Decoupling in non-linear systems with two degrees of freedom

The problem of decoupling a class of non-linear two degrees of freedom systems is studied. The coupled non-linear differential equations of motion of the system are shown to be equivalent to a pair of uncoupled equations. This equivalence is established through transformation techniques involving the transformation of both the dependent and independent variables. The sufficient conditions on the form of the non-linearity, for the case wherein the transformed equations are linear, are presented. Several particular cases of interest are also illustrated.

Non-enzymatic reactions involving vitamin B6: Spectroscopic investigations on the effect of pH and metal ions on the decyclization reactions of the pyridoxal-histamine cyclized Schiff base

The effect of pH and metal ions (Cu2+, Zn2+, Cd2+, Mn2+, Cr3+, Co3+, and Mg2+) on the decyclization reactions of pyridoxal-histamine cyclized Schiff base has been studied using electronic spectroscopy. The study reveals that the cyclization reaction is irreversible with respect to pH and metal ions. Interest in this work derives from the possible involvement of cyclization reactions in the inhibitory activity of a number of pyridoxal-dependent enzymes.

Molecular details of phage phi6 RNA-dependent RNA synthesis

For most RNA viruses RNA-dependent RNA polymerases (RdRPs) encoded by the virus are responsible for the entire RNA metabolism. Thus, RdRPs are critical components in the viral life cycle. However, it is not fully understood how these important enzymes function during viral replication. Double-stranded RNA (dsRNA) viruses perform the synthesis of their RNA genome within a proteinacous viral particle containing an RdRP as a minor constituent. The phi6 bacteriophage is the best-studied dsRNA virus, providing an excellent background for studies of its RNA synthesis. The purified recombinant phi6 RdRP is highly active in vitro and it possesses both RNA replication and transcription activities. The crystal structure of the phi6 polymerase, solved in complex with a number of ligands, provides a working model for detailed in vitro studies of RNA-dependent RNA polymerization. In this thesis, the primer-independent initiation of the phi6 RdRP was studied in vitro using biochemical and structural methods. A C-terminal, four-amino-acid-long loop protruding into the central cavity of the phi6 RdRP has been suggested to stabilize the incoming nucleotides of the initiation complex formation through stacking interactions. A similar structural element has been found from several other viral RdRPs. In this thesis, this so-called initiation platform loop was subjected to site-directed mutagenesis to address its role in the initiation. It was found that the initiation mode of the mutants is primer-dependent, requiring either an oligonucleotide primer or a back-priming initiation mechanism for the RNA synthesis. The crystal structure of a mutant RdRP with altered initiation platform revealed a set of contacts important for primer-independent initiation. Since phi6 RdRP is structurally and functionally homologous to several viral RdRPs, among them the hepatitis C virus RdRP, these results provide further general insight to understand primer-independent initiation. In this study it is demonstrated that manganese phasing could be used as a practical tool for solving structures of large proteins with a bound manganese ion. The phi6 RdRP was used as a case study to obtain phases for crystallographic analysis. Manganese ions are naturally bound to the phi6 RdRP at the palm domain of the enzyme. In a crystallographic experiment, X-ray diffraction data from a phi6 RdRP crystal were collected at a wavelength of 1.89 Å, which is the K edge of manganese. With this data an automatically built model of the core region of the protein could be obtained. Finally, in this work terminal nucleotidyl transferase (TNTase) activity of the phi6 RdRP was documented in the isolated polymerase as well as in the viral particle. This is the first time that such an activity has been reported in a polymerase of a dsRNA virus. The phi6 RdRP used uridine triphosphates as the sole substrate in a TNTase reaction but could accept several heterologous templates. The RdRP was able to add one or a few non-templated nucleotides to the 3' end of the single- or double-stranded RNA substrate. Based on the results on particle-mediated TNTase activity and previous structural information of the polymerase, a model for termination of the RNA-dependent RNA synthesis is suggested in this thesis.

