University of Iceland

About: University of Iceland is a education organization based out in Reykjavik, Suðurnes, Iceland. It is known for research contribution in the topics: Population & Genome-wide association study. The organization has 5423 authors who have published 16199 publications receiving 694762 citations. The organization is also known as: Háskóli Íslands.

Identification of a large set of rare complete human knockouts

Abstract: Loss-of-function mutations cause many mendelian diseases. Here we aimed to create a catalog of autosomal genes that are completely knocked out in humans by rare loss-of-function mutations. We sequenced the whole genomes of 2,636 Icelanders and imputed the sequence variants identified in this set into 101,584 additional chip-genotyped and phased Icelanders. We found a total of 6,795 autosomal loss-of-function SNPs and indels in 4,924 genes. Of the genotyped Icelanders, 7.7% are homozygotes or compound heterozygotes for loss-of-function mutations with a minor allele frequency (MAF) below 2% in 1,171 genes (complete knockouts). Genes that are highly expressed in the brain are less often completely knocked out than other genes. Homozygous loss-of-function offspring of two heterozygous parents occurred less frequently than expected (deficit of 136 per 10,000 transmissions for variants with MAF <2%, 95% confidence interval (CI) = 10-261).

Late‐glacial and Holocene palaeoceanography of the North Icelandic shelf

Abstract: High-resolution gravity cores and box cores from the North Icelandic shelf have been studied for palaeoceanographic history based on lithological and biostratigraphical foramin- iferal data. Results from two outer shelf cores covering the last 13.6 k 14 C yr BP are presented in this paper. The sediments accumulated in north-south trending basins on each side of the Kolbeinsey Ridge at water depths of ca. 400 m. Sedimentation rates up to 1.5 m kyr -1 are observed during the Late-glacial and Holocene. The Vedde and Saksunarvatn tephras are present in the cores as well as the Hekla 1104. A new tephra, KOL-GS-2, has been identified and dated to 13.4 k 14 C yr BP, and another tephra, geochemically identical to the Borrobol Tephra, has been found at the same level. At present, the oceanographic Polar Front is located on the North Icelandic shelf, which experiences sharp oceanographic surface boundaries between the cold East Icelandic Current and the warmer Irminger Current. Past changes in sedimentological and biological processes in the study area are assumed to be related to fluctuations of the Polar Front. The area was deglaciated before ca. 14 kyr BP, but there is evidence of ice rafting up to the end of the GS-1 (Greenland Stadial 1, Younger Dryas) period, increasing again towards the end of the Holocene. Foraminiferal studies show a relatively strong GS-2 (pre-13 kyr BP) palaeo-Irminger Current, followed by severe cooling and then by unstable conditions during the remainder of the GI-1 (Greenland Interstadial 1, Bolling-Allerod) and GS-1 (Younger Dryas). Another cooling event occurred during the Preboreal before the Holocene current system was established at about 9 kyr BP. After a climatic optimum between 9 and 6 kyr BP the climate began to deteriorate and fluctuate. Copyright © 2000 John Wiley & Sons, Ltd.

Association of Stress-Related Disorders With Subsequent Autoimmune Disease.

Abstract: Importance Psychiatric reactions to life stressors are common in the general population and may result in immune dysfunction. Whether such reactions contribute to the risk of autoimmune disease remains unclear. Objective To determine whether there is an association between stress-related disorders and subsequent autoimmune disease. Design, Setting, and Participants Population- and sibling-matched retrospective cohort study conducted in Sweden from January 1, 1981, to December 31, 2013. The cohort included 106 464 exposed patients with stress-related disorders, with 1 064 640 matched unexposed persons and 126 652 full siblings of these patients. Exposures Diagnosis of stress-related disorders, ie, posttraumatic stress disorder, acute stress reaction, adjustment disorder, and other stress reactions. Main Outcomes and Measures Stress-related disorder and autoimmune diseases were identified through the National Patient Register. The Cox model was used to estimate hazard ratios (HRs) with 95% CIs of 41 autoimmune diseases beyond 1 year after the diagnosis of stress-related disorders, controlling for multiple risk factors. Results The median age at diagnosis of stress-related disorders was 41 years (interquartile range, 33-50 years) and 40% of the exposed patients were male. During a mean follow-up of 10 years, the incidence rate of autoimmune diseases was 9.1, 6.0, and 6.5 per 1000 person-years among the exposed, matched unexposed, and sibling cohorts, respectively (absolute rate difference, 3.12 [95% CI, 2.99-3.25] and 2.49 [95% CI, 2.23-2.76] per 1000 person-years compared with the population- and sibling-based reference groups, respectively). Compared with the unexposed population, patients with stress-related disorders were at increased risk of autoimmune disease (HR, 1.36 [95% CI, 1.33-1.40]). The HRs for patients with posttraumatic stress disorder were 1.46 (95% CI, 1.32-1.61) for any and 2.29 (95% CI, 1.72-3.04) for multiple (≥3) autoimmune diseases. These associations were consistent in the sibling-based comparison. Relative risk elevations were more pronounced among younger patients (HR, 1.48 [95% CI, 1.42-1.55]; 1.41 [95% CI, 1.33-1.48]; 1.31 [95% CI, 1.24-1.37]; and 1.23 [95% CI, 1.17-1.30] for age at ≤33, 34-41, 42-50, and ≥51 years, respectively;Pfor interaction Conclusions and Relevance In this Swedish cohort, exposure to a stress-related disorder was significantly associated with increased risk of subsequent autoimmune disease, compared with matched unexposed individuals and with full siblings. Further studies are needed to better understand the underlying mechanisms.

Antimicrobial polypeptides of human vernix caseosa and amniotic fluid: implications for newborn innate defense.

Abstract: Antimicrobial peptides/proteins are widespread in nature and play a critical role in host defense. To investigate whether these components contribute to surface protection of newborns at birth, we have characterized antimicrobial polypeptides in vernix caseosa (vernix) and amniotic fluid (AF). Concentrated peptide/protein extracts were obtained from 11 samples of vernix and six samples of AF and analyzed for antimicrobial activity using an inhibition zone assay. Proteins/peptides in all vernix extracts exhibited strong antibacterial activity against Bacillus megaterium (strain Bm11), in addition to antifungal activity against Candida albicans, whereas AF-derived proteins/peptides showed only the former activity. Fractions obtained after separation by reverse-phase HPLC exhibited antibacterial activity, with the most pronounced activity in a fraction containing alpha-defensins (HNP1-3). The presence of HNP1-3 was proved by dot blot analysis and confirmed by mass spectrometry. Lysozyme and ubiquitin were identified by sequence analysis in two fractions with antibacterial activity. Fractions of vernix and AF were also positive for LL-37 with dot blot and Western blot analyses, and one fraction apparently contained an extended form of LL-37. Interestingly, psoriasin, a calcium-binding protein that is up-regulated in psoriatic skin and was found recently to exhibit antimicrobial activity, was characterized in the vernix extract. The presence of all of these antimicrobial polypeptides in vernix suggests that they are important for surface defense and may have an active biologic role against microbial invasion at birth.