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  • Javela, Kaija (Helsingin yliopisto, 2006)
    High quality of platelet analytics requires specialized knowledge and skills. It was applied to analyze platelet activation and aggregation responses in a prospective controlled study of patients with Finnish type of amyloidosis. The 20 patients with AGel amyloidosis displayed a delayed and more profound platelet shape change than healthy siblings and healthy volunteers, which may be related to altered fragmentation of mutated gelsolin during platelet activation. Alterations in platelet shape change have not been reported in association with platelet disorders. In the rare Bernard-Soulier syndrome with Asn45Ser mutation of glycoprotein (GP) IX, the diagnostic defect in the expression of GPIb-IX-V complex was characterized in seven Finnish patients, also an internationally exceptionally large patient series. When measuring thrombopoietin in serial samples of amniotic fluid and cord blood of 15 pregnant women with confirmed or suspected fetal alloimmune thrombocytopenia, the lower limit of detection could be extended. The results approved that thrombopoietin is present already in amniotic fluid. The application of various non-invasive means for diagnosing thrombocytopenia (TP) revealed that techniques for estimating the proportion of young, i.e. large platelets, such as direct measurement of reticulated platelets and the mean platelet size, would be useful for evaluating platelet kinetics in a given patient. Due to different kinetics between thrombopoietin and increase of young platelets in circulation, these measurements may have most predictive value when measured from simultaneous samples. Platelet autoantibodies were present not only in isolated autoimmune TP but also in patients without TP where disappearance of platelets might be compensated by increased production. The autoantibodies may also persist after TP has been cured. Simultaneous demonstration of increased young platelets (or increased mean platelet volume) in peripheral blood and the presence of platelet associated IgG specificities to major glycoproteins (GPIb-IX and GPIIb-IIIa) may be considered diagnostic for autoimmune TP. Measurement of a soluble marker as a sign of thrombin activation and proceeding deterioration of platelet components was applied to analyze the alterations under several stress factors (storage, transportation and lack of continuous shaking under controlled conditions) of platelet products. The GPV measured as a soluble factor in platelet storage medium showed good correlation with an array of other measurements commonly applied in characterization of stored platelets. The benefits of measuring soluble analyte in a quantitative assay were evident.
  • Leiviskä, Jaana (Helsingin yliopisto, 2013)
    Dyslipidemia - high serum cholesterol, LDL-cholesterol (LDL-C), or triglycerides or low HDL-cholesterol (HDL-C) concentration - is one among the most important factors increasing the risk for cardiovascular disease. Apolipoprotein A-I (apoA-I) is the main apolipoprotein of atheroprotective HDL particles and apoB is the main apolipoprotein in all other atherogenic lipoprotein particles. An increased number of apoB-containing particles and low HDL-C together with almost normal LDL-C is a common feature in obesity, metabolic syndrome, and type 2 diabetes. The first aim of this study was to assess the systematic errors in cholesterol, triglycerides, and HDL-C measurements. Secondly, the effect of fasting and non-fasting triglyceride values on the prevalences of high LDL-C and metabolic syndrome was estimated. The reference intervals for apoA-I, apoB, and apoB/apoA-I ratio were calculated and they were compared with the traditional lipid and lipoprotein concentrations in different pathophysiological conditions. Finally, two direct HDL-C methods and two turbidimetric apoA-I methods in two independent laboratories were compared to discover the concordance between these methods. The data for estimating accuracy of cholesterol, triglycerides, and HDL-C measurements was obtained from different external quality assessment (EQA) programs, in which the Laboratory of Analytical Biochemistry at the National Institute for Health and Welfare has participated since 1978. The laboratory data for lipid and lipoprotein population trends was obtained from the FINRISK population-based health surveys during 1982 2012. During this time systematic error for cholesterol and triglyceride measurements remained within the range of 4% but for HDL-C error was larger. Comparison of two direct HDL-C methods showed a concentration-dependent difference between these methods. At low HDL-C concentrations difference between methods was negative -12.0 %, but at higher concentrations turned out to be positive: +9.0 %. However, apoA-I methods demonstrated better agreement than HDL-C in the method comparisons. Obese men and women had the highest apoB concentrations and apoB/apoA-I ratios compared to the healthy reference group. Men with self-reported cardiovascular disease (CVD) or diabetes had lower apoB concentrations and apoB/apoA-I ratio than the averages in the healthy reference group. In contrast women had higher apoB concentrations and apoB/apoA-I ratios in obesity, CVD, hypertension, or diabetes than in the healthy reference group. Participating in the external quality assessment programs with target values measured by the reference methods was essential, when interpreting the effects of the systematic errors on the population lipid trends. The concentration-dependent differences in homogeneous HDL-C methods may cause misclassificatios in the risk assessment of cardiovascular disease. Because an increased number of apoB-containing lipoproteins but a normal or even low LDL-cholesterol is a common feature in obesity, metabolic syndrome and type 2 diabetes, apoB measurements may produce more specific information in the risk assessment for CVD in these conditions than total cholesterol and LDL-C measurements.
