Browsing Lääketieteellinen tiedekunta by Title

Sort by: Order: Results:

Now showing items 1-20 of 2384
  • Ylikoski, Ari (Helsingin yliopisto, 2016)
    The diagnosis of Parkinson's disease has remained essentially a clinical one. The diagnostic criteria consist of cardinal motor symptoms and signs, such as bradykinesia and at least one of the following: rest tremor, muscular rigidity or postural instability. However, non-motor symptoms (i.e. cognition, mood, sleep, pain, dysautonomy) constitute a major clinical challenge. The total burden of non-motor symptoms is likely to be more important than the motor symptoms in determining the quality of life across all stages of the disease. The current study aims to evaluate, by means of a structured questionnaire approach, the occurrence of sleep disorders, sleeping difficulties, health-related quality of life and other comorbidities in a non-selected population of Finnish Parkinson patients. The response rate was 59% (N=854). The occurrence of rapid eye movement sleep behavior disorder was 39.0%, restless legs syndrome 20.3%, chronic insomnia disorder 36.9%, narcolepsy like symptoms 11.0%, sleep disordered breathing 22.1%, respectively. Low quality of life occurred in 45.0% of the participants, depression in 20.9%, excessive daytime sleepiness in 30.2%, fatigue in 43.9%.
  • Pérez Tanoira, Ramón (Helsingin yliopisto, 2019)
    Prosthetic infection represents a major problem in the outcome of patients after implantation of a foreign body. The presence of biomaterial in the body provides a substratum to host either tissue-cell integration or bacterial colonization. In obliteration of an infected bone, artificial bone substitutes and rigid fixation materials are usually necessary to fill bone cavity and to restore the properties of the bone respectively. This study attempted to discover the effect of bioactive glass bone substitute granules (BAG) S53P4 on bacterial and human-cell adhesion on other implant used simultaneously (I, II). During development of new infection-resistant biomaterials, adherence and colonization of either bacterial cells or tissue cells on biomaterials must be evaluated in parallel. A methodology allowing study of the simultaneous growth of bacteria and tissue cells on the same biomaterial surface was developed. This will allow discovery of the effect of various bacterial concentrations on host-cell viability and integration with an implant surface, and their relation to increasing reactive oxygen species (ROS) levels and cell apoptosis (III). Finally, considering our first results and that microorganisms frequently infect an implant surface during surgery and start to compete for the surface before tissue integration, it was hypothesized that incubation of implants with host cells before implantation may be one way to reduce the bacterial living space available and would prevent bacterial adhesion and consequently the infection of biomaterials (IV). Bacterial and human osteoblast-like osteosarcoma cells (SaOS-2) or primary osteoblast (hOB) cells were incubated for 4.5 hours, 2 days, or 4 days at 37°C. As substratum, titanium (Ti), polytetrafluoroethylene (PTFE), polydimethyl-siloxane (PDMS), or bioactive glass plates (IV) were used. The study was done separately (I, II), in competition with SaOS-2 or hOB (III), or in competition with SaOS-2 after 24-hour pre-incubation with SaOS-2 (IV). The effect of BAG S53P4 on bacteria (I) and cell (II) adhesion was studied in either a normal atmosphere or in hypoxia-simulating atmospheric conditions of the middle ear, mastoid cavity, or sinuses. Human osteoblast-like SaOS-2 cells or primary osteoblast (hOB) cells (III) (both, 1x105cells/mL), and collection strains of Staphylococcus aureus and Staphylococcus epidermidis (I) [108 colony forming units (CFU) (I) or (serial 1:10 dilutions of 108 CFU (III, IV)] were employed. The bacteria and cell proliferation, cytotoxicity (III, IV), and production of reactive oxygen species (ROS) (III) were evaluated by colorimetric (MTT, LDH, and crystal violet) (III, IV) as well as by fluorometric methods (fluorescent microscopy and flow cytometry) (III). Bacterial cell viability was studied by use of a drop-plate method after sonication. Effects of BAG S53P4 on cell adhesion were linked intimately with modifications of cellular attachment organs (vinculin containing focal adhesions), rearrangement of the actin cytoskeleton, and cellular spreading. The presence of bioglass under normoxic and hypoxic conditions prevented bacterial and biofilm adhesion for most of the materials and promoted integration of SaOS-2 cells with various biomaterial surfaces, especially under hypoxic conditions, in which S53P4 granules cause increased pH (I, II). In the competitive study, the presence of bacteria resulted in reduced adherence of human cells to the surface of the biomaterials, increased production of ROS, and increased apoptosis. The presence of either type of human cell was associated with a reduction in bacteria compared with that for the materials incubated with S. aureus only (III). Pretreatment with human cells was also associated with a reduction in bacterial colonization of the biomaterial compared with that of the non-pretreated materials, but the presence of bacteria produced a decrease in viable human cells for all materials (IV). In conclusion, the presence of S53P4 granules may both protect implants from bacterial colonization and promote their osteointegration. In the presence of bacteria and cells, colonization of the surface by one reduces colonization by the other. The bacteria produce cellular oxidative stress in human cells, which may be related to the cellular death. The preoperative incubation of prostheses with host cells could be a new way to prevent infection of biomaterials and lessen the risk for bacterial antibiotic resistance.
