions

    The current article provides means for researchers to adjust their middle cerebral artery occlusion (MCAo) protocols to minimize infarct size variability and mortality.

  • 20.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Effects of high and low 17 beta-estradiol doses on focal cerebral ischemia: negative results2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3Article in journal (Refereed)
    Abstract [en]

    The reasons why some animal studies indicate that estrogens increase focal cerebral ischemic damage while others show estrogen-induced neuroprotection has hitherto not been fully elucidated. Recent evidence indicates that discrepancies in hormone administration paradigms, resulting in highly different serum hormone concentrations, may account for the dichotomy. The current study aimed to test this hypothesis. Sixty ovariectomized female rats were randomized into three groups differing in 17 beta-estradiol regimens, and transient focal cerebral ischemia was subsequently induced. All animals were subjected to a small functional testing battery, and three days after MCAo they were sacrificed for infarct size assessment. Infarct sizes did not differ between groups, however clear discrepancies were seen in body weight and feeding behavior. In comparison to sham-operated animals, ovariectomized rats rapidly increased in body weight, whereas the opposite was seen in rats receiving 17beta-estradiol. The weight gain in the ovariectomized rats was paralleled by an increased food intake.

  • 21.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Effects of high and low 17β-estradiol doses on cerebral ischemiaManuscript (preprint) (Other academic)
    Abstract [en]

    INTRODUCTION: Estrogens’ effects on cerebral ischemia have during the last two decades been the subject of intense research efforts. Notwithstanding this, the reasons that some studies indicate that estrogens are damaging while others show estrogen-induced neuroprotection has hitherto not been fully elucidated. Recent evidence indicates that discrepancies in hormone administration paradigms, resulting in highly different serum hormone concentrations, may account for this dichotomy. The current study was designed to test this  ypothesis.

    METHODS: Sixty ovariectomized female rats were randomized into three groups differing in subsequent 17β-estradiol regimen (vehicle, low dose and high dose respectively). Following two weeks of treatment, focal cerebral ischemia was induced via an intraluminal filament middle cerebral artery occlusion (MCAo) method. All animals were subjected to a small functional testing battery, and three days after MCAo they were sacrificed for infarct size assessment.

    RESULTS AND DISCUSSION: The hormone administration regimens significantly affected animal weights and feeding behavior, but infarct sizes did not differ between groups. Further, random intra-group variations in infarct size were too large to allow negative conclusions to be drawn. The large variation was possibly a consequence of too large occluding filament diameter in combination with that the animals were allowed to wake up during ongoing MCAo. After correcting the large variation, the hypothesis needs to be addressed anew.

  • 22.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry. County Council of Örebro, Sweden.
    Nilsson, Tove
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Effects of 17β-estradiol on galanin(1-29)- and galanin(1-16)-like immunoreactivities2013In: Peptides, ISSN 0196-9781, E-ISSN 1873-5169, Vol. 43, p. 1-7Article in journal (Refereed)
    Abstract [en]

    There are reasons to believe that the galanin neuropeptide family could include more than the two hitherto known members (galanin(1-29) and galanin-like peptide), such as the existence of at least three galanin receptors and the fact that synthetic short-chain homologues have effects and binding sites that are distinct from those of galanin(1-29). The current study uses a radioimmunoassay based on a polyclonal rabbit antiserum raised against galanin(1-16) to study the concentrations of galanin(1-16) like immunoreactivity (LI) in the various parts of the brain and gut of ovariectomized female rats, and investigates the effects of different concentrations of estradiol on these concentrations in relation to galanin(1-29)-LI. Galanin(1-29) concentrations were increased by 17 beta-estradiol administration in almost all examined tissues whereas galanin(1-16)-LI was increased by 17 beta-estradiol treatment in most of the gut, but only in the pituitary of the brain. Furthermore, the relation between galanin(1-29)-LI and galanin(1-16)-LI varied substantially from tissue to tissue. The main hypothesis, that galanin(1-16)LI would be affected by 17 beta-estradiol in brain and/or gut, was confirmed in addition to the secondary hypothesis, stating that the pattern of galanin(1-16)-LI changes would differ from that of galanin(1-29). The study indicates that galanin(1-16)-LI is estrogen-responsive but that its concentrations are regulated differently from that of galanin(1-29). This is strongly indicative of a biological relevance of this potentially new member of the galanin neuropeptide family.

