Lääketieteellinen tiedekunta

 

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  • Nevalainen, Maarit (Unigrafia, 2014)
    The aim of this study was to investigate medical students and primary care physicians feelings of uncertainty, experiences of medical errors and ways of coping with them, and attitudes towards the career of a GP. In Study I the learning diaries (n=79) and writings on specific themes (n=94) of 22 students during their first clinical year were analysed by thematic content analysis. The topics uncertainty and medical errors were studied in more detail. Studies II and III are based on the responses of 5th-year students to a cross-sectional survey (Study II, n=307 and Study III, n=309, response rate 86%) during their main course in general practice. Study IV concerned younger (n=85) and experienced physicians (n=80) responses to an electronic survey related to uncertainty and experiences of medical errors (response rate 68%). Factors predisposing physicians to medical errors and means to avoid making them were assessed. In the second, third and fourth studies the responses were cross-tabulated. The variables are presented as means with standard deviations and percentages. Comparisons of categorial variables were carried out by using the X2 test or Fischer s exact test, comparisons of non-normally distributed continuous variables were made by using the Mann-Whitney U-test. (P values less than 0.05 were considered significant.) 95% CIs are presented for the most important results. Logistic regression analysis was used to explore which factors predicted good tolerance of uncertainty among GPs. A developmental path among the 3rd- to 4th-year medical students was discovered regarding their experiences of uncertainty and fears medical errors. All students wrote about several aspects of uncertainty. They also feared mistakes. However, they started gradually to be more confident in coping with responsibility. The 5th-year medical students were divided into two groups based on their tolerance of uncertainty and fear of medical errors. Those who tolerated uncertainty quite well or well (n=240, 78%) were older, more often males, and had been working for a longer time as locum doctors than those tolerating uncertainty poorly (n=67, 22%). In the latter group, 100% were afraid of medical errors, in the former group the figure was 86%. Those tolerating uncertainty poorly felt more often that a GP s work is too challenging and difficult and involves too much responsibility. About 3/4 of the fifth-year medical students considered the work of a GP positively versatile and challenging, but about 2/3 of them considered it to be too hasty and pressing. The females thought that a GP s work is too lonely. The males considered that a GP deals too much with non-medical problems and the work may be too routine and tedious. According to the majority of the students (82%) the most important aim of a GP s work is to identify serious diseases and refer such patients to specialized care. In the fourth study 6% of the younger and 1% of the experienced physicians tolerated uncertainty poorly. The younger physicians feared medical errors more (70% vs. 48%) and more often admitted having made an error (84% vs. 69%) compared to the experienced ones (48%). The experienced physicians apologized more willingly to their patients for an error. The younger physicians were more prone to use electronic databases and consult on site. Tolerance of uncertainty seems to develop gradually during the medical studies and this development also continues after graduation. Students are already aware of the possibility of a medical error. Almost all of them are afraid of them. Also half of the experienced physicians admitted to feeling some fear. The attitudes of fifth-year medical students reflect their experiences of general practice.
  • Niinistö, Sari (Unigrafia, 2014)
    The aim of the present study was to evaluate the associations between the maternal intakes of fatty acids, vitamin D, and their respective dietary sources during pregnancy or lactation, as well as the child s fatty acid status, and the risk of type 1 diabetes. The present study is a prospective cohort belonging to the nutrition part of the Finnish Type 1 Diabetes Prediction and Prevention Study (DIPP). The cohort comprised children at increased genetic risk for type 1 diabetes (n=6069) born at the Oulu and Tampere University Hospitals between the years 1997 and 2004. Maternal diet was assessed with a validated food frequency questionnaire during the 8th month of pregnancy and the 3rd month of lactation. The children were monitored for the appearance of autoantibodies associated with type 1 diabetes and for the development of clinical type 1 diabetes, at intervals between 3 and 12 months. The associations between the maternal intakes of fatty acids, vitamin D, as well as their respective food sources and the endpoints, were analyzed by the piecewise linear log-hazard survival model and Cox proportional hazard analyses. The associations between the children s serum fatty acid composition and the risk of type 1 diabetes were studied in a nested case-control study design that included 108 children with preclinical type 1 diabetes and 216 matched controls. The total serum fatty acid composition was analyzed by gas chromatography from samples that were taken from the children between the ages of 1 and 6 years. Conditional logistic regression was applied in the statistical analysis. After adjustment for putative confounders, neither the maternal intake of fatty acids during pregnancy and lactation nor the intake of vitamin D during pregnancy, showed any association with the development of type 1 diabetes. The maternal use of fresh milk and cheese, and the intake of protein from fresh milk during pregnancy, were associated with a lower risk of clinical type 1 diabetes. The maternal total consumption of red meat and meat products, particularly processed meat, during lactation was associated with an increased risk of type 1 diabetes. The child s serum profile of milk-associated fatty acids at, or closest to, the time of seroconversion, was associated with a higher risk of preclinical type 1 diabetes. Findings give one of the first indications that prenatal exposure to certain dairy foods may affect immune regulation, and our results on the milk-associated fatty acid biomarkers confirm the previous findings that the child s own direct cow s milk exposure is associated with autoimmunity in children with increased genetic risk of type 1 diabetes. These results thus indicate that milk and meat products in particular, are interesting topics for future studies on potential nutritional risk and protective factors for type 1 diabetes.