  • Peuhkuri, Katri (Helsingin yliopisto, 2000)
  • Vuoristo, Sanna (Helsingin yliopisto, 2013)
    Extracellular matrix consists of complex proteins, like collagens, which primarily provide mechanical support and non-collagenous proteins, like fibronectin and laminins (LM). Essentially, extracellular matrix can be divided into interstitial matrix, where the stromal cells, growth factors and ions are embedded or basement membranes, a specialized type of extracellular matrix, which for instance segregates epithelial cells from the surrounding stroma. The first basement membranes of a mouse embryo can be detected already around 3.5 days after fertilization. Laminins initiate basement membrane assembly and are indispensable for a proper basement membrane structure and function during embryogenesis and in adulthood. Human embryonic stem cells have been cultured in vitro for fifteen years and human induced pluripotent stem cells have been reprogrammed from somatic cells since 2007. Originally, human embryonic stem cells were derived in undefined conditions. During the past decade, progress has been made in development of optimized and defined culture conditions for human pluripotent (including embryonic and induced) stem cells. However, the extracellular matrix of human pluripotent stem cells has been poorly understood. An overall aim of this thesis was to study the laminins in human pluripotent stem cells. We found that human embryonic stem cells synthesize LM-111 and -511, the first laminin isoforms synthesized also in mouse embryos. Human embryonic stem cells bound efficiently to LM-511 through integrin α3β1 heterodimer and Lutheran/basal cell adhesion molecule. We showed that undifferentiated human embryonic stem cells could be maintained on LM-511 purified from human cells and that LM-511 was essential also in feeder-dependent stem cell cultures. In large scale, human pluripotent stem cells have been mostly cultured on mouse extracellular matrix preparations. We therefore decided to optimize a novel culture matrix, based on human laminin isoforms secreted by a human carcinoma cell line. Using this novel culture matrix, we were able not only to maintain human pluripotent stem cells but also to reprogram human somatic cells to pluripotency. Adhesion of the newly formed human induced pluripotent stem cell colonies to this matrix was significantly more efficient than to commonly used feeder-free culture systems, suggesting that the matrix could be used in large-scale induced pluripotent stem cell expansion. Finally, we showed that LM α5 synthesis is dependent on the size of the stem cell colony, as well as on the position of the cell in large colonies. The data indicated that LM-511 is mostly produced in context of cell adhesion, cell spreading and migration. Knockdown of LM α5 in human pluripotent stem cells resulted in stress fiber formation in the cells and disorganization in the stem cell colonies. Moreover, the knockdown cells suffered from impaired self-renewal and colony expansion, as compared to the control cells. Taken together, our results suggest that LM-511 maintains human pluripotent stem cells in vitro by mediating cell adhesion, as well as by supporting stem cell morphology and self-renewal, likely via integrin-mediated signaling. This thesis provide essential information about how human pluripotent stem cells modify their adjacent microenvironment, especially LM-511. Based on the primary characterization of human pluripotent cells and their growth requirements, we developed a novel culture matrix, which can be utilized in various stem cell applications, especially in derivation of new induced pluripotent stem cell lines. Finally, our results regarding the functions of LM-511 in undifferentiated human pluripotent stem cells will facilitate the optimization of defined culture and differentiation protocols.
