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  • Laurila, Jouni (Helsingin yliopisto, 2002)
  • Leppä, Elli (Helsingin yliopisto, 2011)
    Neurons can be divided into various classes according to their location, morphology, neurochemical identity and electrical properties. They form complex interconnected networks with precise roles for each cell type. GABAergic neurons expressing the calcium-binding protein parvalbumin (Pv) are mainly interneurons, which serve a coordinating function. Pv-cells modulate the activity of principal cells with high temporal precision. Abnormalities of Pv-interneuron activity in cortical areas have been linked to neuropsychiatric illnesses such as schizophrenia. Cerebellar Purkinje cells are known to be central to motor learning. They are the sole output from the layered cerebellar cortex to deep cerebellar nuclei. There are still many open questions about the precise role of Pv-neurons and Purkinje cells, many of which could be answered if one could achieve rapid, reversible cell-type specific modulation of the activity of these neurons and observe the subsequent changes at the whole-animal level. The aim of these studies was to develop a novel method for the modulation of Pv-neurons and Purkinje cells in vivo and to use this method to investigate the significance of inhibition in these neuronal types with a variety of behavioral experiments in addition to tissue autoradiography, electrophysiology and immunohistochemistry. The GABA(A) receptor γ2 subunit was ablated from Pv-neurons and Purkinje cells in four separate mouse lines. Pv-Δγ2 mice had wide-ranging behavioral alterations and increased GABA-insensitive binding indicative of an altered GABA(A) receptor composition, particularly in midbrain areas. PC-Δγ2 mice experienced little or no motor impairment despite the lack of inhibition in Purkinje cells. In Pv-Δγ2-partial rescue mice, a reversal of motor and cognitive deficits was observed in addition to restoration of the wild-type γ2F77 subunit to the reticular nucleus of thalamus and the cerebellar molecular layer. In PC-Δγ2-swap mice, zolpidem sensitivity was restored to Purkinje cells and the administration of systemic zolpidem evoked a transient motor impairment. On the basis of these results, it is concluded that this new method of cell-type specific modulation is a feasible way to modulate the activity of selected neuronal types. The importance of Purkinje cells to motor control supports previous studies, and the crucial involvement of Pv-neurons in a range of behavioral modalities is confirmed.
  • Uhlenius, Nina (Helsingin yliopisto, 2002)
  • von Schantz-Fant, Carina (Helsingin yliopisto, 2009)
    Neuronal ceroid lipofuscinoses (NCLs) are a family of inherited pediatric neurodegenerative disorders, leading to retinal degeneration, death of selective neuronal populations and accumulation of autofluorscent ceroid-lipopigments. The clinical manifestations are generally similar in all forms. The Finnish variant late infantile neuronal ceroid lipofuscinosis (vLINCLFin) is a form of NCL, especially enriched in the Finnish population. The aim of this thesis was to analyse the brain pathology of vLINCLFin utilising the novel Cln5-/- mouse model. Gene expression profiling of the brains of already symptomatic Cln5-/- mice revealed that inflammation, neurodegeneration and defects in myelinization are the major characteristics of the later stages of the disease. Histological characterization of the brain pathology confirmed that the thalamocortical system is affected in Cln5-/- mice, similarly to the other NCL mouse models. However, whereas the brain pathology in all other analyzed NCL mice initiate in the thalamus and spread only months later to the cortex, we observed that the sequence of events is uniquely reversed in Cln5-/- mice; beginning in the cortex and spreading to the thalamus only months later. We could also show that even though neurodegeneration is inititated in the cortex, reactive gliosis and loss of myelin are evident in specific nuclei of the thalamus already in the 1 month old brain. To obtain a deeper insight into the disturbed metabolic pathways, we performed gene expression profiling of presymptomatic mouse brains. We validated these findings with immunohistological analyses, and could show that cytoskeleton and myelin were affected in Cln5-/- mice. Comparison of gene expression profiling results of Cln5-/- and Cln1-/- mice, further highlighted that these two NCL models share a common defective pathway, leading to disturbances in the neuronal growth cone and cytoskeleton. Encouraged by the evidence of this defected pathway, we analyzed the molecular interactions of NCL-proteins and observed that Cln5 and Cln1/Ppt1 proteins interact with each other. Furthermore, we demonstrated that Cln5 and Cln1/Ppt1 share an interaction partner, the F1-ATP synthase, potentially linking both vLINCLFIN and INCL diseases to disturbed lipid metabolism. In addition, Cln5 was shown to interact with other NCL proteins; Cln2, Cln3, Cln6 and Cln8, implicating a central role for Cln5 in the NCL pathophysiology. This study is the first to describe the brain pathology and gene expression changes in the Cln5-/- mouse. Together the findings presented in this thesis represent novel information of the disease processes and the molecular mechanisms behind vLINCLFin and have highlighted that vLINCLFin forms a very important model to analyze the pathophysiology of NCL diseases.
