Browsing by Title

Sort by: Order: Results:

Now showing items 562-581 of 1593
  • Strandin, Tomas (Helsingin yliopisto, 2011)
    Hantaviruses (family Bunyaviridae, genus Hantavirus) are enveloped viruses incorporating a segmented, negative-sense RNA genome. Each hantavirus is carried by its specific host, either a rodent or an insectivore (shrew), in which the infection is asymptomatic and persistent. In humans, hantaviruses cause Hemorrhagic fever with renal syndrome (HFRS) in Eurasia and Hantavirus cardiopulmonary syndrome (HCPS) in the Americas. In Finland, Puumala virus (genus Hantavirus) is the causative agent of NE, a mild form of HFRS. The HFRS-type diseases are often associated with renal failure and proteinuria that might be mechanistically explained by infected kidney tubular cell degeneration in patients. Previously, it has been shown that non-pathogenic hantavirus, Tula virus (TULV), could cause programmed cell death, apoptosis, in cell cultures. This suggested that the infected kidney tubular degeneration could be caused directly by virus replication. In the first paper of this thesis the molecular mechanisms involved in TULV-induced apoptosis was further elucidated. A virus replication-dependent down-regulation of ERK1/2, concomitantly with the induced apoptosis, was identified. In addition, this phenomenon was not restricted to TULV or to non-pathogenic hantaviruses in general since also a pathogenic hantavirus, Seoul virus, could inhibit ERK1/2 activity. Hantaviruses consist of membrane-spanning glycoproteins Gn and Gc, RNA-dependent RNA polymerase (L protein) and nucleocapsid protein N, which encapsidates the viral genome, and thus forms the ribonucleoprotein (RNP). Interaction between the cytoplasmic tails of viral glycoproteins and RNP is assumed to be the only means how viral genetic material is incorporated into infectious virions. In the second paper of this thesis, it was shown by immunoprecipitation that viral glycoproteins and RNP interact in the purified virions. It was further shown that peptides derived from the cytoplasmic tails (CTs) of both Gn and Gc could bind RNP and recombinant N protein. In the fourth paper the cytoplamic tail of Gn but not Gc was shown to interact with genomic RNA. This interaction was probably rather unspecific since binding of Gn-CT with unrelated RNA and even single-stranded DNA were also observed. However, since the RNP consists of both N protein and N protein-encapsidated genomic RNA, it is possible that the viral genome plays a role in packaging of RNPs into virions. On the other hand, the nucleic acid-binding activity of Gn may have importance in the synthesis of viral RNA. Binding sites of Gn-CT with N protein or nucleic acids were also determined by peptide arrays, and they were largely found to overlap. The Gn-CT of hantaviruses contain a conserved zinc finger (ZF) domain with an unknown function. Some viruses need ZFs in entry or post-entry steps of the viral life cycle. Cysteine residues are required for the folding of ZFs by coordinating zinc-ions, and alkylation of these residues can affect virus infectivity. In the third paper, it was shown that purified hantavirions could be inactivated by treatment with cysteine-alkylating reagents, especially N-ethyl maleimide. However, the effect could not be pin-pointed to the ZF of Gn-CT since also other viral proteins reacted with maleimides, and it was, therefore, impossible to exclude the possibility that other cysteines besides those that were essential in the formation of ZF are required for hantavirus infectivity.
  • Korpela, Antti (Helsingin yliopisto, 2000)
  • Sarvikivi, Emmi (Helsingin yliopisto, 2008)
    Healthcare-associated infections (HAIs) are known to increase the risk for patient morbidity and mortality in different healthcare settings and thereby to cause additional costs. HAIs typically affect patients with severe underlying conditions. HAIs are prevalent also among pediatric patients, but the distribution of the types of infection and the causative agents differ from those detected in adults. The aim of this study was to obtain information on pediatric HAIs in Finland through an assessment of the surveillance of bloodstream infections (BSIs), through two outbreak investigations in a neonatal intensive care unit (NICU), and through a study of postoperative HAIs after open-heart surgery. The studies were carried out at the Hospital for Children and Adolescents of Helsinki University Central Hospital. Epidemiological features of pediatric BSIs were assessed. For the outbreak investigations, case definitions were set and data collected from microbiological and clinical records. The antimicrobial susceptibilities of the Serratia marcescens and the Candida parapsilosis isolates were determined and they were genotyped. Patient charts were reviewed for the case-control and cohort studies during the outbreak investigations, as well as for the patients who acquired surgical site infections (SSIs) after having undergone open-heart surgery. Also a prospective postdischarge study was conducted to detect postoperative HAIs in these patients. During 1999-2006, the overall annual BSI rate was 1.6/1,000 patient days (range by year, 1.2–2.1). High rates (average, 4.9 and 3.2 BSIs/1,000 patient days) were detected in hematology and neonatology units. Coagulase-negative staphylococci were the most common pathogens both hospital-wide and in each patient group. The overall mortality was 5%. The genotyping of the 15 S. marcescens isolates revealed three independent clusters. All of the 26 C. parapsilosis isolates studied proved to be indistinguishable. The NICU was overcrowded during the S. marcescens clusters. A negative correlation between C. parapsilosis BSIs and fluconazole use in the NICU was detected, and the isolates derived from a single initially susceptible strain became less susceptible to fluconazole over time. Eighty postoperative HAIs, including all severe infections, were detected during hospitalization after open-heart surgery; 34% of those HAIs were SSIs and 25% were BSIs. The postdischarge study found 65 infections that were likely to be associated with hospitalization. The majority (89%) of them were viral respiratory or gastrointestinal infections, and these often led to rehospitalizations. The annual hospital-wide BSI rates were stable, and the significant variation detected in some units could not be seen in overall rates. Further studies with data adequately adjusted for risk factors are needed to assess BSI rates in the patient groups with the highest rates (hematology, neonatology). The outbreak investigations showed that horizontal transmission was common in the NICU. Overcrowding and lapses in hand hygiene probably contributed to the spreading of the pathogens. Following long-term use of fluconazole in the NICU, resistance to fluconazole developed in C. parapsilosis. Almost one-fourth of the patients who underwent open-heart surgery acquired at least one HAI. All severe HAIs were detected during hospitalization. The postdischarge study found numerous viral infections, which often caused rehospitalization.
