22 resultados para four-stroke

em Helda - Digital Repository of University of Helsinki


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Ischemic stroke (IS) is a heterogeneous disease in which outcome is influenced by many factors. The hemostatic system is activated in association with cerebral ischemia, and thus, markers measuring coagulation, fibrinolysis, and vasoactivity could be useful tools in clinical practice. We investigated whether repeated measurements of these markers reveal patterns that might help in evaluating IS patients, including the early diagnosis of stroke subtypes, in estimating prognosis and risk of recurrence, and in selecting a treatment for secondary prevention of stroke. Vasoconstrictor peptide endothelin-1 (ET-1), homocysteine (Hcy), indicators of thrombin formation and activation (prothrombin fragment 1+2/F1+2, thrombin-antithrombin complex/TAT), indicators of plasmin formation and fibrinolysis (tissue plasminogen activator/t-PA, plasminogen activator inhibitor-1/PAI-1, and D-dimer), and natural anticoagulants (antithrombin/AT, protein C/PC, and protein S/PS) were measured in 102 consecutive mild to moderate IS patients on four occasions: on admission and at 1 week, 1 month, and 3 months after stroke, and once in controls. All patients underwent neurological examination and blood sampling in the same session. Furthermore, 42 IS patients with heterozygous factor V Leiden mutation (FVLm) were selected from 740 IS patients without an obvious etiology, and evaluated in detail for specific clinical, laboratory, and radiological features. Measurements of ET-1 and Hcy levels did not disclose information that could aid in the diagnostic evaluation of IS patients. F1+2 level at 3 months after IS had a positive correlation with recurrence of thromboembolic events, and thus, may be used as a predictive marker of subsequent cerebral events. The D-dimer and AT levels on admission and 1 week after IS were strongly associated with stroke severity, outcome, and disability. The specific analysis of IS patients with FVLm more often revealed a positive family history of thrombosis, a higher prevalence of peripheral vascular disease, and multiple infarctions in brain images, most of which were `silent infarcts´. Results of this study support the view that IS patients with sustained activation of both the fibrinolytic and the coagulation systems and increased thrombin generation may have an unfavorable prognosis. The level of activation may reflect the ongoing thrombotic process and the extent of thrombosis. Changes in these markers could be useful in predicting prognosis of IS patients. A clear need exists for a randomized prospective study to determine whether a subgroup of IS patients with markers indicating activation of fibrinolytic and coagulation systems might benefit from more aggressive secondary prevention of IS.

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The present study discusses the theme of St. Petersburg-Leningrad in Joseph Brodsky's verse works. The chosen approach to the evolving im-age of the city in Brodsky's poetry is through four metaphors: St. Petersburg as "the common place" of the Petersburg Text, St. Petersburg as "Paradise and/or Hell", St. Petersburg as "a Utopian City" and St. Petersburg as "a Void". This examination of the city-image focusses on the aspects of space and time as basic categories underlying the poet's poetic world view. The method used is close reading, with an emphasis on semantical interpretation. The material consists of eighteen poems dating from 1958 to 1994. Apart from investigating the spatio-temporal features, the study focusses on exposing and analysing the allusions in the scrutinised works to other texts from Russian and Western belles lettres. Terminology (introduced by Bakhtin and Yury Lotman, among others) concerning the poetics of space in literature is employed in the present study. Conceptions originating from the paradigm of possible worlds are also used in elucidating the position of fictional and actual chronotopes and heroes in Brodsky's poetry. Brodsky's image of his native city is imbued with intertextual linkings. Through reminiscences of the "Divine Comedy" and Russian modernists, the city is paralleled with Dante's "lost and accursed" Florence, as well as with the lost St. Petersburg of Mandel'shtam and Akhmatova. His city-image is related to the Petersburg myth in Russian literature through their common themes of death and separation as well as through the merging of actual realia with the fictional worlds of the Petersburg Text. In his later poems, when his view of the city is that of an exiled poet, the city begins to lose its actual world referents, turning into a mental realm which is no longer connected to any particular geographical location or historical time. It is placed outside time. The native city as the homeland in its entirety is replaced by another existence created in language.