  • Jansson, Kim (Helsingin yliopisto, 2007)
    Anterior cruciate ligament (ACL) tear is a common sports injury of the knee. Arthroscopic reconstruction using autogenous graft material is widely used for patients with ACL instability. The grafts most commonly used are the patellar and the hamstring tendons, by various fixation techniques. Although clinical evaluation and conventional radiography are routinely used in follow-up after ACL surgery, magnetic resonance imaging (MRI) plays an important role in the diagnosis of complications after ACL surgery. The aim of this thesis was to study the clinical outcome of patellar and hamstring tendon ACL reconstruction techniques. In addition, the postoperative appearance of the ACL graft was evaluated using several MRI sequences. Of the 175 patients who underwent an arthroscopically assisted ACL reconstruction, 99 patients were randomized into patellar tendon (n=51) or hamstring tendon (n=48) groups. In addition, 62 patients with hamstring graft ACL reconstruction were randomized into either cross-pin (n=31) or interference screw (n=31) fixation groups. Follow-up evaluation determined knee laxity, isokinetic muscle performance and several knee scores. Lateral and anteroposterior view radiographs were obtained. Several MRI sequences were obtained with a 1.5-T imager. The appearance and enhancement pattern of the graft and periligamentous tissue, and the location of bone tunnels were evaluated. After MRI, arthroscopy was performed on 14 symptomatic knees. The results revealed no significant differences in the 2-year outcome between the groups. In the hamstring tendon group, the average femoral and tibial bone tunnel diameter increased during 2 years follow-up by 33% and 23%, respectively. In the asymptomatic knees, the graft showed homogeneous and low signal intensity with periligamentous streaks of intermediate signal intensity on T2-weighted MR images. In the symptomatic knees, arthroscopy revealed 12 abnormal grafts and two meniscal tears, each with an intact graft. Among 3 lax grafts visible on arthroscopy, MRI showed an intact graft and improper bone tunnel placement. For diagnosing graft failure, all MRI findings combined gave a specificity of 90% and a sensitivity of 81%. In conclusion, all techniques appeared to improve patients' performance, and were therefore considered as good choices for ACL reconstruction. In follow-up, MRI permits direct evaluation of the ACL graft, the bone tunnels, and additional disorders of the knee. Bone tunnel enlargement and periligamentous tissue showing contrast enhancement were non-specific MRI findings that did not signify ACL deficiency. With an intact graft and optimal femoral bone tunnel placement, graft deficiency is unlikely, and the MRI examination should be carefully scrutinized for possible other causes for the patients symptoms.
  • Nyamdorj, Regzedmaa (Helsingin yliopisto, 2010)
    Clinical trials have shown that weight reduction with lifestyles can delay or prevent diabetes and reduce blood pressure. An appropriate definition of obesity using anthropometric measures is useful in predicting diabetes and hypertension at the population level. However, there is debate on which of the measures of obesity is best or most strongly associated with diabetes and hypertension and on what are the optimal cut-off values for body mass index (BMI) and waist circumference (WC) in this regard. The aims of the study were 1) to compare the strength of the association for undiagnosed or newly diagnosed diabetes (or hypertension) with anthropometric measures of obesity in people of Asian origin, 2) to detect ethnic differences in the association of undiagnosed diabetes with obesity, 3) to identify ethnic- and sex-specific change point values of BMI and WC for changes in the prevalence of diabetes and 4) to evaluate the ethnic-specific WC cutoff values proposed by the International Diabetes Federation (IDF) in 2005 for central obesity. The study population comprised 28 435 men and 35 198 women, ≥ 25 years of age, from 39 cohorts participating in the DECODA and DECODE studies, including 5 Asian Indian (n = 13 537), 3 Mauritian Indian (n = 4505) and Mauritian Creole (n = 1075), 8 Chinese (n =10 801), 1 Filipino (n = 3841), 7 Japanese (n = 7934), 1 Mongolian (n = 1991), and 14 European (n = 20 979) studies. The prevalence of diabetes, hypertension and central obesity was estimated, using descriptive statistics, and the differences were determined with the χ2 test. The odds ratios (ORs) or  coefficients (from the logistic model) and hazard ratios (HRs, from the Cox model to interval censored data) for BMI, WC, waist-to-hip ratio (WHR), and waist-to-stature ratio (WSR) were estimated for diabetes and hypertension. The differences between BMI and WC, WHR or WSR were compared, applying paired homogeneity tests (Wald statistics with 1 df). Hierarchical three-level Bayesian change point analysis, adjusting for age, was applied to identify the most likely cut-off/change point values for BMI and WC in association with previously undiagnosed diabetes. The ORs for diabetes in men (women) with BMI, WC, WHR and WSR were 1.52 (1.59), 1.54 (1.70), 1.53 (1.50) and 1.62 (1.70), respectively and the corresponding ORs for hypertension were 1.68 (1.55), 1.66 (1.51), 1.45 (1.28) and 1.63 (1.50). For diabetes the