  • Malmivaara, Kirsi (Helsingin yliopisto, 2014)
    The overall purpose of this study was to evaluate the health-related quality of life (HRQoL) and cost-effectiveness of the treatment of severely, acutely ill neurosurgical patients. The majority of the study illnesses and conditions are known to have a relatively high mortality or an otherwise poor outcome but, they are also known to be highly resource-demanding. Since the economics of health care is attracting more and more interest, it will become more important to evaluate the cost-effectiveness of treatment so that it can be demonstrated that the resource allocation is justified. The patients (n=620) for these four separate studies were treated in the Department of Neurosurgery of Helsinki University Central Hospital between 1998 and 2006. The first of these four studies was a Step-Down Unit study in which we evaluated a group of patients (n=346) who underwent a major neurosurgical operation and were treated in the neurosurgical intensive care unit (NICU) and, due to a poor prognosis, were then discharged from the NICU to the step-down unit, still depending on life support devices. The following two studies evaluated patients who underwent a decompressive craniectomy (DC) for intractable intracranial pressure. The first of these, the DC after SAH study, concerned patients (n=42) with subarachnoid haemorrhage (SAH) or other neurological emergencies, and the second one, the DC after TBI study, evaluated patients (n=54) with traumatic brain injury (TBI). The fourth study, the SAH study (n=178), evaluated the long-term outcome, HRQoL and cost-effectiveness of the treatment of the SAH patients. The mortality in the Step-Down Unit study and both of the DC studies was high and moderate in the SAH study, 59%, 53%, 41%, and 24% respectively. The median follow-up times were 5, 3, 5.6 and 10.8 years. The health-related quality of life was assessed with the EuroQol EQ5D instrument and the median HRQoL index was compared to the median index of the Finnish reference population (0.85). The indices were 0.71, 0.41, 0.85 and 1.00. The outcome was also evaluated on the Glasgow outcome scale (GOS), and 49%, 25%, 69% and 75% of the patients achieved a good outcome (GOS 1-2). An important measure of well-being is the ability to live at home, and 49%, 50%, 78% and 88% of the study patients were able to live at home. The direct costs of the neurosurgical treatment per quality adjusted life year (QALY) were 2521 , 5000 , 2400 and 1700 . For the total of 620 severely ill neurosurgical patients treated in the Helsinki Department of Neurosurgery between 1998 and 2006, we found the treatment to be cost-effective, and it resulted in health-related quality of life that varied from acceptable to good when compared to the reference population. We found no evidence of unnecessary prolongation of human suffering when death was inevitable. The worst state of health-related quality of life did not occur among the survivors. In summary, these studies indicate that current healthcare resources are utilized cost-effectively to achieve a life that is meaningful. Allocation of healthcare resources to the severely ill neurosurgical patients seems to be justified.
  • Zheng, Wei (2013)
    Blood vessels deliver nutrients and oxygen to tissues, whereas lymphatic vessels collect interstitial fluid and absorb lipids. Both types of vessels are involved in immune surveillance. Malformation or malfunction of either vasculature is closely associated with various diseases. Although the molecular mechanisms regulating the growth, development and function of these vessels have begun to emerge in recent decades, many questions remain. This study aimed to understand if and how the growth of new blood and lymphatic vessels (angiogenesis and lymphangiogenesis, respectively) is regulated by the endothelial signaling molecules BMX, VEGFR-3, notch 1 and angiopoietin-2. BMX, a non-receptor tyrosine kinase, is upregulated in some types of cancer and promotes cell survival, migration and proliferation. Under physiological conditions, it is also highly expressed in blood endothelial cells (BECs). Thus, we hypothesized that BMX might contribute to tumor growth by promoting tumor angiogenesis. Using multiple tumor implantation and spontaneous tumor models in Bmx gene-deleted mice, we found that tumor angiogenesis and growth were significantly reduced in the absence of BMX. Conversely, when BMX was overexpressed in epithelial keratinocytes, chemical carcinogen led to increased tumor angiogenesis and growth. VEGFR-3 is a growth factor receptor on the surface of endothelial cells (ECs). Here, we characterized a blocking antibody that inhibits VEGFR-3 signaling by a novel mechanism. In contrast to conventional blocking antibodies that prevent ligand-receptor binding, this new antibody inhibited dimerization of two identical VEGFR-3 molecules, thereby impairing signaling activation and sprouting of lymphatic endothelial cells (LECs). These inhibitory effects persisted even at ligand concentrations so high that conventional blocking antibodies were no longer effective. Importantly, concurrent treatment with both types of antibodies yielded combined additive benefits. Notch signaling regulates angiogenic sprouting. We found in this study that Notch inhibitors enhance VEGF-induced lymphatic sprouting in 3-dimensional EC sprouting assays in vitro. In vivo, VEGF alone induced only lymphatic dilation but not sprouting. However, concomitant treatment with a Notch inhibitor induced both vascular events. In addition, a mosaic-sprouting assay showed that Notch signaling also determined the fates of tip/stalk cells (the cell leading a vessel sprout and the following cells, respectively) during lymphatic sprouting. Angiopoietin-2 (Ang2) is an endothelial growth factor required for proper lymphatic remodeling during development, but the exact mechanisms of this process have previously remained unclear. In contrast to the zipper-like pattern of cell-cell junctions (zippers) in collecting lymphatic vessels, mature lymphatic capillaries have a distinct pattern of button-like junctions (buttons), which transform from zippers during development. We found in this study that Ang2 is indispensable for such transformation of the junctional patterns during embryogenesis. At the molecular level, Ang2 is required for phosphorylation of the adherens junction marker vascular endothelial cadherin (VE-cadherin) at the tyrosine residue 685. Ang2 blocking antibody treatment of mouse neonates disrupted cell-cell junctions in the mesenteric lymphatic vessels, causing leakage of chyle (milky fluids containing fat droplets and lymph). Ang2 blockade also inhibited lymphatic valve formation and maturation and resulted in abnormal smooth muscle recruitment. Together, these results provide new insights into the molecular mechanisms of angiogenesis and lymphangiogenesis. Elucidation of these mechanisms is important in developing new drugs for the treatment of vessel-related diseases, including cancer and pathological inflammation. Moreover, these findings introduce the reorganization of cell-cell junctions as a novel parameter for evaluating lymphatic development and call for future research into this new field.
