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Sökning: WFRF:(Wikström Johan Docent)

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1.
  • 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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2.
  • 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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3.
  • 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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4.
  • 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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5.
  • 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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6.
  • Jonasson, My, et al. (författare)
  • Quantification of aromatase binding in the female human brain using [11 C]cetrozole positron emission tomography.
  • 2020
  • Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 98:11, s. 2208-2218
  • Tidskriftsartikel (refereegranskat)abstract
    • Aromatase, the enzyme that in the brain converts testosterone and androstenedione to estradiol and estrone, respectively, is a putative key factor in psychoneuroendocrinology. In vivo assessment of aromatase was performed to evaluate tracer kinetic models and optimal scan duration, for quantitative analysis of the aromatase positron emission tomography (PET) ligand [11 C]cetrozole. Anatomical magnetic resonance and 90-min dynamic [11 C]cetrozole PET-CT scans were performed on healthy women. Volume of interest (VOI)-based analyses with a plasma-input function were performed using the single-tissue and two-tissue (2TCM) reversible compartment models and plasma-input Logan analysis. Additionally, the simplified reference tissue model (SRTM), Logan reference tissue model (LRTM), and standardized uptake volume ratio model, with cerebellum as reference region, were evaluated. Parametric images were generated and regionally averaged voxel values were compared with VOI-based analyses of the reference tissue models. The optimal reference model was used for evaluation of a decreased scan duration. Differences between the plasma-input- and reference tissue-based methods and comparisons between scan durations were assessed by linear regression. The [11 C]cetrozole time-activity curves were best described by the 2TCM. SRTM nondisplaceable binding potential (BPND ), with cerebellum as reference region, can be used to estimate [11 C]cetrozole binding and generated robust and quantitatively accurate results for a reduced scan duration of 60 min. Receptor parametric mapping, a basis function implementation of SRTM, as well as LRTM, produced quantitatively accurate parametric images, showing BPND at the voxel level. As PET tracer, [11 C]cetrozole can be employed for relatively short brain scans to measure aromatase binding using a reference tissue-based approach.
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7.
  • Wänman, Johan, 1983- (författare)
  • Clinical and morphological aspects of metastatic spinal cord compression
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Background: Metastatic spinal cord compression (MSCC) is a serious complication of cancer leading to demyelination and axonal damage of the spinal cord with a risk of para/tetraplegia. It is most common in patients with known cancer but may also be the initial manifestation of malignancy (IMM). Patients with MSCC as the IMM have rarely been studied as a separate group. The interaction between the tumour and bone in spinal bone metastasis interferes with regulatory mechanisms, causing the formation of less mechanically competent bone and increasing the risk of spinal instability and fracture. The Spinal Instability Neoplastic Score (SINS) has been proposed as a tool in order to help clinicians evaluate tumour-related spinal instability. The SINS has shown excellent inter- and intraobserver reliability, but its prognostic value is still controversial. Bone metastases from prostate cancer are generally classified as osteoblastic due to increased bone formation. However, this categorization is probably oversimplified since there are overlapping bone cell activities between osteoblastic and osteolytic metastases. Prostate cancer bone metastases can also have a myeloma-like radiological appearance, but little is known about this subgroup of lesions. Aims: The aims of this work were as follows: a) to evaluate outcomes after surgery in patients with MSCC as the IMM; b) to analyse the prognostic value of the SINS regarding survival and neurological function after surgery for MSCC in patients with prostate cancer and haematological malignancies; and c) to analyse the clinical and morphological features of prostate cancer spinal bone metastases with a myeloma-like radiological appearance. Patients and methods: In studies I-III, we retrospectively evaluated the outcomes after surgery for MSCC in patients with MSCC as the IMM (study I, n=69), prostate cancer (study II, n=110) and haematological malignancies (study III, n=48). In study IV, tumour tissue samples from bone metastases obtained during surgery for MSCC in 110 patients with prostate cancer were analysed by immunohistochemistry and molecular transcriptomic analyses, and the results were related to the radiological appearance and clinical outcomes. Results: Study I: The primary tumour was identified in 59 of 69 patients. The median postoperative survival after surgery for MSCC was 20 months. Patients with prostate cancer had the longest median survival (6 years), and patients who were defined as having cancer of unknown primary tumour had the shortest median survival (3.5 months). Surgery maintained and improved the ability to walk in these patients. Study II: A total of 106 of 110 patients met the SINS criteria for potential instability or instability. There was no statistically significant difference in the overall risk of death between the SINS potentially unstable and unstable SINS categories, or in the risk of loss of ambulation one month after surgery. Study III: The median postoperative survival was 71.5 months in patients with myeloma and 58.7 months in patients with lymphoma. The SINS was not related to postoperative survival or neurological outcomes. The ability to walk before surgery was strongly associated with the postoperative ambulatory status. On multivariate Cox regression analysis, the ability to walk and a higher blood haemoglobin level prior to surgery were associated with superior survival. Study IV: A myeloma-like radiological appearance of prostate cancer spinal bone metastases was associated with poor survival and neurological outcomes after surgery for MSCC. Conclusions: Patients with MSCC as the IMM resemble a heterogeneous group in which survival is highly dependent on the type of primary tumour. A diagnostic workup is essential before a prognosis can be estimated in order to select candidates for surgery. The SINS may be helpful in selecting patients for surgery for MSCC, but it cannot be used to predict postoperative survival or neurological outcomes in patients with prostate cancer or in patients with haematological malignancies. A myeloma-like radiological appearance of prostate cancer spinal bone metastases is a strong negative predictor for survival and neurological outcomes after surgery for MSCC.
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