  • Mattila, Antti (Helsingin yliopisto, 2001)
  • Virkki, Liisa (Helsingin yliopisto, 2014)
    Biological antirheumatic drugs are biotechnologically produced antibodies or fusion proteins that are used if rheumatic inflammation is not sufficiently ameliorated with conventional antirheumatic drugs. Approximately 10% of Finnish rheumatoid arthritis (RA) patients use biological drugs. Biological antirheumatic drugs target inflammatory mediators and cells. Tumor necrosis factor inhibitors (TNFi) have been used since the beginning of the 2000s, and they are still the primarily used type of biological antirheumatic drug. The efficacy and safety has been assessed in clinical drug trials usually of 6 to 12 months duration with strict inclusion and exclusion criteria. In practice these drugs are used for much longer and in very diverse patient populations. In this work, the effectiveness and adverse events (AEs) of TNFi treatment in a routine care setting were assessed using the national register of biological drugs. Biological drugs are expensive, and therefore also their cost-effectiveness and the outcomes of switching a TNFi to another one were assessed. The effectiveness of the TNFi infliximab (IFX) was similar to its efficacy in clinical trials. In about 2/3 of the patients clinically significant symptom relief was achieved within 3 months, and 42% achieved remission within the first year. The need of glucocorticoid and pain medication was reduced. In addition to methotrexate assessed in clinical trials, also other conventional antirheumatic drugs were suitable concomitant drugs. The most frequent AEs of TNFi treatment were infections, eczemas, and infusion reactions. AEs were reported in 17% of patients using biologicals, serious ones in 3.1%. No unexpected AEs were reported. 76% of RA patients benefited from IFX in terms of quality-adjusted life years (QALY); their functional capacity and subjective health improved. The median price of a QALY was 51884 . The best cost-effectiveness was achieved in patients with particularly high disease activity and significant response to the treatment. The IFX dose and methotrexate use also affected the cost-effectiveness. Switching a TNFi to another one was useful in cases where initial effectiveness was lost, and in cases of AEs such as infusion reactions, eczemas, or local injection site reactions, which did not require discontinuation of TNFi treatment altogether; in these cases the switch led to a similar or even better effect. The register research indicates that TNFi treatment is effective and relatively safe in RA refractory to other treatments. It was cost-effective in a significant portion of the patients; new drug alternatives (including biosimilars) and the contemporary treatment aim of remission may further improve the cost-effectiveness.
  • Kuusio, Hannamaria (Helsingin yliopisto, 2014)
    The shortage of general practitioners (GPs) threatens the effective functioning of public primary health care in many countries. Working as a GP has lost much of its attractiveness as a career option also among Finnish physicians during the past 15 years, and foreign-born physicians are being increasingly recruited to primary health care. The first aim of the present study was to examine the psychosocial work environment of physicians and how it is associated with their wellbeing and future career plans. GPs were compared to medical specialists and private physicians. The second aim of the study was to investigate the process of foreign-born physicians entering their profession in Finland and also to explore their job satisfaction, work-related stressors and future career interests. The study data was obtained from two surveys conducted in 2006 and 2010 among random samples of Finnish physicians (N=2,841, response rate 57%; and N=3780, response rate 56%, respectively). In 2010, a survey of all foreign-born physicians resident in Finland (N=1,292) was also conducted (553 respondents, response rate 43%). Qualitative theme interviews were conducted with foreign-born physicians in Finnish primary health care to explore their work history, career choices and plans, job satisfaction and health. The results showed that the work ability and self-rated health of Finnish GPs were lower than those of Finnish medical specialists and private physicians. Finnish GPs and medical specialists both reported more psychological distress than private physicians. Wellbeing differences were to some extent explained by higher job stressors among public-sector physicians. Furthermore, Finnish GPs expressed their intention to leave their job more often than other Finnish physicians. For foreign-born physicians, the extensive and challenging licensing process slowed down their career possibilities, particularly among physicians trained outside the EU/EEA. The job satisfaction of foreign-born public-sector physicians was lower than that of foreign-born private physicians, and they also reported higher work-related stressors. Foreign-born GPs more often expressed an intention to leave primary health care than foreign-born medical specialists, private physicians or Finnish GPs. The present study suggests that the retention of both Finnish and foreign-born GPs will remain a challenge due to the more often expressed intention among GPs to leave primary health care and higher stressors in comparison to private physicians. Investing in a more efficient and monicultural human resource policy in primary health care and giving GPs more influence in decisions concerning their work could attract more GPs to primary health care - both native and foreign.
