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Sökning: WFRF:(Wikström Johan) > Wikström Johan Docent

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1.
  • Bergman, Lina, 1982- (författare)
  • Cerebral biomarkers in women with preeclampsia
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Preeclampsia and eclampsia are among the most common causes of maternal and fetal mortality and morbidity worldwide. There are no reliable means to predict eclampsia or cerebral edema in women with preeclampsia and knowledge of the brain involvement in preeclampsia is still limited. S100B and neuron specific enolase (NSE) are two cerebral biomarkers of glial- and neuronal origin respectively. They are used as predictors for neurological outcome after traumatic brain injuries and cardiac arrest but have not yet been investigated in preeclampsia.This thesis is based on one longitudinal cohort study of pregnant women (n=469, Paper I and III), one cross sectional study of women with preeclampsia and women with normal pregnancies (n=53 and 58 respectively, Paper II and IV) and one experimental animal study of eclampsia (Paper V).In Paper I and III, plasma concentrations of S100B and NSE were investigated throughout pregnancy in women developing preeclampsia (n=16) and in women with normal pregnancies (n=36) in a nested case control study. Plasma concentrations were increased in women developing preeclampsia in gestational week 33 and 37 for S100B and in gestational week 37 for NSE compared to women with normal pregnancies.In Paper II and IV, increased plasma concentrations of S100B and NSE were confirmed among women with preeclampsia compared to women with normal pregnancies. Furthermore, increased plasma concentrations of S100B correlated to visual disturbances among women with preeclampsia (Paper II) and plasma concentrations of S100B and NSE remained increased among women with preeclampsia one year after delivery (Paper IV).In Paper V, an experimental rat model of preeclampsia and eclampsia demonstrated increased serum concentrations of S100B after seizures in normal pregnancy (n=5) and a tendency towards increased plasma concentrations of S100B in preeclampsia (n=5) compared to normal pregnancy (n=5) without seizures. Furthermore, after seizures, animals with magnesium sulphate treatment demonstrated increased serum concentrations of S100B and NSE compared to no treatment.In conclusion; plasma concentrations of S100B and NSE are increased in preeclampsia during late pregnancy and postpartum and S100B correlates to visual disturbances in women with preeclampsia. The findings are partly confirmed in an animal model of eclampsia.
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2.
  • Amini, Hashem (författare)
  • Fetal Anomalies : Surveillance and Diagnostic Accuracy of Ultrasound and Magnetic Resonance Imaging
  • 2010
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The aims were to investigate the accuracy of ultrasound in diagnosis of structural fetal anomalies with special focus on false positive findings (I), to evaluate the additional value of second trimester fetal MRI on pregnancy management (II-III) and to estimate the ascertainment in the Swedish Birth Defects Registry and incidence of spina bifida and cleft lip/palate (IV). Retrospectively, 328 fetal autopsies were identified where pregnancies were terminated due to ultrasonographically diagnosed fetal anomalies. In 175 (53.4 %) cases ultrasound and fetal autopsy were identical, in 124 (37.8 %) ultrasound was almost correct, in 23 (7.0 %)  ultrasound diagnoses could not be verified, but fetal autopsy showed other anomalies with at least the same prognostic value and in six (1.8 %)  ultrasound diagnosis could not be verified and autopsy showed no or less severe anomalies (I). Prospectively, 29 pregnancies with CNS- (II) and 63 with non-CNS-anomalies (III) were included. In the CNS study MRI provided no additional information in 18 fetuses (62 %), additional information without changing the management in 8 (28 %) and additional information altering the pregnancy management in 3 (10%). In the non-CNS study the corresponding figures were 43 (68 %), 17 (27 %) and three (5 %), respectively. MRI in the second trimester might be a clinically valuable adjunct to ultrasound for the evaluation of CNS anomalies, especially when the ultrasound is inconclusive due to maternal obesity (II) and in non-CNS anomalies in cases of diaphragmatic hernia or oligohydramnios (III). In newborns, the ascertainments of birth defects are relatively high and assessable, but in pregnancy terminations they are lower or unknown. The incidence of newborns with spina bifida has decreased because of an increased rate of pregnancy terminations (>60%). There is room for improvement concerning the reporting of anomalies from terminated pregnancies (IV).
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3.