  • Nieminen, Tarja (Helsingin yliopisto, 2015)
    Social capital has been widely discussed in research. An increasing amount of literature has linked social capital to various health outcomes and well-being. However, both health and social capital are complex phenomena, and there is still inconsistency in the research findings. The general aim of this study was to examine the associations between social capital, health behaviour and health among adult Finnish population. The conceptualization and operationalization of social capital varies according to discipline and level. In this study, social capital is measured at the individual level assuming that an individual s investment in group activity reflects social capital seen as a resource related to social networks and group membership. Individual benefits are accessed through social connections in varied groups and society. Thus the resources do not reside within the individual but rather in the structure of person s social networks. Social capital was measured on three dimensions in this study: 1) social support, 2) social networks and participation and 3) trust and reciprocity. The association between these dimensions and health were examined. Health was investigated as self-rated health, psychological well-being and mortality. This study utilised the data of the Health 2000 Survey conducted in 2000−2001. Of people aged 30 and over, 89% participated in the home interview and 80% in the general health examination. The study material presents the whole population unusually well. The National Institute for Health and Welfare (THL; formerly the National Public Health Institute, KTL) had the overall responsibility for the project. In addition, the project organization involved a wide range of research and funding agencies. This survey contains a rich armoury of questions about health and illnesses, health behaviour, capacity for work, functional capacity and use of health services. Furthermore, it includes a broad selection of questions used in measuring social capital. The results found an accumulation of social capital and general welfare for the same groups: the highest levels of social capital were found among the young, well-educated and married people. However, all socio-demographic subgroups seem to benefit from social capital. Regardless of all socio-demographic characteristics, high levels of social capital were associated with good health, associations which varied among different health-related behaviours, but social participation had a strong statistical association with all components of health and all health behaviours. Regardless of chronic diseases people with high levels of social capital felt healthier than those with low levels. The positive association between social capital and survival was statistically significant among men and suggestive among women. These findings indicate that social capital contributes to health. Health inequalities between population sub-groups are still substantial. Health could be promoted and health inequalities reduced by developing tools for increasing social participation especially in those groups lacking social capital−and who often also suffer from several health problems.
  • Siikamäki, Heli (Helsingin yliopisto, 2015)
    Study I analyzed Finnish travellers health problems abroad during 2010 2012. Information was drawn from a database kept by an assistance organization of insurance companies covering 95% of Finnish cases requiring aid abroad. The study included 50 710 cases. These data were compared to numbers of Finnish travellers from the Official Statistics of Finland to calculate incidences of illness and injury at various destinations. The most common diagnostic categories proved to be infections (60%) and injuries (14%); the most frequent diagnoses were acute gastroenteritis (23%) and respiratory infections (21%). Incidence was high in Africa, southern Europe plus the eastern Mediterranean, and Asia. Pre-travel counselling appears advisable also for visitors to southern Europe. Means for preventing gastrointestinal and respiratory infections are needed. Study II explored the final diagnoses of returning travellers with fever. This retrospective investigation comprised 462 febrile adults returning from malaria-endemic areas admitted to the Helsinki University Central Hospital emergency room during 2005 2009. The most common diagnostic categories were acute diarrhoeal disease (27%), systemic febrile illness (15%), and respiratory illness (15%). One traveller in four had a potentially life-threatening illness; septicemia proved as common as malaria (5% vs. 4%); one in ten had more than one diagnosis. The results suggest that the diagnostic protocol in tertiary hospital should in addition to malaria smears comprise blood cultures, influenza rapid test, and HIV test. Study III analyzed surveillance data on malaria cases reported to the National Infectious Disease Register 1995 2008 totalling 484 cases, and related them to travel statistics and antimalarial drug sales. The number of visits to malaria-endemic areas increased, whereas malaria cases did not, and a decreasing trend appeared in antimalarial drug sales. Infections were mostly acquired in Africa (76%). The most common species was Plasmodium falciparum (61%). Of all cases, 42% proved of foreign origin; in 89%, the infection was contracted in the region of birth, implying that immigrants visiting friends and relatives constitute a risk group with a particular need for pre-travel advice. Study IV analyzed in detail the background information on malaria cases diagnosed in Finland 2003 2011. The data included 265 cases, 54% of whom were born in malaria-endemic countries, and 86% currently lived in non-endemic regions. Of those born in non-endemic regions, 81% had received pre-travel advice, but only 20% of those born in endemic ones. Among travellers infected with P. falciparum, 4% reported regular use of appropriate chemoprophylaxis, yet individual rechecking by interview revealed that none had been fully compliant. These data suggest that, if taken conscientiously, mefloquine, atovaquone/proguanil, and doxycycline are effective as chemoprophylaxis against P. falciparum malaria.