  • Pekkarinen, Pirkka (Helsingin yliopisto, 2014)
    The human immune system consists of the innate and the adaptive immunity that together protect the body from pathogens. To complete this task, the immune system must be able to recognize and destroy the dangerous foreign structures but also not to react to host structures or innocuous foreign structures, such as proteins of food or the commensal microbes residing in the gut. The innate immunity includes the phagocytes, such as the macrophages and neutrophils, and multiple molecular defensive systems, most importantly the complement system. The innate immunity reacts quickly to pathogens but its functions remain unchanged with repeated encounters with the intruder. The adaptive immunity is slower in its response, but it is more specific and it has memory; upon repeated exposure to a given pathogen, the adaptive immunity is activated more rapidly. Immunological tolerance, the unresponsiveness to self antigens, is a feature of the adaptive immunity. The adaptive immunity includes T and B lymphocytes and the antibodies produced by the B lymphocytes. In spite of their interdependency, the innate and adaptive immune systems have often been studied separately. This thesis focuses on their interface by investigating the role of the innate complement system in the regulation of the adaptive immunity and of the T lymphocyte function in particular. We followed the immune response and the establishment of oral tolerance in a C3 deficient mouse model, where the function of the complement system is blocked. We also studied vaccination responses and mucosal immune homeostasis in C3 deficient human subjects. The mice were immunized with ovalbumin in Complete Freund s adjuvant. In order to induce oral tolerance, some of the mice were given ovalbumin to the gastrointestinal tract prior to the immunizations. The ensuing immune response was monitored by assessing the lymphocyte fractions by flow cytometry and by stimulating splenocytes with ovalbumin and monoclonal antibodies in vitro, and measuring the proliferative response with a radioactive thymidine incorporation assay. The expression of cytokines and transcription factors in isolated cells and tissue samples was analyzed with quantitative real-time PCR. Serum antibody levels were determined by ELISA. We isolated leukocytes from peripheral blood samples collected from the patients and healthy control subjects and analyzed the lymphocyte population with flow cytometry. Serum antibodies specific for intestinal commensal microbes and the vaccine antigens tetanus toxoid and diphtheria toxoid were measured with ELISA. Serum samples were also analyzed for the presence of a set of key cytokines. The results indicate that complement plays a crucial role in the regulation of the functional differentiation of the T helper lymphocytes central to the adaptive immunity. Immunization with ovalbumin produced a weaker T cell proliferative response in the C3 deficient mouse model compared to the wild-type controls. The response of the T lymphocytes was also qualitative different, since the development of a TH1 response was particularly impaired in the absence of a functional complement system, whereas the TH2 response showed no difference between the mouse strains. This was also reflected on the B lymphocyte response: The IgG2a and IgG3 response to the immunization was reduced in the C3 deficient mice but the IgE response was normal. In addition to the general attenuation of the adaptive immunity, the C3 deficiency resulted in a disturbance of the intestinal immune tolerance in both mice and men. The administration of a foreign protein into the gastrointestinal tract of the C3 deficient mice failed to prevent the systemic immune response to the subsequent immunization with the same protein, i.e. the establishment of oral tolerance failed. The C3 deficient human subjects had more mucosally homing activated T lymphocytes in the peripheral blood and higher levels of serum IgG specific for intestinal commensal microbes. A further sign of the deficient immune tolerance in the C3 deficient human system was the lack of IgG4 response to the vaccine antigens. IgG3 antibodies specific for vaccine antigens were present at higher concentrations in the patient sera and the levels of the inflammatory cytokines IL-12 and IL-21 were also elevated. In contrast to the mouse, the profile of serum cytokines and antibody subclasses in the C3 deficient human subjects pointed at a pronounced TH1 response. The work presented in this thesis defines the complement system as a versatile regulator of the adaptive immunity and helper T lymphocytes. The normal functional differentiation of the T lymphocytes requires signals from the complement system and the establishment of immune tolerance both in the mucosal and systemic immune systems is particularly dependent on complement. The results present novel information on the interplay of the innate and adaptive immune systems and will probably affect the treatment strategies for food allergies and inflammatory bowel diseases.
  • Kantola, Taru (Helsingin yliopisto, 2010)
    The Molecular Adsorbent Recirculating System (MARS) is an extracorporeal albumin dialysis device which is used in the treatment of liver failure patients. This treatment was first utilized in Finland in 2001, and since then, over 200 patients have been treated. The aim of this thesis was to evaluate the impact of the MARS treatment on patient outcome, the clinical and biochemical variables, as well as on the psychological and economic aspects of the treatment in Finland. This thesis encompasses 195 MARS-treated patients (including patients with acute liver failure (ALF), acute-on-chronic liver failure (AOCLF) and graft failure), and a historical control group of 46 ALF patients who did not undergo MARS. All patients received a similar standard medical therapy at the same intensive care unit. The baseline data (demographics, laboratory and clinical variables) and MARS treatment-related and health-related quality-of-life data were recorded before and after treatment. The direct medical costs were determined for a period of 3.5 years.Additionally, the outcome of patients (survival, native liver recovery and need for liver transplantation) and survival predicting factors were investigated. In the outcome analysis, for the MARS-treated ALF patients, their 6-month survival (75% vs. 61%, P=0.07) and their native liver recovery rate (49% vs. 17%, P<0.001) were higher, and their need for transplantations was lower (29% vs. 57%, P= 0.001) than for the historical controls. However, the etiological distribution of the ALF patients referred to our unit has changed considerably over the past decade and the percentage of patients with a more favorable prognosis has increased. The etiology of liver failure was the most important predictor of the outcome. Other survival predicting factors in ALF included hepatic encephalopathy, the coagulation factors and the liver enzyme levels prior to MARS treatment. In terms of prognosis, the MARS treatment of the cirrhotic AOCLF patient seems meaningful only when the patient is eligible for transplantation. The MARS treatment appears to halt the progression of encephalopathy and reduce the blood concentration of neuroactive amino acids, albumin-bound and water-soluble toxins. In general, the effects of the MARS treatment seem to stabilize the patients, thus allowing additional time either for the native liver to recover, or for the patients to endure the prolonged waiting for transplantation. Furthermore, for the ALF patients, the MARS treatment appeared to be less costly and more cost-efficient than the standard medical therapy alone. In conclusion, the MARS treatment appears to have a beneficial effect on the patient outcome in ALF and in those AOCLF patients who can be bridged to transplantation.