  • Teinonen, Tuomas (Helsingin yliopisto, 2009)
    Although immensely complex, speech is also a very efficient means of communication between humans. Understanding how we acquire the skills necessary for perceiving and producing speech remains an intriguing goal for research. However, while learning is likely to begin as soon as we start hearing speech, the tools for studying the language acquisition strategies in the earliest stages of development remain scarce. One prospective strategy is statistical learning. In order to investigate its role in language development, we designed a new research method. The method was tested in adults using magnetoencephalography (MEG) as a measure of cortical activity. Neonatal brain activity was measured with electroencephalography (EEG). Additionally, we developed a method for assessing the integration of seen and heard syllables in the developing brain as well as a method for assessing the role of visual speech when learning phoneme categories. The MEG study showed that adults learn statistical properties of speech during passive listening of syllables. The amplitude of the N400m component of the event-related magnetic fields (ERFs) reflected the location of syllables within pseudowords. The amplitude was also enhanced for syllables in a statistically unexpected position. The results suggest a role for the N400m component in statistical learning studies in adults. Using the same research design with sleeping newborn infants, the auditory event-related potentials (ERPs) measured with EEG reflected the location of syllables within pseudowords. The results were successfully replicated in another group of infants. The results show that even newborn infants have a powerful mechanism for automatic extraction of statistical characteristics from speech. We also found that 5-month-old infants integrate some auditory and visual syllables into a fused percept, whereas other syllable combinations are not fully integrated. Auditory syllables were paired with visual syllables possessing a different phonetic identity, and the ERPs for these artificial syllable combinations were compared with the ERPs for normal syllables. For congruent auditory-visual syllable combinations, the ERPs did not differ from those for normal syllables. However, for incongruent auditory-visual syllable combinations, we observed a mismatch response in the ERPs. The results show an early ability to perceive speech cross-modally. Finally, we exposed two groups of 6-month-old infants to artificially created auditory syllables located between two stereotypical English syllables in the formant space. The auditory syllables followed, equally for both groups, a unimodal statistical distribution, suggestive of a single phoneme category. The visual syllables combined with the auditory syllables, however, were different for the two groups, one group receiving visual stimuli suggestive of two separate phoneme categories, the other receiving visual stimuli suggestive of only one phoneme category. After a short exposure, we observed different learning outcomes for the two groups of infants. The results thus show that visual speech can influence learning of phoneme categories. Altogether, the results demonstrate that complex language learning skills exist from birth. They also suggest a role for the visual component of speech in the learning of phoneme categories.
  • Härkki-Sirén, Päivi (Helsingin yliopisto, 1999)
  • Kaasinen, Eevi (Helsingin yliopisto, 2014)
    Diseases can occur due to genetic changes that alter the normal function of genes. These alterations may be either inherited or acquired somatically during lifetime. Aims of this thesis work were to efficiently analyze large quantities of epidemiological and molecular data, and to characterize new susceptibility conditions and genetic causes of human diseases. First, genetic basis of right atrial isomerism (RAI) was studied in a Finnish family with five affected siblings and healthy parents. RAI is a heterotaxy syndrome with disturbances in the left-right axis development resulting in anomalies in heart and other asymmetrical organs. Linkage analysis and candidate-gene approach followed by sequencing revealed two truncating mutations in GDF1 segregating with RAI in an autosomal recessive manner. This finding, supported by the similar phenotype of laterality defects in Gdf1 knockout mice, provides evidence that RAI can be recessively inherited with GDF1 as the causative gene. Second, six patients with severe intellectual disability (ID) of unknown etiology were studied by genetic mapping and whole-genome sequencing (WGS) analysis. Autosomal recessive inheritance of severe ID was confirmed by extensive genealogy, and by linkage analysis showing high statistical significance for a homozygous region at 3p22.1-3p21.1. Three genes, TKT, P4HTM and USP4, with potentially protein damaging sequence changes were identified within the locus. The variants were rare and present only in heterozygous form in population-matched controls. This study facilitates clinical and molecular diagnosis of similar patients and further research on the role of the genes in the development of severe ID. Third, we performed WGS and transcriptome profiling of 38 uterine leiomyomas and corresponding myometrium from 30 women. Uterine leiomyomas are benign tumors that affect approximately three-quarters of women and may cause severe symptoms including abdominal pain and excessive uterine bleeding. Abundant complex chromosomal rearrangement events resembling the recently described chromothripsis phenomenon were detected. The events had created leiomyoma-specific driver changes, and occurred sequentially in some tumors. Four molecular pathways driven by alterations of MED12, FH, HMGA2/HMGA1 or COL4A5/COL4A6 were identified. The clonal origin of multiple separate tumors was also proven. The molecular genetic characterization of uterine leiomyomas will hopefully lead to better understanding of tumor growth and personalized treatment of patients. Fourth, a systematic search for familial aggregation of all tumor types was performed to identify new susceptibility phenotypes. We employed the entire population based data in the Finnish Cancer Registry and clustered 878,593 patients according to family name at birth, municipality of birth and tumor type. The rate of familial occurrence was estimated with a cluster score method. Among known cancer predisposition syndromes, Kaposi sarcoma (KS) with largely unknown genetic background was highlighted. Population records verified majority of the clustered KS patients as true relatives, providing further evidence that the clustering works well in estimating familiality. This study enabled identification of families suitable for a succeeding research on genetic basis of novel tumor predisposition phenotypes.