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Approximately one-third of stroke patients experience depression. Stroke also has a profound effect on the lives of caregivers of stroke survivors. However, depression in this latter population has received little attention. In this study the objectives were to determine which factors are associated with and can be used to predict depression at different points in time after stroke; to compare different depression assessment methods among stroke patients; and to determine the prevalence, course and associated factors of depression among the caregivers of stroke patients. A total of 100 consecutive hospital-admitted patients no older than 70 years of age were followed for 18 months after having their first ischaemic stroke. Depression was assessed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R), Beck Depression Inventory (BDI), Hamilton Rating Scale (HRSD), Visual Analogue Mood Scale (VAMS), Clinical Global Impression (CGI) and caregiver ratings. Neurological assessments and a comprehensive neuropsychological test battery were performed. Depression in caregivers was assessed by BDI. Depressive symptoms had early onsets in most cases. Mild depressive symptoms were often persistent with little change during the 18-month follow-up, although there was an increase in major depression over the same time interval. Stroke severity was associated with depression especially from 6 to 12 months post-stroke. At the acute phase, older patients were at higher risk of depression, and a higher proportion of men were depressed at 18 months post-stroke. Of the various depression assessment methods, none stood clearly apart from the others. The feasibility of each did not differ greatly, but prevalence rates differed widely according to the different criteria. When compared against DSM-III-R criteria, sensitivity and specificity were acceptable for the CGI, BDI, and HRSD. The CGI and BDI had better sensitivity than the more specific HRSD. The VAMS seemed not to be a reliable method for assessing depression among stroke patients. The caregivers often rated patients depression as more severe than did the patients themselves. Moreover, their ratings seemed to be influenced by their own depression. Of the caregivers, 30-33% were depressed. At the acute phase, caregiver depression was associated with the severity of the stroke and the older age of the patient. The best predictor of caregiver depression at later follow-up was caregiver depression at the acute phase. The results suggest that depression should be assessed during the early post-stroke period and that the follow-up of those at risk of poor emotional outcome should be extended beyond the first year post-stroke. Further, the assessment of well-being of the caregivers of stroke patients should be included as a part of a rehabilitation plan for stroke patients.

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Cardiovascular diseases (CVD) are a major cause of death and disability in Western countries and a growing health problem in the developing world. The genetic component of both coronary heart disease (CHD) and ischemic stroke events has been established in twin studies, and the traits predisposing to CVD, such as hypertension, dyslipidemias, obesity, diabetes, and smoking behavior, are all partly hereditary. Better understanding of the pathophysiology of CVD-related traits could help to target disease prevention and clinical treatment to individuals at an especially high disease risk and provide novel pharmaceutical interventions. This thesis aimed to clarify the genetic background of CVD at a population level using large Nordic population cohorts and a candidate gene approach. The first study concentrated on the allelic diversity of the thrombomodulin (THBD) gene in two Finnish cohorts, FINRISK-92 and FINRISK-97. The results from this study implied that THBD variants do not substantially contribute to CVD risk. In the second study, three other candidate genes were added to the analyses. The study investigated the epistatic effects of coagulation factor V (F5), intercellular adhesion molecule -1 (ICAM1), protein C (PROC), and THBD in the same FINRISK cohorts. The results were encouraging; we were able to identify several single SNPs and SNP combinations associating with CVD and mortality. Interestingly, THBD variants appeared in the associating SNP combinations despite the negative results from Study I, suggesting that THBD contributes to CVD through gene-gene interactions. In the third study, upstream transcription factor -1 (USF1) was analyzed in a cohort of Swedish men. USF1 was associated with metabolic syndrome, characterized by accumulation of different CVD risk factors. A putative protective and a putative risk variant were identified. A direct association with CVD was not observed. The longitudinal nature of the study also clarified the effect of USF1 variants on CVD risk factors followed in four examinations throughout adulthood. The three studies provided valuable information on the study of complex traits, highlighting the use of large study samples, the importance of replication, and the full coverage of the major allelic variants of the target genes to assure reliable findings. Although the genetic basis of coronary heart disease and ischemic stroke remains unknown, single genetic findings may facilitate the recognition of high-risk subgroups.