  • Siikamäki, Heli (Helsingin yliopisto, 2014)
    Study I analyzed Finnish travellers health problems abroad during 2010 2012. Information was drawn from a database kept by an assistance organization of insurance companies covering 95% of Finnish cases requiring aid abroad. The study included 50 710 cases. These data were compared to numbers of Finnish travellers from the Official Statistics of Finland to calculate incidences of illness and injury at various destinations. The most common diagnostic categories proved to be infections (60%) and injuries (14%); the most frequent diagnoses were acute gastroenteritis (23%) and respiratory infections (21%). Incidence was high in Africa, southern Europe plus the eastern Mediterranean, and Asia. Pre-travel counselling appears advisable also for visitors to southern Europe. Means for preventing gastrointestinal and respiratory infections are needed. Study II explored the final diagnoses of returning travellers with fever. This retrospective investigation comprised 462 febrile adults returning from malaria-endemic areas admitted to the Helsinki University Central Hospital emergency room during 2005 2009. The most common diagnostic categories were acute diarrhoeal disease (27%), systemic febrile illness (15%), and respiratory illness (15%). One traveller in four had a potentially life-threatening illness; septicemia proved as common as malaria (5% vs. 4%); one in ten had more than one diagnosis. The results suggest that the diagnostic protocol in tertiary hospital should in addition to malaria smears comprise blood cultures, influenza rapid test, and HIV test. Study III analyzed surveillance data on malaria cases reported to the National Infectious Disease Register 1995 2008 totalling 484 cases, and related them to travel statistics and antimalarial drug sales. The number of visits to malaria-endemic areas increased, whereas malaria cases did not, and a decreasing trend appeared in antimalarial drug sales. Infections were mostly acquired in Africa (76%). The most common species was Plasmodium falciparum (61%). Of all cases, 42% proved of foreign origin; in 89%, the infection was contracted in the region of birth, implying that immigrants visiting friends and relatives constitute a risk group with a particular need for pre-travel advice. Study IV analyzed in detail the background information on malaria cases diagnosed in Finland 2003 2011. The data included 265 cases, 54% of whom were born in malaria-endemic countries, and 86% currently lived in non-endemic regions. Of those born in non-endemic regions, 81% had received pre-travel advice, but only 20% of those born in endemic ones. Among travellers infected with P. falciparum, 4% reported regular use of appropriate chemoprophylaxis, yet individual rechecking by interview revealed that none had been fully compliant. These data suggest that, if taken conscientiously, mefloquine, atovaquone/proguanil, and doxycycline are effective as chemoprophylaxis against P. falciparum malaria.
  • Simonsen, Nina (Helsingin yliopisto, 2013)
    Municipalities are important arenas in health promotion as many of the determinants of health relate to, and exert their influence in, local contexts. Accordingly, one key question in public-health work is how to support health promotion on the local level. The present study explores and compares health promotion actions in four medium-sized municipalities, with an emphasis on factors influencing engagement. The point of departure is the health promotion strategies described in the Ottawa Charter (WHO 1986) – the focus being on community action for health, health-promoting health services and healthy public policy – and the multilevel health promotion model (Rütten et al. 2000). The overall aim is to further enhance understanding of health promotion action in local contexts. The specific aims are to explore the role of local voluntary associations in health promotion, to compare the emphasis on health promotion in four municipalities with different forms of primary healthcare service production, and, especially, to identify factors associated with comprehensive health promotion action and with health policy impact (effective health promotion actions). The study – part of an evaluation of the production model of primary healthcare in four municipalities in the southern part of Finland – is based on cross-sectional surveys conducted in the four municipalities in 2000, 2002 and 2004 and including all registered local voluntary associations (LVAs), primary healthcare (PHC) personnel (including services for older people) and local politicians. The data were analysed by means of descriptive statistics as well as logistic and linear regression analysis. The findings suggest that a fair proportion of LVAs are interested in action for community health and could be seen as a resource for health promotion in local contexts. There was agreement that the promotion of residents’ health requires cooperation between municipal agencies and LVAs, although cooperation was not particularly strongly emphasized in municipal budget and action plans according to the politicians. Cooperation with municipal agencies was independently associated with LVA engagement in health promotion. PHC personnel appear to be engaged in health promotion primarily on an individual basis. On all three levels (individual, group and population) it was most prevalent in ambulatory care. This was also true in the case of comprehensive action, as well as when health promotion was conceptualized as addressing risk behaviour. There were some differences between the municipalities in terms of level of engagement; the respondents' focus in health promotion and varying opportunities for cooperation are two potential explanations for these differences. Moreover, variables reflecting all the proposed determinants (organizational values, competence and opportunities) were independently associated with the PHC personnel’s engagement in comprehensive health promotion action. These included working conditions that are conducive to health promotion such as being able to use one’s skills and knowledge, and having possibilities for reflection and learning as well as collegial support; knowledge about residents’ health and living conditions; and opportunities to cooperate with partners outside the organization. Similarly, perceived competence and a value orientation towards health as well as opportunities for community participation were independently associated with LVA engagement in comprehensive health promotion action. In addition to the determinants in the theoretical model, the municipality had an influence. There were no inter-municipality differences in the politicians’ evaluations of health promotion actions and their effectiveness (health policy impact). In terms of impact, an emphasis on promoting health and quality of life among older people and the resources (in the form of capacity of PHC and care for older people) were among the most significant elements of health promotion policy on the local level. Contrary to expectations, opportunities for community participation were not associated with the evaluations. The findings reinforce the value of empowerment, community participation and intersectoral cooperation – in other words the principles of health promotion – in the context of Finnish municipalities, providing further evidence as well as highlighting their significance for engagement in health promotion action. The study also provides novel empirical confirmation concerning the applicability of the multilevel health promotion model to the actions of different actors in municipalities, in other words in local contexts. In support of action on the local level, the findings – the equally strong associations of organizational values, competence and opportunities with engagement in health promotion – suggest the need for a multilevel approach. However, local policy makers may need more evidence concerning the impact of cooperation and community participation.
