Venous thrombosis in children : the roles of vascular access and critical illness

Venous thromboembolism (VT) is a rare event in the general pediatric population. However, the incidence in hospitalized children is higher and has increased dramatically reaching 58 per 10 000 children. The single most important risk factor for pediatric VT is the presence of a central venous catheter. The overall aim of this thesis was to achieve a better knowledge and understanding of risk factors for VT in children, specifically related to the use of vascular catheters and to critical illness The studies in this thesis were performed at the department of Pediatric Perioperative Medicine and Intensive care at Karolinska University Hospital, Stockholm. All patients studied were under 18 years of age. In study I the incidence of CVC-related VT was prospectively investigated in 211 non-tunneled pediatric CVCs using doppler ultrasonography. CVC-related VT occurred in 30% of cases. Risk factors for any CVC-related VT were internal jugular vein insertion, multiple lumen CVCs and male sex. However, risk factors for small asymptomatic VTs differed from risk factors for VTs with larger thrombotic mass that were symptomatic and/ or occluded vein blood flow. Symptomatic and/or occlusive VT was more likely to occur with femoral vein insertion, a catheter/vein diameter ratio >0.33, PICU admission, and young age. In study II, the risk for VT related to vascular access catheters used for pediatric CRRT was retrospectively evaluated. Patients with vascular access used for CRRT for at least 48 hours were included. In this study, 5.7% (95% CI: 2-12%) of vascular catheters used for CRRT were complicated by a VT event. Five out of six patients with thromboembolic complications were neonates. In study III, the incidence of VTs not related to a vascular catheter was prospectively investigated in 70 PICU patients considered to be at high risk of VT. Patients admitted to PICU for ≥72 hours and with at least two risk factors for VT were eligible for inclusion. The incidence of symptomatic VT or asymptomatic not related to a vascular catheter was 0% (95% CI: 0-5.1%). This corresponds to a VT incidence of 0% (95% CI: 0–5.1%). In study IV the frequency of catheter-related VT and other complications related to the use of pediatric midline catheters was prospectively evaluated. One hundred patients who received a midline catheter at Astrid Lindgren Children´s Hospital were included. Midline catheter-related VT was found in 30% (95% CI 21-40%) of catheters. Mechanical complications occurred in 33 (33%, 95% CI 24-43%) midline catheters but no midline-related bloodstream infection was found. 78% of patients completed iv therapy without the need for additional iv access. The main conclusions of this thesis are: - VT is a common complication of pediatric CVCs. Risk factors for smaller, asymptomatic VTs are different from risk factors for VTs with larger thrombotic mass - VT is a clinically relevant complication of pediatric CRRT. Neonates seem to be at the highest risk for this complication. - The risk for VT not related to a venous catheter is low in PICU patients. - Based on the incidences of clinical complications and the observed dwell-time, midline catheters could be alternative to CVCs for short-term iv therapy inselected patients

Exact Transformation for Spin-Charge Separation of Spin-half Fermions without Constraints

We demonstrate an exact local transformation which maps a purely Fermionic manybody system to a system of spinfull Bosons and spinless Fermions, demonstrating a possible path to a non-Fermi liquid state. We apply this to the half-filled Hubbard model and show how the transformation maps the ordinary spin half Fermionic degrees of freedom exactly and without introducing Hilbert space constraints to a charge-like ``quasicharge'' fermion and a spin-like ``quasispin'' Boson while preserving all the symmetries of the model. We present approximate solutions with localized charge which emerge naturally from the Hubbard model in this form. Our results strongly suggest that charge tends to remain localized for large values of the Hubbard U