  • 23.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Druvefors, Emma
    Ryhov County Hospital, County Council of Jönköping, Sweden.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    The female menstrual cycle does not influence testosterone concentrations in male partners2012In: Journal of Negative Results in Biomedicine, ISSN 1477-5751, E-ISSN 1477-5751, Vol. 11, no 1Article in journal (Refereed)
    Abstract [en]

    Background

    The time of ovulation has since long been believed to be concealed to male heterosexual partners. Recent studies have, however, called for revision of this notion. For example, male testosterone concentrations have been shown to increase in response to olfactory ovulation cues, which could be biologically relevant by increasing sexual drive and aggressiveness. However, this phenomenon has not previously been investigated in real-life human settings. We therefore thought it of interest to test the hypothesis that males' salivary testosterone concentrations are influenced by phases of their female partners' menstrual cycle; expecting a testosterone peak at ovulation.

    Methods

    Thirty young, healthy, heterosexual couples were recruited. During the course of 30-40 days, the women registered menses and ovulation, while the men registered sexual activity, physical exercise, alcohol intake and illness (confounders), and obtained daily saliva samples for testosterone measurements. All data, including the registered confounders, were subjected to multiple regression analysis.

    Results

    In contrast to the hypothesis, the ovulation did not affect the testosterone levels, and the resulting testosterone profile during the menstrual cycle was on the average flat. The specific main hypothesis, that male testosterone levels on the day of ovulation would be higher than day 4 of the cycle, was clearly contradicted by a type II error(β)-analysis (< 14.3% difference in normalized testosterone concentration; β = 0.05).

    Conclusions

    Even though an ovulation-related salivary testosterone peak was observed in individual cases, no significant effect was found on a group level.

  • 24.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Isaksson, Ida-Maria
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ovariectomy and 17β-estradiol replacement in rats and mice: a visual demonstration2012In: Journal of Visualized Experiments, ISSN 1940-087X, E-ISSN 1940-087X, no 64, p. 4013-Article in journal (Refereed)
    Abstract [en]

    Estrogens are a family of female sexual hormones with an exceptionally wide spectrum of effects. When rats and mice are used in estrogen research they are commonly ovariectomized in order to ablate the rapidly cycling hormone production, replacing the 17β-estradiol exogenously. There is, however, lack of consensus regarding how the hormone should be administered to obtain physiological serum concentrations This is crucial since the 17β-estradiol level/administration method profoundly influences the experimental results1-3. We have in a series of studies characterized the different modes of 17β-estradiol administration, finding that subcutaneous silastic capsules and per-oral nut-cream Nutella are superior to commercially available slow-release pellets (produced by the company Innovative Research of America) and daily injections in terms of producing physiological serum concentrations of 17β-estradiol4-6. Amongst the advantages of the nut-cream method, that previously has been used for buprenorphine administration7, is that when used for estrogen administration it resembles peroral hormone replacement therapy and is non-invasive. The subcutaneous silastic capsules are convenient and produce the most stable serum concentrations. This video article contains step-by-step demonstrations of ovariectomy and 17β-estradiol hormone replacement by silastic capsules and peroral Nutella in rats and mice, followed by a discussion of important aspects of the administration procedures.

  • 25.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Dose-related neuroprotective versus neurodamaging effects of estrogens in rat cerebral ischemia: a systematic analysis2009In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 29, no 8, p. 1359-1372Article, review/survey (Refereed)
    Abstract [en]

    Numerous studies of the effects of estrogens for stroke prevention have yielded conflicting results in human and animal studies alike. We present a systematical analysis of study design and methodological differences between 66 studies where estrogens impact on ischemic brain damage in rat models has been investigated, providing evidence that the differences in results may be explained by high estrogen doses produced by slow-release pellets. These pellets have been used in all studies showing increased neurologic damage because of estrogens. Our data indicate that the increased neurologic damage is related to the pellets plasma concentration profile with an early, prolonged, supraphysiological peak. Neither the method of inducing the ischemic brain lesions, the choice of variables for measuring outcome, the measured plasma concentrations of estrogens at the time of ischemia nor rat population attributes (sex, strain, age, and diseases) are factors contributing to the discrepancies in results. This suggests that the effects of estrogens for stroke prevention are concentration related with a complex dose-response curve, and underscores the importance of carefully validating the experimental methods used. Future studies of hormone-replacement therapy in women may have to take dosage and administration regimens into account.