  • Saarni, Samuli (Helsingin yliopisto, 2008)
    Quality of life (QoL) and Health-related quality of life (HRQoL) are becoming one of the key outcomes of health care due to increased respect for the subjective valuations and well-being of patients and an increasing part of the ageing population living with chronic, non-fatal conditions. Preference-based HRQoL measures enable estimation of health utility, which can be useful for rational rationing, evidence-based medicine and health policy. This study aimed to compare the individual severity and public health burden of major chronic conditions in Finland, including and focusing on reliably diagnosed psychiatric conditions. The study is based on the Health 2000 survey, a representative general population survey of 8028 Finns aged 30 and over. Depressive, anxiety and alcohol use disorders were diagnosed with the Composite International Diagnostic Interview (M-CIDI). HRQoL was measured with the 15D and the EQ-5D, with 83% response rate. This study found that people with psychiatric disorders had the lowest 15D HRQoL scores at all ages, in comparison to other main groups of chronic conditions. Considering 29 individual conditions, three of the four most severe (on 15D) were psychiatric disorders; the most severe was Parkinson s disease. Of the psychiatric disorders, chronic conditions that have sometimes been considered relatively mild - dysthymia, agoraphobia, generalized anxiety disorder and social phobia - were found to be the most severe. This was explained both by the severity of the impact of these disorders on mental health domains of HRQoL, and also by the fact that decreases were widespread on most dimensions of HRQoL. Considering the public health burden of conditions, musculoskeletal disorders were associated with the largest burden, followed by psychiatric disorders. Psychiatric disorders were associated with the largest burden at younger ages. Of individual conditions, the largest burden found was for depressive disorders, followed by urinary incontinence and arthrosis of the hip and knee. The public health burden increased greatly with age, so the ageing of the Finnish population will mean that the disease burden caused by chronic conditions will increase by a quarter up to year 2040, if morbidity patterns do not change. Investigating alcohol consumption and HRQoL revealed that although abstainers had poorer HRQoL than moderate drinkers, this was mainly due to many abstainers being former drinkers and having the poorest HRQoL. Moderate drinkers did not have significantly better HRQoL than abstainers who were not former drinkers. Psychiatric disorders are associated with a large part of the non-fatal disease burden in Finland. In particular anxiety disorders appear to be more severe and have a larger public health burden than previously thought.
  • Laas, Karin (Helsingin yliopisto, 2009)
    Rheumatoid arthritis (RA) and other chronic inflammatory joint diseases already begin to affect patients health-related quality of life (HRQoL) in the earliest phases of these diseases. In treatment of inflammatory joint diseases, the last two decades have seen new strategies and treatment options introduced. Treatment is started at an earlier phase; combinations of disease-modifying anti-rheumatic drugs (DMARDs) and corticosteroids are used; and in refractory cases new drugs such as tumour necrosis factor (TNF) inhibitors or other biologicals can be started. In patients with new referrals to the Department of Rheumatology of the Helsinki University Central Hospital, we evaluated the 15D and the Stanford Health Assessment Questionnaire (HAQ) results at baseline and approximately 8 months after their first visit. Altogether the analysis included 295 patients with various rheumatic diseases. The mean baseline 15D score (0.822, SD 0.114) was significantly lower than for the age-matched general population (0.903, SD 0.098). Patients with osteoarthritis (OA) and spondyloarthropathies (SPA) reported the poorest HRQoL. In patients with RA and reactive arthritis (ReA) the HRQoL improved in a statistically significant manner during the 8-month follow-up. In addition, a clinically important change appeared in patients with systemic rheumatic diseases. HAQ score improved significantly in patients with RA, arthralgia and fibromyalgia, and ReA. In a study of 97 RA patients treated either with etanercept or adalimumab, we assessed their HRQoL with the RAND 36-Item Health Survey 1.0 (RAND-36) questionnaire. We also analysed changes in clinical parameters and the HAQ. With etanercept and adalimumab, the values of all domains in the RAND-36 questionnaire increased during the first 3 months. The efficacy of each in improving HRQoL was statistically significant, and the drug effects were comparable. Compared to Finnish age- and sex-matched general population values, the HRQoL of the RA patients was significantly lower at baseline and, despite the improvement, remained lower also at follow-up. Our RA patients had long-standing and severe disease that can explain the low HRQoL also at follow-up. In a pharmacoeconomic study of patients treated with infliximab we evaluated medical and work disability costs for patients with chronic inflammatory joint disease during one year before and one year after institution of infliximab treatment. Clinical and economic data for 96 patients with different arthritis diagnoses showed, in all patients, significantly improved clinical and laboratory variables. However, the medical costs increased significantly during the second period by 12 015 (95% confidence interval, 6 496 to 18 076). Only a minimal decrease in work disability costs occurred mean decrease 130 (-1 268 to 1 072). In a study involving a switch from infliximab to etanercept, we investigated the clinical outcome in 49 patients with RA. Reasons for switching were in 42% failure to respond by American College of Rheumatology (ACR) 50% criteria; in 12% adverse event; and in 46% non-medical reasons although the patients had responded to infliximab. The Disease Activity Score with 28 joints examined (DAS28) allowed us to measure patients disease activity and compare outcome between groups based on the reason for switching. In the patients in whom infliximab was switched to etanercept for nonmedical reasons, etanercept continued to suppress disease activity effectively, and 1-year drug survival for etanercept was 77% (95% CI, 62 to 97). In patients in the infliximab failure and adverse event groups, DAS28 values improved significantly during etanercept therapy. However, the 1-year drug survival of etanercept was only 43% (95% CI, 26 to 70) and 50% (95% CI, 33 to 100), respectively. Although the HRQoL of patients with inflammatory joint diseases is significantly lower than that of the general population, use of early and aggressive treatment strategies including TNF-inhibitors can improve patients HRQoL effectively. Further research is needed in finding new treatment strategies for those patients who fail to respond or lose their response to TNF-inhibitors.