Aspects of fatigue in post-polio

Fatigue is a subjectively experienced and complex phenomenon and one of the most common symptoms in the post-polio syndrome (PPS) occurring in up to 90% of the patients. Experiencing fatigue, negatively impacts work performance, family life, social relationships, and the quality of life (QOL). The origin of fatigue can be central or peripheral and can be experienced in different ways, for example as general, physical, mental, or muscle fatigue. The overall aim of the thesis was to evaluate and analyse fatigue in PPS patients. Specific aims were: to find if generally fatigued PPS patients demonstrate deficits in cognition compared with non-fatigued: to evaluate vitality and fatigue and the relative contribution of physiological and psychological parameters on the level of vitality: to characterise fatigued and non fatigued PPS patients, and to define subgroups across the fatigue continuum; and finally, to describe quality of life characteristics as measured by SF-36 in responders and non-responders after intravenous immunoglobulin treatment (IVIG). The work encompasses three samples of PPS patients. Study I includes twenty PPS patients with and without general fatigue from the post-polio out-patient clinic at Huddinge University Hospital. Study II and III analyses baseline data from 143 PPS patient from a Swedish multicenter study and Study IV is based on follow-up data from 112 patients from the post-polio out-patient clinic at Danderyds University Hospital before and after IVIG treatment. Cognitive performance differences could not be detected between the fatigued and nonfatigued PPS patients and systematic varying of the test order did not significantly trigger mental fatigue. Vitality in PPS patients was mostly dependent on physiological rather than psychological parameters and mental fatigue was not a prominent predictor. On the contrary to what were expected vitality increased and fatigue as well as pain decreased with increasing age. Fatigued PPS patients were characterized by significant lower age, more physical problems and lower QOL than non-fatigue PPS patients. Furthermore, in the fatigued group mental fatigue had a relatively greater importance than physical fatigue. In the total sample of PPS patients the scores for SF-36 sub domains Vitality, Bodily pain, Social function, Role emotional and MCS were significantly improved after IVIG treatment at the 6-month follow-up. Vitality and Bodily pain were identified as possible outcome variables for IVIG treatment and positive-, non- and negative responders were identified. Responders for treatment were characterised by a low vitality i.e. a high fatigue before treatment. It is concluded that fatigue in PPS is mostly physical in its character; General fatigue does not affect cognition in PPS. Mental fatigue is not a prominent phenomenon. Fatigued PPS patients may be considered as a subgroup and there are PPS patients with both positive and negative responses to IVIG treatment. PPS patients with high levels of fatigue and pain before treatment are the ones who may benefit from the IVIG treatment

Peaceableness as a Weapon in Wars of Swedology

This article brings forward a set of examples from the “Swedological” literature that had its golden era circa 1930–1980 – i.e. non-Swedish interpretations of Swedish society (or features of it), done in order to fight ideological wars on non-Swedish soil, using Sweden as a case in point. The theme of Sweden as a peaceful nation, both in its internal developments and in its role in the world, was a crucial feature of the genre from the outset. It has been possible to interpret Sweden’s neutrality policies (including heavy production and exports of arms) in different ways. This has also been the case with Swedish attempts to take responsibility in the world, showing global conscience (e.g. through criticism against international bullies or through foreign aid). The theme of peaceableness has, over the decades, been a tool in fights between “Swedophiles” and “Swedoclasts”, both sides applying a certain “logic of debunkery” in their mutual attempts to disclose the opposite camp’s depictions as myths

“Laissez-faire under a bell jar” Marquis Childs and the Sweden-fad of the Roosevelt Era

For decades “Swedology” was a rich and polemically charged genre. “Swedophiles” and “Swedoclasts” were quite as eager to deploy images of Sweden as weapons in foreign contexts as they were interested in the country as such. A telling example is the genre’s early classic, Marquis W. Childs’s Sweden: The Middle Way from 1936. With the backdrop of Dwight Eisenhower’s attempt to get back at Childs by branding Sweden as an extreme society in 1960, this essay aims to see Childs’s book as an argument in its original context during the New Deal. Rather than initiating the 1930s’ American wave of Swedophilia, Childs phrased his argument as an implicit polemic against its apparent exaggerations. Sweden was not a Utopia; the point in studying its example was on the contrary the pragmatism shown in the Swedes’ attempts to solve everyday problems in a reasonable and genuinely democratic way, negotiating and compromising. As a text implicitly supporting the Roosevelt agenda, Childs’s book was far from encouraging federal dirigisme, expert rule and central planning (“social engineering”): on the contrary the message to other New Dealers was to shun such things in favor of grass-roots activities and initiatives. The predominant theme – the consumers’ cooperation movement’s central role in counteracting monopolies, thus creating economic efficiency and turning Sweden into the world’s only truly working laissez-faire economy – harmonized with Childs’s commitment to projects like the federal rural electrification program, which in a “Swedish” manner was founded on co-ops and a vision of popular self-determination