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This study was carried out to compare the fasting plasma glucose (FPG) and 2-h plasma glucose (2-h PG) criteria for diabetes with regard to their relation to stroke mortality and the incidence of ischemic and hemorrhagic stroke. In addition, the age-and gender difference in the incidence of coronary heart disease (CHD) and stroke and their relation with known cardiovascular disease risk factors and diabetes mellitus was examined. The study was a sub-data analysis of the Diabetes Epidemiology: Collaborative analysis Of Diagnostic criteria in Europe (DECODE) study including 25 181 individuals, 11 844 (47%) men and 13 345 (53%) women aged 25 to 90 years, from 14 European cohorts. In individuals without a history of diabetes elevated 2-h post-challenge glucose was a better predictor of stroke mortality than elevated fasting glucose in men, whereas the latter was better than the former in women. Elevated FPG and 2-h PG levels were associated with an increased risk of ischemic stroke incidence. 2-h PG contributed to the risk more strongly than FPG. No relationship between hyperglycemia and the risk of hemorrhagic stroke was found. The risk of CHD and ischemic stroke incidence increased with age in both genders, but was higher in all age groups in men than in women. The gender difference was, however, more marked for CHD than for ischemic stroke. Age, smoking and diabetes contributed to the development of both CHD and ischemic stroke. Elevated cholesterol levels predicted CHD only, whereas elevated blood pressure was a risk predictor for the incidence of ischemic stroke. The CHD and ischemic stroke risk was higher in men than in women with and without diabetes, however, the gender difference diminished for CHD but enlarged for ischemic stroke in diabetic individuals. The known risk factors including diabetes contributed differently to the risk of CHD and ischemic stroke in women and in men. Hyperglycemia defined by FPG or 2-h PG increases the risk of ischemic stroke in individuals without diabetes. FPG better predicts stroke mortality in women and 2-h PG in men. The risk of acute CHD and ischemic stroke is higher in men than in women in all ages, but such gender difference is more marked for CHD than for ischemic stroke. CHD risk is higher in men than in women, but the difference is reduced in diabetic population. Diabetes, however, increases stroke risk more in men than in women in all ages.

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This study describes and analyses two Lebanese Muslims and two Lebanese Christians ideas about Christian-Muslim dialogue, its nature, aims, and methods and its different dimensions, which include doctrinal, ethical, and social dimensions. On the basis of the analysis, the four thinkers contributions for promoting constructive dialogue are evaluated. The persons studied are two religious authorities, the Shiite Great Ayatollah Muhammad Husayn Fadlallah (b. 1935) and the Eastern Orthodox Metropolitan of Mount Lebanon, Georges Khodr (b. 1923), and two academic scholars, Doctor Mahmoud Ayoub (b. 1935) and Doctor, Father Mouchir Aoun (b. 1964), from the Shiite and Greek Catholic communities, respectively. The method of the study is systematic analysis. The sources consist of the four thinkers writings on Christian-Muslim relations, the most of which have been published in Lebanon in the 1990s and 2000s in the Arabic language. In their general guidelines for Christian-Muslim dialogue, the four authors do not offer any novel or unusual insights. However, their dialogue visions are multi-faceted, motivating interreligious encounter both on religious and practical grounds and clarifying the theological grounds and socio-political conditions of this endeavour. The major challenge appears to be the tension between loyalty to one s own convictions and taking into account the particular self-understanding of the other. While this tension may be ultimately unsolvable, it is obvious that linking dialogue tightly to missionary motivations or certain theological agenda imposed on the others is not conducive for better mutual understanding. As for how diverse theologies of religions affect interreligious dialogue, narrow exclusivism hardly promotes mutual knowledge and appreciation, but also inclusive and pluralistic positions have their particular dilemmas. In the end, dialogue is possible from diverse positions on theology of religions. All the authors discuss the theological themes of divine revelation, concept of God, and human condition and ultimate destiny. The two religions particular views on these issues cannot be reconciled, but the authors offer diverse means to facilitate mutual understanding on them, such as increasing mutual knowledge, questioning certain traditional condemnations, showing theological parallels between the two religions, and transcending doctrinal disagreements by stressing common religious experience or ethical concerns. Among the theological themes, especially the concept of God seems to offer possibilities for better understanding than has traditionally been the case. Significantly, all the four authors maintain that Christians and Muslims share the faith in the one God, irrespective of their disagreements about the nature of his oneness. Basic ethical principles are not discussed as widely by the four authors as might be expected, which may reflect the shared cultural background and common ethical values of the Lebanese Muslims and Christians. On this level, Christians alienation from the Islamic law appears as the most significant challenge to mutual understanding, while neighbourly love and the golden rule of ethics offer a fruitful basis for further dialogue. As for the issue of political power-sharing in Lebanon, it is clear that the proposal of an Islamic state is problematic in a country with a sizable Christian minority and a heterogeneous Muslim population. Some form of democracy seems more viable for a multireligious country, but the question remains how to retain religion as a vital force in society, which is felt to be important by all the four Lebanese authors.