  • Matilainen, Olli (2013)
    The ubiquitin-proteasome system (UPS) is the major pathway for controlled protein degradation in the cell. Substrates destined for degradation are polyubiquitinated by ubiquitin ligating enzymes and degraded by the proteasome, which is a complex multisubunit enzyme of over 2.5 MDa. Due to its essential role in maintenance of the cellular protein homeostasis, dysfunctions in proteasome activity have been linked to many severe disorders, such as Alzheimer s, Parkinson s and Huntington s disease and some cancers. Although the proteasome takes part in almost all cellular processes, it is still unclear which factors contribute to regulation of proteasome function. The aim of this thesis was to elucidate mechanisms of how proteasome activity is regulated in a multicellular organism. To enable monitoring and quantification of proteasome activity in vivo, a photoconvertible reporter system was developed to live image proteasome activity in C. elegans. By using this system, it was uncovered that proteasome activity varies between different tissues, as GABAergic and dopaminergic neurons showed faster reporter degradation than muscle cells, and that aging affects proteasome activity in a tissue-dependent manner. Subsequently, it was investigated whether signaling pathways regulating aging also affect proteasome activity. Insulin/IGF-1 signaling (IIS) is an evolutionarily conserved signaling pathway regulating lifespan in worms, flies, rodents and possibly humans. By using C. elegans as a model organism, this thesis shows that IIS regulates proteasome activity through the FOXO/DAF-16 and Nrf/SKN-1 transcription factors. Moreover, it was demonstrated that DAF-16, which is activated by reduced IIS, inhibits the expression of the proteasome-associated deubiquitinating enzyme UBH-4, which was shown to function as a tissue-specific proteasome inhibitor. The role of UBH-4 appears to be well-conserved, as downregulation of its mammalian ortholog, UCHL-5, increases proteasome activity and degradation of proteotoxic proteins in mammalian cells. Taken together, this thesis provides tools to study proteasome activity in vivo, and establishes a molecular mechanism linking IIS to efficiency of proteasomal degradation. These results can be utilized when designing new therapies for proteasome-associated diseases, especially for disorders that may be alleviated with tissue-specific modulation of proteasome activity.
  • Hankaniemi, Minna (2012)
    Bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) are growth factors expressed by oocytes and are among the key regulators transmitting the signaling between the oocyte and the surrounding granulosa cells. Genetic studies have shown that these factors are essential regulators of normal fertility in mammals. BMP15 gene deficient mice exhibit a mild reduction in fertility, whereas sheep homozygous for a mutant form of BMP15 are sterile. In the case of GDF9, knockout mice and homozygous mutant sheep are also sterile the ovaries being non functional due to an early block in folliculogenesis. In humans, aberrant expression of these factors has been involved in premature ovarian failure (POF), polycystic ovary syndrome (PCOS) or dizygotic twinning. ----- This thesis was aimed to define the signaling and activation of human BMP15 (hBMP15) and GDF9 (hGDF9) proteins. The lack of bioactive hGDF9 had restricted the in vitro studies previously and the first aim of this thesis was to produce and purify bioactive hGDF9 protein. We found that hGDF9 is secreted in a latent form. Although mouse GDF9 (mGDF9) and hBMP15 are produced in active form their bioactivity is lost when a C-terminal affinity purification tag is added. We found also, that an N-terminal epitope tag does not have a deleterious effect on the bioactivity of mGDF9 or hBMP15 and they can be purified using immobilized metal affinity (IMAC) and high performance liquid chromatography approaches. A purified wild type hGDF9 (hGDF9wt) mature region became available to us during this thesis project and we found that it is a highly bioactive and stable protein activating the Smad3/4 signaling pathway. Subsequently we produced and purified a bioactive wild type hBMP15 (hBMP15wt) form, which was highly bioactive and activated the Smad1/5/8 signaling pathway in human granulosa luteal (hGL) cells. Physico-chemical characterization of BMP15 revealed that it consists of P16 and P17 forms, where P16 seems to be phosphorylated and P17 glycosylated. ------ It has been shown previously that a recombinant BMP type II receptor ectodomain Fc fusion protein (BMPR2ecd Fc) is able to inhibit the actions of BMP15 and GDF9 in vitro. For studying the effect of BMPR2ecd Fc on mouse folliculogenesis, we produced and purified this protein. These in vivo studies demonstrated that by administering the BMPR2ecd-Fc protein, we were able to dose-dependently modulate ovarian folliculogenesis in mice. -------- In order to determine the cell surface receptor binding components for human BMP15, we engineered and produced a covalent dimer of hBMP15 and labeled it radioactively. We found that it behaves biologically in a similar manner as the hBMP15wt. Human BMP15 strongly bound to BMPR1B and BMPR2 on the COV434 cell surface, an association which was further verified in COS-7 cells by overexpression of these receptors. In conclusion, we have for the first time produced and characterized recombinant human GDF9 and BMP15 protein in native form and thus developed valuable tools for studies aiming at understanding their role in human reproductive medicine. The production and purification methods developed during this thesis are widely applicable for the isolation and characterization of comparable oocyte growth factors in other species and thus have wide applicability in reproductive biology studies in the future.
