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  • Kekäläinen, Eliisa (Helsingin yliopisto, 2011)
    Autoimmune regulator (AIRE) is the gene mutated in the human polyglandular autoimmune disease called Autoimmune polyendocrinopathy, candidiasis, and ectodermal dystrophy (APECED) that belongs to the Finnish disease heritage. Murine Aire has been shown to be important in the generation of the T cell central tolerance in the thymus by promoting the expression of ectopic tissue-specific antigens in the thymic medulla. Aire is also involved in the thymus tissue organization during organogenesis. In addition to the thymus, AIRE/Aire is expressed in the secondary lymphoid organs. Accordingly, a role for AIRE/Aire in the maintenance of peripheral tolerance has been suggested. Peripheral tolerance involves mechanisms that suppress immune responses in secondary lymphoid organs. Regulatory T cells (Tregs) are an important suppressive T cell population mediating the peripheral tolerance. Tregs are generated in the thymus but also in the peripheral immune system T cells can acquire the Treg-phenotype. The aim of this study was to characterize Tregs in APECED patients and in the APECED mouse model (Aire-deficient mice). In the mouse model, it was possible to separate Aire expression in the thymus and in the secondary lymphoid organs. The relative importance of thymic and peripheral Aire expression in the maintenance of immunological tolerance was studied in an experimental model that was strongly biased towards autoimmunity, i.e. lymphopenia-induced proliferation (LIP) of lymphocytes. This experimental model was also utilised to study the behaviour of T cells with dual-specific T cell receptors (TCR) during the proliferation. The Treg phenotype was studied by flow cytometry and relative gene expression with real-time polymerase chain reaction. TCR repertoires of the Tregs isolated from APECED patients and healthy controls were also compared. The dual-specific TCRs were studied with the TCR repertoire analysis that was followed with sequencing of the chosen TCR genes in order to estimate changes in the dual-specific TCR diversity. The Treg function was tested with an in vitro suppression assay. The APECED patients had normal numbers of Tregs but the phenotype and suppressive functions of the Tregs were impaired. In order to separate Aire functions in the thymus from its yet unknown role in the secondary lymphoid organs, the phenomenon of LIP was utilised. In this setting, the lymphocytes that are adoptively transferred to a lymphopenic recipient proliferate to stimuli from self-originating antigens. This proliferation can result in autoimmunity if peripheral tolerance is not fully functional. When lymphocytes that had matured without Aire in the thymus were transferred to lymphopenic Aire-sufficient recipients, no clinical autoimmunity followed. The Aire-deficient donor-originating lymphocytes hyperproliferated, and other signs of immune dysregulation were also found in the recipients. Overt autoimmunity, however, was prevented by the Aire-deficient donor-originating Tregs that hyperproliferated in the recipients. Aire-deficient lymphopenic mice were used to study whether peripheral loss of Aire had an impact on the maintenance of peripheral tolerance. When normal lymphocytes were transferred to these Aire-deficient lymphopenic recipients, the majority of recipients developed a clinically symptomatic colitis. The colitis was confirmed also by histological analysis of the colon tissue sections. In the Aire-deficient lymphopenic recipients Tregs were proliferating significantly less than in the control group s recipients that had normal Aire expression in their secondary lymphoid organs. This study shows that Aire is not only important in the central tolerance but is also has a significant role in the maintenance of the peripheral tolerance both in mice and men. Aire expressed in the secondary lymphoid organs is involved in the functions of Tregs during an immune response. This peripheral expression appears to be relatively more important in some situations since only those lymphopenic recipients that had lost peripheral expression of Aire developed a symptomatic autoimmune disease. This AIRE-related Treg defect could be clinically important in understanding the pathogenesis of APECED.