Distribution of non-biting midges (Diptera, Chironomidae) in subarctic lakes of Finnish Lapland applications in lake classification and palaeolimnology

Climate change contributes directly or indirectly to changes in species distributions, and there is very high confidence that recent climate warming is already affecting ecosystems. The Arctic has already experienced the greatest regional warming in recent decades, and the trend is continuing. However, studies on the northern ecosystems are scarce compared to more southerly regions. Better understanding of the past and present environmental change is needed to be able to forecast the future. Multivariate methods were used to explore the distributional patterns of chironomids in 50 shallow (≤ 10m) lakes in relation to 24 variables determined in northern Fennoscandia at the ecotonal area from the boreal forest in the south to the orohemiarctic zone in the north. Highest taxon richness was noted at middle elevations around 400 m a.s.l. Significantly lower values were observed from cold lakes situated in the tundra zone. Lake water alkalinity had the strongest positive correlation with the taxon richness. Many taxa had preference for lakes either on tundra area or forested area. The variation in the chironomid abundance data was best correlated with sediment organic content (LOI), lake water total organic carbon content, pH and air temperature, with LOI being the strongest variable. Three major lake groups were separated on the basis of their chironomid assemblages: (i) small and shallow organic-rich lakes, (ii) large and base-rich lakes, and (iii) cold and clear oligotrophic tundra lakes. Environmental variables best discriminating the lake groups were LOI, taxon richness, and Mg. When repeated, this kind of an approach could be useful and efficient in monitoring the effects of global change on species ranges. Many species of fast spreading insects, including chironomids, show a remarkable ability to track environmental changes. Based on this ability, past environmental conditions have been reconstructed using their chitinous remains in the lake sediment profiles. In order to study the Holocene environmental history of subarctic aquatic systems, and quantitatively reconstruct the past temperatures at or near the treeline, long sediment cores covering the last 10000 years (the Holocene) were collected from three lakes. Lower temperature values than expected based on the presence of pine in the catchment during the mid-Holocene were reconstructed from a lake with great water volume and depth. The lake provided thermal refuge for profundal, cold adapted taxa during the warm period. In a shallow lake, the decrease in the reconstructed temperatures during the late Holocene may reflect the indirect response of the midges to climate change through, e.g., pH change. The results from three lakes indicated that the response of chironomids to climate have been more or less indirect. However, concurrent shifts in assemblages of chironomids and vegetation in two lakes during the Holocene time period indicated that the midges together with the terrestrial vegetation had responded to the same ultimate cause, which most likely was the Holocene climate change. This was also supported by the similarity in the long-term trends in faunal succession for the chironomid assemblages in several lakes in the area. In northern Finnish Lapland the distribution of chironomids were significantly correlated with physical and limnological factors that are most likely to change as a result of future climate change. The indirect and individualistic response of aquatic systems, as reconstructed using the chironomid assemblages, to the climate change in the past suggests that in the future, the lake ecosystems in the north do not respond in one predictable way to the global climate change. Lakes in the north may respond to global climate change in various ways that are dependent on the initial characters of the catchment area and the lake.

NUPARM and NUCGEN: software for analysis and generation of sequence dependent nucleic acid structures

Software packages NUPARM and NUCGEN, are described, which can be used to understand sequence directed structural variations in nucleic acids, by analysis and generation of non-uniform structures. A set of local inter basepair parameters (viz. tilt, roll, twist, shift, slide and rise) have been defined, which use geometry and coordinates of two successive basepairs only and can be used to generate polymeric structures with varying geometries for each of the 16 possible dinucleotide steps. Intra basepair parameters, propeller, buckle, opening and the C6...C8 distance can also be varied, if required, while the sugar phosphate backbone atoms are fixed in some standard conformation ill each of the nucleotides. NUPARM can be used to analyse both DNA and RNA structures, with single as well as double stranded helices. The NUCGEN software generates double helical models with the backbone fixed in B-form DNA, but with appropriate modifications in the input data, it can also generate A-form DNA ar rd RNA duplex structures.