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The overall aim of this dissertation was to study the public's preferences for forest regeneration fellings and field afforestations, as well as to find out the relations of these preferences to landscape management instructions, to ecological healthiness, and to the contemporary theories for predicting landscape preferences. This dissertation includes four case studies in Finland, each based on the visualization of management options and surveys. Guidelines for improving the visual quality of forest regeneration and field afforestation are given based on the case studies. The results show that forest regeneration can be connected to positive images and memories when the regeneration area is small and some time has passed since the felling. Preferences may not depend only on the management alternative itself but also on the viewing distance, viewing point, and the scene in which the management options are implemented. The current Finnish forest landscape management guidelines as well as the ecological healthiness of the studied options are to a large extent compatible with the public's preferences. However, there are some discrepancies. For example, the landscape management instructions as well as ecological hypotheses suggest that the retention trees need to be left in groups, whereas people usually prefer individually located retention trees to those trees in groups. Information and psycho-evolutionary theories provide some possible explanations for people's preferences for forest regeneration and field afforestation, but the results cannot be consistently explained by these theories. The preferences of the different stakeholder groups were very similar. However, the preference ratings of the groups that make their living from forest - forest owners and forest professionals - slightly differed from those of the others. These results provide support for the assumptions that preferences are largely consistent at least within one nation, but that knowledge and a reference group may also influence preferences.