  • Joutsi-Korhonen, Lotta (Helsingin yliopisto, 2000)
  • Lehtinen, Miia (Helsingin yliopisto, 2015)
    Background: Worldwide, the leading cause of morbidity and mortality is heart failure. It is most often caused by coronary artery disease (CAD) and myocardial infarction (MI), which causes death of myocardial tissue. Although coronary interventions such as coronary bypass graft surgery (CABG) can restore blood flow to ischemic areas, and established pharmacotherapy for heart failure exists, no treatment available in the clinics can regenerate the dead cardiomyocytes. For surgical treatment, patients with heart failure represent a challenge, as they are prone to surgical complications, and suitable preoperative imaging modalities to assess possible benefit from surgery are few. Aims: Cell therapies have recently emerged as a possible alternative for treating heart failure. We wanted to explore the capacity of autologous bone marrow mononuclear cells to regenerate myocardial tissue as an adjunct to CABG. The aim was to assess the therapy s safety and detect the cells possible effects on cardiac function and viability. In addition, we investigated whether it would be possible to predict benefit from CABG in these heart-failure patients with 3-vessel CAD with the aid of combined nuclear imaging data. For this, we used 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to measure cardiac viability, and 99m-technetium-tetrofosmin single-photon emission computed tomography (99mTc-SPECT) to measure cardiac perfusion. Methods: Between 2006 and 2010, we enrolled 104 patients scheduled for CABG who suffered from CAD and ischemic heart failure. Preoperatively, pharmacotherapy was optimized, after which 39 patients still had left ventricular ejection fraction (LVEF) ≤45%. These patients received injections of bone marrow mononuclear cells (BMMCs) (N=20) or vehicle (N=19) intraoperatively into the myocardial infarction border area in a randomized and double-blind manner. During surgery and at the intensive care unit (ICU), the patients hemodynamics, arterial blood gases, systemic venous oxygen level, blood glucose, acid-base balance, lactate, hemoglobin, body temperature, and diuresis as well as medications needed were monitored and recorded every four hours throughout the first postoperative 24 hours. BMMC effects on the heart were evaluated by use of pre- and 1-year postoperative cardiac magnetic resonance imaging (MRI), FDG-PET, and 99mTc-SPECT and by measuring pro-B-type amino-terminal natriuretic peptide (proBNP) levels. As we later decided to extend the follow-up, these same variables, except for nuclear imaging data, as well as current quality of life were measured at a late follow-up visit in 2013. For this, we could contact 36 of the 39 patients recruited for the original study, of which 30 participated in the extended follow-up. Preoperatively, we also analyzed FDG-PET and 99mTc-SPECT data by using three quantitative techniques with a software tool to measure defects with hypoperfused but viable and non-viable myocardium in 15 control patients. One method used solely PET, two others combined PET and SPECT at different thresholds. As a reference, we used change in LV function and volume by MRI. Results: During the first-year follow-up, improvement was similar in both groups in LVEF, the predefined primary end-point measure (P=0.59), and similar improvement also occurred in local wall thickening (WT) (P=0.68) in the injected segments. Neither changes in viability by PET and SPECT and levels of proBNP differed between these groups. Myocardial scar size by MRI in injected segments rose by a median of 5.1% in the control group (interquartile range, IQR -3.3 to 10.8) but fell by 13.1% in the BMMC group (IQR -21.4 to -6.5) (P=0.0002). During surgery and ICU stay, hemodynamics, arterial blood gases, systemic venous oxygen level, blood glucose, acid-base balance, lactate, hemoglobin, body temperature, and diuresis and levels of medications administered were similar between the study groups. For the extended follow-up, the median period was 60.7 months (IQR 45.1 to 72.6). No statistically significant difference was observable in change in proBNP values or in quality of life between groups. LVEF in both groups remained similarly improved (P=0.647), as also did WT (P=0.434). For controls, scar size in injected segments increased with a median of 2% (IQR -7 to 19); for BMMC patients it remained reduced with a median change of -17% (IQR -30 to -6) (P=0.011). When assessing the benefit-predictive capacity of the two techniques combining FDG-PET and 99mTc-SPECT with different thresholds and one technique using FDG-PET data only, no correlation appeared with preoperative PET- or PET-SPECT-derived viable or non-viable tissue, when compared with global functional outcome (change in LVEF) or local change in WT. Conclusions: In patients with 3-vessel disease and heart failure, the three techniques using SPECT perfusion and PET viability imaging data failed to predict the functional benefit received from CABG. Thus, these imaging modalities may provide no additional advantage to preoperative patient selection, which should be considered when planning treatment for this patient group in the clinics. In the treatment of chronic ischemic heart failure, during surgery and perioperatively in the ICU, both intramyocardial BMMC and placebo injections appear safe. Although failing to affect cardiac function, combining intramyocardial BMMC therapy with CABG can sustainably reduce scar size.