  • Sarajuuri, Anne (Unigrafia Oy, 2012)
    Hypoplastic left heart syndrome (HLHS) and other forms of functionally univentricular heart (UVH) are complex congenital heart defects (CHD) that during the past few decades have gained viability with staged palliative surgery. It results in the passive return of systemic venous blood to the lungs without passing through the heart. The aim of this study was to evaluate the neurodevelopmental outcome of children with HLHS and UVH in Finland with neurological, neuropsychological, and motor assessments and brain imaging, and to detect possible risk factors associated with an adverse outcome. Parental perceptions of child behavior and parenting stress were also assessed with parental question-naires. The first study cohort of patients born between 1995 and 1999, which included most of the first HLHS survivors in Finland, showed a significantly lower cognitive outcome compared to normative data among both patients with HLHS (n = 7) and with UVH (n = 19). Cerebral palsy was present in 14% of the patients with HLHS and in 10% of those with UVH, and milder difficulties in gross and fine motor functions were also commonly found. Patients with HLHS or UVH born between 2002 and 2005 were recruited in a prospective neurodevelopmental follow-up study as newborns. The neurodevelopmental evaluations at the ages of 12 months, 30 months, and 5 years revealed a significantly lower cognitive and motor outcome among the patients with HLHS (n = 23) compared to healthy age- and gender-matched controls (n = 40). The patients with UVH (n = 14) only demonstrated a statistically significant difference to controls in motor development during the earlier assessments, and at the age of 5 years also in cognitive development. A smaller sample size may have contributed to the lack of statistically significant difference in cognitive development in the earlier assessments. Major neurodevelopmental impairment was found in 26% of the patients with HLHS, and 23% of the patients with UVH at the age of 5 years. Brain magnetic resonance imaging revealed abnormalities in 82% of the patients with HLHS and 56% of those with UVH most commonly infarcts or ischemic findings of different degrees. Other than minimal ischemic findings were significantly associated with neurodevelopmental outcome. The level of parenting stress was significantly higher among the patients with HLHS compared to controls at the age of 18 months. The parents of the patients with UVH, however, did not report more stress than those of the controls. In conclusion, neurodevelopmental deficits remain a major concern among patients with UVH, and especially among those with HLHS. Neurodevelopmental follow-up is recommended for this seriously ill patient group and psychosocial support for their parents.
  • Päiväniemi, Outi (2011)
    Chronic rejection in the form of obliterative bronchiolitis (OB) is the major cause of death 5 years after lung transplantation. The exact mechanism of OB remains unclear. This study focused on the role of cyclo-oxygenase (COX) -2, tenascin, and C-reactive protein (CRP) expression, and the occurrence of ingraft chimerism (= cells from two genetically distinct individuals in a same individual) in post-transplant OB development. In our porcine model, OB developed invariably in allografts, while autografts stayed patent. The histological changes were similar to those seen in human OB. In order to delay or prevent obliteration, animals were medicated according to certain protocol. In the beginning of the bronchial allograft reaction, COX-2 induction occurred in airway epithelial cells prior to luminal obliteration. COX-2 expression in macrophages and fibroblasts paralleled the onset of inflammation and fibroblast proliferation. This study demonstrated for the first time, that COX-2 expression is associated with the early stage of post- transplant obliterative airway disease. Tenascin expression in the respiratory epithelium appeared to be predictive of histologic features observed in human OB, and influx of immune cells. Expression in the bronchial wall and in the early obliterative lesions coincided with the onset of onset of fibroblast and inflammatory cell proliferation in the early stage of OB and was predictive of further influx of inflammatory and immune cells. CRP expression in the bronchial wall coincided with the remodelling process. High grade of bronchial wall CRP staining intensity predicted inflammation, accelerated fibroproliferation, and luminal obliteration, which are all features of OB. In the early obliterative plaque, majority of cells expressed CRP, but in mature, collagen-rich plaque, expression declined. Local CRP expression might be a response to inflammation and it might promote the development of OB. Early appearance of chimeric (= recipient-derived) cells in the graft airway epithelium predicted epithelial cell injury and obliteration of the bronchial lumen, which both are features of OB. Chimeric cells appeared in the airway epithelium after repair following transplantation-induced ischemic injury. Ingraft chimerism might be a mechanism to repair alloimmune-mediated tissue injury and to protect allografts from rejection after transplantation. The results of this study indicate, that COX-2, tenascin, CRP, and ingraft chimerism have a role in OB development. These findings increase the understanding of the mechanisms of OB, which may be beneficial in further development of diagnostic options.