  • Wood, Graham (Helsingin yliopisto, 2017)
    The research focus is a specific case study analysis of collective violence in the North of England, in particular West and South Yorkshire. There are three cases: the Bradford Riots June 9-11th, 1995, The Battle of Orgreave, June 18th, 1984 and a violent encounter between Leeds United and Manchester United fans at Elland Road on October 11th, 1975. The cases are set within the dynamic of violence mutation revealed in both their specific genres and in the fusion of violence that draws together the cases and manifestations of violence in the region throughout the period covered. The unique challenges of violence research are addressed and a triangulation methodology was employed drawing upon extensive newspaper sources, official reports, secondary sources and a limited sample of supporting interviews to garner an insight into the events. Fundamental problems of definition were broached, highlighting the difficulties of undertaking a multidisciplinary study of violence. This was compounded by different disciplines seeing the phenomenon through their own restrictive lens, resulting in divergent and contradictory conceptualisations of violence. This necessitated the formulation of a conceptual framework - violent conflictual contention, to obviate some of the weaknesses in violence definition. Inculcated within the framework were thematic strands of grievance and identity formation set within the contentious repertoire of non-institutional actors leading up to and emanating from the cases themselves. Primary attention was devoted to the non-institutional actors, although recognition was made of the role played by the police in all the cases. Yet irrespective of the level of social control employed by the police, and all three cases exhibited differing crowd control strategies, they nonetheless could not prevent the outbreak of violence and may have in fact have inadvertently exacerbated an increased recourse to violence. A grievance framework was proposed in which suddenly imposed grievances were identified in the unfolding events and reference was made to grievances of illegitimate inequality and violated principles that may have been key causal factors or factors that perpetuated the continuation of the violence. Grievance factors were juxtaposed with identity considerations that highlighted the fragility and transitory nature of identity formation. As the research developed it became evident that those confronting the non-institutional actors in the cases were derived not from some external other but were in part sourced from their own fractured communities. Compounding the volatility of grievance and identity formation was a realisation of violence that transformed in both time and space and effectively negated any essentialist approach to the study of violence, thereby compromising the concept of violent conflictual contention. The actors involved could only access a limited and at times vicarious contentious repertoire, so their invocation of violence reflected an instrumentality and a self-belief in the virtuosity of their use of violence at specific points in time. Placed within their historical pathways, the cases moved from the 1970's, through the 1980's and 1990's and finally into the twenty-first century. Demarcated in their own clearly defined temporal context, the cases demonstrated significant levels of non-fatal violence. When transfused into a totality that merged the cases together into a landscape of violence, then the region was witness to significant and perpetual levels of violence during this period. This has resulted in a Yorkshire particularism fraught with contradiction and a resort to violence that has found refuge in the different communities.
  • Lyytinen, Heli (Helsingin yliopisto, 2009)
    Since national differences exist in genes, environment, diet and life habits and also in the use of postmenopausal hormone therapy (HT), the associations between different hormone therapies and the risk for breast cancer were studied among Finnish postmenopausal women. All Finnish women over 50 years of age who used HT were identified from the national medical reimbursement register, established in 1994, and followed up for breast cancer incidence (n= 8,382 cases) until 2005 with the aid of the Finnish Cancer Registry. The risk for breast cancer in HT users was compared to that in the general female population of the same age. Among women using oral or transdermal estradiol alone (ET) (n = 110,984) during the study period 1994-2002 the standardized incidence ratio (SIR) for breast cancer in users for < 5 years was 0.93 (95% confidence interval (CI) 0.80–1.04), and in users for ≥ 5 years 1.44 (1.29–1.59). This therapy was associated with similar rises in ductal and lobular types of breast cancer. Both localized stage (1.45; 1.26–1.66) and cancers spread to regional nodes (1.35; 1.09–1.65) were associated with the use of systemic ET. Oral estriol or vaginal estrogens were not