Intensive versus conventional glycaemic control for treating diabetic foot ulcers

Background The estimated likelihood of lower limb amputation is 10 to 30 times higher amongst people with diabetes compared to those without diabetes. Of all non-traumatic amputations in people with diabetes, 85% are preceded by a foot ulcer. Foot ulceration associated with diabetes (diabetic foot ulcers) is caused by the interplay of several factors, most notably diabetic peripheral neuropathy (DPN), peripheral arterial disease (PAD) and changes in foot structure. These factors have been linked to chronic hyperglycaemia (high levels of glucose in the blood) and the altered metabolic state of diabetes. Control of hyperglycaemia may be important in the healing of ulcers. Objectives To assess the effects of intensive glycaemic control compared to conventional control on the outcome of foot ulcers in people with type 1 and type 2 diabetes. Search methods In December 2015 we searched: The Cochrane Wounds Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; EBSCO CINAHL; Elsevier SCOPUS; ISI Web of Knowledge Web of Science; BioMed Central and LILACS. We also searched clinical trial databases, pharmaceutical trial databases and current international and national clinical guidelines on diabetes foot management for relevant published, non-published, ongoing and terminated clinical trials. There were no restrictions based on language or date of publication or study setting. Selection criteria Published, unpublished and ongoing randomised controlled trials (RCTs) were considered for inclusion where they investigated the effects of intensive glycaemic control on the outcome of active foot ulcers in people with diabetes. Non randomised and quasi-randomised trials were excluded. In order to be included the trial had to have: 1) attempted to maintain or control blood glucose levels and measured changes in markers of glycaemic control (HbA1c or fasting, random, mean, home capillary or urine glucose), and 2) documented the effect of these interventions on active foot ulcer outcomes. Glycaemic interventions included subcutaneous insulin administration, continuous insulin infusion, oral anti-diabetes agents, lifestyle interventions or a combination of these interventions. The definition of the interventional (intensive) group was that it should have a lower glycaemic target than the comparison (conventional) group. Data collection and analysis All review authors independently evaluated the papers identified by the search strategy against the inclusion criteria. Two review authors then independently reviewed all potential full-text articles and trials registry results for inclusion. Main results We only identified one trial that met the inclusion criteria but this trial did not have any results so we could not perform the planned subgroup and sensitivity analyses in the absence of data. Two ongoing trials were identified which may provide data for analyses in a later version of this review. The completion date of these trials is currently unknown. Authors' conclusions The current review failed to find any completed randomised clinical trials with results. Therefore we are unable to conclude whether intensive glycaemic control when compared to conventional glycaemic control has a positive or detrimental effect on the treatment of foot ulcers in people with diabetes. Previous evidence has however highlighted a reduction in risk of limb amputation (from various causes) in people with type 2 diabetes with intensive glycaemic control. Whether this applies to people with foot ulcers in particular is unknown. The exact role that intensive glycaemic control has in treating foot ulcers in multidisciplinary care (alongside other interventions targeted at treating foot ulcers) requires further investigation.

Studies of Immune Regulation in Type 1 Diabetes

Type 1 diabetes (T1D) is considered to be an autoimmune disease. In T1D insulin producing pancreatic β cells are destroyed. The disease process begins years before the clinical diagnosis of T1D. During the pathogenesis of T1D, pancreatic islets are infiltrated by cells of the immune system and T-lymphocytes are considered to be the main mediators of the β-cell destruction. In children with an active β-cell destruction process, autoantibodies against β-cell antigens appear in the blood. Individuals at increased risk of developing T1D can often be identified by detecting serum autoantibodies against β-cell antigens. Immunological aberrancies associated with T1D are related to defects in the polarization of T cells and in the function of regulatory mechanisms. T1D has been considered as an organ-specific autoimmune disease mediated by uncontrolled Th1-responses. In human T1D, the evidence for the role of over-expression of cytokines promoting cytotoxicity is controversial. For the past 15 years, regulatory T cells (Tregs) have been recognized as having a key role in the initiation and maintenance of tolerance, limiting harmful autoantigen-specific inflammation processes. It is possible that, if regulatory mechanisms fail to be initiated, the subtle inflammation targeting β cells lead to insulitis and eventually to overt T1D in some individuals. In the present thesis, we studied the induction of Tregs during the generation of T-cell responses in T1D. The results suggest that the generation of regulatory mechanisms and effector mechanisms upon T-cell activation is aberrant in children with T1D. In our studies, an in vitro cytotoxic environment inhibited the induction of genes associated with regulatory functions upon T-cell activation. We also found T1D patients to have an impaired cytotoxic response against coxsackievirus B4. Ineffective virus clearance may increase the apoptosis of β cells, and thus the risk of β-cell specific autoimmunity, due to the increased presentation of β-cell-derived peptides by APCs to T cells in pancreatic lymph nodes. Recently, a novel T helper cell subset called Th17 has been discovered. Animal models have associated Th17 cells and especially co-producers of IL-17 and IFN-γ with the pathogenesis of T1D. We aimed to characterize the role of Th17 immunity in human T1D. We demonstrated IL-17 activation to be a major alteration in T1D patients in comparison to healthy children. Moreover, alterations related to the FOXP3-mediated regulatory mechanisms were associated with the IL-17 up-regulation seen in T1D patients. These findings may have therapeutic implications for the treatment and prevention of T1D.