  • Aaltonen, Leena-Maija (Helsingin yliopisto, 1999)
  • Vehviläinen, Piia (Helsingin yliopisto, 2010)
    Latent transforming growth factor-beta (TGF-beta) binding proteins (LTBPs) -1, -3 and -4 are ECM components whose major function is to augment the secretion and matrix targeting of TGF-beta, a multipotent cytokine. LTBP-2 does not bind small latent TGF-beta but has suggested functions as a structural protein in ECM microfibrils. In the current work we focused on analyzing possible adhesive functions of LTBP-2 as well as on characterizing the kinetics and regulation of LTBP-2 secretion and ECM deposition. We also explored the role of TGF-beta binding LTBPs in endothelial cells activated to mimic angiogenesis as well as in malignant mesothelioma. We found that, unlike most adherent cells, several melanoma cell lines efficiently adhered to purified recombinant LTBP-2. Further characterization revealed that the adhesion was mediated by alpha3beta1 and alpha6beta1 integrins. Heparin also inhibited the melanoma cell adhesion suggesting a role for heparan sulphate proteoglycans. LTBP-2 was also identified as a haptotactic substrate for melanoma cell migration. We used cultured human embryonic lung fibroblasts to analyze the temporal and spatial association of LTBP-2 into ECM. By We found that LTBP-2 was efficiently assembled to the ECM only in confluent cultures following the deposition of fibronectin (FN) and fibrillin-1. In early, subconfluent cultures it remained primarily in soluble form after secretion. LTBP-2 colocalized transiently with FN and fibrillin-1. Silencing of fibrillin-1 expression by lentiviral shRNAs profoundly disrupted the deposition of LTBP-2 indicating that the ECM association of LTBP-2 depends on a pre-formed fibrillin-1 network. Considering the established role of TGF-beta as a regulator of angiogenesis we induced morphological activation of endothelial cells by phorbol 12-myristate 13-acetate (PMA) and followed the fate of LTBP-1 in the endothelial ECM. This resulted in profound proteolytic processing of LTBP-1 and release of latent TGF-beta complexes from the ECM. The processing was coupled with increased activation of MT-MMPs and specific upregulation of MT1-MMP. The major role of MT1-MMP in the proteolysis of LTBP-1 was confirmed by suppressing the expression with lentivirally induced short-hairpin RNAs as well as by various metalloproteinases inhibitors. TGF-beta can promote tumorigenesis of malignant mesothelioma (MM), which is an aggressive tumor of the pleura with poor prognosis. TGF-beta activity was analyzed in a panel of MM tumors by immunohistochemical staining of phosphorylated Smad-2 (P-Smad2). The tumor cells were strongly positive for P-Smad2 whereas LTBP-1 immunoreactivity was abundant in the stroma, and there was a negative correlation between LTBP-1 and P-Smad2 staining. In addition, the high P-Smad2 immunoreactivity correlated with shorter survival of patients. mRNA analysis revealed that TGF-beta1 was the most highly expressed isoform in both normal human pleura and MM tissue. LTBP-1 and LTBP-3 were both abundantly expressed. LTBP-1 was the predominant isoform in established MM cell lines whereas the expression of LTBP-3 was high in control cells. Suppression of LTBP-3 expression by siRNAs resulted in increased TGF-beta activity in MM cell lines accompanied by decreased proliferation. Our results suggest that decreased expression of LTBP-3 in MM could alter the targeting of TGF-beta to the ECM and lead to its increased activation. The current work emphasizes the coordinated process of the assembly and appropriate targeting of LTBPs with distinct adhesive or cytokine harboring properties into the ECM. The hierarchical assembly may have implications in the modulation of signaling events during morphogenesis and tissue remodeling.
  • Kantola, Anna (Helsingin yliopisto, 2010)
    Extracellular matrix (ECM) is a complex network of various proteins and proteoglycans which provides tissues with structural strength and resilience. By harvesting signaling molecules like growth factors ECM has the capacity to control cellular functions including proliferation, differentiation and cell survival. Latent transforming growth factor β (TGF-β) binding proteins (LTBPs) associate fibrillar structures of the ECM and mediate the efficient secretion and ECM deposition of latent TGF-β. The current work was conducted to determine the regulatory regions of LTBP-3 and -4 genes to gain insight into their tissue-specific expression which also has impact on TGF-β biology. Furthermore, the current research aimed at defining the ECM targeting of the N-terminal variants of LTBP-4 (LTBP-4S and -4L), which is required to understand their functions in tissues and to gain insight into conditions in which TGF-β is activated. To characterize the regulatory regions of LTBP-3 and -4 genes in silico and functional promoter analysis techniques were employed. It was found that the expression of LTBP-4S and -4L are under control of two independent promoters. This finding was in accordance with the observed expression patterns of LTBP-4S and -4L in human tissues. All promoter regions characterized in this study were TATAless, GC-rich and highly conserved between human and mouse species. Putative binding sites for Sp1 and GATA family of transcription factors were recognized in all of these regulatory regions. It is possible that these transcription factors control the basal expression of LTBP-3 and -4 genes. Smad binding element was found within the LTBP-3 and -4S promoter regions, but it was not present