OR for BMI did not differ from that for WC or WHR, but was lower than that for WSR (p = 0.001) in men while in women the ORs were higher for WC and WSR than for BMI (both p < 0.05). Hypertension was more strongly associated with BMI than with WHR in men (p < 0.001) and most strongly with BMI than with WHR (p < 0.001), WSR (p < 0.01) and WC (p < 0.05) in women. The HRs for incidence of diabetes and hypertension did not differ between BMI and the other three central obesity measures in Mauritian Indians and Mauritian Creoles during follow-ups of 5, 6 and 11 years. The prevalence of diabetes was highest in Asian Indians, lowest in Europeans and intermediate in others, given the same BMI or WC category. The  coefficients for diabetes in BMI (kg/m2) were (men/women): 0.34/0.28, 0.41/0.43, 0.42/0.61, 0.36/0.59 and 0.33/0.49 for Asian Indian, Chinese, Japanese, Mauritian Indian and European (overall homogeneity test: p > 0.05 in men and p < 0.001 in women). Similar results were obtained in WC (cm). Asian Indian women had lower  coefficients than women of other ethnicities. The change points for BMI were 29.5, 25.6, 24.0, 24.0 and 21.5 in men and 29.4, 25.2, 24.9, 25.3 and 22.5 (kg/m2) in women of European, Chinese, Mauritian Indian, Japanese, and Asian Indian descent. The change points for WC were 100, 85, 79 and 82 cm in men and 91, 82, 82 and 76 cm in women of European, Chinese, Mauritian Indian, and Asian Indian. The prevalence of central obesity using the 2005 IDF definition was higher in Japanese men but lower in Japanese women than in their Asian counterparts. The prevalence of central obesity was 52 times higher in Japanese men but 0.8 times lower in Japanese women compared to the National Cholesterol Education Programme definition. The findings suggest that both BMI and WC predicted diabetes and hypertension equally well in all ethnic groups. At the same BMI or WC level, the prevalence of diabetes was highest in Asian Indians, lowest in Europeans and intermediate in others. Ethnic- and sex-specific change points of BMI and WC should be considered in setting diagnostic criteria for obesity to detect undiagnosed or newly diagnosed diabetes.
  • Mattsson, Johanna (Helsingin yliopisto, 2014)
    Prostate-specific antigen (PSA) is a very useful biomarker for prostate cancer. The PSA concentration in circulation increases due to leakage of PSA from cancerous tissue. Normally PSA, a serine protease with chymotrypsin-like enzymatic activity, is secreted into seminal fluid by the epithelial cells of the prostate. The major physiological function of PSA in seminal fluid is to digest semenogelins, which leads to liquefaction of the seminal clot. Several other functions have also been suggested for PSA, some of which are associated with cancer. PSA exerts antiangiogenic activity, but PSA may also promote tumor growth and metastatic dissemination. The aim of the research presented in this thesis was to characterize the antiangiogenic and proteolytic activities of PSA. One of the main goals was to elucidate whether the enzymatic activity of PSA is a requirement for its antiangiogenic activity. The antiangiogenic activity of PSA was studied using an in vitro angiogenesis model based on tube formation of human umbilical vein endothelial cells (HUVEC). In this model only enzymatically active PSA was able to inhibit angiogenesis. Peptides that stimulate the proteolytic activity of PSA enhanced the antiangiogenic activity, while small molecule compounds that inhibit PSA abolished this activity. DNA microarray study showed that PSA-induced changes in the gene expression of HUVECs were small during tube formation, and it was not clear whether these changes were primary or secondary to the antiangiogenic activity of PSA. The results of this thesis suggest that the antiangiogenic activity of PSA is mediated by a proteolytic product generated by PSA. The proteolytic activity of PSA was studied using several peptide and protein substrates. Semenogelins are the major physiological substrates of PSA and they were shown to be degraded much more rapidly than any other protein substrate studied. Nidogen-1, a component of the basement membrane, was identified as a novel substrate for PSA by mass spectrometry. However, the cleavage of nidogen-1 did not explain the antiangiogenic activity of PSA, since either its fragments or full-length form did not affect HUVEC tube formation. Contrary to a previous report, we showed that the antiangiogenic activity of PSA was not mediated by angiostatin-like fragments generated by the cleavage of plasminogen. The results of this thesis established that the proteolytic activity is necessary for the antiangiogenic activity of PSA and that the antiangiogenic activity can be enhanced by PSA-stimulating peptides and abolished by PSA-inhibitors. The comparison of the efficiency of PSA to cleave different protein substrates and the identification of nidogen-1 as one of these substrates provided new information about the biological role of PSA. The typically slow growth of most prostate cancers may be caused by the antiangiogenic activity of PSA, as there are high concentrations of active PSA present in prostatic tissue. Therefore, peptides that stimulate the antiangiogenic activity of PSA and reduce tumor angiogenesis could be used to control prostate cancer growth.