Spectroscopy of tissue triglyceride composition : In vitro and in vivo studies

Lipid analysis is commonly performed by gas chromatography (GC) in laboratory conditions. Spectroscopic techniques, however, are non-destructive and can be implemented noninvasively in vivo. Excess fat (triglycerides) in visceral adipose tissue and liver is known predispose to metabolic abnormalities, collectively known as the metabolic syndrome. Insulin resistance is the likely cause with diets high in saturated fat known to impair insulin sensitivity. Tissue triglyceride composition has been used as marker of dietary intake but it can also be influenced by tissue specific handling of fatty acids. Recent studies have shown that adipocyte insulin sensitivity correlates positively with their saturated fat content, contradicting the common view of dietary effects. A better understanding of factors affecting tissue triglyceride composition is needed to provide further insights into tissue function in lipid metabolism. In this thesis two spectroscopic techniques were developed for in vitro and in vivo analysis of tissue triglyceride composition. In vitro studies (Study I) used infrared spectroscopy (FTIR), a fast and cost effective analytical technique well suited for multivariate analysis. Infrared spectra are characterized by peak overlap leading to poorly resolved absorbances and limited analytical performance. In vivo studies (Studies II, III and IV) used proton magnetic resonance spectroscopy (1H-MRS), an established non-invasive clinical method for measuring metabolites in vivo. 1H-MRS has been limited in its ability to analyze triglyceride composition due to poorly resolved resonances. Using an attenuated total reflection accessory, we were able to obtain pure triglyceride infrared spectra from adipose tissue biopsies. Using multivariate curve resolution (MCR), we were able to resolve the overlapping double bond absorbances of monounsaturated fat and polyunsaturated fat. MCR also resolved the isolated trans double bond and conjugated linoleic acids from an overlapping background absorbance. Using oil phantoms to study the effects of different fatty acid compositions on the echo time behaviour of triglycerides, it was concluded that the use of long echo times improved peak separation with T2 weighting having a negligible impact. It was also discovered that the echo time behaviour of the methyl resonance of omega-3 fats differed from other fats due to characteristic J-coupling. This novel insight could be used to detect omega-3 fats in human adipose tissue in vivo at very long echo times (TE = 470 and 540 ms). A comparison of 1H-MRS of adipose tissue in vivo and GC of adipose tissue biopsies in humans showed that long TE spectra resulted in improved peak fitting and better correlations with GC data. The study also showed that calculation of fatty acid fractions from 1H-MRS data is unreliable and should not be used. Omega-3 fatty acid content derived from long TE in vivo spectra (TE = 540 ms) correlated with total omega-3 fatty acid concentration measured by GC. The long TE protocol used for adipose tissue studies was subsequently extended to the analysis of liver fat composition. Respiratory triggering and long TE resulted in spectra with the olefinic and tissue water resonances resolved. Conversion of the derived unsaturation to double bond content per fatty acid showed that the results were in accordance with previously published gas chromatography data on liver fat composition. In patients with metabolic syndrome, liver fat was found to be more saturated than subcutaneous or visceral adipose tissue. The higher saturation observed in liver fat may be a result of a higher rate of de-novo-lipogenesis in liver than in adipose tissue. This thesis has introduced the first non-invasive method for determining adipose tissue omega-3 fatty acid content in humans in vivo. The methods introduced here have also shown that liver fat is more saturated than adipose tissue fat.