in LTBP-4L promoter. Although this element important for TGF-β signaling was present in LTBP-4S promoter, TGF-β did not induce its transcriptional activity. LTBP-3 promoter activity and mRNA expression instead were stimulated by TGF-β1 in osteosarcoma cells. It was found that the stimulatory effect of TGF-β was mediated by Smad and Erk MAPK signaling pathways. The current work explored the ECM targeting of LTBP-4S and identified binding partners of this protein. It was found that the N-terminal end of LTBP-4S possesses fibronectin (FN) binding sites which are critical for its ECM targeting. FN deficient fibroblasts incorporated LTBP-4S into their ECM only after addition of exogenous FN. Furthermore, LTBP-4S was found to have heparin binding regions, of which the C-terminal binding site mediated fibroblast adhesion. Soluble heparin prevented the ECM association of LTBP-4S in fibroblast cultures. In the current work it was observed that there are significant differences in the secretion, processing and ECM targeting of LTBP-4S and -4L. Interestingly, it was observed that most of the secreted LTBP-4L was associated with latent TGF-β1, whereas LTBP-4S was mainly secreted as a free form from CHO cells. This thesis provides information on transcriptional regulation of LTBP-3 and -4 genes, which is required for the deeper understanding of their tissue-specific functions. Further, the current work elucidates the structural variability of LTBPs, which appears to have impact on secretion and ECM targeting of TGF-β. These findings may advance understanding the abnormal activation of TGF-β which is associated with connective tissue disorders and cancer.
  • Jutila, Arimatti (Helsingin yliopisto, 2001)
  • Rossani, Romana (Helsingin yliopisto, 2011)
    Objective The anterior skull base region can be reached through different surgical approaches. The most frequently used are the pterional, bifrontal, and orbitozygomatic approaches. No previous reports describe the microsurgical technique when treating olfactory groove meningiomas (OGMs), anterior clinoidal meningiomas (ACMs), and tuberculum sellae meningiomas (TSMs)through the small lateral supraorbital (LSO) approach. The purpose here was to assess the reliability and safety of the LSO for the treatment of vascular and neoplastic lesions of the anterior skull base. The neuroanesthesia method when using this small approach is also presented. When needed, anterior clinoidectomy, intradurally or extradurally, is also possible through the LSO approach. Patients and Methods Between September 1997 and August 2010, we analyzed the clinical data, radiological findings, surgical treatment, anesthesiological procedure, histology, outcome, and long-term follow-up of 66 OGMs, 73 ACMs, 52 TSMs consecutive patients treated by the senior author (J.H.) through the LSO approach. Anterior clinoidectomy technique through the LSO is presented after reviewing 82 patients who underwent surgery for vascular and neoplastic lesions between June 2007 and January 2011. Altogether 273 patients of a total of 3000 LSO approaches were analyzed, and 15 videos were selected to show the approach and the microsurgical techniques used. Results Olfactory groove meningiomas: There was no surgical mortality. Six patients (9%) had CSF leakage, four (6%) had wound infections and cotton granulomas, and one (2%) had postoperative hematoma. The median Karnofsky score at discharge was 80 (range, 40-100). Six patients had residual tumors: three were re-operated on after an average of 21 (range, 1-41) months, one was treated with radiosurgery, and two were followed up. During the median follow-up of 45 (range, 2-128) months there were four recurrences (6%) diagnosed on average 32 (range, 17-59) months after surgery. Anterior clinoidal meningiomas: At three months after discharge, 60 patients (82%) had a good recovery, nine (12%) were moderately disabled, one (1%) presented with severe disability, and three (4%) died due to surgery-related complications. Sixteen patients (22%) had residual tumors, six of which required re-operation. Of 39 patients, pre-existing visual deficit improved in 11 (28%), worsened in four (5%), and three (4%) had de novo visual deficit. During the median follow-up of 36 (range, 3-146) months tumor recurred in three patients: two were followed up and one was reoperated. Tuberculum sellae meningiomas: At three months postdischarge, 47 patients (90%) had a good recovery, four (8%) were moderately disabled, and one (2%) died 40 days after surgery of unexplained cardiac arrest. Of 42 patients, pre-existing visual deficit improved in 22 (42%), remained the same in 13 (25%), and worsened in seven (13%), and de novo visual deficit occurred in one patient (2%). Seven patients (13%) had minimal residual tumors, two of which required re-operation. During the median follow-up of 59 (range, 1-133) months tumor recurred in one of the patients who had received a second operation. Anesthesia: Surgical conditions with slack brain were good in 154 meningioma patients. Slack brain was achieved by a head position elevated 20 cm above cardiac level in all patients; administering mannitol preoperatively in medium or large meningiomas (60 cases); propofol infusion (46 cases) or volatile anesthetics (107 cases) also in patients with large tumor (37 cases); and controlling intraoperative hemodynamics. The mean systolic blood pressure was 95-110 mmHg during surgery. The median intraoperative blood loss was 200 (range, 0-2000) ml and 9% of patients had red blood cell transfusion. One-hundred and fifty-seven