  • Söderlund, Sanni (2011)
    AIMS An independent, powerful coronary heart disease (CHD) predictor is a low level of high-density lipoprotein cholesterol (HDL-C). Discoidal preβ-HDL particles and large HDL2 particles are the primary cholesterol acceptors in reverse cholesterol transport, a key anti-atherogenic HDL mechanism. The quality of HDL subspecies may provide better markers of HDL functionality than does HDL-C alone. We aimed I) to study whether alterations in the HDL subspecies profile exist in low-HDL-C subjects II) to explore the relationship of any changes in HDL subspecies profile in relation to atherosclerosis and metabolic syndrome; III) to elucidate the impact of genetics and acquired obesity on HDL subspecies distribution. SUBJECTS The study consisted of 3 cohorts: A) Finnish families with low HDL-C and premature CHD (Study I: 67 subjects with familial low HDL-C and 64 controls; Study II: 83 subjects with familial low HDL-C, 65 family members with normal HDL-C, and 133 controls); B) a cohort of 113 low- and 133 high-HDL-C subjects from the Health 2000 Health Examination Survey carried out in Finland (Study III); and C) a Finnish cohort of healthy young adult twins (52 monozygotic and 89 dizygotic pairs) (Study IV). RESULTS AND CONCLUSIONS The subjects with familial low HDL-C had a lower preβ-HDL concentration than did controls, and the low-HDL-C subjects displayed a dramatic reduction (50-70%) in the proportion of large HDL2b particles. The subjects with familial low HDL-C had increased carotid atherosclerosis measured as intima-media-thickness (IMT), and HDL2b particles correlated negatively with IMT. The reduction in both key cholesterol acceptors, preβ-HDL and HDL2 particles, supports the concept of impaired reverse cholesterol transport contributing to the higher CHD risk in low-HDL-C subjects. The family members with normal HDL-C and the young adult twins with acquired obesity showed a reduction in large HDL2 particles and an increase in small HDL3 particles, which may be the first changes leading to the lowering of HDL-C. The low-HDL-C subjects had a higher serum apolipoprotein E (apoE) concentration, which correlated positively with the metabolic syndrome components (waist circumference, TG, and glucose), highlighting the need for a better understanding of apoE metabolism in human atherosclerosis. In the twin study, the increase in small HDL3b particles was associated with obesity independent of genetic effects. The heritability estimate, of 73% for HDL-C and 46 to 63% for HDL subspecies, however, demonstrated a strong genetic influence. These results suggest that the relationship between obesity and lipoproteins depends on different elements in each subject. Finally, instead of merely elevating HDL-C, large HDL2 particles and discoidal preβ-HDL particles may provide beneficial targets for HDL-targeted therapy.
  • Hovi, Petteri (Helsingin yliopisto, 2011)
    Background: The improved prognosis of early preterm birth has created a generation of surviving very low birth weight (PIENEMPI KUIN 1500 g, VLBW) infants whose health risks in adulthood are poorly known. Of every 1000 live-born infants in Finland, about 8 are born at VLBW. Variation in birth weight, even within the normal range, relates to considerable variation in the risk for several common adult disorders, including cardiovascular disease and osteoporosis. Small preterm infants frequently exhibit severe postnatal or prenatal growth retardation, or both. Much reason for concern thus exists, regarding adverse health effects in surviving small preterm infants later lives. We studied young adults, aiming at exploring whether VLBW birth and postnatal events after such a birth are associated with higher levels of risk factors for cardiovascular disease or osteoporosis. Subjects and Methods: A follow-up study for VLBW infants began in 1978; by the end of 1985, 335 VLBW survivors at Helsinki University Central Hospital participated in the follow-up. Their gestational ages ranged from 24 to 35 weeks, mean 29.2 and standard deviation 2.2 weeks. In 2004, we invited for a clinic visit 255 subjects, aged 18 to 27, who still lived in the greater Helsinki area. From the same birth hospitals, we also invited 314 term-born controls of similar age and sex. These two study groups underwent measurements of body size and composition, function of brachial arterial endothelium (flow-mediated dilatation, FMD) and carotid artery intima-media thickness (cIMT) by ultrasound. In addition, we measured plasma lipid concentrations, ambulatory blood pressure, fasting insulin, glucose tolerance and, by dual-energy x-ray densitometry, bone-mineral density. Results: 172 control and 166 VLBW participants underwent lipid measurements and a glucose tolerance test. VLBW adults fasting insulin (adjusted for body mass index) was 12.6% (95% confidence interval, 0.8 to 25.8) higher than that of the controls. The glucose and insulin concentrations 120 minutes after 75 g glucose ingestion showed similar differences (N=332) (I). VLBW adults had 3.9 mmHg (1.3 to 6.4) higher office systolic blood pressure, 3.5 mmHg (1.7 to 5.2) higher office diastolic blood pressure (I), and, when adjusted for body mass index and height, 3.1 mmHg (0.5 to 5.5) higher 24-hour mean systolic blood pressure (N=238) (II). VLBW birth was associated neither with HDL- or total cholesterol nor triglyceride concentrations (N=332) (I), nor was it associated with a low FMD or a high cIMT (N=160) (III). VLBW adults had 0.51-unit (0.28 to 0.75) lower lumbar spine Z scores and 0.56-unit (0.34 to 0.78) lower femoral neck Z scores (N=283). Adjustments for size attenuated the differences, but only partially (IV). Conclusions: These results imply that those born at VLBW, although mostly healthy as young adults, already bear several risk factors for chronic adult disease. The significantly higher fasting insulin level in adults with VLBW suggests increased insulin resistance. The higher blood pressure in young adults born at VLBW may indicate they later are at risk for hypertension, although their unaffected endothelial function may be evidence for some form of protection from cardiovascular disease. Lower bone mineral density around the age of peak bone mass may suggest increased risk for later osteoporotic fractures. Because cardiovascular disease and osteoporosis are frequent, and their prevention is relatively cheap and safe, one should focus on prevention now. When initiated early, preventive measures are likely to have sufficient time to be effective in preventing or postponing the onset of chronic disease.