Glycaemic behaviour during breastfeeding in women with Type 1 diabetes

Aim To describe glycaemia in both breastfeeding women and artificially feeding women with Type 1 diabetes, and the changes in glycaemia induced by suckling. Methods A blinded continuous glucose monitor was applied for up to 6 days in eight breastfeeding and eight artificially feeding women with Type 1 diabetes 2–4 months postpartum. Women recorded glucose levels, insulin dosages, oral intake and breastfeeding episodes. A standardized breakfast was consumed on 2 days. A third group (clinic controls) were identified from a historical database. Results Carbohydrate intake tended to be higher in breastfeeding than artificially feeding women (P = 0.09) despite similar insulin requirements. Compared with breastfeeding women, the high blood glucose index and standard deviation of glucose were higher in artificially feeding women (P = 0.02 and 0.06, respectively) and in the clinical control group (P = 0.02 and 0.05, respectively). The low blood glucose index and hypoglycaemia were similar. After suckling, the low blood glucose index increased compared with before (P < 0.01) and during (P < 0.01) suckling. Hypoglycaemia (blood glucose < 4.0 mmol/l) occurred within 3 h of suckling in 14% of suckling episodes, and was associated with time from last oral intake (P = 0.04) and last rapid-acting insulin (P = 0.03). After a standardized breakfast, the area under the glucose curve was positive. In breastfeeding women the area under the glucose curve was positive if suckling was avoided for 1 h after eating and negative if suckling occurred within 30 min of eating. Conclusions Breastfeeding women with Type 1 diabetes had similar hypoglycaemia but lower glucose variability than artificially feeding women. Suckling reduced maternal glucose levels but did not cause hypoglycaemia in most episodes.

Individual variation in in vitro efficacy of antiplatelet medication - aspirin and clopidogrel

Antiplatelet medication is known to decrease adverse effects in patients with atherothrombotic disease. However, despite ongoing antiplatelet medication considerable number of patients suffer from atherothrombotic events. The aims of the study were 1) to evaluate the individual variability in platelet functions and compare the usability of different methods in detecting it, 2) to assess variability in efficacy of antiplatelet medication with aspirin (acetylsalicylic acid) or the combination of aspirin and clopidogrel and 3) to investigate the main genetic and clinical variables as well as potential underlying mechanisms of variability in efficacy of antiplatelet medication. In comparisons of different platelet function tests in 19 healthy individuals PFA-100® correlated with traditional methods of measuring platelet function and was thus considered appropriate for testing individual variability in platelet activity. Efficacy of ongoing 100mg aspirin daily was studied in 101 patients with coronary artery disease (CAD). Aspirin response was measured with arachidonic acid (AA)-induced platelet aggregation, which reflects cyclo-oxygenase (COX)-1 dependent thromboxane (Tx) A2 formation, and PFA-100®, which evaluates platelet activation under high shear stress in the presence of collagen and epinephrine. Five percent of patients failed to show inhibition of AA-aggregation and 21% of patients had normal PFA-100® results despite aspirin and were thus considered non-responders to aspirin. Interestingly, the two methods of assessing aspirin efficacy, platelet aggregation and PFA-100®, detected different populations as being aspirin non-responders. It could be postulated that PFA-100® actually measures enhanced platelet function, which is not directly associated with TxA2 inhibition exerted by aspirin. Clopidogrel efficacy was assessed in 50 patients who received a 300mg loading dose of clopidogrel 2.5 h prior to percutaneous coronary intervention (PCI) and in 51 patients who were given a loading dose of 300mg combined with a five day treatment of 75mg clopidogrel daily mimicking ongoing treatment. Clopidogrel response was assessed with ADP-induced aggregations, due to its mechanism of action as an inhibitor of ADP-induced activation. When patients received only a loading dose of clopidogrel prior to PCI, 40% did not gain measurable inhibition of their ADP-induced platelet activity (inhibition of 10% or less). Prolongation of treatment so that all patients had reached a plateau of inhibition exerted by clopidogrel, decreased the incidence of non-responders to 20%. Polymorphisms of COX-1 and GP VI, as well as diabetes and female gender, were associated with decreased in vitro aspirin efficacy. Diabetes also impaired the in vitro efficacy of short-term clopidogrel. Decreased response to clopidogrel was associated with limited inhibition by ARMX, an antagonist of P2Y12-receptor, suggesting the reason for clopidogrel resistance to be receptor-dependent. Conclusions: Considerable numbers of CAD patients were non-responders either to aspirin, clopidogrel or both. In the future, platelet function tests may be helpful to individually select effective and safe antiplatelet medication for these patients.