patients (84%) were extubated on the day of the surgery. The median (25th/75th percentiles) time to extubation after surgery was 18 (8/105) min. Anterior clinoidectomy: Eighty-two patients underwent anterior clinoidectomy: 45 patients (55%) were treated for aneurysms, 35 patients (43%) were treated for intraorbital, parasellar, and suprasellar tumors, and two patients (2%) presented with carotid-cavernous fistula. Intradural anterior clinoidectomy was performed in 67 cases (82%); in 15 cases (18%), an extradural approach was used. We performed a tailored anterior clinoidectomy: in five patients (6%), only the medial tip of the anterior clinoid process (ACP) was removed, in eight (10%) the head of the ACP, in 18 (22%) the body of the ACP, and in 51 (62%) the entire ACP. Four patients (5%) had new postoperative visual deficits and 12 (15%) improved their preoperative visual deficits after intradural anterior clinoidectomy. Extradural anterior clinoidectomy and use of ultrasonic bone device (Sonopet) may increase the risk of postoperative visual deficits. There was no mortality in the series. Conclusions The LSO approach can be used safely for OGMs, ACMs, and TSMs of all sizes, with a low mortality and a relatively low morbidity. Anterior clinoidectomy can be performed through the LSO approach. However, it is required only in selected cases and we prefer the intradural route. A slack brain is mandatory when performing the small LSO approach and can be achieved by patient positioning, propofol or inhaled anesthetics, preoperative mannitol, and optimizing cerebral perfusion pressure. With advancements in the neurosurgical field, the skull opening should be simple and as minimally invasive as possible. Surgical results with the simple, clean, and fast LSO approach are comparable with those achieved with more extensive, complex, and time-consuming approaches. We highly recommend the use of LSO for removal of vascular and neoplastic lesions of the anterior skull base.
  • Nieminen, Heta (Helsingin yliopisto, 2009)
    Background: Congenital heart defects include a wide range of inborn malformations. Depending on the defect, the life expectancy of a newborn with cardiac anomaly varies from a few days to a normal life span. In most instances surgery, is the only treatment available. The late results of surgery have not been comprehensively investigated. Aims: Mortality, morbidity and the life situation of all Finnish patients who had been operated on for congenital heart defect during childhood were investigated. Methods: Patient and surgical data were gathered from all hospitals that had performed heart surgeries on children. Late mortality and survival data were obtained from the population registry, and the causes of deaths from Statistics Finland. Morbidity of patients operated on during 1953-1989 was assessed by the usage of medicines. The pharmacotherapy data of patients and controls were obtained from the Social Insurance Institute. The life situation of patients was surveyed by mailed questionnaire. Survival, causes of deaths and life situation of patients were compared with those of the general population. Results: A total of 7240 cardiac operations were performed on 6461 children during the first 37 years of cardiac surgery (1953-1989). The number of procedures constantly rose during this period, and the increase continued in later years. The patient material varied over time, as more defects became surgically treatable. During 1953-1989 the operative mortality (death within 30 days of surgery) was 6.9%. In the 1990s a slight rise occurred in early mortality, as increasingly complicated patients were surgically treated. During 2000-2003 practically no defects were beyond the operative range. Thus, the operative mortality of 4.4% was excellent, decreasing even further to 2.0% in 2004-2007. The overall 45-year survival of patients operated on in 1953-1989 was 78%, and the corresponding figure for the general population was 93%. Survival depended on the defect, being worst among patients with univentricular heart. Late survival was also better during the 1990s and at the beginning of the 21st century. Of the 6028 early survivors, 592 died late (>30 days) after surgery. A total of 397 deaths (67%) were related and 185 (31%) unrelated to congenital heart defect. The cause of death was unknown in 10 cases. Of those 5774 patients who survived their first operation and had complete follow-up, 16% were operated on several times. Seventeen percent of patients used medicines for cardiac symptoms (heart failure, arrhythmia, hypertension and coronary disease). Patients risk of using cardiac medicines was 2.16 (Cl 1.97-2.37) times higher than that of controls. Patients also had more genetic syndromes and mental retardation and more often used medicines for asthma and epilepsy. Adult patients who had been operated on as children had coped surprisingly well with their defects. Their level of education was similar and their employment level even higher than expected, and they were living in a steady relationship as often as the general population. Conclusions: Cardiac surgery developed rapidly, and nowadays practically all defects can be treated. The overall survival of all operated patients was 78%, 16% less than that of the general population. However, it was significantly better than the anticipated natural survival. However, many patients had health problems; 16% needed reoperations and 17% cardiac medicines to maintain their condition. Most of the patients assessed their general health as good and lived a normal life.