  • Kaukua, Jarmo (Helsingin yliopisto, 2004)
  • Haapamäki, Johanna (Helsingin yliopisto, 2011)
    Health-related quality of life (HRQoL) measurement has become an important outcome in treatment trials and in health policy decisions. HRQoL can be measured by using generic or disease-specific tools. Generic instruments can be used for comparing health status among patients in different health states and conditions but they do not focus specifically on the issues relevant in a particular disease. Disease-specific tools may be more responsive to changes within a specific condition. In earlier studies, impairment of HRQoL has been evident in patients with inflammatory bowel disease (IBD), especially when the disease is active. Data about the impact of comorbidity or demographic characteristics of the patients on HRQoL are partly controversial. This study, which comprised 2913 adult IBD patients, examined HRQoL using the disease-specific IBDQ and the general 15D instruments. The 15D scores of IBD patients were compared with scores of a gender and age matched general population sample. Frequency of IBD symptoms and arrangement of therapy were studied and compared with those of IBD patients in an earlier European study. Furthermore, data of other chronic diseases of the patients were obtained from the Social Insurance Institution s reimbursement register and comorbidity of IBD patients was compared with that of age and gender matched controls. --- Of the respondents, 37% reported that they suffered from disturbing IBD symptoms weekly. In 17% of the patients, the symptoms greatly affected the ability to enjoy leisure activities, and 14% stated that these symptoms greatly affected their capacity to work. Despite that, the great majority (93%) of patients expressed satisfaction with their current treatment, which exceeded the rate observed in the other European patients. The mean IBDQ score was 163, as the possible range is 32-224, and disease activity was strongly correlated with HRQoL. Older age, comorbid diseases, and female gender were also related to impairment of HRQoL. Lower HRQoL scores were seen also in newly-diagnosed patients and in those with a history of surgery, especially after stoma or ileal pouch-anal anastomosis (IPAA) operation. The range of 15D scores was 0.30-1.00, with mean of 0.87. As with the IBDQ, disease activity, older age and history of surgery were correlated with the score. Both the newly-diagnosed patients and patients with a long-lasting disease had lower scores than average even after adjusting for age. The 15D scores of IBD patients were significantly lower than those of the control group. A strong correlation was seen between the 15D and the IBDQ scores. Comorbidity with other chronic diseases was observed in 29% of IBD patients. Connective tissue diseases, chronic obstructive pulmonary diseases, pernicious anaemia, and coronary heart disease (CHD) were significantly increased in patients with IBD. Especially female IBD patients appeared to be at increased risk for CHD, and patients who reported weekly IBD symptoms had a higher risk for having other chronic diseases in addition to IBD. Comorbidity impaired HRQoL, as measured with both generic and disease-specific tools. In conclusion, HRQoL is impaired in IBD patients. An understanding of predictors of HRQoL will help to recognise patients who will need special support.
  • Nihtilä, Annamari (Helsingin yliopisto, 2014)
    A reform to Dental Care legislation in 2002 abolished age limits restricting adults use of public dental services in Finland. This Dental Reform aimed to increase equity by improving adults´ access to care and reducing cost barriers. The adult population´s increased demand for dental care put pressure on the Public Dental Service (PDS). The aim of this study was to compare heavy and low use of dental services in the PDS of Espoo in order to identify reasons for heavy use and to suggest improvements to care provision. This study is based on register data. All patients who had visited the PDS of Espoo in 2004 (n=63 850) were divided into two groups: children and adolescents and adults. Within each group, all patients who had made six or more dental visits to the PDS in 2004 were defined as heavy users of oral health services and all the patients who had had three or fewer visits as low users. A random sample of 320 adult patients and a 245 children and adolescent patients was drawn from each group. All adult heavy and low consumers of dental services identified in 2004, were followed for five years. Information on age, sex, number and types of visits, oral health status and treatment provided was collected from treatment records. Seven per cent of the children and adolescents in 2004 could be classified as heavy users and the main reasons of heavy use were high numbers of orthodontic treatment occasions provided by dentists and high numbers of decayed teeth in a small number of children. For adults, 10% were heavy users. A need for complicated treatment, dentists´ and dental hygienists´ lack of experience of adult dental care and lack of specialist resulted in high numbers of visits for these patients. The adult heavy users were older and had lower social status than low users. Of these baseline adult heavy users 11% persisted as chronic frequent users during 2005-2009. Typical for adult heavy use in the baseline and the follow-up study was a lack of proper examinations, poor quality of periodontal diagnosis, lack of preventive care, and a cycle of repetitive repair or replacement of restorations, often as emergency treatment. Fixed prosthetic treatment was seldom used in the PDS of Espoo. The PDS should seek to early identify possible heavy users and they should be offered a comprehensive approach to treatment and a responsible team of a dentist and dental hygienist. In order to manage adult dental health effectively, the PDS should encourage regular examinations, treatment plans and recall visits based on patients´ oral health and risk factors.