Assessment of Risk for Type 1 Diabetes in Children of Affected Families and in the General Population : Role of Immunological and Metabolic Markers

Background and aims. Type 1 diabetes (T1D), an autoimmune disease in which the insulin producing beta cells are gradually destroyed, is preceded by a prodromal phase characterized by appearance of diabetes-associated autoantibodies in circulation. Both the timing of the appearance of autoantibodies and their quality have been used in the prediction of T1D among first-degree relatives of diabetic patients (FDRs). So far, no general strategies for identifying individuals at increased disease risk in the general population have been established, although the majority of new cases originate in this population. The current work aimed at assessing the predictive role of diabetes-associated immunologic and metabolic risk factors in the general population, and comparing these factors with data obtained from studies on FDRs. Subjects and methods. Study subjects in the current work were subcohorts of participants of the Childhood Diabetes in Finland Study (DiMe; n=755), the Cardiovascular Risk in Young Finns Study (LASERI; n=3475), and the Finnish Type 1 Diabetes Prediction and Prevention Study (DIPP) Study subjects (n=7410). These children were observed for signs of beta-cell autoimmunity and progression to T1D, and the results obtained were compared between the FDRs and the general population cohorts. --- Results and conclusions. By combining HLA and autoantibody screening, T1D risks similar to those reported for autoantibody-positive FDRs are observed in the pediatric general population. Progression rate to T1D is high in genetically susceptible children with persistent multipositivity. Measurement of IAA affinity failed in stratifying the risk assessment in young IAA-positive children with HLA-conferred disease susceptibility, among whom affinity of IAA did not increase during the prediabetic period. Young age at seroconversion, increased weight-for-height, decreased early insulin response, and increased IAA and IA-2A levels predict T1D in young children with genetic disease susceptibility and signs of advanced beta-cell autoimmunity. Since the incidence of T1D continues to increase, efforts aimed at preventing T1D are important, and reliable disease prediction is needed both for intervention trials and for effective and safe preventive therapies in the future. Our observations confirmed that combined HLA-based screening and regular autoantibody measurements reveal similar disease risks in pediatric general population as those seen in prediabetic FDRs, and that risk assessment can be stratified further by studying glucose metabolism of prediabetic subjects. As these screening efforts are feasible in practice, the knowledge now obtained can be exploited while designing intervention trials aimed at secondary prevention of T1D.

Mulibrey nanism : Clinical characteristics and pathophysiologic features of growth restriction, insulin resistance and tumour development

Background: Mulibrey nanism (MUL; Muscle-liver-brain-eye nanism; OMIM 253250) is an autosomal recessive growth disorder more prevalent in Finland than elsewhere in the world. Clinical characteristics include severe prenatal onset growth restriction, cardiopathy, multiple organ manifestations but no major neurological handicap. MUL is caused by mutations in the TRIM37 gene on chromosome 17q22-23, encoding a peroxisomal protein TRIM37 with ubiquitin E3-ligase activity. Nineteen different mutations have been detected, four of them present in the Finnish patients. Objective: This study aimed to characterize clinical and histopathological features of MUL in the national cohort of Finnish patients. Patients and methods: A total of 92 Finnish patients (age 0.7 to 77 years) participated in the clinical follow-up study. Patients hospital records and growth charts were reviewed. Physical, radiographic and laboratory examinations were performed according to a clinical protocol. Thirty patients (18 females) were treated with recombinant human GH for a median period of 5.7 years. Biopsies and autopsy samples were used for the histopathological and immunohistochemical analyses. Results: MUL patients were born small for gestational age (SGA) with immature craniofacial features after prenatal-onset growth restriction. They experienced a continuous deceleration in both height SDS and weight-for-height (WFH) postnatally. In infancy feeding difficulties and frequent pneumonias were common problems. At the time of diagnosis (median age 2.1 years) characteristic craniofacial, radiological and ocular features were the most constant findings. MUL patients showed a dramatic change in glucose metabolism with increasing age. While the children had low fasting glucose and insulin levels, 90% of the adults were insulin resistant, half had type 2 diabetes and an additional 42% showed impaired glucose tolerance (IGT). Seventy percent fulfilled the National Cholesterol Education Program (NCEP) Adult Treatment Panel III criteria for metabolic syndrome as adults. GH therapy improved pre-pubertal growth but had only minor impact on adult height (+5 cm). Interestingly, treated subjects were slimmer and had less frequent metabolic concerns as young adults. MUL patients displayed histologically a disturbed architecture with ectopic tissues and a high frequency of both benign and malignant tumours present in several internal organs. A total of 232 tumorous lesions were detected in our patient cohort. The majority of the tumours showed strong expression of endothelial cell marker CD34 as well as α-smooth muscle actin (α-SMA). Fifteen of the tumours were malignant and seven of them (five Wilms tumours) occurred in the kidney. Conclusions: MUL patients present a distinct postnatal growth pattern. Short-term response of GH treatment is substantial but the long-term impact remains modest. Although MUL patients form a distinct clinical and diagnostic entity, their clinical findings vary considerably from infancy to adulthood. While failure to thrive dominates early life, MUL adults develop metabolic syndrome and have a tendency for malignancies and vascular lesions in several organs. This speaks for a central role of TRIM37 in regulation of key cellular functions, such as proliferation, migration, angiogenesis and insulin signalling.