  • Kreutzman, Anna (Helsingin yliopisto, 2012)
    Tyrosine kinase inhibitors (TKIs), such as imatinib (Glivec®) and dasatinib (Sprycel®), have dramatically improved the outcome of chronic myeloid leukemia (CML) patients. Besides inhibiting the actual on-target BCR-ABL1 kinase in leukemic cells, TKIs also inhibit several off-target kinases, which may affect healthy cells. Dasatinib has a particularly wide kinase-inhibition profile and inhibits kinases important in immune effector cells, such as SRC-kinases. Opposite to immunosuppressive in vitro effects, dasatinib induces an oligoclonal expansion of large granular lymphocytes (LGLs) in the blood in vivo, which has been associated with improved therapy responses. The purpose of this PhD thesis was to uncover the cellular and molecular mechanisms of dasatinib-related LGL lymphocytosis. Unlike healthy controls, clonal lymphocytes were detected in the majority of CML patients at diagnosis. During dasatinib therapy these clones expanded, eventually leading to absolute lymphocytosis. Hypothetically, the lymphocyte clones detected at diagnosis are unresponsive (anergic) anti-leukemic clones, which recover, reactivate and expand during dasatinib therapy. In concord, the expanded CD8+ T cells and NK cells had a late differentiated phenotype of long-lived T-cells. The long-term dasatinib treatment also differentiated CD4+ T cells into cytotoxic LGLs. These unique CD4-LGLs secreted increased amounts of IFN-gamma indicating a sensitized role in eliminating leukemic cells. Dasatinib therapy also enhanced the cytotoxicity of NK cells. Immunomodulatory effects of IFN-α treatment in CML patients were also studied. Previous work have shown that a small proportion of IFN-α treated patients can permanently discontinue therapy without relapse. This curative property of IFN-α could be caused by an immune mediated mechanism and as a proof of this, we noticed that patients who had responded very well to treatment, had an increased number of CD8+ T cells and unique clonal γ/δ T cells. Intriguingly, patients who were able to stop the treatment also had significantly higher numbers of NK cells. Taken together, the results in this PhD project provide a proof of a unique, previously unrecognized dual mode of action of TKI-treatment: direct cytotoxic effects are accompanied with the activation of immune system which is potentially relevant for the long-term control of CML. These findings can be utilized in developing novel immunotargeting therapies of leukemia and other cancers.