accompanied with a risk for breast cancer. The use of estrogen-progestagen therapy (EPT) in the study period 1994-2005 (n= 221,551) was accompanied with an increased incidence of breast cancer (1.31;1.20-1.42) among women using oral or transdermal EPT for 3-5 years, and the incidence increased along with the increasing duration of exposure (≥10 years, 2.07;1.84-2.30). Continuous EPT entailed a significantly higher (2.44; 2.17-2.72) breast cancer incidence compared to sequential EPT (1.78; 1.64-1.90) after 5 years of use. The use of norethisterone acetate (NETA) as a supplement to estradiol was accompanied with a higher incidence of breast cancer after 5 years of use (2.03; 1.88-2.18) than that of medroxyprogesterone acetate (MPA) (1.64; 1.49-1.79). The SIR for the lobular type of breast cancer was increased within 3 years of EPT exposure (1.35; 1.18-1.53), and the incidence of the lobular type of breast cancer (2.93; 2.33-3.64) was significantly higher than that of the ductal type (1.92; 1.67-2.18) after 10 years of exposure. To control for some confounding factors, two case control studies were performed. All Finnish women between the ages of 50-62 in 1995-2007 and diagnosed with a first invasive breast cancer (n= 9,956) were identified from the Finnish Cancer Registry, and 3 controls of similar age (n=29,868) without breast cancer were retrieved from the Finnish national population registry. Subjects were linked to the medical reimbursement register for defining the HT use. The use of ET was not associated with an increased risk for breast cancer (1.00; 0.92-1.08). Neither was progestagen-only therapy used less than 3 years. However, the use of tibolone was associated with an elevated risk for breast cancer (1.39; 1.07-1.81). The case-control study confirmed the results of EPT regarding sequential vs. continuous use of progestagen, including progestagen released continuously by an intrauterine device; the increased risk was seen already within 3 years of use (1.65;1.32-2.07). The dose of NETA was not a determinant as regards the breast cancer risk. Both systemic ET, and EPT are associated with an elevation in the risk for breast cancer. These risks resemble to a large extent those seen in several other countries. The use of an intrauterine system alone or as a complement to systemic estradiol is also associated with a breast cancer risk. These data emphasize the need for detailed information to women who are considering starting the use of HT.
  • Laurila, Jouni (Helsingin yliopisto, 2002)
  • Leppä, Elli (Helsingin yliopisto, 2011)
    Neurons can be divided into various classes according to their location, morphology, neurochemical identity and electrical properties. They form complex interconnected networks with precise roles for each cell type. GABAergic neurons expressing the calcium-binding protein parvalbumin (Pv) are mainly interneurons, which serve a coordinating function. Pv-cells modulate the activity of principal cells with high temporal precision. Abnormalities of Pv-interneuron activity in cortical areas have been linked to neuropsychiatric illnesses such as schizophrenia. Cerebellar Purkinje cells are known to be central to motor learning. They are the sole output from the layered cerebellar cortex to deep cerebellar nuclei. There are still many open questions about the precise role of Pv-neurons and Purkinje cells, many of which could be answered if one could achieve rapid, reversible cell-type specific modulation of the activity of these neurons and observe the subsequent changes at the whole-animal level. The aim of these studies was to develop a novel method for the modulation of Pv-neurons and Purkinje cells in vivo and to use this method to investigate the significance of inhibition in these neuronal types with a variety of behavioral experiments in addition to tissue autoradiography, electrophysiology and immunohistochemistry. The GABA(A) receptor γ2 subunit was ablated from Pv-neurons and Purkinje cells in four separate mouse lines. Pv-Δγ2 mice had wide-ranging behavioral alterations and increased GABA-insensitive binding indicative of an altered GABA(A) receptor composition, particularly in midbrain areas. PC-Δγ2 mice experienced little or no motor impairment despite the lack of inhibition in Purkinje cells. In Pv-Δγ2-partial rescue mice, a reversal of motor and cognitive deficits was observed in addition to restoration of the wild-type γ2F77 subunit to the reticular nucleus of thalamus and the cerebellar molecular layer. In PC-Δγ2-swap mice, zolpidem sensitivity was restored to Purkinje cells and the administration of systemic zolpidem evoked a transient motor impairment. On the basis of these results, it is concluded that this new method of cell-type specific modulation is a feasible way to modulate the activity of selected neuronal types. The importance of Purkinje cells to motor control supports previous studies, and the crucial involvement of Pv-neurons in a range of behavioral modalities is confirmed.