The impact of the metabolic syndrome and parental risk factors in patients with type 1 diabetes

Background: One-third of patients with type 1 diabetes develop diabetic complications, such as diabetic nephropathy. The diabetic complications are related to a high mortality from cardiovascular disease, impose a great burden on the health care system, and reduce the health-related quality of life of patients. Aims: This thesis assessed, whether parental risk factors identify subjects at a greater risk of developing diabetic complications. Another aim was to evaluate the impact of a parental history of type 2 diabetes on patients with type 1 diabetes. A third aim was to assess the role of the metabolic syndrome in patients with type 1 diabetes, both its presence and its predictive value with respect to complications. Subjects and methods: This study is part of the ongoing nationwide Finnish Diabetic Nephropathy (FinnDiane) Study. The study was initiated in 1997, and, thus far, 4,800 adult patients with type 1 diabetes have been recruited. Since 2004, follow-up data have also been collected in parallel to the recruitment of new patients. Studies I to III have a cross-sectional design, whereas Study IV has a prospective design. Information on parents was obtained from the patients with type 1 diabetes by a questionnaire. Results: Clustering of parental hypertension, cardiovascular disease, and diabetes (type 1 and type 2) was associated with diabetic nephropathy in patients with type 1 diabetes, as was paternal mortality. A parental history of type 2 diabetes was associated with a later onset of type 1 diabetes, a higher prevalence of the metabolic syndrome, and a metabolic profile related to insulin resistance, despite no difference in the distribution of human leukocyte antigen genotypes or the presence of diabetic complications. A maternal history of type 2 diabetes, seemed to contribute to a worse metabolic profile in the patients with type 1 diabetes than a paternal history. The metabolic syndrome was a frequent finding in patients with type 1 diabetes, observed in 38% of males and 40% of females. The prevalence increased with worsening of the glycemic control and more severe renal disease. The metabolic syndrome was associated with a 3.75-fold odds ratio for diabetic nephropathy, and all of the components of the syndrome were independently associated with diabetic nephropathy. The metabolic syndrome, independent of diabetic nephropathy, increased the risk of cardiovascular events and cardiovascular and diabetes-related mortality over a 5.5-year follow-up. With respect to progression of diabetic nephropathy, the role of the metabolic syndrome was less clear, playing a strong role only in the progression from macroalbuminuria to end-stage renal disease. Conclusions: Familial factors and the metabolic syndrome play an important role in patients with type 1 diabetes. Assessment of these factors is an easily applicable tool in clinical practice to identify patients at a greater risk of developing diabetic complications.

Cluster based training for scaling non-linear support vector machines

Support Vector Machines(SVMs) are hyperplane classifiers defined in a kernel induced feature space. The data size dependent training time complexity of SVMs usually prohibits its use in applications involving more than a few thousands of data points. In this paper we propose a novel kernel based incremental data clustering approach and its use for scaling Non-linear Support Vector Machines to handle large data sets. The clustering method introduced can find cluster abstractions of the training data in a kernel induced feature space. These cluster abstractions are then used for selective sampling based training of Support Vector Machines to reduce the training time without compromising the generalization performance. Experiments done with real world datasets show that this approach gives good generalization performance at reasonable computational expense.