  • Rummukainen, Maija-Liisa (Helsingin yliopisto, 2013)
    Background and aims. The rapidly growing ageing population results in a demand for new types of housing that may face the same challenges as nursing homes (NHs) do today. Elderly persons are at particular risk for healthcare-associated infections, since few long-term care facilities (LTCFs) have in-house expertise in infection control or in infectious diseases. This may lead to inappropriate prescription of antimicrobials and promote development of multidrug-resistant bacteria. The movement of residents between LTCFs and acute-care hospitals facilitates the spread of resistant bacteria. The aim of the present study was to determine the use of antimicrobials and prevalence of infections in LTCFs in Finland. An additional aim was to evaluate the feasibility of different methods in assessing antibiotic use and prevalence of infections in LTCFs. Methods. A team comprising an infectious disease consultant, an infection control nurse, and a geriatrician visited all 123 LTCFs for elderly persons in the Central Finland Healthcare District during 2004 2005. The site visits consisted of a structured interview concerning patients, ongoing systemic antimicrobial use, diagnostic practices for urinary tract infection (UTI), and monthly amount in liters of alcohol-based hand rubs used and in patient-days. Following the visits, regional guidelines for prudent use of antimicrobials in LTCFs were published and the use of antimicrobials was followed up by an annual questionnaire during 2006-2008. All residents present in nine voluntary NHs for ≥ 24 hours (n = 5,791) and receiving systemic antimicrobials on the day of the survey were included in the study. Data on antibiotics and their indications (prophylaxis or treatment, type of infection) were collected in April and November 2009 and May-September 2010. All residents for whom a Minimum Data Set (MDS) form (n = 12,784) was completed in 753 LTCFs using a Resident Assessment Instrument (RAI) in April and September 2011 were included. Results. The proportions of patients receiving antimicrobials in surveys varied between 10% and 19%. Most of the antimicrobials were used for UTI prophylaxis (42-69%) and treatment (13-25%). The proportion of patients on UTI prophylaxis decreased in the Central Finland Healthcare District from 13% to 6% and in eight NHs from 12% to 6%. The most common antimicrobial used was methenamine (36-44%), followed by trimetoprim (14-31%), cephalexin (6-9%), and pivmecillinam (6-11%). In Central Finland Healthcare District LTCFs, the total amount of alcohol-based hand rub used increased by 70%, from the mean (SD) of 7.3 (5.1) L/1000 patient-days on the baseline visit in 2005 to 12.4 (14.9) L in 2008. In LTCFs using RAI, the risk factors for antimicrobial prescription included female sex, age < 85 years, urinary catheter, urinary incontinence, confusion, restriction to bed, pressure ulcers, diarrhea, and hospital stay during the previous 90 days. Conclusions. Antimicrobial use was common in Finnish LTCFs and most were used for UTI prophylaxis and treatment. The decrease in antimicrobial usage during the surveys suggests that LTCFs may benefit from antimicrobial stewardship interventions focused on UTI. The multidisciplinary team succeeded in promoting hand hygiene in LTCFs, which was sustained over the 3-year follow-up. RAI with MDS data also constitutes a feasible tool for collecting data on antibiotic use and infections in LTCFs.
  • Järvinen, Kristiina (Helsingin yliopisto, 2001)
  • Kataja-Tuomola, Merja (Helsingin yliopisto, 2011)
    The incidence of type 2 diabetes has increased rapidly worldwide. Obesity is one of the most important modifiable risk factors of type 2 diabetes: weight gain increases and weight loss decreases the risk. However, the effects of weight fluctuation are unclear. Reactive oxygen species are presumably part of the complicated mechanism for the development of insulin resistance and beta-cell destruction in the pancreas. The association of antioxidants with the risk of incident type 2 diabetes has been studied in longitudinal prospective human studies, but so far there is no clear conclusion about protective effect of dietary or of supplementary antioxidants on diabetes risk. The present study examined 1) weight change and fluctuation as risk factors for incident type 2 diabetes; 2) the association of baseline serum alpha-tocopherol or beta-carotene concentration and dietary intake of antioxidants with the risk of type 2 diabetes; 3) the effect of supplementation with alpha-tocopherol or beta-carotene on the risk of incident type 2 diabetes; and on macrovascular complications and mortality among type 2 diabetics. This investigation was part of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a randomized, double-blind, placebo-controlled prevention trial, which has undertaken to examine the effect of alpha-tocopherol and beta-carotene supplementation on the development of lung cancer, other cancers, and cardiovascular diseases in male smokers aged 50-69 years at baseline. Participants were assigned to receive either 50 mg alpha-tocopherol, 20mg beta-carotene, both, or placebo daily in a 2 x 2 factorial design experiment during 1985-1993. Cases of incident diabetes were identified through a nationwide register of drug reimbursements of the Social Insurance Institution. At baseline 1700 men had a history of diabetes. Among those (n = 27 379) with no diabetes at baseline 305 new cases of type 2 diabetes were recognized during the intervention period and 705 during the whole follow-up to 12.5 years. Weight gain and weight fluctuation measured over a three year period were independent risk factors for subsequent incident type 2 diabetes. Relative risk (RR) was 1.77 (95% confidence interval [CI] 1.44-2.17) for weight gain of at least 4 kg compared to those with a weight change of less than 4 kg. The RR in the highest weight fluctuation quintile compared to the lowest was 1.64 (95% CI 1.24-2.17). Dietary tocopherols and tocotrienols as well as dietary carotenoids, flavonols, flavones and vitamin C were not associated with the risk of type 2 diabetes. Baseline serum alpha-tocopherol and beta-carotene concentrations were not associated with the risk of incident diabetes. Neither alpha-tocopherol nor beta-carotene supplementation affected the risk of diabetes. The relative risks for participants who received alpha-tocopherol compared with nonrecipients and for participants who received beta-carotene compared with nonrecipients were 0.92 (95% CI 0.79-1.07) and 0.99 (95% CI 0.85-1.15), respectively. Furthermore, alpha-tocopherol or beta-carotene supplementation did not affect the risk of macrovascular complications or mortality of diabetic subjects during the 19 years follow-up time. In conclusion, in this study of older middle-aged male smokers, weight gain and weight fluctuation were independent risk factors for type 2 diabetes. Intake of antioxidants or serum alpha-tocopherol or beta-carotene concentrations were not associated with the risk of type 2 diabetes. Supplementation with of alpha-tocopherol or beta-carotene did not prevent type 2 diabetes. Neither did they prevent macrovascular complications, or mortality among diabetic subjects.