  • Lajunen, Hanna-Reetta (Helsingin yliopisto, 2010)
    The aims of this dissertation were 1) to investigate associations of weight status of adolescents with leisure activities, and computer and cell phone use, and 2) to investigate environmental and genetic influences on body mass index (BMI) during adolescence. Finnish twins born in 1983–1987 responded to postal questionnaires at the ages of 11-12 (5184 participants), 14 (4643 participants), and 17 years (4168 participants). Information was obtained on weight and height, leisure activities including television viewing, video viewing, computer games, listening to music, board games, musical instrument playing, reading, arts, crafts, socializing, clubs, sports, and outdoor activities, as well as computer and cell phone use. Activity patterns were studied using latent class analysis. The relationship between leisure activities and weight status was investigated using logistic and linear regression. Genetic and environmental effects on BMI were studied using twin modeling. Of individual leisure activities, sports were associated with decreased overweight risk among boys in both cross-sectional and longitudinal analyses, but among girls only cross-sectionally. Many sedentary leisure activities, such as video viewing (boys/girls), arts (boys), listening to music (boys), crafts (girls), and board games (girls), had positive associations with being overweight. Computer use was associated with a higher prevalence of overweight in cross-sectional analyses. However, musical instrument playing, commonly considered as a sedentary activity, was associated with a decreased overweight risk among boys. Four patterns of leisure activities were found: ‘Active and sociable’, ‘Active but less sociable’, ‘Passive but sociable’, and ‘Passive and solitary’. The prevalence of overweight was generally highest among the ‘Passive and solitary’ adolescents. Overall, leisure activity patterns did not predict overweight risk later in adolescence. An exception were 14-year-old ‘Passive and solitary’ girls who had the greatest risk of becoming overweight by 17 years of age. Heritability of BMI was high (0.58-0.83). Common environmental factors shared by family-members affected the BMI at 11-12 and 14 years but their effect had disappeared by 17 years of age. Additive genetic factors explained 90-96% of the BMI stability across adolescence. Genetic correlations across adolescence were high, which suggests similar genetic effects on BMI throughout adolescence, while unique environmental effects on BMI appeared to vary. These findings suggest that family-based interventions hold promise for obesity prevention into early and middle adolescence, but that later in adolescence obesity prevention should focus on individuals. A useful target could be adolescents' leisure time, and our findings highlight the importance of versatility in leisure activities.
  • Lahti, Jouni (Helsingin yliopisto, 2011)
    Physical inactivity has become a major threat to public health worldwide. The Finnish health and welfare policies emphasize that the working population should maintain good health and functioning until their normal retirement age and remain in good health and independence later in life. Health behaviours like physical activity potentially play an important role in reaching this target as physical activity contributes to better physical fitness and to reduced risk of major chronic diseases. The aim of this study was to examine first whether the volume and intensity of leisure-time physical activity impacts on subsequent physical health functioning, sickness absence and disability retirement. The second aim was to examine changes in leisure-time physical activity of moderate and vigorous intensity after transition to retirement. This study is part of the ongoing Helsinki Health Study. The baseline data were collected by questionnaires in 2000 - 02 among the employees of the City of Helsinki aged 40 to 60. The follow-up survey data were collected in 2007. Data on sickness absence were obtained from the employer s (City of Helsinki) sickness absence registers and pension data were obtained from the Finnish Centre for Pensions. Leisure-time physical activity was measured in four grades of intensity and classified according to physical activity recommendations considering both the volume and intensity of physical activity. Statistical techniques including analysis of covariance, logistic regression, Cox proportional hazards models and Poisson regression were used. Employees who were vigorously active during leisure time especially had better physical health functioning than those physically inactive. High physical activity in particular contributed to the maintenance of good physical health functioning. High physical activity also reduced the risk of subsequent sickness absences as well as the risk of all-cause disability retirement and retirement due to musculoskeletal and mental causes. Among those transferred to old-age retirement moderate-intensity leisure-time physical activity increased on average by more than half an hour per week and in addition the occurrence of physical inactivity reduced. Such changes were not observed among those remained employed and those transferred to disability retirement. This prospective cohort study provided novel results on the effects of leisure-time physical activity on health related functioning and changes in leisure-time physical activity after retirement. Although the benefits of moderate-intensity physical activity for health are well known these results suggest the importance of vigorous physical activity for subsequent health related functioning. Thus vigorous physical activity to enhance fitness should be given more emphasis from a public health perspective. In addition, physical activity should be encouraged among those who are about to retire.