Effects of bariatric surgery

Globally, 500 million people are obese (body mass index [BMI] ≥30). In Sweden, 14% of the population is obese. Obesity is associated with an increased risk of mortality, cancer and several co morbidities. Bariatric surgery is the only treatment with documented long-term benefits, i.e. decreased mortality and co morbidities and sustainable weight loss. The aim of the thesis was to clarify effects of clinically relevant aspects of bariatric surgery and make comparisons with the general population of corresponding age, sex and calendar period. The included studies are nationwide Swedish population based retrospective cohort studies, comparing defined outcomes before and after bariatric surgery. Study I tested the hypothesis that the risk of obesity-related cancer decreases with increasing time after bariatric surgery. It included 13,123 patients who had undergone bariatric surgery in 1980-2006 in Sweden. Standardised incidence ratios (SIR) were calculated to assess risk. There was no overall decreased risk of cancer with increasing time after bariatric surgery (p for trend 0.4). Rather, the risk of colorectal cancer was increased with time after bariatric surgery (p=0.01). In study II, the risk of in-hospital care for obesity related diseases before and after bariatric surgery in 13,273 patients during 1980-2006 was compared to a matched random sample of 132,730 individuals from the general population. Preoperative incidence rate ratios (IRR) and postoperative hazard ratios (HR) were calculated. The postoperative risk of diabetes, myocardial infarction, hypertension, stroke and angina remained increased compared to the general population. The risk estimates for diabetes (HR 1.2, 95% CI 0.9-1.7) and myocardial infarction (HR 0.8, 0.4-1.5) were lower after gastric bypass than after restrictive bariatric procedures (HR 2.8, 96% CI 2.5-3.1 and HR 1.6, 95% CI 1.4-1.9, respectively). Study III assessed whether cholecystectomy is indicated as part of the bariatric surgery due to the known increased preoperative risk of gallstone formation. The need for cholecystectomy in a bariatric surgery cohort (n=13,443) during 1987-2008 was compared to the general population, and to two cohorts of patients who had undergone antireflux surgery (n=16,176) or appendectomy (n=154,751). An increased need for cholecystectomy after bariatric surgery was confirmed (SIR 5.5, 95% CI 5.1-5.8), but the absolute rate of cholecystectomy was low (8.5%) and the increased SIR after antireflux surgery (SIR 2.4, 95% CI 2.2-2.6) and appendectomy (SIR 1.7, 95% CI 1.6-1.7) indicated detection bias. Study IV addressed the risk of hospital admission for psychiatric disorders, including substance- and alcohol abuse, before (IRR) and after (HR) bariatric surgery was compared to such admissions of the general population. The bariatric surgery cohort (n=12,277) during 1980-2006 was compared to a matched sample from the general population (n=122,770). Patients undergoing bariatric surgery were more likely to be hospitalised for all studied diagnoses prior to surgery compared to the general population, e.g. IRR of depression was 2.8 (95% CI 2.5-3.0). After gastric bypass, there was an increased risk of inpatient care for alcohol abuse compared to those undergoing a restrictive surgical procedure (HR 2.3, 95% CI 1.7-3.2). To conclude, bariatric surgery might not entail any reduced risk of obesity-related cancer with increasing time after surgery. The need for cholecystectomy following bariatric surgery was increased, but prophylactic cholecystectomy might not be generally recommended. Gastric bypass surgery seems to reduce the risk of inpatient care for diabetes and myocardial infarction, but increase the risk of inpatient care for alcohol abuse as compared to restrictive bariatric procedures

Effects of final felling and soil scarification on terrestrial lichens in Swedish forests : a study of differences in coverage area of terrestrial lichens before and after final felling with and without soil scarification