  • Niittymäki, Iina (2011)
    Both inherited genetic variations and somatically acquired mutations drive cancer development. The aim of this thesis was to gain insight into the molecular mechanisms underlying colorectal cancer (CRC) predisposition and tumor progression. Whereas one-third of CRC may develop in the context of hereditary predisposition, the known highly penetrant syndromes only explain a small fraction of all cases. Genome-wide association studies have shown that ten common single nucleotide polymorphisms (SNPs) modestly predispose to CRC. Our population-based sample series of around thousand CRC cases and healthy controls was genotyped for these SNPs. Tumors of heterozygous patients were analyzed for allelic imbalance, in an attempt to reveal the role of these SNPs in somatic tumor progression. The risk allele of rs6983267 at 8q24 was favored in the tumors significantly more often than the neutral allele, indicating that this germline variant is somatically selected for. No imbalance targeting the risk allele was observed in the remaining loci, suggesting that most of the low-penetrance CRC SNPs mainly play a role in the early stages of the neoplastic process. The ten SNPs were further analyzed in 788 CRC cases, 97 of which had a family history of CRC, to evaluate their combined contribution. A significant association appeared between the overall number of risk alleles and familial CRC and these ten SNPs seem to explain around 9% of the familial clustering of CRC. Finding more CRC susceptibility alleles may facilitate individualized risk prediction and cancer prevention in the future. Microsatellite instability (MSI), resulting from defective mismatch repair function, is a hallmark of Lynch syndrome and observed in a subset of all CRCs. Our aim was to identify microsatellite frameshift mutations that inactivate tumor suppressor genes in MSI CRCs. By sequencing microsatellite repeats of underexpressed genes we found six novel MSI target genes that were frequently mutated in 100 MSI CRCs: 51% in GLYR1, 47% in ABCC5, 43% in WDTC1, 33% in ROCK1, 30% in OR51E2, and 28% in TCEB3. Immunohistochemical staining of GLYR1 revealed defective protein expression in homozygously mutated tumors, providing further support for the loss of function hypothesis. Another mutation screening effort sought to identify MSI target genes with putative oncogenic functions. Microsatellites were similarly sequenced in genes that were overexpressed and, upon mutation, predicted to avoid nonsense-mediated mRNA decay. The mitotic checkpoint kinase TTK harbored protein-elongating mutations in 59% of MSI CRCs and the mutant protein was detected in heterozygous MSI CRC cells. No checkpoint dysregulation or defective protein localization was observable however, and the biological relevance of this mutation may hence be related to other mechanisms. In conclusion, these two large-scale and unbiased efforts identified frequently mutated genes that are likely to contribute to the development of this cancer type and may be utilized in developing diagnostic and therapeutic applications.