  • Hytinantti, Timo Kalevi (Helsingin yliopisto, 2001)
  • Linnankivi, Tarja (Helsingin yliopisto, 2006)
    Within the last 15 years, several new leukoencephalopathies have been recognized. However, more than half of children with cerebral white matter abnormalities still have no specific diagnosis. Our aim was to classify unknown leukoencephalopathies and to identify new diseases among them. During the study, three subgroups of patients were delineated and examined further. First, we evaluated 38 patients with unknown leukoencephalopathy. Brain MRI findings were grouped into seven categories according to the predominant location of the abnormalities. The largest subgroups were myelination abnormalities (n=20) and periventricular white matter abnormalities (n=12). Six patients had uniform MRI findings with signal abnormalities in hemispheric white matter and in selective brain stem and spinal cord tracts. Magnetic resonance spectroscopy (MRS) showed elevated lactate and decreased N-acetylaspartate in the abnormal white matter. The patients presented with ataxia, tremor, distal spasticity, and signs of dorsal column dysfunction. This phenotype - leukoencephalopathy with brain stem and spinal cord involvement and elevated white matter lactate (LBSL) - was first published elsewhere in 2003. A new finding was development of a mild axonal neuropathy. The etiopathogenesis of this disease is unknown, but elevated white matter lactate in MRS suggests a mitochondrial disorder. Secondly, we studied 22 patients with 18q deletions. Clinical and MRI findings were correlated with molecularly defined size of the deletion. All patients with deletions between markers D18S469 and D18S1141 (n=18) had abnormal myelination in brain MRI, while four patients with interstitial deletions sparing that region, had normal myelination pattern. Haploinsufficiency of myelin basic protein is suggested to be responsible for this dysmyelination. Congenital aural atresia/stenosis was found in 50% of the cases and was associated with deletions between markers D18S812 (at 18q22.3) and D18S1141 (at q23). Last part of the study comprised 13 patients with leukoencephalopathy and extensive cerebral calcifications. They showed a spectrum of findings, including progressive cerebral cysts, retinal telangiectasias and angiomas, intrauterine growth retardation, skeletal and hematologic abnormalities, and severe intestinal bleeding, which overlap with features of the previously reported patients with "Coats plus" syndrome and "leukoencephalopathy with calcifications and cysts", suggesting that these disorders are related. All autopsied patients had similar neuropathologic findings showing calcifying obliterative microangiopathy. Our patients may represent an autosomally recessively inherited disorder because there were affected siblings and patients of both sexes. We have started genealogic and molecular genetic studies of this disorder.
  • Põder, Pentti (Helsingin yliopisto, 2006)
    Levosimendan is a drug developed for the treatment of heart failure. Its mechanism of action includes calcium sensitization of contractile proteins and the opening of ATP-sensitive potassium channels. The combination of positive inotropy with possible anti-ischaemic effects via potassium channel opening may offer benefits in comparison with currently available intravenous inotropes, which are contraindicated in patients with ongoing myocardial ischaemia. The active levosimendan metabolite OR-1896 significantly prolongs the duration of the haemodynamic effects of levosimendan. The aims of the present study were to investigate: 1) the clinical effects and safety of intravenous and oral levosimendan and 2) the pharmacodynamics and pharmacokinetics of intravenous and oral levosimendan and its metabolites in patients with ischaemic heart disease. Levosimendan was administered intravenously or orally in four studies to 557 patients with ischaemic heart disease with or without concomitant heart failure. One study included patients with acute myocardial infarction, while the other three studies included stable ischaemic patients. Non-invasive haemodynamic measurements were used in all studies, and blood samples for pharmacokinetics were drawn in three studies. Safety was followed by ECG recordings, adverse event inquiries and laboratory assessments. Intravenous levosimendan, administered as a 6-hour infusion did not cause clinically significant hypotension or ischaemia in comparison with placebo and reduced worsening heart failure and short- and long-term mortality. Increase in incidence of hypotension and ischaemia was seen only with the highest dose (0.4 µg/kg/min). Both intravenous and oral levosimendan possessed a moderate positive inotropic effect. Vasodilatory effect was more pronounced with intravenous levosimendan. A chronotropic effect was seen in all studies; however, it was not accompanied by any increase in arrhythmic events. The formation of levosimendan metabolites after oral dosing increased linearly with the daily dose of the parent drug, leading to increased inotropic and chronotropic response. Levosimendan was well tolerated in all studies. In conclusion, levosimendan was safe and effective in the treatment of patients with acute or chronic ischaemia. The risk-benefit ratio of intravenous levosimendan is favourable up to the dose of 0.2 µg/kg/min. The daily dose of oral levosimendan in patients with ischaemic heart failure should not exceed 4 mg due to an increase in chronotropic response.