  • Koskenpato, Jari (Helsingin yliopisto, 2001)
  • Salomaa-Räsänen, Anniina (Helsingfors universitet, 2008)
    Helicobacter pylori (H. pylori) causes a life long infection on the gastric mucosa which can lead to peptic ulcers and premalignant and malignant conditions. The infection, mainly acquired in childhood, rarely resolves spontaneously. Timely eradication of H. pylori improves dramatically the prognosis of peptic ulcer disease and seems to prevent subsequent gastric malignancies. We started in the primary health care practice in Vammala, Finland, a unique population-based, voluntary 'screen-and-treat' H. pylori pilot study in 1994. In 1996 the study was extended to include all inhabitants aged 15 to 40 years and in 1997-2000 all inhabitants aged 15 and 45 years; the participitation rate was 75%. Altogether 4626 subjects were screened for H. pylori infection using serology. All infected ones were offered eradication therapy. The eradication rates were 82.2% per-protocol and 71.9% in intention-to-treat analysis among the 3326 15 to 40-year-old participants in 1996. H. pylori seroprevalence rates were calculated to have decreased from 12% to 4% among them. Differences between H. pylori antibody-positive and -negative subjects and risk factors for H. pylori infection were studied using a questionnaire. In multivariate analysis, crowding in the childhood household, low education of the mother, smoking and alcohol consumption, unfavourable housing conditions, and sick leave due to dyspepsia were associated with H. pylori infection. We determined in different age-groups the accuracy of H. pylori IgG and IgA antibody tests used in the 'screen-and-treat' programme, with special emphasis on the presence of atrophic gastritis. In 561 consecutive adult patients who underwent gastroscopy for clinical indications the IgG test was highly sensitive (99%) in all age groups. The specificity was 99% in subjects aged 15- 49, and high also in those aged 50-64 and those aged 65 or older (97% and 93%, respectively), when patients with atrophic gastritis were excluded. Both IgA and CagA antibody responses during H. pylori infection have been found to be associated with an increased risk of peptic ulcers and gastric malignancies. By reanalysing paired serum samples collected with two decade’s interval from 560 subjects we found that the increase in the prevalence of IgA antibodies with age was due not only to the birth cohort phenomenon and seroconverters, but also to increasing IgA antibody levels during infection. The change in the prevalence of CagA antibodies was studied by reanalysing sera collected from 408 subjects in 1973 and from 503 subjects in 1994. The proportion of subjects infected with CagA+ H. pylori strains had declined faster than that of subjects infected with CagA- H. pylori strains, while the overall prevalence of H. pylori had declined.
  • Koivisto, Tarmo (Helsingin yliopisto, 2008)
    Background: Helicobacter pylori infection is usually acquired in early childhood and is rarely resolved spontaneously. Eradication therapy is currently recommended virtually to all patients. While the first and second therapies are prescribed without knowing the antibiotic resistance of the bacteria, it is important to know the primary resistance in the population. Aim: This study evaluates the primary resistance of H. pylori among patients in primary health care throughout Finland, the efficacy of three eradication regimens, the symptomatic response to successful therapy, and the effect of smoking on gastric histology and humoral response in H. pylori-positive patients. Patients and methods: A total of 23 endoscopy referral centres located throughout Finland recruited 342 adult patients with positive rapid urease test results, who were referred to upper gastrointestinal endoscopy from primary health care. Gastric histology, H. pylori resistance and H. pylori serology were evaluated. The patients were randomized to receive a seven-day regimen, comprising 1) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and metronidazole 400 mg t.d. (LAM), 2) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and clarithromycin 500 mg b.d. (LAC) or 3) ranitidine bismuth citrate 400 mg b.d., metronidazole 400 mg t.d. and tetracycline 500 mg q.d. (RMT). The eradication results were assessed, using the 13C-urea breath test 4 weeks after therapy. The patients completed a symptom questionnaire before and a year after the therapy. Results: Primary resistance of H. pylori to metronidazole was 48% among women and 25% among men. In women, metronidazole resistance correlated with previous use of antibiotics for gynaecologic infections and alcohol consumption. Resistance rate to clarithromycin was only 2%. Intention-to-treat cure rates of LAM, LAC, and RMT were 78%, 91% and 81%. While in metronidazole-sensitive cases the cure rates with LAM, LAC and RMT were similar, in metronidazole resistance LAM and RMT were inferior to LAC (53%, 67% and 84%). Previous antibiotic therapies reduced the efficacy of LAC, to the level of RMT. Dyspeptic symptoms in the Gastrointestinal Symptoms Rating Scale (GSRS) were decreased by 30.5%. In logistic regression analysis, duodenal ulcer, gastric antral neutrophilic inflammation and age from 50 to 59 years independently predicted greater decrease in dyspeptic symptoms. In the gastric body, smokers had milder inflammation and less atrophy and in the antrum denser H. pylori load. Smokers also had lower IgG antibody titres against H. pylori and a smaller proportional decrease in antibodies after successful eradication. Smoking tripled the risk of duodenal ulcers. Conclusions: in Finland H. pylori resistance to clarithromycin is low, but metronidazole resistance among women is high making metronidazole-based therapies unfavourable. Thus, LAC is the best choice for first-line eradication therapy. The effect of eradication on dyspeptic symptoms was only modest. Smoking slows the progression of atrophy in the gastric body.