  • Tynjälä, Pirjo (Helsingin yliopisto, 2008)
    Juvenile idiopathic arthritis (JIA) is a heterogeneous group of childhood chronic arthritides, associated with chronic uveitis in 20% of cases. For JIA patients responding inadequately to conventional disease-modifying anti-rheumatic drugs (DMARDs), biologic therapies, anti-tumor necrosis factor (anti-TNF) agents are available. In this retrospective multicenter study, 258 JIA-patients refractory to DMARDs and receiving biologic agents during 1999-2007 were included. Prior to initiation of anti-TNFs, growth velocity of 71 patients was delayed in 75% and normal in 25%. Those with delayed growth demonstrated a significant increase in growth velocity after initiation of anti-TNFs. Increase in growth rate was unrelated to pubertal growth spurt. No change was observed in skeletal maturation before and after anti-TNFs. The strongest predictor of change in growth velocity was growth rate prior to anti-TNFs. Change in inflammatory activity remained a significant predictor even after decrease in glucocorticoids was taken into account. In JIA-associated uveitis, impact of two first-line biologic agents, etanercept and infliximab, and second-line or third-line anti-TNF agent, adalimumab, was evaluated. In 108 refractory JIA patients receiving etanercept or infliximab, uveitis occurred in 45 (42%). Uveitis improved in 14 (31%), no change was observed in 14 (31%), and in 17 (38%) uveitis worsened. Uveitis improved more frequently (p=0.047) and frequency of annual uveitis flares was lower (p=0.015) in those on infliximab than in those on etanercept. In 20 patients taking adalimumab, 19 (95%) had previously failed etanercept and/or infliximab. In 7 patients (35%) uveitis improved, in one (5%) worsened, and in 12 (60%) no change occurred. Those with improved uveitis were younger and had shorter disease duration. Serious adverse events (AEs) or side-effects were not observed. Adalimumab was effective also in arthritis. Long-term drug survival (i.e. continuation rate on drug) with etanercept (n=105) vs. infliximab (n=104) was at 24 months 68% vs. 68%, and at 48 months 61% vs. 48% (p=0.194 in log-rank analysis). First-line anti-TNF agent was discontinued either due to inefficacy (etanercept 28% vs. infliximab 20%, p=0.445), AEs (7% vs. 22%, p=0.002), or inactive disease (10% vs. 16%, p=0.068). Females, patients with systemic JIA (sJIA), and those taking infliximab as the first therapy were at higher risk for treatment discontinuation. One-third switched to the second anti-TNF agent, which was discontinued less often than the first. In conclusion, in refractory JIA anti-TNFs induced enhanced growth velocity. Four-year treatment survival was comparable between etanercept and infliximab, and switching from first-line to second-line agent a reasonable therapeutic option. During anti-TNF treatment, one-third with JIA-associated anterior uveitis improved.