  • Konsti, Juho (Helsingin yliopisto, 2012)
    Emerging large-scale digitization of microscopic tissue samples (i.e. virtual microscopy) in biomarker research and clinical pathology enables rapid, objective and repeatable computational analysis of the images. Automated image analysis is likely to be especially useful in personalized medicine, where high-throughput analysis is required for risk prediction, advanced diagnostics and targeted treatment of patients. Malignant tumors are profiled in detail to identify clinically relevant mutations and aberrant protein expression levels. Human observers are still predominantly visually interpreting the increasing number of biomarker assays with fluorescence in situ hybridization (FISH) and immunohistochemical (IHC) stainings. To aid in these quantification tasks, novel applications for automated image analysis of cancer tissues are needed. Virtual microscopy samples require large digital storage space, and image size reduction techniques should be addressed prior to archiving of the images. In this thesis, tools for high-throughput biomarker research in a digital microscopy environment were developed, assessed and adapted to a virtual microscopy setting. The first algorithm developed is intended for automated quantitative assessment of FISH signals to determine the HER2 gene amplification status in breast cancer tissue images, and proved to be comparable to visual scoring. The extent of Ki-67 staining determined in breast cancer tissue images by the second automated algorithm was a significant predictor of patient outcome in both uni- and multivariate analyses. The third algorithm for automated segmentation of tissue images divided the colorectal cancer images into epithelial and stromal compartments with high accuracy. In addition, image compression and scaling led to significant reductions in image sizes without compromising the results of the second and third algorithms introduced previously. The algorithms developed in this thesis are freely accessible to be used by the research community, facilitating external validation of the algorithms. After further validation studies, the algorithms can potentially be applied in clinical pathology especially within diagnostics, risk prediction and targeted treatment of cancer patients in a personalized medicine setting.
  • Ranta, Seppo (Helsingin yliopisto, 2002)
  • Leskinen, Kimmo (Helsingin yliopisto, 2004)
  • Janér, Joakim (Helsingin yliopisto, 2009)
    The aims of this Thesis was to evaluate the role of proangiogenic placental growth factor (PlGF), antiangiogenic endostatin and lymphangiogenic vascular endothelial growth factor (VEGF) -C as well as the receptors vascular endothelial growth factor receptor (VEGFR) -2 and VEGFR-3 during lung development and in development of lung injury in preterm infants. The studied growth factors were selected due to a close relationship with VEGF-A; a proangiogenic growth factor important in normal lung angiogenesis and lung injury in preterm infants. The thesis study consists of three analyses. I: Lung samples from fetuses, preterm and term infants without lung injury, as well as preterm infants with acute and chronic lung injury were stained by immunohistochemistry for PlGF, endostatin, VEGF-C, VEGFR-2 and VEGFR-3. II: Tracheal aspirate fluid (TAF) was collected in the early postnatal period from a patient population consisting of 59 preterm infants, half developing bronchopulmonary dysplasia (BPD) and half without BPD. PlGF, endostatin and VEGF-C concentrations were measured by commercial enzyme-linked immunosorbent assay (ELISA). III: Cord plasma was collected from very low birth weight (VLBW) (n=92) and term (n=48) infants in conjuncture with birth and endostatin concentrations were measured by ELISA. I: All growth factors and receptors studied were consistently stained in immunohistochemistry throughout development. For endostatin in early respiratory distress syndrome (RDS), no alveolar epithelial or macrophage staining was seen, whereas in late RDS and BPD groups, both alveolar epithelium and macrophages stained positively in approximately half of the samples. VEGFR-2 staining was fairly consistent, except for the fact that capillary endothelial staining in the BPD group was significantly decreased. II: During the first postnatal week in TAF mean PlGF concentrations were stable whereas mean endostatin and VEGF-C concentrations decreased. Higher concentrations of endostatin and VEGF-C correlated with lower birth weight (BW) and associated with administration of antenatal betamethasone. Parameters reflecting prenatal lung inflammation associated with lower PlGF, endostatin and VEGF-C concentrations. A higher mean supplemental fraction of inspired oxygen during the first 2 postnatal weeks (FiO2) correlated with higher endostatin concentrations. III: Endostatin concentrations in term infants were significantly higher than in VLBW infants. In VLBW infants higher endostatin concentrations associated with the development of BPD, this association remained significant after logistic regression analysis. We conclude that PlGF, endostatin and VEGF-C all have a physiological role in the developing lung. Also, the VEGFR-2 expression profile seems to reflect the ongoing differentiation of endothelia during development. Both endostatin and VEGFR-2 seem to be important in the development of BPD. During the latter part of the first postnatal week, preterm infants developing BPD have lower concentrations of VEGF-A in TAF. Our findings of disrupted VEGFR-2 staining in capillary and septal endothelium seen in the BPD group, as well as the increase in endostatin concentrations both in TAF and cord plasma associated with BPD, seem to strengthen the notion that there is a shift in the angiogenic balance towards a more antiangiogenic environment in BPD. These findings support the vascular hypothesis of BPD.