  • Gekas, Christos (Helsingin yliopisto, 2008)
    The continuous production of blood cells, a process termed hematopoiesis, is sustained throughout the lifetime of an individual by a relatively small population of cells known as hematopoietic stem cells (HSCs). HSCs are unique cells characterized by their ability to self-renew and give rise to all types of mature blood cells. Given their high proliferative potential, HSCs need to be tightly regulated on the cellular and molecular levels or could otherwise turn malignant. On the other hand, the tight regulatory control of HSC function also translates into difficulties in culturing and expanding HSCs in vitro. In fact, it is currently not possible to maintain or expand HSCs ex vivo without rapid loss of self-renewal. Increased knowledge of the unique features of important HSC niches and of key transcriptional regulatory programs that govern HSC behavior is thus needed. Additional insight in the mechanisms of stem cell formation could enable us to recapitulate the processes of HSC formation and self-renewal/expansion ex vivo with the ultimate goal of creating an unlimited supply of HSCs from e.g. human embryonic stem cells (hESCs) or induced pluripotent stem cells (iPS) to be used in therapy. We thus asked: How are hematopoietic stem cells formed and in what cellular niches does this happen (Papers I, II)? What are the molecular mechanisms that govern hematopoietic stem cell development and differentiation (Papers III, IV)? Importantly, we could show that placenta is a major fetal hematopoietic niche that harbors a large number of HSCs during midgestation (Paper I)(Gekas et al., 2005). In order to address whether the HSCs found in placenta were formed there we utilized the Runx1-LacZ knock-in and Ncx1 knockout mouse models (Paper II). Importantly, we could show that HSCs emerge de novo in the placental vasculature in the absence of circulation (Rhodes et al., 2008). Furthermore, we could identify defined microenvironmental niches within the placenta with distinct roles in hematopoiesis: the large vessels of the chorioallantoic mesenchyme serve as sites of HSC generation whereas the placental labyrinth is a niche supporting HSC expansion (Rhodes et al., 2008). Overall, these studies illustrate the importance of distinct milieus in the emergence and subsequent maturation of HSCs. To ensure proper function of HSCs several regulatory mechanisms are in place. The microenvironment in which HSCs reside provides soluble factors and cell-cell interactions. In the cell-nucleus, these cell-extrinsic cues are interpreted in the context of cell-intrinsic developmental programs which are governed by transcription factors. An essential transcription factor for initiation of hematopoiesis is Scl/Tal1 (stem cell leukemia gene/T-cell acute leukemia gene 1). Loss of Scl results in early embryonic death and total lack of all blood cells, yet deactivation of Scl in the adult does not affect HSC function (Mikkola et al., 2003b. In order to define the temporal window of Scl requirement during fetal hematopoietic development, we deactivated Scl in all hematopoietic lineages shortly after hematopoietic specification in the embryo . Interestingly, maturation, expansion and function of fetal HSCs was unaffected, and, as in the adult, red blood cell and platelet differentiation was impaired (Paper III)(Schlaeger et al., 2005). These findings highlight that, once specified, the hematopoietic fate is stable even in the absence of Scl and is maintained through mechanisms that are distinct from those required for the initial fate choice. As the critical downstream targets of Scl remain unknown, we sought to identify and characterize target genes of Scl (Paper IV). We could identify transcription factor Mef2C (myocyte enhancer factor 2 C) as a novel direct target gene of Scl specifically in the megakaryocyte lineage which largely explains the megakaryocyte defect observed in Scl deficient mice. In addition, we observed an Scl-independent requirement of Mef2C in the B-cell compartment, as loss of Mef2C leads to accelerated B-cell aging (Gekas et al. Submitted). Taken together, these studies identify key extracellular microenvironments and intracellular transcriptional regulators that dictate different stages of HSC development, from emergence to lineage choice to aging.