  • 26.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Hormesis and Female Sex Hormones2011In: Pharmaceuticals, ISSN 1424-8247, E-ISSN 1424-8247, Vol. 4, p. 726-740Article in journal (Refereed)
    Abstract [en]

    Hormone replacement after menopause has in recent years been the subject of intense scientific debate and public interest and has sparked intense research efforts into the biological effects of estrogens and progestagens. However, there are reasons to believe that the doses used and plasma concentrations produced in a large number of studies casts doubt on important aspects of their validity. The concept of hormesis states that a substance can have diametrically different effects depending on the concentration. Even though estrogens and progestagens have proven prone to this kind of dose-response relation in a multitude of studies, the phenomenon remains clearly underappreciated as exemplified by the fact that it is common practice to only use one hormone dose in animal experiments. If care is not taken to adjust the concentrations of estrogens and progestagens to relevant biological conditions, the significance of the results may be questionable. Our aim is to review examples of female sexual steroids demonstrating bidirectional dose-response relations and to discuss this in the perspective of hormesis. Some examples are highlighted in detail, including the effects on cerebral ischemia, inflammation, cardiovascular diseases and anxiety. Hopefully, better understanding of the hormesis phenomenon may result in improved future designs of studies of female sexual steroids.

  • 27.
    Ström, Jakob O.
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Substantial discrepancies in 17β-estradiol concentrations obtained with three different commercial direct radioimmunoassay kits in rat sera2008In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 68, no 8, p. 806-813Article in journal (Refereed)
    Abstract [en]

    The extensive use of estrogen for contraception and amelioration of post-menopausal symptoms has made it the subject of substantial recent research efforts. Ovariectomized (ovx) rats treated with exogenous ovarial hormones constitute important tools in the investigation of the effects and mechanisms of estrogen actions. The crucial need to control and to monitor plasma levels of 17β-estradiol calls for accurate, precise and robust assay methods. The performance of direct radioimmunoassays (RIAs) for measurement of 17β-estradiol has previously been reported for human samples, but – to our knowledge – not for rat samples. In the current study, 552 serum samples from ovx, native and hormone treated rats were used to compare the performance of three commercially manufactured direct RIAs from the companies DPC (Siemens Healthcare Diagnostics Inc., formerly Diagnostic Products Corporation), DSL (Diagnostic Systems Labs) and MPB (MP Biomedicals, formerly ICN Biomedicals). Substantial differences in results between the three assay methods were found when measuring serum 17β-estradiol concentrations. The following formulas, describing the relation between the different methods’ results, were obtained using weighted Deming’s orthogonal regression (all regression formulae in the abstract are based on pg/mL): DSL= 0.43*DPC+12.3, MPB= 2.1*DPC+84.7 and DSL= 4.8*MPB+22.2. Furthermore, a preceding diethyl ether extraction step of the serum appears to impair the RIAs’ performances in the present samples: DPCex= 0.39*DPCunex+0.76, DSLex= 0.32*DSLunex-1.7 and MPBex= 0.22*MPBunex+1.4.

  • 28.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Holm, Lovisa
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Different methods for administering 17 beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage2010In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 11, p. 39-Article in journal (Refereed)
    Abstract [en]

    Background: Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17 beta-estradiol administration; home-made silastic capsules instead of commercial slow-release 17 beta-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17 beta-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later.

    Results: In contrast to our earlier results using the commercial pellets, the group receiving 17 beta-estradiol during the entire experiment had significantly smaller lesions than the group receiving placebo (mean +/- SEM: 3.85 +/- 0.70% versus 7.15 +/- 0.27% of total slice area, respectively; p = 0.015). No significant neuroprotection was found when the 17 beta-estradiol was administered only during the two weeks before or the three days immediately after MCAo.

    Conclusions: The results indicate that different estrogen treatment regimens result in diametrically different effects on cerebral ischemia. Thus the effects of estrogens on ischemic damage seem to be concentration-related, with a biphasic, or even more complex, dose-response relation. These findings have implications for the design of animal experiments and also have a bearing on the estrogen doses used for peri-menopausal hormone replacement therapy.

  • 29.
    Ström, Jakob O.
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Order of magnitude differences between methods for maintaining physiological 17β-estradiol concentrations in ovariectomized rats2008In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 68, no 8, p. 814-822Article in journal (Refereed)
    Abstract [en]

    The use of animal, especially rat, models, is crucial for elucidating the biological effects and mechanisms of the widely used hormone 17β-estradiol. Unfortunately there is a lack of consensus on optimal means of obtaining and maintaining physiological 17β-estradiol concentrations in plasma. This may be the reason for varying results in several studies including the disagreement on whether 17β-estradiol is neuroprotective or not. Very few studies have been devoted to investigating the characteristics and biological relevance of different methods of 17β-estradiol administration. We therefore ovariectomized 75 Sprague-Dawley rats and, following a 2 weeks wash-out period, administered 17β-estradiol using three different methods; daily injections (10 µg 17β-estradiol/kg), slow-release pellets (0.25 mg 60 day-release pellets, 0.10 mg 90 day-release pellets) and silastic capsules (with/without wash-out periods) (silastic laboratory tubing, inner/outer diameter: 1.575/3.175 mm, filled with 20 mm columns of 180 µg 17β-estradiol/mL sesame oil). Further 45 animals were used as ovariectomized and native controls, studied in different parts of the estrous cycle. Silastic capsules produced concentrations of 17β-estradiol within the physiological range for 4-5 weeks independent of whether a prior wash-out period was included or not. The slow-release pellets, irrespective of dose or release period, resulted in initial concentrations which were an order of magnitude above physiological concentrations during the first two weeks followed by a substantial decrease. Daily injections resulted in increasing 17β-estradiol concentrations, however within physiological levels. Silastic capsules are conveniently manufactured and used, and are superior to pellets and injections in reliably producing long-term 17β-estradiol concentrations within the physiological range.