  • Mäkitie, Ilkka (Helsingin yliopisto, 2006)
    The occurrence and nature of civilian firearm- and explosion-injuries in Finland, and the nature of severe gunshot injuries of the extremities were described in seven original articles. The main data sources used were the National Hospital Discharge Register, the Cause-of-Death Register, and the Archive of Death Certificates at Statistics Finland. The present study was population based. Epidemiologic methods were used in six and clinical analyses in five papers. In these clinical studies, every original hospital record and death certificate was critically analyzed. The trend of hospitalized firearm injuries has slightly declined in Finland from the late 1980s to the early 2000s. The occurrence decreased from 5.1 per 100 000 person-years in 1990 to 2.6 in 2003. The decline was found in the unintentional firearm injuries. A high incidence of unintentional injuries by firearms was characteristic of the country, while violence and homicides by firearms represented a minor problem. The incidence of fatal non-suicidal firearm injuries has been stable, 1.8 cases per 100 000 person-years. Suicides using firearms were eight times more common during the period studied. This is contrary to corresponding reports from many other countries. However, the use of alcohol and illegal drugs or substances was detected in as many as one-third of the injuries studied. The median length of hospitalization was three days and it was significantly associated (p<0.001) with the type of injury. The mean length of hospital stay has decreased from the 1980s to the early 2000s. In this study, there was a special interest in gunshot injuries of the extremities. From a clinical point of view, the nature of severe extremital gunshot wounds, as well as the primary operative approach in their management, varied. The patients with severe injuries of this kind were managed at university and central hospital emergency departments, by general surgeons in smaller hospitals and by cardiothoracic or vascular surgeons in larger hospitals. Injuries were rarities and as such challenges for surgeons on call. Some noteworthy aspects of the management were noticed and these should be focused on in the future. On the other hand, the small population density and the relatively large geographic area of Finland do not favor high volume, centralized trauma management systems. However, experimental war surgery has been increasingly taught in the country from the 1990s, and excellent results could be expected during the present decade. Epidemiologically, explosion injuries can be considered a minor problem in Finland at present, but their significance should not be underestimated. Fatal explosion injuries showed up sporadically. An increase occurred from 2002 to 2004 for no obvius reason. However, in view of the historical facts, a possibility for another rare major explosion involving several people might become likely within the next decade. The national control system of firearms is mainly based on the new legislations from 1998 and 2002. However, as shown in this study, there is no reason to assume that the national hospitalization policies, or the political climate, or the legislation might have changed over the study period and influenced the declining development, at least not directly. Indeed, the reason for the decline to appear in the incidence of unintentional injuries only remains unclear. It may derive from many practical steps, e.g. locked firearm cases, or from the stability of the community itself. For effective reduction of firearm-related injuries, preventive measures, such as education and counseling, should be targeted at recreational firearm users. To sum up, this study showed that the often reported increasing trend in firearm as well as explosion-related injuries has not manifested in Finland. Consequently, it can be recognized that, overall, the Finnish legislation together with the various strategies have succeeded in preventing firearm- and explosion-related injuries in the country.
  • Räsänen, Jari (Helsingin yliopisto, 2007)
    Esophageal and gastroesophageal junction (GEJ) adenocarcinoma is rapidly increasing disease with a pathophysiology connected to oxidative stress. Exact pre-treatment clinical staging is essential for optimal care of this lethal malignancy. The cost-effectiviness of treatment is increasingly important. We measured oxidative metabolism in the distal and proximal esophagus by myeloperoxidase activity (MPA), glutathione content (GSH), and superoxide dismutase (SOD) in 20 patients operated on with Nissen fundoplication and 9 controls during a 4-year follow-up. Further, we assessed the oxidative damage of DNA by 8-hydroxydeoxyguanosine (8-OHdG) in esophageal samples of subjects (13 Barrett s metaplasia, 6 Barrett s esophagus with high-grade dysplasia, 18 adenocarcinoma of the distal esophagus/GEJ, and 14 normal controls). We estimated the accuracy (42 patients) and preoperative prognostic value (55 patients) of PET compared with computed tomography (CT) and endoscopic ultrasound (EUS) in patients with adenocarcinoma of the esophagus/GEJ. Finally, we clarified the specialty-related costs and the utility of either radical (30 patients) or palliative (23 patients) treatment of esophageal/GEJ carcinoma by the 15 D health-related quality-of-life (HRQoL) questionnaire and the survival rate. The cost-utility of radical treatment of esophageal/GEJ carcinoma was investigated using a decision tree analysis model comparing radical, palliative, and hypothetical new treatment. We found elevated oxidative stress ( measured by MPA) and decreased antioxidant defense (measured by GSH) after antireflux surgery. This indicates that antireflux surgery is not a perfect solution for oxidative stress of the esophageal mucosa. Elevated oxidative stress in turn may partly explain why adenocarcinoma of the distal esophagus is found even after successful fundoplication. In GERD patients, proximal esophageal mucosal anti-oxidative defense seems to be defective before and even years after successful antireflux surgery. In addition, antireflux surgery apparently does not change the level of oxidative stress in the proximal esophagus, suggesting that defective mucosal anti-oxidative capacity plays a role in development of oxidative damage to the esophageal mucosa in GERD. In the malignant transformation of Barrett s esophagus an important component appears to be oxidative stress. DNA damage may be mediated by 8-OHdG, which we found to be increased in Barrett s epithelium and in high-grade dysplasia as well as in adenocarcinoma of the esophagus/GEJ compared with controls. The entire esophagus of Barrett s patients suffers from increased oxidative stress ( measured by 8-OhdG). PET is a useful tool in the staging and prognostication of adenocarcinoma of the esophagus/GEJ detecting organ metastases better than CT, although its accuracy in staging of paratumoral and distant lymph nodes is limited. Radical surgery for esophageal/GEJ carcinoma provides the greatest benefit in terms of survival, and its cost-utility appears to be the best of currently available treatments.