  • Kanerva, Kristiina (Helsingin yliopisto, 2010)
    Polyamines are organic polycations that participate in various physiological functions, including cell proliferation, differentiation and apoptosis. Cellular polyamines originate from endogenous biosynthesis and exogenous sources. Their subcellular pool is under strict control, achieved by regulating their uptake and metabolism. Polyamine-induced proteins called antizymes (AZ) act as key regulators of intracellular polyamine concentration. They regulate both the transport of polyamines and the activity and degradation of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis. AZs themselves are negatively regulated by antizyme inhibitor (AZIN). AZIN functions as a positive regulator of cellular polyamine homeostasis, which by binding to AZs reactivates ODC and induces the uptake of polyamines. In various pathological conditions, including cancer, polyamine levels are misregulated. Polyamine homeostasis has therefore become an attractive target for therapeutic interventions and it is thus crucial to characterize the molecular basis underlying the homeostatic regulation. A novel human AZIN-resembling protein was previously identified in our group. The purpose of this study was to elucidate the function and distribution of this protein, termed as an antizyme inhibitor 2 (AZIN2). According to my results, AZIN2 functions as a novel regulator of polyamine homeostasis. It shows no enzymatic activity, but instead it binds AZs and negates their activity, which subsequently leads to reactivation of ODC and inhibition of its degradation. Expression of AZIN2 is restricted to terminally differentiated cells, such as mast cells (MC) and neurosecretory cells. In these actively secreting cell types, AZIN2 localizes to subcellular vesicles or granules where its function is important for the vesicle-mediated secretion. In MCs, AZIN2 localizes to the serotonin-containing subset of MC granules, and its expression is coupled to MC activation. The functional role of polyamines as potential mediators of MC activity was also investigated, and it was observed that the secretion of serotonin is selectively dependent on activation of ODC. In neurosecretory cells, AZIN2-positive vesicles localize mainly to the trans-Golgi network (TGN). Depletion of AZIN2 or cellular polyamines causes selective fragmentation of the TGN and retards secretion of proteins. Since addition of exogenous polyamines reverses these effects, the data indicate that AZIN2 and its downstream effectors, polyamines, are functionally implicated in the regulation of secretory vesicle transport. My studies therefore reveal a novel function for polyamines as modulators of both constitutive and regulated secretion. Based on the results, I propose that the role of AZIN2 is to act as a local in situ activator of polyamine biosynthesis.
  • Viheriäranta, Anni (Helsingin yliopisto, 2014)
    Escaping apoptosis is an important, acquired capability of tumor cells and is considered a hallmark of cancer. Furthermore, tumor suppressors and apoptotic proteins function as natural barriers for excessive proliferation induced by oncogenes and can be often found as mutated or lost in cancer. Understanding how tumor cell specific apoptotic pathways are working, may guide development of future therapeutic strategies inducing apoptosis specifically in tumor cells. One of the highly overexpressed oncogene in cancers is Myc that is a global transcription factor regulating variety of cellular functions such as proliferation and apoptosis. One of the major aims in this study was to elucidate mechanisms for Myc-induced sensitization of cells to cell death. Herein, the results presented here provide evidence that Myc-induced apoptosis is strictly mitochondria-dependent. Furthermore, our findings expose new evidence for Bcl-2 family member mediated control of Myc-induced apoptosis showing that Myc expression results in activation of Bak. Interestingly, our data suggest a novel Bak activation step, where Myc induces Bak to undergo conformational change and expose its N-termini, however, without further homo-oligomerization or apoptosis. Hence, we open new ideas for the current Bak/Bax activation models suggested earlier. In addition, our data indicate that Myc expression results in phosphorylation and accumulations of mitochondrial p53 that is priming the mitochondria for death stimuli. Herein, these results indicate that cytoplasmic p53 has a crucial role in Myc-induced stress responses. The data presented here also suggest that BH3 mimetic drugs can sensitize tumor cells to Myc-apoptosis in vivo, which also highlights the role of Bcl-xL as a key controller of Myc-dependent apoptosis in epithelial tumors. Thereby, our results point new therapeutic possibilities that could be used in combination to treat breast cancer. Finally, in this study we found an interesting connection between the Myc-induced metabolic transformation and the apoptotic signaling of Myc. We suggest that Myc expression induces activation of metabolic pathways specific for cancer cell such as activating the glutaminolytic pathway and promoting a catabolic mode of metabolism through increasing fatty acid oxidation. Furthermore, our results indicate that Myc-induced decline in the ATP contents of the cell is leading to an activation of a cellular energy sensor AMPK. Consequently, AMPK is able to induce Bak activation and apoptotic sensitivity via phosphorylation and stabilization of p53. Importantly, our results bring new insight into oncogenic stress and apoptotic sensitivity by Myc highlighting the role of metabolism. All together, it will be future challenge to understand how that knowledge of coupled metabolic stress and apoptotic sensitivity can be used for therapeutic interventions in cancer.