  • Utge, Siddheshwar J. (Helsingin yliopisto, 2012)
    Depression is a complex psychiatric disorder that comprises a variety of symptoms. In addition to depressed mood state, depression has symptoms of disturbed sleep such as early morning awakenings and fatigue. Poor sleep has been demonstrated to be one of the modifiable risk factors in the onset of depression. However, the mechanisms remain largely unknown. In the present study, depressive patients from the Finnish population-based samples were grouped according to the presence or absence of disturbed sleep. The genetic background of depression was hypothesized to be different between the groups. The regulation of sleep, and of mood, was assumed to partly share a common genetic background. The aim of this thesis was to identify genetic variants associated with depression and disturbed sleep in order to gain a better understanding of this hypothesis in the population-based Finnish samples. First, the association between genetic markers from 14 functionally-relevant candidate genes was assessed. These genes were related to serotonergic and glutamatergic neurotransmission, to neural plasticity, and to the hypothalamic-pituitary-adrenal axis (HPA-axis) with depression, depression with early morning awakenings, and depression with fatigue in a sample from the population-based Health 2000 survey. Overall, 1654 individuals were studied (384 depressed patients and 1270 population-matched controls). The data suggested that allelic variants from a gene coding for a key regulatory protein of the serotonergic neurotransmission system, TPH2, is associated with depression accompanied by fatigue in females. An association between a numbers of genes related to glutamatergic neurotransmission and neural plasticity, such as GAD1, GRIA3, and BDNF with depression accompanied by fatigue in females. A significant association between CREB1, a neural plasticity related gene, and depression in men, was also identified. Of the genes related to the HPA-axis, an association was found between CRHR1 and depression accompanied by early morning awakenings in females. The hypothesis was then expanded to encompass 18 genes from the circadian system in the same study subjects (N=1654) from the Health 2000 cohort. In this study, a significant association of two distinctive allelic variants of TIMELESS was associated with depression accompanied by fatigue (Permutation-based corrected empirical P=0.0056), to seasonal mood fluctuation (Pointwise P=0.016) in females, and with depression accompanied by early morning awakenings (Permutation-based corrected empirical P=0.0374) in males. In an independent set of 1512 control individuals (Genmets (D-) sample) from the complete Health 2000 cohort, the same variant was also associated with seasonal mood fluctuation (Pointwise P=0.036) in females, and with early morning awakenings (Pointwise P=0.038) or fatigue (Pointwise P=0.0016) in healthy males. Finally, the shared genetic background for sleep and mood in healthy individuals (N=3147) drawn from the population-based Health 2000 and FINRISK study 2007 survey was examined. In this study, for association analyses with sleep duration, 23 variants from 12 candidate genes were selected that had shown association (P less than 0.05) with depression and disturbed sleep in studies I and II. A significant association of a GRIA3 variation with sleep duration in females (Permutation-based corrected empirical P=0.00001) was identified. The frequency of the allele which associated with depression was highest among females who slept for 8 hours or less in all age groups younger than 70 years. However, no prominent associations were found among males, suggesting a sex-specific effect for the X-chromosomal GRIA3 gene. In conclusion, these results support the involvement of genes related to serotonergic (TPH2) or glutamatergic neurotransmission (GAD1, GRIA3), to neural plasticity (CREB1), to the HPA-axis (CRHR1), and the circadian system (TIMELESS), in the genetic aetiology of depression and disturbed sleep. The results obtained in this thesis support the hypothesis that the different phenotypes of depression and disturbed sleep would also be genetically distinct. Depression is heterogeneous and its genetic background may be partly different in women and men. This study also shows that the regulation of sleep and of mood may have a common genetic background.
  • Polinati, Padmini (Unigrafia, 2015)
    Mitochondrial diseases are generally caused by genetic variants that may affect cell function during the process of energy generation: right from the start of protein translocation to the fatty acid degradation by beta-oxidation (β-oxidation). The main objective of this PhD thesis is to study genetic variants that cause mitochondrial diseases and also to understand the disease pathogenesis of a known disease using the induced pluripotent stem cell (iPSC) method, a revolutionary approach in regenerative medicine. In the first study, we carried out a long-term follow up of six metabolic diseased patients and subsequently we performed a carrier frequency study of the identified carnitine palmitoyl transferase 1A (CPT1A) gene variant in the Finnish population. We identified a novel homozygous variant c.1364A>C (p.Lys455Thr) in exon 12 of the CPT1A gene. No carriers of the variant c.1364A>C were detected upon minisequencing of 150 control samples but the allele frequency of CPT1A variant in global population is 0.0002142 (ExAC Browser) whereas in the Finnish population (6614 allele number) the frequency is 0.001966. The identified variant was predicted to cause improper folding of the CPT1A protein, which leads to its degradation. All patients were treated with a high-carbohydrate and a low fat diet. In the second study, we focused on the human DnaJ (Hsp40 homolog) subfamily C, member 19 (DNAJC19) deficiency. Our studies showed that it causes early onset dilated cardiomyopathy syndrome (DCMA). This is the first report of a genetic defect in the mitochondrial protein, DNAJC19, outside of the Canadian Dariusleut Hutterite population. This defect is characterized by an unusual aetiology for an early onset recessively inherited dilated cardiomyopathy that is associated with ataxia and male genital anomalies. Sequencing of the human DNAJC19 gene revealed a homozygous single nucleotide (A) deletion in exon 6 that cause a frameshift and lead to the premature termination of the protein. In the third study, the pathogenesis of retinopathy in long-chain acyl-CoA dehydrogenase deficiency (LCHADD) was studied using iPSC technology. Retinopathy is an unusual manifestation of LCHADD, as mitochondrial fatty acid β-oxidation (FAβO) has not been considered to play a major role in the metabolism of the retina. Among all defects of mitochondrial FAβO, only long-chain acyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (TFP) deficiencies have developed pigmentary retinopathy and peripheral neuropathy. We elucidated how a genetic variant in the FAβO cycle can disrupt the retinal pigment epithelium (RPE) that can eventually lead to blindness. In addition, we developed a new in vitro cell model; iPSC clones were generated from LCHADD patient fibroblasts and further differentiated into RPE cells. Several changes were observed in patient RPE cells such as decreased cell size, lower pigmentation and irregular pattern of morphology. Electron microscopy analysis showed an accumulation of a few melanosomes, more melanolysosomes, and large sized lipid droplets in patient RPE cells. Furthermore, increased levels of triglycerides in patient RPE cells were observed upon mass spectrometric analysis. We concluded that all these changes had contributed to the disruption of the RPE layer that leads to blindness in LCHAD deficiency patients. Finally, the research done for this thesis succeeded in identifying novel variants in CPT1A and DNAJC19 genes in Finnish patients. Our long-term follow up studies on CPT1A deficiency can help patients in better diagnosis, which further helps clinicians to identify the genetic cause. We also found a novel phenotype with DNAJC19 deficiency. Further we established the groundwork to understand the pathogenesis of retinopathy in LCHADD patients using an advanced method that helps to study in depth pathogenesis mechanism.