  • Mikkola, Arto (2008)
    Patients with locally advanced (T3-4 M0) or metastasized (T1-4 M1) prostate cancer (PCa) were randomized to orchiectomy or intramuscular polyestradiol phosphate (PEP) 240 mg/month (Estradurin®, Pfizer) therapy, and the clinical effect and cardiovascular (CV) complications were analyzed. In addition, the pretreatment plasma testosterone (ppT) and estradiol (ppE2) levels between T3-4 M0 and T1-4 M1 patients were compared and the effect of the patients´ general condition on hormone levels was examined, and a prognostic classification of metastatic prostate cancer using conventional prognostic factors was created. The progression-free survival, disease specific survival and overall survival (OS) were significantly poorer in the T1-4 M1 patients than in the T3-4 M0 patients (p < 0.001), but there was no statistical difference in efficacy between the orchiectomy or PEP therapies. In the T1-4 M1 patients, there was no statistically significant difference in CV mortality between the therapy modes, but there was a tendency towards a higher number of non-lethal cardiovascular complications in the PEP treated patients (5.9%) compared with the orchiectomized patients (2.0%). In the T3-4 M0 patients, PEP therapy was associated with an increased risk of CV complications, especially CV deaths, compared with orchiectomy (p = 0.001). Most CV deaths (67%) were due to acute myocardial infarction (AMI). This PEP therapy associated risk of AMI (lethal or not) was significantly lower in patients with a high ppE2 level (≥93 pmol/l) (p = 0.022). The mean ppE2 level was significantly lower in the T1-4 M1 patients (74.7 pmol/l) than in the T3-4 M0 patients (87.9 pmol/l), but there was no such difference in ppT levels. In both the T3-4 M0 and T1-4 M1 patients, a decline in general condition partly explained the decrease of ppT and ppE2 levels. A risk group (Rg) classification (three groups) was created by using alkaline phosphatase (ALP), prostate specific antigen (PSA), erythrocyte sedimentation rate (ESR), and the patient`s age. Patients were given one risk point each for ALP > 180 U/l (with the present method of analysis of ALP, the cut-off point would have been > 83 U/l), PSA > 35 µg/l, ESR > 80 mm/h, and age < 60 years. The following groups were formed according to the number of points: Rg-a (0 - 1 risk points), Rg-b (2 risk points) and Rg-c (3 - 4 risk points). The risk of PCa death increased statistically significantly with advancing prognostic group (p < 0.001). This grouping system was clinically practical and efficient, especially in detecting patients with very poor disease specific survival.
  • Tyynismaa, Henna (Yliopistopaino, 2007)
    Mitochondrial diseases are caused by disturbances of the energy metabolism. The disorders range from severe childhood neurological diseases to muscle diseases of adults. Recently, mitochondrial dysfunction has also been found in Parkinson s disease, diabetes, certain types of cancer and premature aging. Mitochondria are the power plants of the cell but they also participate in the regulation of cell growth, signaling and cell death. Mitochondria have their own genetic material, mtDNA, which contains the genetic instructions for cellular respiration. Single cell may host thousands of mitochondria and several mtDNA molecules may reside inside single mitochondrion. All proteins needed for mtDNA maintenance are, however, encoded by the nuclear genome, and therefore, mutations of the corresponding genes can also cause mitochondrial disease. We have here studied the function of mitochondrial helicase Twinkle. Our research group has previously identified nuclear Twinkle gene mutations underlying an inherited adult-onset disorder, progressive external ophthalmoplegia (PEO). Characteristic for the PEO disease is the accumulation of multiple mtDNA deletions in tissues such as the muscle and brain. In this study, we have shown that Twinkle helicase is essential for mtDNA maintenance and that it is capable of regulating mtDNA copy number. Our results support the role of Twinkle as the mtDNA replication helicase. No cure is available for mitochondrial disease. Good disease models are needed for studies of the cause of disease and its progression and for treatment trials. Such disease model, which replicates the key features of the PEO disease, has been generated in this study. The model allows for careful inspection of how Twinkle mutations lead to mtDNA deletions and further causes the PEO disease. This model will be utilized in a range of studies addressing the delay of the disease onset and progression and in subsequent treatment trials. In conclusion, in this thesis fundamental knowledge of the function of the mitochondrial helicase Twinkle was gained. In addition, the first model for adult-onset mitochondrial disease was generated.
  • Nikku, Risto (2009)
    A total of 177 patients with primary dislocation of the patella (PDP) were admitted to two trauma centers in Helsinki, Finland during 1991 to 1992. The inclusion criteria were: 1. Acute (≤14 days old) first-time lateral dislocation of the patella. 2. No previous knee operations or major knee injuries. 3. No ligament injuries to be repaired. 4. No osteochondral fractures requiring fixation. 50 patients were excluded. 30 of these excluded patients would have met the inclusion criteria, 19 patients received treatment by consultants not involved in the study, 7 refused to participate and 4 had an erroneous randomization. 127 patients including, 82 females, were then randomized to have either tailor-made operative procedure (group O) or conservative treatment (group C). The aftercare was similar for both groups. The mean age of the patients was 20 (9-47) years. All patients were subjected to analysis of trauma history (starting position and knee movement during the dislocation), examination under anesthesia (EUA) and arthroscopy. 