Brukandet av den svenska skogen har intensifierats under det senaste århundradet vilket har lett till en ökning av störningar i skogsekosystemen. Variationen i markvegetationens arter och dess sammansättning är en viktig del av den biologiska mångfalden i skogsekosystemen. Markvegetationen utgör även habitat och föda för många andra skogslevande arter. Både naturliga störningar och antropogena störningar i form av skogsbruksåtgärder påverkar markvegetationen i boreala skogar. Vanliga skogsbruksåtgärder på svensk produktiv skogsmark är slutavverkning i form av kalavverkning samt markberedning. Båda skogsbruksåtgärderna påverkar förekomst och sammansättning av arter i botten- och fältskiktet. Den här studien syftade till att undersöka huruvida slutavverkning och markberedning påverkar täckningsgraden av marklavar i produktiva skogar i Sverige. Riksskogstaxeringens permanenta provytor låg till grund för studien. Studien genomfördes genom att, på 556 provytor, fastställa skillnader i täckningsgrad av marklavar vid två inventeringstillfällen med tio års mellanrum, där provytorna behandlats med slutavverkning utan efterföljande markberedning alternativt med slutavverkning med efterföljande markberedning. De lavar som studerades var uppdelade i grupperna; renlavar (Cladina spp.), tratt- och bägarlavar (Cladonia spp.) samt resterande lavar. Denna studie visade en statistiskt signifikant lägre täckningsgrad av resterande lavar med behandling slutavverkning med efterföljande markberedning. Däremot visades ingen statistiskt signifikant skillnad i täckningsgrad mellan de två olika behandlingarna för varken renlavar eller tratt- och bägarlavar. Studien visade att täckningsgraden av tratt- och bägarlavar samt resterande lavar hade minskat av enbart slutavverkning. Studien visade inte att täckningsgraden av renlavar hade minskat av enbart slutavverkning. Resultaten i denna studie skiljer sig något från resultat i tidigare gjorda studier.The utilization of the Swedish forests has intensified during the past century which has led to an increase in disturbances of the forest ecosystems. The variation of species and their composition in the ground vegetation is an important part of the biodiversity in the forest ecosystems. The ground vegetation also works as habitat and food source for many other forest living species. Both natural disturbances and anthropogenic disturbances like silvicultural measures affects the ground vegetation in the boreal forests. Common silvicultural measures in the productive forests in Sweden are final felling and soil scarification. These measures both affectthe presence and composition of the species in the bottom layer and field layer of the ground vegetation. This study aimed to investigate whether final felling and soil scarification affects the coverage area of terrestrial lichens in productive forests in Sweden. The permanent sample plots of the Swedish National Forest Inventory were the basis for the examination. The study was performed by, on 556 sample plots, determining differences in coverage area of terrestrial lichens between two inventory occasions executed ten years apart, where the sample plots had been treated with final felling without a following soil scarification and final felling with a following soil scarification. The studied lichens were divided into the groups; reindeer lichens (Cladina spp.), cup lichens (Cladonia spp.) and remaining lichens. This study showed a statistically significant lower coverage area of remaining lichens with the treatment final felling with a following soil scarification. However, it showed no statistically significant difference in the coverage area between the two treatments for reindeer lichens nor cup lichens. The study showed that the coverage area of cup lichens and remaining lichens had decreased from final felling solely. The study did not show a decrease in the coverage area of reindeer lichens from the final felling. The results in this study differs slightly from results in previous studies

A Sacred Tree in the Boreal forest: A Narrative About a Sami Shaman, her Tree, and the Forest Landscape

Since the early nineteenth century, forest landscapes and socio-economic contexts have significantly changed in northernmost Sweden. These processes include agrarian colonisation, the Christianisation of the indigenous Sami people, and the transfer of land tenure. We aim to analyse how Sami religious practice manifested itself in a time of dramatic social transition in northern Sweden by focussing on the life and religious practice of a Sami woman known as the shaman Guoksik-gummo, 'the Lady of the Siberian Jay.' We analyse a range of historical records and one specific sacred tree related to her to understand this period better and illuminate the changes in land-use religious practice and landscape transformation between the early nineteenth century and the early twenty-first century. We conclude that better documentation, more vital protection by law of Sami cultural traces in northern landscapes, and better consultation with Sami are needed in the future