Papers by Ragnar Bjarnason
Arteriosclerosis, Thrombosis, and Vascular Biology
Objective: Familial hypercholesterolemia (FH) is traditionally defined as a monogenic disease cha... more Objective: Familial hypercholesterolemia (FH) is traditionally defined as a monogenic disease characterized by severely elevated LDL-C (low-density lipoprotein cholesterol) levels. In practice, FH is commonly a clinical diagnosis without confirmation of a causative mutation. In this study, we sought to characterize and compare monogenic and clinically defined FH in a large sample of Icelanders. Approach and Results: We whole-genome sequenced 49 962 Icelanders and imputed the identified variants into an overall sample of 166 281 chip-genotyped Icelanders. We identified 20 FH mutations in LDLR , APOB , and PCSK9 with combined prevalence of 1 in 836. Monogenic FH was associated with severely elevated LDL-C levels and increased risk of premature coronary disease, aortic valve stenosis, and high burden of coronary atherosclerosis. We used a modified version of the Dutch Lipid Clinic Network criteria to screen for the clinical FH phenotype among living adult participants (N=79 058). Clini...
Cells
Fertility preservation for male childhood cancer survivors not yet capable of producing mature sp... more Fertility preservation for male childhood cancer survivors not yet capable of producing mature spermatozoa, relies on experimental approaches such as testicular explant culture. Although the first steps in somatic maturation can be observed in human testicular explant cultures, germ cell depletion is a common obstacle. Hence, understanding the spermatogonial stem cell (SSC) niche environment and in particular, specific components such as the seminiferous basement membrane (BM) will allow progression of testicular explant cultures. Here, we revealed that the seminiferous BM is established from 6 weeks post conception with the expression of laminin alpha 1 (LAMA 1) and type IV collagen, which persist as key components throughout development. With prepubertal testicular explant culture we found that seminiferous LAMA 1 expression is disrupted and depleted with culture time correlating with germ cell loss. These findings highlight the importance of LAMA 1 for the human SSC niche and its...
Journal of pediatric psychology, 2018
To assess additive effects of incorporating appetite awareness training (AAT), a strategy to enco... more To assess additive effects of incorporating appetite awareness training (AAT), a strategy to encourage eating in response to hunger and satiety cues, within a family-based behavioral treatment (FBT) for childhood obesity. Total 84 families with a child with obesity in the age range of 8-12 years, Body Mass Index Standard Deviation Score (BMI-SDS) ≥ 2, and a participating parent were randomly allocated to two conditions; standard FBT was compared with FBT incorporating AAT strategies (FBT-AAT). Treatment consisted of group therapy sessions (held separately for children and parents) as well as single-family (parent-child dyad) sessions (24 sessions total) delivered over 18 weeks at a tertiary care outpatient clinic. One booster session was provided 1-year posttreatment and a final follow-up assessment was conducted at 2 years. The primary outcome was change in child standardized body mass index (BMI-SDS). The two conditions did not differ significantly at posttest, but the FBT-AAT gr...
Acta paediatrica (Oslo, Norway : 1992), 2018
This study investigated the associations, by sex, between sleep and adiposity, dietary habits, ca... more This study investigated the associations, by sex, between sleep and adiposity, dietary habits, cardiorespiratory fitness and metabolic risk in 18-year-old students. We carried out a cross-sectional study of 199 randomly chosen, healthy 18-year-old students (53% girls) in Iceland's capital region. The data collection took place in the winter months of 2012 to 2015. The anthropometric measurements were body mass index, waist circumference and body fat percentage. Sleep duration and dietary habits were self-reported. Cardiorespiratory fitness was measured on a stationary bicycle. A subsample of 152 participants gave blood samples. A quarter of the adolescents failed to reach the minimum recommended sleep duration of seven hours per night on weekdays. In girls, the average sleep score was associated with body mass index and waist circumference, after adjusting for cardiorespiratory fitness and unhealthy eating scores. In boys, the average sleep score was not associated with anthropo...
International Journal of Exercise Science Conference Proceedings, 2011
Laeknabladid, Mar 1, 2014
Laeknabladid, Feb 1, 2011
Laeknablađiđ, May 1, 2010
Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/Open ... more Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/Open INTRODUCTION: The importance of adequate metabolic control in Type 1 DM has been repeatedly demonstrated in recent years. The care of diabetic children and adolescents in Iceland is centralized to one unit. The aim of the study was to analyze the quality of treatment and acute complications of Icelandic children with Type 1 diabetes. METHODOLOGY: The total number of diabetic children in paediatric care was 98. A cross-sectional survey was done for the period March 15th to July 14th, 2004. The results for the patient last visit to the diabetes clinic were recorded. HbA1c levels (DCA 2000) and number of severe hypoglycaemic episodes, were evaluated. RESULTS: The number of visits to the clinic during the 4 month interval were 83 (43 boys, 40 girls), mean age 13.3+/-3.78 years. Mean value of HbA1c in the cross-sectional survey was 8.16+/-1.31%. No difference in HbA1c was found between girls ...
Læknablađiđ, 2011
Pulmonary embolism is an uncommon but potentially life threatening disease in children and adoles... more Pulmonary embolism is an uncommon but potentially life threatening disease in children and adolescents. The clinical findings can be similar to other more common conditions such as pneumonia. Therefore high level of suspicion is required for early and accurate diagnosis. Most children have at least one underlying risk factor, either inherited or acquired. Computed tomography is the most widely used method in diagnosing pulmonary embolism. Anticoagulation is the mainstay of therapy for pulmonary embolism, however, acute surgery may be required for removal of the embolism. We report a case of pulmonary embolism in a teenage girl with serious circulatory failure where emergency surgery was needed.
Scandinavian journal of plastic and reconstructive surgery and hand surgery / Nordisk plastikkirurgisk forening [and] Nordisk klubb for handkirurgi, 1991
A 4-year-old girl with scattered full-thickness skin and soft tissue wounds mainly on the extremi... more A 4-year-old girl with scattered full-thickness skin and soft tissue wounds mainly on the extremities and corresponding to roughly 35% of the total body surface area was treated with early excision and transplantation of cultured autologous epidermal grafts. The transplantation was accomplished in one stage, three weeks after admission. The epidermal cells were cultured in Stockholm, Sweden and the time of transportation of the grafts to Reykjavik, Iceland (seven hours) did not seem to affect the quality, as 85% had taken one week after transplantation. The patient healed completely without further transplantation, but a few local skin flaps were needed to cover exposed articular surfaces. The patient was discharged from hospital with stable grafts five weeks after transplantation.
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Papers by Ragnar Bjarnason