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Nitrogen (N) and phosphorus (P) are essential elements for all living organisms. However, in excess, they contribute to several environmental problems such as aquatic and terrestrial eutrophication. Globally, human action has multiplied the volume of N and P cycling since the onset of industrialization. The multiplication is a result of intensified agriculture, increased energy consumption and population growth. Industrial ecology (IE) is a discipline, in which human interaction with the ecosystems is investigated using a systems analytical approach. The main idea behind IE is that industrial systems resemble ecosystems, and, like them, industrial systems can then be described using material, energy and information flows and stocks. Industrial systems are dependent on the resources provided by the biosphere, and these two cannot be separated from each other. When studying substance flows, the aims of the research from the viewpoint of IE can be, for instance, to elucidate the ways how the cycles of a certain substance could be more closed and how the flows of a certain substance could be decreased per unit of production (= dematerialization). In Finland, N and P are studied widely in different ecosystems and environmental emissions. A holistic picture comparing different societal systems is, however, lacking. In this thesis, flows of N and P were examined in Finland using substance flow analysis (SFA) in the following four subsystems: I) forest industry and use of wood fuels, II) food production and consumption, III) energy, and IV) municipal waste. A detailed analysis at the end of the 1990s was performed. Furthermore, historical development of the N and P flows was investigated in the energy system (III) and the municipal waste system (IV). The main research sources were official statistics, literature, monitoring data, and expert knowledge. The aim was to identify and quantify the main flows of N and P in Finland in the four subsystems studied. Furthermore, the aim was to elucidate whether the nutrient systems are cyclic or linear, and to identify how these systems could be more efficient in the use and cycling of N and P. A final aim was to discuss how this type of an analysis can be used to support decision-making on environmental problems and solutions. Of the four subsystems, the food production and consumption system and the energy system created the largest N flows in Finland. For the creation of P flows, the food production and consumption system (Paper II) was clearly the largest, followed by the forest industry and use of wood fuels and the energy system. The contribution of Finland to N and P flows on a global scale is low, but when compared on a per capita basis, we are one of the largest producers of these flows, with relatively high energy and meat consumption being the main reasons. Analysis revealed the openness of all four systems. The openness is due to the high degree of internationality of the Finnish markets, the large-scale use of synthetic fertilizers and energy resources and the low recycling rate of many waste fractions. Reduction in the use of fuels and synthetic fertilizers, reorganization of the structure of energy production, reduced human intake of nutrients and technological development are crucial in diminishing the N and P flows. To enhance nutrient recycling and replace inorganic fertilizers, recycling of such wastes as wood ash and sludge could be promoted. SFA is not usually sufficiently detailed to allow specific recommendations for decision-making to be made, but it does yield useful information about the relative magnitude of the flows and may reveal unexpected losses. Sustainable development is a widely accepted target for all human action. SFA is one method that can help to analyse how effective different efforts are in leading to a more sustainable society. SFA's strength is that it allows a holistic picture of different natural and societal systems to be drawn. Furthermore, when the environmental impact of a certain flow is known, the method can be used to prioritize environmental policy efforts.

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Carotid artery disease is the most prevalent etiologic precursor of ischemic stroke, which is a major health hazard and the second most common cause of death in the world. If a patient presents with a symptomatic high-grade (>70%) stenosis in the internal carotid artery, the treatment of choice is carotid endarterectomy. However, the natural course of radiologically equivalent carotid lesions may be clinically quite diverse, and the reason for that is unknown. It would be of utmost importance to develop molecular markers that predict the symptomatic phenotype of an atherosclerotic carotid plaque (CP) and help to differentiate vulnerable lesions from stable ones. The aim of this study was to investigate the morphologic and molecular factors that associate with stroke-prone CPs. In addition to immunohistochemistry, DNA microarrays were utilized to identify molecular markers that would differentiate between symptomatic and asymptomatic CPs. Endothelial adhesion molecule expression (ICAM-1, VCAM-1, P-selectin, and E-selectin) did not differ between symptomatic and asymptomatic patients. Denudation of endothelial cells was associated with symptom-generating carotid lesions, but in studies on the mechanism of decay of endothelial cells, markers of apoptosis (TUNEL, activated caspase 3) were found to be decreased in the endothelium of symptomatic lesions. Furthermore, markers of endothelial apoptosis were directly associated with those of cell proliferation (Ki-67) in all plaques. FasL expression was significantly increased on the endothelium of symptomatic CPs. DNA microarray analysis revealed prominent induction of specific genes in symptomatic CPs, including those subserving iron and heme metabolism, namely HO-1, and hemoglobin scavenger receptor CD163. HO-1 and CD163 proteins were also increased in symptomatic CPs and associated with intraplaque iron deposits, which, however, did not correlate with symptom status itself. ADRP, the gene for adipophilin, was also overexpressed in symptomatic CPs. Adipophilin expression was markedly increased in ulcerated CPs and colocalized with extravasated red blood cells and cholesterol crystals. Taken together, the phenotypic characteristics and the numerous possible molecular mediators of the destabilization of carotid plaques provide potential platforms for future research. The denudation of the endothelial lining observed in symptomatic CPs may lead to direct thromboembolism and maintain harmful oxidative and inflammatory processes, predispose to plaque microhemorrhages, and contribute to lipid accumulation into the plaque, thereby making it vulnerable to rupture.