Glycemic Control in Diabetic Pregnancies: Effects on Fetal and Maternal Outcome

Background: Both maternal and fetal complications are increased in diabetic pregnancies. Although hypertensive complications are increased in pregnant women with pregestational diabetes, reports on hypertensive complications in women with gestational diabetes mellitus (GDM) have been contradictory. Congenital malformations and macrosomia are the main fetal complications in Type 1 diabetic pregnancies, whereas fetal macrosomia and birth trauma but not congenital malformations are increased in GDM pregnancies. Aims: To study the frequency of hypertensive disorders in gestational diabetes mellitus. To evaluate the risk of macrosomia and brachial plexus injury (Erb’s palsy) and the ability of the 2-hour glucose tolerance test (OGTT) combined with the 24-hour glucose profile to distinguish between low and high risks of fetal macrosomia among women with GDM. To evaluate the relationship between glycemic control and the risk of fetal malformations in pregnancies complicated by Type 1 diabetes mellitus. To assess the effect of glycemic control on the occurrence of preeclampsia and pregnancy-induced hypertension in Type 1 diabetic pregnancies. Subjects: A total of 986 women with GDM and 203 women with borderline glucose intolerance (one abnormal value in the OGTT) with a singleton pregancy, 488 pregnant women with Type 1 diabetes (691 pregnancies and 709 offspring), and 1154 pregnant non-diabetic women (1181 pregnancies and 1187 offspring) were investigated. Results: In a prospective study on 81 GDM patients the combined frequency of preeclampsia and PIH was higher than in 327 non-diabetic controls (19.8% vs 6.1%, p<0.001). On the other hand, in 203 women with only one abnormal value in the OGTT, the rate of hypertensive complications did not differ from that of the controls. Both GDM women and those with only one abnormal value in the OGTT had higher pre-pregnancy weights and BMIs than the controls. In a retrospective study involving 385 insulin-treated and 520 diet-treated GDM patients, and 805 non-diabetic control pregnant women, fetal macrosomia occurred more often in the insulin-treated GDM pregnancies (18.2%, p<0.001) than in the diet-treated GDM pregnancies (4.4%), or the control pregnancies (2.2%). The rate of Erb’s palsy in vaginally delivered infants was 2.7% in the insulin-treated group of women and 2.4% in the diet-treated women compared with 0.3% in the controls (p<0.001). The cesarean section rate was more than twice as high (42.3% vs 18.6%) in the insulin-treated GDM patients as in the controls. A major fetal malformation was observed in 30 (4.2%) of the 709 newborn infants in Type 1 diabetic pregnancies and in 10 (1.4%) of the 735 controls (RR 3.1, 95% CI 1.6–6.2). Even women whose levels of HbA1c (normal values less than 5.6%) were only slightly increased in early pregnancy (between 5.6 and 6.8%) had a relative risk of fetal malformation of 3.0 (95% CI 1.2–7.5). Only diabetic patients with a normal HbA1c level (<5.6%) in early pregnancy had the same low risk of fetal malformations as the controls. Preeclampsia was diagnosed in 12.8% and PIH in 11.4% of the 616 Type 1 diabetic women without diabetic nephropathy. The corresponding frequencies among the 854 control women were 2.7% (OR 5.2; 95% CI 3.3–8.4) for preeclampsia and 5.6% (OR 2.2, 95% CI 1.5–3.1) for PIH. Multiple logistic regression analysis indicated that glycemic control, nulliparity, diabetic retinopathy and duration of diabetes were statistically significant independent predictors of preeclampsia. The adjusted odds ratios for preeclampsia were 1.6 (95% CI 1.3–2.0) for each 1%-unit increment in the HbA1c value during the first trimester and 0.6 (95% CI 0.5–0.8) for each 1%-unit decrement during the first half of pregnancy. In contrast, changes in glycemic control during the second half of pregnancy did not alter the risk of preeclampsia. Conclusions: In type 1 diabetic pregnancies it is extremely important to achieve optimal glycemic control before pregnancy and maintain it throughout pregnancy in order to decrease the complication rates both in the mother and in her offspring. The rate of fetal macrosomia and birth trauma in GDM pregnancies, especially in the group of insulin-treated women, is still relatively high. New strategies for screening, diagnosing, and treatment of GDM must be developed in order to decrease fetal and neonatal complications.