  • Bannbers, Elin, 1984- (författare)
  • The Effect of Steroid Hormones in the Female Brain During Different Reproductive States
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Women are twice as likely as men to suffer from depression and anxiety disorders and have an increased risk of onset during periods associated with hormonal changes, such as the postpartum period and the menopausal transition. Furthermore, some women seem more sensitive to normal hormone fluctuations across the menstrual cycle, since approximately 3-5% suffers from premenstrual dysphoric disorder (PMDD). Why these disorders are so common in women has not been established but there is a probable involvement of the ovarian hormones.The aim of this thesis was to investigate the effect of the ovarian hormones on the female brain during different reproductive states using psychological tests known to affect brain activity in different ways.Paper one examined the effect of the ovarian hormones on prepulse inhibition (PPI) on the acoustic startle response (ASR) and comprised cycling women and postmenopausal women. The cycling women had lower levels of PPI compared to postmenopausal women and postmenopausal women with moderate estradiol levels had lower PPI compared to postmenopausal women with low estradiol levels.Paper two examined the effect of anticipation and affective modulation on the ASR in women with PMDD and healthy controls. Women with PMDD have an increased modulation during anticipation of affective pictures compared to healthy controls during the luteal phase of the menstrual cycle.Paper three examined brain activity during response inhibition among women with PMDD and healthy controls by the use of a Go/NoGo task and fMRI. Women with PMDD displayed a decreased activity in the left insula during follicular phase and an increased activity during the luteal phase compared to controls.Paper four comprised women in the postpartum period and non-pregnant controls to examine brain activity during response inhibition. While this study revealed decreased activity at 4 weeks postpartum compared to 48 hours postpartum we cannot ascertain the role of the ovarian steroids, since none of the significant brain areas correlated with ovarian steroid or neurosteroid serum concentrations.The results of this thesis demonstrate that the ovarian hormones, or at least various hormonal states, have a probable impact on how the female brain works.
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4.
  • Canto Moreira, Nuno (författare)
  • MRI Studies of the Fetal Brain and Cranium
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Ultrasound is the primary modality for fetal imaging, but Magnetic Resonance Imaging nowadays has a valuable complementary role as it often reveals findings that alter pregnancy management. Knowledge on some clinically relevant areas of the normal fetal development is still lacking, and this was the aim of this project. We wanted 1) to obtain reference MRI data of normal brain measurements before 24 gestation weeks (GW), 2) to study the development of the hippocampus, 3) to study the development of the ear and 4) to test the ability of MRI for evaluating the lip and palate. For this, we retrospectively analysed a database with 464 in vivo and 21 post mortem fetal MRI examinations. Study I evaluated a series of 70 normal fetuses. A table of normal brain measurements from 17 to 23 GW was built, the first in the literature that includes ages below 20 GW. Study II focused on the evolution of the hippocampus from 18 to 38 GW by evaluating 3 post mortem and 60 in vivo MRI examinations. Our results suggested this area to develop later and more asymmetrically than previously thought. Study III analysed a series of 122 normal MRI in vivo and 16 MRI post mortem. We described the development of the fetal ear in vivo for the first time in the literature, realizing that the value of MRI is limited by the size of the structures evaluated. In study IV, 60 brain-targeted MRI examinations of 55 normal fetuses and 5 fetuses with orofacial clefts were blindly reviewed by two readers, focusing on the lips and palates. Our results suggest a high accuracy of MRI in the evaluation of this area, regardless of fetal age or previous ultrasound findings. This thesis brings new knowledge on the normal development of the fetal brain and cranium.
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5.
  • Sohlberg, Sara, 1977- (författare)
  • Placental Function : An Epidemiological and Magnetic Resonance Study
  • 2015
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Placental function is central for normal pregnancy and in many of the major pregnancy disorders. We used magnetic resonance imaging techniques to investigate placental function in normal pregnancy, in early and late preeclampsia and in intrauterine growth restriction. We also investigated maternal body mass index and height, as risk factors for preeclampsia.A high body mass index and a short maternal stature increase the risk of preeclampsia, of all severities. The association seems especially strong between short stature and early preeclampsia, and a high body mass index and late preeclampsia. (Study I)Using diffusion-weighted magnetic resonance imaging, we found that the placental perfusion fraction decreases with increasing gestational age in normal pregnancy. Also, the placental perfusion fraction is smaller in early preeclampsia, and larger in late preeclampsia, compared with normal pregnancies. That these differences are in opposite directions, suggests that there are differences in the underlying pathophysiology of early and late preeclampsia. (Study II)Using magnetic resonance spectroscopy, we found that the phosphodiester spectral intensity fraction and the phosphodiester/phosphomonoester spectral intensity ratio increases with increasing gestational age. Also, we found that the phosphodiester spectral intensity fraction and the phosphodiester/phosphomonoester spectral intensity ratio are higher in early preeclampsia, compared with early normal pregnancy. These findings indicate increased apoptosis with increasing gestational age in normal pregnancy, and increased apoptosis in early preeclampsia. (Study III)The placental perfusion fraction is smaller in intrauterine growth restriction than in normal pregnancy. Fetal growth, Doppler blood flow in maternal and fetal vessels, infant birth weight and plasma markers of placental function are all correlated to the placental perfusion fraction. The placental perfusion fraction examination seems therefore to offer a fast, direct estimate of the degree of placental dysfunction. (Study IV)In conclusion: Our findings in studies I-III all support the hypothesis of partly different pathophysiology between early and late preeclampsia, and suggest a strong link between early preeclampsia and placental dysfunction. Study IV shows that the placental perfusion fraction has potential to contribute to the clinical assessment of placental dysfunction.
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