  • Lavikainen, Antti (Helsingin yliopisto, 2014)
    The most pathogenic zoonotic cestodes of humans belong to the family Taeniidae. Members of this family (taeniids) are parasites of mammals requiring predatory definitive hosts and herbivorous or omnivorous intermediate hosts. Due to the major medical, veterinary and economic importance, taeniids have been a topic of intensive taxonomic, ecological and epidemiological studies resulting in contrasting conclusions about the diversity within the family. Currently, two genera, Echinococcus and Taenia, are widely recognized. Identification of taeniid tapeworms and their taxonomic classification have traditionally been based on morphological criteria. Development of molecular genetic techniques has provided more accurate tools for identification. The aims of the present thesis were to elucidate evolutionary relationships of taeniids, to explore the diversity within the family and to evaluate the taeniid taxonomy on the basis of phylogenetic relationships. Special emphasis was on species occurring in the Holarctic region. Parasite material collected mainly in northern Europe, a worldwide collection of taeniid DNA specimens and previously published sequence data were used in phylogenetic analyses. Molecular genetic characterization of taeniid taxa and preliminary phylogenies were based on short mitochondrial DNA (mtDNA) sequences. For further phylogenetic analyses, longer mtDNA regions, complete genes and finally mitochondrial genomes, as well as nuclear genes, were used. Based on the molecular analyses, cryptic or previously unknown species and intraspecific entities were detected, and the specific status of some taeniid taxa was confirmed. The genus Taenia was shown to be a highly diversified and paraphyletic assemblage justifying a generic level taxonomic revision. A new genus, Versteria, was created for Taenia mustelae, which was placed as a sister taxon to Echinococcus in phylogenies. An old generic name, Hydatigera, was resurrected for Taenia taeniaeformis and closely related species. The knowledge of taxonomy and evolutionary history of taeniids is essential for better understanding of the epidemiology and transmission of these parasites. The present thesis clarifies the taxonomy of the Taeniidae and creates a framework for further phylogenetic studies, possible additional revisions and comparative research.
  • Kieseppä, Tuula (Helsingin yliopisto, 2005)
  • Heinola, Ivika (Helsingin yliopisto, 2019)
    Background. Abdominal aortic infections are dreaded disorders in vascular surgery, linked to high morbidity and mortality. Mycotic aneurysm as a primary infection of the abdominal aorta (MAAA) and an aortic graft infection (AGI) are different entities; however, due to bacterial presence in aorta and perivascular tissue, the principles of management are the same. Due to low incidence and complexity of disease, the high-quality evidence is lacking to define whether prosthetic aortic reconstructions in infectious conditions are utterly safe or whether biological reconstruction material should be preferred despite some shortcomings in durability. In complex abdominal surgery encompassing visceral aorta, prolonged aortic clamping above renal arteries is a risk factor for acute ischaemic kidney injury. In such situations, renal protection is recommended in order to avoid irreversible damage and renal replacement therapy. Aims. The aim of current study was to evaluate the infection resistance and durability of biological grafts as an aortic reconstruction material in abdominal aortic infections and to estimate the mortality after such reconstructions. Furthermore, efficacy of temporary axillo-renal bypass in prevention of renal ischaemic damage from major aortic surgery was estimated. Materials. The study comprises two parts. In the first part, 132 patients were analysed after being treated for aorto-iliac infections with arterial resection and reconstruction with a biological graft. Study I included patients treated due to AGI with femoral vein grafts, Study II included patients in whom the arterial infection was treated using cryopreserved venous allografts, and Study III included patients who were treated with various biological grafts for a primary aortic infection. The primary endpoints were postoperative mortality and reinfection rates, secondary endpoints were treatment-related mortality, overall mortality and graft reinterventions. During the second part of the study, (Study IV) patients who underwent temporary axillo-renal bypass during a major aortic intervention were retrospectively analysed. Outcome measures were postoperative kidney injury and 30-day mortality. Studies I, II and IV entailed retrospective analyses of patients treated at Helsinki University Hospital, while Study II was multicentre retrospective analysis of patients from six countries. Results. Sixty-four percent (64%, n=85) of the patients underwent surgery for an abdominal aortic infection with autologous femoral veins (FV), 17% (n=23) with cryopreserved venous allografts (CVA), 9% (n=12) with xenopericardial tube grafts, 5% (n=7) with cryopreserved arterial allografts, and 4% (n=5) with fresh arterial allografts. Most common indications for operation were aortic graft infection with an incidence of 51% (n=67) and mycotic abdominal aneurysm with 45% (n=60). The 30-day mortality was 9% for patients treated with FV for an AGI, 9% for patients treated for mixed infectious indications with cryopreserved venous allografts, and 5% for patients treated with various biological reconstructions due to MAAA,. The respective treatment-related mortality rates in these cohorts were 18%,13% and 9%. The reinfection rate was 2% (n=3) and 11% (n=14) of the grafts needed reinterventions at the mid-term follow-up, with stenotic lesions in femoral veins as the most common indication (n=9/14). Kaplan-Meier estimation of survival at 5 years was 59% (95% confidence interval, [CI] 43% – 73%) for patients treated with FV due to AGI and 71% (95% CI 52% –89%) for patients treated with mixed biological materials for MAAA. For patients treated with cryopreserved allografts for mixed indications, estimated survival at 2-years was 70% (95% CI 49% – 91%). Sixteen patients were operated with temporary axillo-renal bypass during aortic surgery. Despite short median renal ischaemia time of 24.5 minutes, 6 (38%) patients suffered acute kidney injury (AKI), of whom 4 had renal insufficiency preoperatively. One patient needed temporary renal replacement therapy, at one-month follow-up, however, renal function had returned to its baseline level or improved in all patients. The 30-day and in-hospital mortality was nil. Conclusions. Biological reconstruction material is infection resistant and reasonably durable in midterm analysis. Early postoperative and overall mortality rates are acceptable after treatment of such a complex entity as abdominal aortic infections. Furthermore, temporary axillo-renal bypass is safe and feasible in diminishing acute kidney injury during major aortic surgery.