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Stroke is the second leading cause of death and the leading cause of disability worldwide. Of all strokes, up to 80% to 85% are ischemic, and of these, less than 10% occur in young individuals. Stroke in young adults—most often defined as stroke occurring under the age of 45 or 50—can be particularly devastating due to long expected life-span ahead and marked socio-economic consequences. Current basic knowledge on ischemic stroke in this age group originates mostly from rather small and imprecise patient series. Regarding emergency treatment, systematic data on use of intravenous thrombolysis are absent. For this Thesis project, we collected detailed clinical and radiological data on all consecutive patients aged 15 to 49 with first-ever ischemic stroke between 1994 and 2007 treated at the Helsinki University Central Hospital. The aims of the study were to define demographic characteristics, risk factors, imaging features, etiology, and long-term mortality and its predictors in this patient population. We additionally sought to investigate, whether intravenous thrombolysis is safe and beneficial for the treatment of acute ischemic stroke in the young. Of our 1008 patients, most were males (ratio 1.7:1), who clearly outnumbered females after the age of 44, but females were preponderant among those aged <30. Occurrence increased exponentially. The most frequent risk factors were dyslipidemia (60%), smoking (44%), and hypertension (39%). Risk factors accumulated in males and along aging. Cardioembolism (20%) and cervicocerebral artery dissection (15%) were the most frequent etiologic subgroups, followed by small-vessel disease (14%), and large-artery atherosclerosis (8%). A total of 33% had undetermined etiology. Left hemisphere strokes were more common in general. Posterior circulation infarcts were more common among those aged <45. Multiple brain infarcts were present in 23% of our patients, 13% had silent infarcts, and 5% had leukoaraiosis. Of those with silent brain infarcts, majority (54%) had only a single lesion, and most of the silent strokes were located in basal ganglia (39%) and subcortical regions (21%). In a logistic regression analysis, type 1 diabetes mellitus in particular predicted the presence of both silent brain infarcts (odds ratio 5.78, 95% confidence interval 2.37-14.10) and leukoaraiosis (9.75; 3.39-28.04). We identified 48 young patients with hemispheric ischemic stroke treated with intravenous tissue plasminogen activator, alteplase. For comparisons, we searched 96 untreated control patients matched by age, gender, and admission stroke severity, as well as 96 alteplase-treated older controls aged 50 to 79 matched by gender and stroke severity. Alteplase-treated young patients recovered more often completely (27% versus 10%, P=0.010) or had only mild residual symptoms (40% versus 22%, P=0.025) compared to age-matched controls. None of the alteplase-treated young patients had symptomatic intracerebral hemorrhage or died within 3-month follow-up. Overall long-term mortality was low in our patient population. Cumulative mortality risks were 2.7% (95% confidence interval 1.5-3.9%) at 1 month, 4.7% (3.1-6.3%) at 1 year, and 10.7% (9.9-11.5%) at 5 years. Among the 30-day survivors who died during the 5-year follow-up, more than half died due to vascular causes. Malignancy, heart failure, heavy drinking, preceding infection, type 1 diabetes, increasing age, and large-artery atherosclerosis causing the index stroke independently predicted 5-year mortality when adjusted for age, gender, relevant risk factors, stroke severity, and etiologic subtype. In sum, young adults with ischemic stroke have distinct demographic patterns and they frequently harbor traditional vascular risk factors. Etiology in the young is extremely diverse, but in as many as one-third the exact cause remains unknown. Silent brain infarcts and leukoaraiosis are not uncommon brain imaging findings in these patients and should not be overlooked due to their potential prognostic relevance. Outcomes in young adults with hemispheric ischemic stroke can safely be improved with intravenous thrombolysis. Furthermore, despite their overall low risk of death after ischemic stroke, several easily recognizable factors—of which most are modifiable—predict higher mortality in the long term in young adults.