  • Lakkisto, Päivi (Helsingin yliopisto, 2010)
    Myocardial infarction (MI) and heart failure are major causes of morbidity and mortality worldwide. Treatment of MI involves early restoration of blood flow to limit infarct size and preserve cardiac function. MI leads to left ventricular remodeling, which may eventually progress to heart failure, despite the established pharmacological treatment of the disease. To improve outcome of MI, new strategies for protecting the myocardium against ischemic injury and enhancing the recovery and repair of the infarcted heart are needed. Heme oxygenase-1 (HO-1) is a stress-responsive and cytoprotective enzyme catalyzing the degradation of heme into the biologically active reaction products biliverdin/bilirubin, carbon monoxide (CO) and free iron. HO-1 plays a key role in maintaining cellular homeostasis by its antiapoptotic, anti-inflammatory, antioxidative and proangiogenic properties. The present study aimed, first, at evaluating the role of HO-1 as a cardioprotective and prohealing enzyme in experimental rat models and at investigating the potential mechanisms mediating the beneficial effects of HO-1 in the heart. The second aim was to evaluate the role of HO-1 in 231 critically ill intensive care unit (ICU) patients by investigating the association of HO-1 polymorphisms and HO-1 plasma concentrations with illness severity, organ dysfunction and mortality throughout the study population and in the subgroup of cardiac patients. We observed in an experimental rat MI model, that HO-1 expression was induced in the infarcted rat hearts, especially in the infarct and infarct border areas. In addition, pre-emptive HO-1 induction and CO donor pretreatment promoted recovery and repair of the infarcted hearts by differential mechanisms. CO promoted vasculogenesis and formation of new cardiomyocytes by activating c-kit+ stem/progenitor cells via hypoxia-inducible factor 1 alpha, stromal cell-derived factor 1 alpha (SDF-1a) and vascular endothelial growth factor B, whereas HO-1 promoted angiogenesis possibly via SDF-1a. Furthermore, HO-1 protected the heart in the early phase of infarct healing by increasing survival and proliferation of cardiomyocytes. The antiapoptotic effect of HO-1 persisted in the late phases of infarct healing. HO-1 also modulated the production of extracellular matrix components and reduced perivascular fibrosis. Some of these beneficial effects of HO-1 were mediated by CO, e.g. the antiapoptotic effect. However, CO may also have adverse effects on the heart, since it increased the expression of extracellular matrix components. In isolated perfused rat hearts, HO-1 induction improved the recovery of postischemic cardiac function and abrogated reperfusion-induced ventricular fibrillation, possibly in part via connexin 43. We found that HO-1 plasma levels were increased in all critically ill patients, including cardiac patients, and were associated with the degree of organ dysfunction and disease severity. HO-1 plasma concentrations were also higher in ICU and hospital nonsurvivors than in survivors, and the maximum HO-1 concentration was an independent predictor of hospital mortality. Patients with the HO-1 -413T/GT(L)/+99C haplotype had lower HO-1 plasma concentrations and lower incidence of multiple organ dysfunction. However, HO-1 polymorphisms were not associated with ICU or hospital mortality. The present study shows that HO-1 is induced in response to stress in both experimental animal models and severely ill patients. HO-1 played an important role in the recovery and repair of infarcted rat hearts. HO-1 induction and CO donor pretreatment enhanced cardiac regeneration after MI, and HO-1 may protect against pathological left ventricular remodeling. Furthermore, HO-1 induction potentially may protect against I/R injury and cardiac dysfunction in isolated rat hearts. In critically ill ICU patients, HO-1 plasma levels correlate with the degree of organ dysfunction, disease severity, and mortality, suggesting that HO-1 may be useful as a marker of disease severity and in the assessment of outcome of critically ill patients.
  • Karhunen, Janne (Helsingin yliopisto, 2014)
    Sudden hemodynamic collapse after coronary artery bypass surgery is a major complication associated with high mortality and morbidity. There are many well-established risk stratification systems to assess the risk of mortality and morbidity after cardiac surgery. These risk scores, however, do not predict severe immediate postoperative complications such as sudden hemodynamic collapse. This study is based on analysis of patients who suffered from hemodynamic collapse early after coronary artery bypass surgery between 1988 and 1999 in Helsinki University Hospital. One matched control patient was selected for every study patient. Patients, who died, underwent a medico-legal autopsy and a rubber cast angiography to reveal possible surgical errors in myocardial revascularization. Patients still alive in 2009 were traced with respect to mortality data and a health-related quality of life questionnaire was sent to the patients and to the controls. In addition, a comparison was made between patients who suffered from postoperative hemodynamic collapse and patients who underwent a postoperative angiography due to persistent myocardial ischemia. Angiography was introduced in 2000 and this patient series was collected prospectively between 2000 and 2007. This thesis consists of four studies. The specific goals were to explore predictive factors of sudden hemodynamic collapse, to reveal the possible surgical errors that led to hemodynamic collapse and fatal outcome with the means of an autopsy, to find out the impact that postoperative angiography has on the incidence of hemodynamic collapse, and the rate of mortality, and morbidity of patients, and to investigate the quality of life of patients surviving hemodynamic collapse in comparison with an age- and sex-matched national reference population. The results suggest the following: Sudden hemodynamic collapse after CABG is a major complication with high mortality. Inadequate tissue perfusion, postoperative myocardial ischemia, and increased need for inotropic as well as mechanical support are predictive of hemodynamic collapse. Technical graft complications are a major underlying cause of postoperative hemodynamic collapse. Post-mortem angiography improves the accuracy of diagnostics of graft complications. The cause of death could be established in every case. Use of early postoperative angiography in case of hemodynamic compromise or myocardial ischemia reduces the rate of emergency reoperations and decreases morbidity and mortality. It also allows treatment with intravascular medication. Patients who survive hemodynamic collapse and emergency reoperations have a similar prognosis as matched control patients. Health-related quality of life that is also comparable with age- and sex-matched national reference population as long as 15 years postoperatively.