  • Poduval, Praseet (Helsingin yliopisto, 2010)
    The aim of this study was twofold- Firstly, to determine the composition of the type IV collagen which are the major components of the basement membrane (BM), in the synovial lining of the rheumatoid arthritis (RA) patient and in the BM in the labial salivary gland of the Sjögrens syndrome (SS) patient. Secondly, this thesis aimed to investigate the role of the BM component laminin α4 and laminin α5 in the migration of neutrophils from the blood vessels thorough the synovial lining layer into synovial fluid and the presence of vWF in the microvasculature of labial salivary gland in SS. Our studies showed that certain α chains type IV collagen are low in RA compared to control synovial linings, while laminin α5 exhibited a pattern of low expression regions at the synovial lining interface towards the joint cavity and fluid. Also, high numbers of macrophage-like lining cells containing MMP-9 were found in the lining. MMP-9 was also found in the synovial fluid. Collagen α1/2 (IV) mRNA was found to be present in high amount compared to the other α(IV) chains and also showed intense labelling in immunohistochemical staining in normal and SS patients. In healthy glands α5(IV) and α6(IV) chains were found to be continuous around ducts but discontinuous around acini. The α5(IV) and α6(IV) mRNAs were present in LSG explants and HSG cell line, while in SS these chains seemed to be absent or appear only in patches around the ductal BM and tended to be absent around acini in immunohistochemical staining, indicating that their synthesis and/or degradation seemed to be locally regulated around acinar cells. The provisional matrix component vWF serves as a marker of vascular damage. Microvasculature in SS showed signs of focal damage which in turn might impair arteriolar feeding, capillary transudation and venular drainage of blood. However, capillary density was not decreased but rather increased, perhaps as a result of angiogenesis compensatory to microvascular damage. Microvascular involvement of LSG may contribute to the pathogenesis of this syndrome. This twofold approach allows us to understand the intricate relation between the ECM components and the immunopathological changes that occur during the pathogenesis of these inflammatory rheumatic disease processes. Also notably this study highlights the importance of maintaining a healthy ECM to prevent the progression or possibly allow reversal of the disease to a considerable level. Furthermore, it can be speculated that a healthy BM could quarantine the inflamed region or in case of cancer cells barricade the movement of malignant cells thereby preventing further spread to the surrounding areas. This understanding can be further applied to design appropriate drugs which act specifically to maintain a proper BM/BM like intercellular matrix composition.