  • Paavola, Jere (Helsingin yliopisto, 2014)
    Heart disease is the biggest killer world-wide, causing a quarter of all deaths. During the past two decades, it has also risen above infectious diseases as the leading cause of years of life lost. Heart failure, characterized by weak pump function of the heart, and disturbances in heart rhythm (arrhythmias) are common and interrelated mechanisms underlying cardiac mortality. Intracellular calcium ions are crucial to contraction and relaxation of the heart muscle, as well as to control of its rhythm. How calcium is handled and regulated is thus essential to normal cardiac function, and disturbances in these processes can have catastrophic consequences. Understanding the mechanisms of these disturbances is important for improving disease prevention, diagnosis, and management. The studies in this thesis focus on two conditions where cardiac calcium handling is impaired. Studies I - III examine the mechanisms of a genetic arrhythmia disease named catecholaminergic polymorphic ventricular tachycardia (CPVT), which is characterized by stress-induced ventricular tachycardia in a structurally normal heart. Study IV investigates cardiac function in a model of another genetic disease, autosomal dominant polycystic kidney disease (ADPKD). This systemic disease mainly affects the kidneys, and the mechanisms of the concomitant decline in cardiac function have thus far remained underinvestigated. We evaluated clinical data on cardiac function of CPVT patients, including 24h electrocardiograms, intracardiac monophasic action potential recordings, and exercise stress tests. We used cell models to study the underlying disease mechanisms in detail. During conditions of stress, CPVT cells showed increased spontaneous and irregular release of calcium from within the intracellular stores through the cardiac ryanodine receptors. These receptors, which function as intracellular calcium release channels, harbor the disease-causing mutation. The spontaneous release of calcium led to changes in the membrane potential of the cells, manifested as afterdepolarizations during the resting phase of the cardiac cycle. These afterdepolarizations were reproduced in the clinical monophasic action potential recordings of CPVT patients, and were shown to trigger arrhythmias in these patients. Changes in intracellular calcium alter the membrane potential, and these changes are reflected on the electrocardiogram. Thus, irregularities that might correspond to those observed in the cell model were then investigated in 24h electrocardiograms of CPVT patients. Increased irregularity of cardiac repolarization was found in the CPVT patients. Such irregularity was greater in the electrocardiograms of CPVT patients with a history of more severe arrhythmic events. Additionally, we found slowed depolarization in response to stress in CPVT cells and patients, suggesting reduced conduction velocity might contribute to an arrhythmic substrate in these patients. Cardiac function in ADPKD caused by mutations in polycystin-2, another intracellular calcium channel, was investigated in a zebrafish model lacking expression of the polycystin-2 protein. The zebrafish lacking polycystin-2 showed signs of heart failure, including reduced cardiac output, edema, and arrhythmias. Hearts, which were then examined in more detail ex vivo, showed impaired cycling of intracellular calcium, which is likely to underlie the cardiac dysfunction observed in vivo. The association of ADPKD with idiopathic dilated cardiomyopathy (IDCM) was examined using the Mayo ADPKD Mutation Database, which contains data on genotyped ADPKD patients. Examination of the ADPKD Database showed IDCM to be very common among ADPKD patients. IDCM was most prevalent in patients with mutations in polycystin-2, suggesting impaired calcium cycling as a potential pathomechanism. Studies I-III shed new light on mechanisms of arrhythmias in CPVT and related conditions, opening the way for future studies on arrhythmia risk and therapeutic evaluation. Furthermore, the results encourage pursuing the novel stem cell models for studying pathomechanisms and therapeutics. Study IV showed an association between ADPKD and IDCM. The zebrafish model suggested impaired calcium cycling as an underlying mechanism, highlighting the usefulness of zebrafish as a model in cardiac research.