  • Ylinen, Pekka (Helsingin yliopisto, 2006)
    The aim of the present experimental study was to find out if the applications of coralline hydroxyapatite (HA) can be improved by using bioabsorbable containment or binding substance with particulate HA in mandibular contour augmentation and by using bioabsorbable fibre-reinforced HA blocks in filling bone defects and in anterior lumbar interbody fusion. The use of a separate curved polyglycolide (PGA) containment alone or together with a fast resorbing polyglycolide/polylactide (PGA/PLA) binding substance were compared to the conventional non-contained method in ridge augmentation in sheep. The contained methods decreased HA migration, but the augmentations did not differ significantly. The use of the containment caused a risk for wound dehiscence and infection. Histologically there was a rapid connective tissue ingrowth into the HA graft and it was more abundant with the PGA containment compared to the non-contained augmentation and even additionally rich when the HA particles were bound with PGA/PLA copolymer. However, the bone ingrowth was best in the non-contained augmentation exceeding 10-12 % of the total graft area at 24 weeks. Negligible or no bone ingrowth was seen in the cases where the polymer composite was added to the HA particles and, related to that, foreign-body type cells were seen at the interface between the HA and host bone. The PGA and poly-dl/l-lactide (PDLLA) fibre-reinforced coralline HA blocks were studied in the metaphyseal and in the diaphyseal defects in rabbits. A rapid bone ingrowth was seen inside the both types of implants. Both PGA and PDLLA fibres induced an inflammatory fibrous reaction around themselves but it did not hinder the bone ingrowth. The bone ingrowth pattern was directed according to the loading conditions so that the load-carrying cortical ends of the implants as well as the implants sited in the diaphyseal defects were the most ossified. The fibre-reinforced coralline HA implants were further studied as stand-alone grafts in the lumbar anterior interbody implantation in pigs. The strength of the HA implants proved not to be adequate, the implants fractured in six weeks and the disc space was gradually lost similarly to that of the discectomized spaces. Histologically, small quantities of bone ingrowth was seen in some of the PGA and PDLLA reinforced coralline implants while no bone formation was identified in any of the PDLLA reinforced synthetic porous HA implants. While fragmented, the inner structure of the implants was lost, the bone ingrowth was minimal, and the disc was replaced by the fibrous connective tissue. When evaluated radiologically the grade of ossification was assessed as better than histologically, and, when related to the histologic findings, CT was more dependable than the plain films to show ossification of the implanted disc space. Local kyphosis was a frequent finding along with anterior bone bridging and ligament ossification as a consequence of instability of the implanted segment.
  • Diaconu, Iulia (Helsingin yliopisto, 2010)
    Cancer is a devastating disease with poor prognosis and no curative treatment, when widely metastatic. Conventional therapies, such as chemotherapy and radiotherapy, have efficacy but are not curative and systemic toxicity can be considerable. Almost all cancers are caused due to changes in the genetic material of the transformed cells. Cancer gene therapy has emerged as a new treatment option, and past decades brought new insights in developing new therapeutic drugs for curing cancer. Oncolytic viruses constitute a novel therapeutic approach given their capacity to replicate in and kill specifically tumor cells as well as reaching tumor distant metastasis. Adenoviral gene therapy has been suggested to cause liver toxicity. This study shows that new developed adenoviruses, in particular Ad5/19p-HIT, can be redirected towards kidney while adenovirus uptake by liver is minimal. Moreover, low liver transduction resulted in a favorable tumor to liver ratio of virus load. Further, we established a new immunocompetent animal model Syrian hamsters. Wild type adenovirus 5 was found to replicate in Hap-T1 hamster tumors and normal tissues. There are no antiviral drugs available to inhibit adenovirus replication. In our study, chlorpromazine and cidofovir efficiently abrogated virus replication in vitro and showed significant reduction in vivo in tumors and liver. Once safety concerns were addressed together with the new given antiviral treatment options, we further improved oncolytic adenoviruses for better tumor penetration, local amplification and host system modulation. Further, we created Ad5/3-9HIF-Δ24-VEGFR-1-Ig, oncolytic adenovirus for improved infectivity and antiangiogenic effect for treatment of renal cancer. This virus exhibited increased anti-tumor effect and specific replication in kidney cancer cells. The key player for good efficacy of oncolytic virotherapy is the host immune response. Thus, we engineered a triple targeted adenovirus Ad5/3-hTERT-E1A-hCD40L, which would lead to tumor elimination due to tumor-specific oncolysis and apoptosis together with an anti-tumor immune response prompted by the immunomodulatory molecule. In conclusion, the results presented in this thesis constitute advances in our understanding of oncolytic virotherapy by successful tumor targeting, antiviral treatment options as a safety switch in case of replication associated side-effects, and modulation of the host immune system towards tumor elimination.  
  • Eriksson, Minna (Helsingin yliopisto, 2005)