  • Wang, Hongjie (Helsingin yliopisto, 2012)
    Human adenoviruses (Ads) have been classified into six species (A to F) currently containing 55 serotypes. For almost 2 decades vectors derived from group C serotype Ad5 have been extensively used for gene transfer studies. These Ad5 based vectors are able to efficiently infect many mammalian cell types (including both mitotic and post-mitotic cells) through interaction with a primary attachment receptor, the coxsackie and adenovirus receptor (CAR). Despite the many advantages of Ad5 based vectors a number of limitations have affected their therapeutic application to many diseases. Although they can transduce many tissue types, Ad5 based vectors are unable to efficiently transduce several potential disease target cell types, including hematopoietic stem cells and malignant tumor cells. Therefore, newer vectors have been developed based on Ad serotypes other than Ad5. This thesis focuses on species B Ads. Species B Ads are comprised of three groups based on their receptor usage. Group 1 of species B Ads (Ad16, 21, 35, 50) nearly exclusively utilize CD46 as a receptor; Group 2 (Ad3, Ad7, 14) share a common, unidentified receptor/s, which is not CD46 and which was tentatively named receptor X; Group 3 (Ad11) preferentially interacts with CD46, but also utilizes receptor X if CD46 is blocked. Species B group Ads are important human pathogens. Species B group 2 serotypes are isolated from patients with respiratory tract infections, whereas the Group 1 viruses are described as causing kidney and urinary tract infections. B-group Ad infections often occur in immunocompromised patients, including AIDS patients, recipients of bone marrow transplants, or chemotherapy patients. Recent studies performed in U.S. military training facilities indicate an emergence of diverse species B serotypes at the majority of sites. This included the group 1 serotype 21 and the group 2 serotypes 3, 7, and 14. CD46-targeting vectors derived from Ad35 and Ad11 are important tools for in vitro gene transfer into human stem cells, including hematopoietic stem cells and induced pluripotent stem cells. Ad35 and Ad11 have been used as tools for cancer therapy, because CD46 appears to be uniformely overexpressed on many cancers. Furthermore, receptor X-targeting vectors, i.e vectors derived from Ad3 or vectors containing Ad3 fibers have shown superior in the transduction of tumor cells both in vitro and in vivo and are currently being used clinically in cancer patients. While extensive basic virology studies have been done on Ad5, the information of species B group 1 interaction with CD46 is limited. Furthermore, the receptor for a major subgroup of species B Ads (receptor X) is unknown. The goal of this thesis was it therefore to better understand virological and translational aspects of species B Ads. The specific findings described in this thesis include i) the identification of CD46 binding sites within the Ad35 fiber knob, ii) the study of the in vitro and in vivo properties of Ad vectors with increased affinity to CD46. iii) the study of the receptor usage of a newly emergent Ad14a, iv) the identification of desmoglein 2 as the receptor for Ad3, Ad7, Ad11, and Ad14, v) the delineation of structural details of Ad3 virus interaction with DSG2, and vi) the analysis of functional consequences of Ad3-DSG2 interaction. As a result of these basic virology studies two Ad-derived recombinant proteins have been generated that can be used to enhance cancer therapy by monoclonal antibodies.
  • Maksimovic, Milica (Helsingin yliopisto, 2015)
    Bipolar disorder, schizophrenia and schizoaffective disorder are extremely debilitating illnesses that encompass affective and/or psychotic symptoms. Not only is there common symptomatology and genetic susceptibility, but the pharmacotherapy approaches are also similar. Nonetheless, molecular mechanisms underpinning these diseases are not yet fully understood. The theory that there is a dopaminergic dysfunction cannot account for all of the symptoms. Nor can the compounds that act on dopaminergic mechanisms successfully alleviate the symptoms. There is evidence to suggest that there are imbalances in other neurotransmitter systems, particularly the main excitatory pathway - the glutamatergic system. Glutamatergic transmission is essential for development,learning and memory and many other physiological functions of the brain. Glutamatergic receptors of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type mediate the majority of the fast synaptic neurotransmission. Here, Gria1−/− mice, lacking the GluA1 subunit of AMPA receptors, with concurrent schizophrenia-like and affective symptoms were used. The predictive validity was addressed using the standard and novel glutamate-modulating pharmacotherapeutics. The hyperactivity, the most robust feature of Gria1−/− mice and a hallmark of psychotic disorders, was attenuated by drug-treatments. Importantly, chronic treatments with lithium, valproate, topiramate, lamotrigine and perampanel were effective, evidence of their pharmacological efficacy after the acute, often sedative, treatment phase. In addition, excessive novelty-induced activation of the dorsal hippocampus of Gria1−/− mice as measured by c-Fos expression was blunted by the drug-treatments of which all are known to reduce the activity of the glutamatergic transmission. Other behaviours relevant to the schizoaffective symptomatology such as disinhibited risk-taking, less despair-like behaviour and highly exploratory phenotype as well as social deficits were partially responsive to treatment with mood-stabilisers. Moreover, Gria1−/− mice exhibited a slightly higher preference for sucrose and made more impulsive choices towards sucrose. The Gria1−/− mice may represent a suitable model for the screening of the preclinical efficacy of novel drugs on the hyperactive behaviour linked to manic episode of bipolar disorder, schizophrenia and schizoaffective disorder.