70 patients (52 females) were randomized by their odd year of birth to operative group O and 57 patients (30 females) by their even year of birth to conservative group C. The diagnosis of PDP was based on locked dislocation in 68 patients, on dislocatability in EUA in 47 patients, and on subluxation in EUA combined with typical intra-articular lesions in 12 patients. In group O, 63 patients had exploration of the injuries on the medial side of the knee and tailor made reconstruction added with lateral release in 54 cases. The medial injury was operated by suturing in 39 patients, by duplication in 18 patients and by additional augmentation of the medial patellofemoral ligament (MPFL) with adductor magnus tenodesis in 6 patients. 7 patients, without locking in trauma history and only subluxation in EUA had only lateral release for realignment. In adductor magnus tenodesis the proximal end of the distal tendinous part was rerouted to the upper medial border of the patella. In the conservative group C, the treatment was adjusted to the extent of patellar displacement in EUA. Patients with dislocation in EUA had 3 weeks’ immobilization with the knee in slight flexion. Mobilization was started with a soft patellar stabilizing orthosis (PSO) used for additional three weeks. The patients with subluxation in EUA wore an orthosis for six weeks. The aftercare was similar in group O. The outcome was similar in both groups. After an average of 25 (20-45) months´ follow-up, the subjective result was better in group C in respect of the mean Hughston VAS knee score (87 for group O and 90 for group C, p=0.04, visual analog scale), but similar in terms of the patient’s own overall opinion and the mean Lysholm II knee score. Recurrent instability episodes occurred in 18 patients in group O and in 20 patients in group C. After an average of 7 (6-9) years´ follow-up, the groups did not show statistical difference either in respect of the patient’s own overall opinion, or the mean Hughston VAS and Kujala knee scores. The proportions of stable patellae was 25/70 (36%) in group O and 17/57 (30%) in group O (p=0.5). In a multivariate risk analysis, there was a correlation between low Kujala score (<90) as dependent parameter and female gender (OR: 3.5; 95% CI: 1.4-9.0), and loose body on primary radiographs (OR: 4.1; 95% CI: 1.2-15). Recurrent instability correlated with young age at the time of PDP (OR: 0.9; 95% CI: 0.8-1.0/year). Girls with open tibial apophysis had the worst prognosis for instability (88%; 95% CI: 77-98). The most common mechanisms in trauma history of the patients were movement to flexion from a straight start (78%) and movement to extension from a well-bent start (8%). Spontaneous relocation of the patella had taken place in 13/39 of girls, in 11/21 of boys, in 26/42 of women and in 17/24 of men with skeletal maturity of the tibia. The dislocation in EUA was non-rotating in 96/126 patients followed by outward rotating dislocation in 14/126 patients. Operative treatment policy in PDP is not recommended. Locking tendency of the patella in PDP depended on the skeletal maturation. Recurrence rate after PDP was higher than expected.
  • Hakonen, Anna H (Anna Hakonen, 2008)
    Uusi hermoston rappeumasairaus MIRAS: Suomessa kantajia joka 125. väestöstä Tässä väitöskirjatyössä on kuvattu uusi peittyvästi periytyvä hermoston rappeumasairaus, MIRAS (mitochondrial recessive ataxia syndrome), ja sen geenitausta. Tauti osoittautui tutkimuksessamme Suomen yleisimmäksi perinnölliseksi ataksiasairaudeksi. Tutkimuksessa on tutkittu perinnöllisiä aivosairauksia, joissa yhtenä oireena on ataksia (kävelyn epävarmuus, tasapainovaikeus ja liikkeiden haparointi), sekä lukuisia muita aivojen toimintahäiriöstä johtuvia oireita. Seuloessamme suomalaisilta ataksiapotilailta MIRAS-geenivirhettä, 27 potilasta sai diagnoosin aikaisemmin tuntemattomalle, etenevälle ataksiasairaudelleen. Tutkimuksen tuloksena kyseisen geenivirheen DNA-diagnostiikka on otettu käyttöön suomalaisissa ja eurooppalaisissa laboratorioissa, ja toista sataa potilasta ympäri maailman on saanut diagnoosin. Suomen väestössä joka 125. kantaa MIRAS geenivirhettä, mutta taudin saa vain, jos perii geenivirheen molemmilta vanhemmiltaan. MIRAS on taudinkuvaltaan vaihteleva, mutta vaikea etenevä neurologinen sairaus. Useilla potilailla esiintyvät oireet ovat ataksia, puheen puuromaisuus (dysartria), ääreishermorappeuma (neuropatia), pakkoliikkeet, psykiatriset oireet sekä vaikea epilepsia. Erityisen tärkeää MIRAS-taudin tunnistaminen on siihen liittyvän epilepsian hoitopäätöksessä: valproaatti-lääkitys voi aiheuttaa MIRAS-potilaille vaikean maksavaurion. Väitöskirjatyön tuloksena selvisi, että kaikki suomalaiset, norjalaiset, belgialaiset, englantilaiset, australialaiset ja uusi-seelantilaiset MIRAS potilaat olivat kaukaista sukua samalle, tuhansia vuosia sitten eläneelle eurooppalaiselle esivanhemmalle. Ataksiasairauksien tautimekanismeja selvitimme tutkimalla MIRAS-ataksiaa ja sitä muistuttavaa IOSCA sairautta (infantile onset spinocerebellar ataxia), jonka aiheuttaa peittyvästi periytyvä geenivirhe Twinkle-geenissä. Tutkimuksessa löydettiin myös uusi, Twinkle-geenin geenivirheestä johtuva taudinkuva: vaikea-asteinen, varhaisella iällä alkava aivosairaus, jossa on lisäksi viitteitä maksasairaudesta. Löysimme potilaiden aivoista muutoksia mitokondrioiden eli solun voimalaitosten perimän määrässä. Nämä tulokset antavat arvokasta lisätietoa ataksiasairauksien taustalla olevista muutoksista, joiden ymmärtäminen on välttämätön edellytys hoitomahdollisuuksien tutkimiselle tulevaisuudessa.