  • 30.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Strid, Tobias
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Hammarström, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Disruption of the alox5ap gene ameliorates focal ischemic stroke: possible consequence of impaired leukotriene biosynthesis2012In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 13, p. 146-Article in journal (Refereed)
    Abstract [en]

    Background

    Leukotrienes are potent inflammatory mediators, which in a number of studies have been found to be associated with ischemic stroke pathology: gene variants affecting leukotriene synthesis, including the FLAP (ALOX5AP) gene, have in human studies shown correlation to stroke incidence, and animal studies have demonstrated protective properties of various leukotriene-disrupting drugs. However, no study has hitherto described a significant effect of a genetic manipulation of the leukotriene system on ischemic stroke. Therefore, we decided to compare the damage from focal cerebral ischemia between wild type and FLAP knockout mice. Damage was evaluated by infarct staining and a functional test after middle cerebral artery occlusion in 20 wild type and 20 knockout male mice.

    Results

    Mortality-adjusted median infarct size was 18.4 (3.2-76.7) mm3 in the knockout group, compared to 72.0 (16.7-174.0) mm3 in the wild type group (p < 0.0005). There was also a tendency of improved functional score in the knockout group (p = 0.068). Analysis of bone marrow cells confirmed that knockout animals had lost their ability to form leukotrienes.

    Conclusions

    Since the local inflammatory reaction after ischemic stroke is known to contribute to the brain tissue damage, the group difference seen in the current study could be a consequence of a milder inflammatory reaction in the knockout group. Our results add evidence to the notion that leukotrienes are important in ischemic stroke, and that blocked leukotriene production ameliorates cerebral damage.

  • 31.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Mechanisms of estrogens' dose-dependent neuroprotective and neurodamaging effects in experimental models of cerebral ischemia2011In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 12, no 3, p. 1533-1562Article, review/survey (Refereed)
    Abstract [en]

    Ever since the hypothesis was put forward that estrogens could protect against cerebral ischemia, numerous studies have investigated the mechanisms of their effects. Despite initial studies showing ameliorating effects, later trials in both humans and animals have yielded contrasting results regarding the fundamental issue of whether estrogens are neuroprotective or neurodamaging. Therefore, investigations of the possible mechanisms of estrogen actions in brain ischemia have been difficult to assess. A recently published systematic review from our laboratory indicates that the dichotomy in experimental rat studies may be caused by the use of insufficiently validated estrogen administration methods resulting in serum hormone concentrations far from those intended, and that physiological estrogen concentrations are neuroprotective while supraphysiological concentrations augment the damage from cerebral ischemia. This evidence offers a new perspective on the mechanisms of estrogens actions in cerebral ischemia, and also has a direct bearing on the hormone replacement therapy debate. Estrogens affect their target organs by several different pathways and receptors, and the mechanisms proposed for their effects on stroke probably prevail in different concentration ranges. In the current article, previously suggested neuroprotective and neurodamaging mechanisms are reviewed in a hormone concentration perspective in an effort to provide a mechanistic framework for the dose-dependent paradoxical effects of estrogens in stroke. It is concluded that five protective mechanisms, namely decreased apoptosis, growth factor regulation, vascular modulation, indirect antioxidant properties and decreased inflammation, and the proposed damaging mechanism of increased inflammation, are currently supported by experiments performed in optimal biological settings.

  • 32.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Chemistry.
    Research design and statistical power when publishing "negative findings"2011In: The Journal of Neuroscience, ISSN 0270-6474Article, book review (Other academic)
  • 33.
    Vigren, Patrik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Petrini, Pia
    Karolinska University Hospital, Sweden .
    Callander, Margarita
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Treatment of spontaneous intracerebral haemorrhage in Glanzmanns thrombasthenia2012In: Haemophilia, ISSN 1351-8216, E-ISSN 1365-2516, Vol. 18, no 5, p. e381-e383Article in journal (Other academic)
1 - 33 of 33
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