  • Lampela, Hanna (Helsingin yliopisto, 2013)
    Biliary atresia (BA) is a rare, devastating disease of infancy where a fibroinflammatory process destroys the bile ducts. BA is the most common indication for childhood liver transplantation (LT). BA treatment is started with a portoenterostomy (PE) operation and adjuvant medical therapy, and continued with LT if the PE fails. The aim of this study was to investigate the incidence of BA in Finland and to evaluate the outcomes of Finnish BA patients in the era of liver transplantation, with special emphasis on the effects of treatment centralization in 2005. The occurrence and predictors for esophageal varices, the relations between liver histology and clinical outcome variables evaluated, and noninvasive follow-up tools identified. BA patients born in Finland between 1987 and 2010 were identified from the national Register of Congenital Malformations and Children s Hospital database. All hospital records were reviewed for diagnosis confirmation, associated anomalies, treatment, follow-up data, LT, and outcome. Liver biopsies taken at PE and LT were reviewed together with follow-up biopsies. BA was diagnosed in 74 children. The incidence of BA was 1:19 900 live births. Anomalies associated with laterality disorders were observed in 17 (23%) patients. Births with BA were more common in autumn-winter than in spring-summer (p=0.013). After centralization, the clearance of jaundice rate improved significantly from 29% to 73%, p=0.001. This improvement translated into increased native liver survival: before centralization the native liver survival at four years was 21% and after centralization 73% (95% confidence interval, CI 54-91%), p<0.001. Importantly, overall survival improved significantly [50% vs. 86% (95% CI 74-98%), p=0.006]. Esophageal varices were equally common after failed (64%) and successful PE (53%). After failed PE varices bled more often and appeared significantly earlier, at eight months (4-23) vs. 19 months (4-165), p=0.004. Aspartate transferase to platelet ratio index APRI over 1.0 gave 91% sensitivity and 83% specificity for esophageal varices. A native liver biopsy taken from 23 patients at a median of 4.2 years after successful PE revealed cirrhosis in 12 (52%), and cholestasis in 4 (17%). BA incidence and the associated anomaly pattern were similar to other European and North American countries. The clear improvement in results observed after treatment centralization in 2005 supports centralizing BA treatment to designated multidisciplinary teams, despite the fact that annual caseload remained internationally low. Esophageal varices are common in BA. Endoscopic surveillance could be allocated to patients with elevated serum bilirubin levels or clinical signs of portal hypertension. APRI seems a useful tool for predicting varices.
  • Waris, Eero (Helsingin yliopisto, 2008)
    Fractures and arthritic joint destruction are common in the hand. A reliable and stable fracture fixation can be achieved by metal implants, which however, become unnecessary or even harmful after consolidation. The silicone implant arthroplasty is the current method of choice for reconstruction of metacarpophalangeal joints in rheumatoid patients. However, the outcome tends to worsen with long-term follow-up and implant-related complications become frequent. To address these problems, bioabsorbable implants were designed for the hand area. Aims of the studies were: 1) to evaluate the biomechanical stabilities provided by self- reinforced (SR) bioabsorbable implants in a transverse and an oblique osteotomy of small tubular bones and to compare them with those provided by metal implants; 2) to evaluate the SR poly-L/DL-lactide 70/30 plate for osteosynthesis in a proof-of-principle type of experiment in three cases of hand injuries; and 3) to evaluate the poly-L/D-lactide (PLA) 96/4 joint scaffold, a composite joint implant with a supplementary intramedullary Polyactive® stem and Swanson silicone implant in an experimental small joint arthroplasty model. Methods used were: 1) 112 fresh frozen human cadaver and 160 pig metacarpal bones osteotomised transversally or obliquely, respectively, and tested ex vivo in three point bending and in torsion; 2) three patient cases of complex hand injuries; and 3) the fifth metacarpophalangeal joints reconstructed in 18 skeletally-mature minipigs and studied radiologically and histologically. The initial fixation stabilities provided by bioabsorbable implants in the tubular bones of the hand were comparable with currently-employed metal fixation techniques, and were sufficient for fracture stabilisation in three preliminary cases in the hand. However, in torsion the stabilities provided by bioabsorbable implants were lower than that provided by metal counterparts. The bioabsorbable plate enhanced the bending stability for the bioabsorbable fixation construct. PLA 96/4 joint scaffolds demonstrated good biocompatibility and enabled fibrous tissue in-growth in situ. After scaffold degradation, a functional, stable pseudarthrosis with dense fibrous connective tissue was formed. However, the supplementary Polyactive® stem caused a deleterious tissue reaction and therefore the stem can not be applied to the composite joint implant. The bioabsorbable implants have potential for use in clinical hand surgery, but have to await validation in clinical patient series and controlled trials.
  • Wang, Feng (Helsingin yliopisto, 2013)
    Hydrophobic steroid hormone derivatives, carried in plasma exclusively by lipoproteins, constitute a unique hormone family. They are hormonally inactive and must be liberated from their fatty acyl partner before their physiological response. 17β-estradiol (E2) fatty acyl esters are reportedly enriched in adipose tissue, which has the enzyme machinery necessary for synthesis of estrogen from precursor steroids. The aims of the thesis were to explore the enzymes responsible for steroid-ester hydrolysis and to quantify dehydroepiandrosterone (DHEA) and E2 fatty acyl esters in adipose tissue and serum both in men and in women. [3H]DHEA-ester hydrolysis was investigated by use of lysosomal acid lipase (LAL)-depleted HeLa cells and Wolman fibroblasts. LDL-associated [3H]DHEA fatty acyl esters were partially taken up in cells via LDL receptor or LDL receptor-related receptors, after which, they were hydrolyzed and further metabolized to [3H]-5α-androstanedione and [3H]androstenedione that were secreted by the cells. LAL displayed a partial role in the hydrolysis of [3H]DHEA fatty acyl esters. DHEA fatty acyl esters were undetectable in adipose tissue, although 32 to 178 pmol/g of free DHEA was quantified. DHEA fatty acyl ester concentrations in serum ranged from 0.5 to 2.8 pmol/ml, corresponding to 5 to 15% of total DHEA. E2 fatty acyl esters in subcutaneous adipose tissue from the human breast may function as a reservoir for free E2, and conversion process to free E2 was partly dependent on hormone-sensitive lipase (HSL) function. In obese men, E2 fatty acyl ester concentrations in adipose tissues were similar to those of E2, but in obese women ester derivatives were significantly lower than E2. In obese subjects, E2 fatty acyl ester levels in adipose tissue significantly correlated with serum levels whereas in case of E2 this was not the case. Compared to obese men, E2 levels in subcutaneous adipose tissue in obese women were higher, along with higher relative mRNA expression of steroid sulfatase and 17ß-hydroxysteroid dehydrogenases 1, 7, and 12. In summary, DHEA fatty acyl ester concentrations in serum were attributable to 5 to 15 % of total DHEA. Circulating DHEA fatty acyl esters bound to LDL may enter target cells, and after their hydrolysis step to free DHEA it can be metabolized to other active steroids. LAL may partially participate in the hydrolysis of DHEA esters. In addition, subcutaneous adipose tissue from human breast had E2 fatty acyl esterifying and hydrolysing activity, and the hydrolysis was in part dependent on HSL activity. Production of E2 from a large adipose mass was not reflected by increased circulating E2 concentrations in severely obese men or women. Adipose tissue may, however, contribute to serum E2 fatty acyl ester concentrations.
  • Kallijärvi, Jukka (Helsingin yliopisto, 2006)
  • Salmi, Heli-Maria (Helsingin yliopisto, 2012)
    Normal human metabolism is a well-coordinated process involving the whole organism. It can be disturbed in true inborn errors of metabolism or, alternatively, in acquired situations where inappropriate nutrition and impaired energy production compromise normal metabolic control. These situations may share common pathophysiological mechanisms and metabolic markers. Their closer knowledge could provide new approaches for treatment or diagnosis. This thesis had two objectives, both dealing with biochemical changes in situations where significant metabolic perturbations occur. (1) To study thiol metabolism in children with several inborn errors of metabolism (n = 36) and in cell culture models, where similar metabolic conditions are created. Thiol levels and thiol redox status, serving multiple metabolic and regulatory purposes, could be affected in inborn errors of metabolism following inappropriate nutrition and compromised energy metabolism. Changes in thiol status could have an important role in the development of complications and even offer therapeutic potential in these diseases, as thiol levels can be influenced by diet or medication. (2) To investigate end products of metabolism in infants with cow s milk allergy (CMA; n = 35) as metabolic markers of inadequate nutrition in early childhood and altered intestinal microbial metabolism. Eventually, these changes could provide a novel diagnostic tool. Plasma and erythrocyte non-protein thiols (glutathione and cysteine) as well as thiols in cultured human fibroblasts, HEPG2 and 293T cells were measured with a liquid chromatography based method. Mass spectrometry was used for quantification of urinary excretion of end products of metabolism in CMA patients. Activities of enzymes related to thiol metabolism in human erythrocytes were studied in spectrophotometric assays. Patients with inborn errors of energy and nutrient metabolism had altered levels of plasma non-protein thiols glutathione and cysteine. Their plasma thiol redox status was indicative of oxidative stress, which thus seems to play a role in the pathophysiology of complications of these diseases. With further research, the changes in thiol status could have therapeutic implications. CMA is associated with measurable changes in urinary levels of end products of metabolism, which may be seen as markers of inadequate nutrition or altered intestinal bacterial metabolism. If confirmed in future studies, these changes could provide an innovative new approach to the diagnosis of CMA.