Swedish Institute

About: Swedish Institute is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Health care. The organization has 1657 authors who have published 2301 publications receiving 103682 citations. The organization is also known as: Svenska Institutet.

High affinity antibodies to Plasmodium falciparum merozoite antigens are associated with protection from malaria

Abstract: Malaria kills almost 1 million people every year, but the mechanisms behind protective immunity against the disease are still largely unknown. In this study, surface plasmon resonance technology was used to evaluate the affinity (measured as k(d)) of naturally acquired antibodies to the Plasmodium falciparum antigens MSP2 and AMA1. Antibodies in serum samples from residents in endemic areas bound with higher affinities to AMA1 than to MSP2, and with higher affinities to the 3D7 allele of MSP2-3D7 than to the FC27 allele. The affinities against AMA1 and MSP2-3D7 increased with age, and were usually within similar range as the affinities for the monoclonal antibodies also examined in this study. The finding of MSP2-3D7 type parasites in the blood was associated with a tendency for higher affinity antibodies to both forms of MSP2 and AMA1, but this was significant only when analyzing antibodies against MSP2-FC27, and individuals infected with both allelic forms of MSP2 at the same time showed the highest affinities. Individuals with the highest antibody affinities for MSP2-3D7 at baseline had a prolonged time to clinical malaria during 40 weeks of follow-up, and among individuals who were parasite positive at baseline higher antibody affinities to all antigens were seen in the individuals that did not experience febrile malaria during follow up. This study contributes important information for understanding how immunity against malaria arises. The findings suggest that antibody affinity plays an important role in protection against disease, and differs between antigens. In light of this information, antibody affinity measurements would be a key assessment in future evaluation of malaria vaccine formulations.

Accuracy and cut-off values of pepsinogens I, II and gastrin 17 for diagnosis of gastric fundic atrophy: influence of gastritis.

Abstract: Background: To establish optimal cutoff values for serologic diagnosis of fundic atrophy in a high-risk area for oesophageal squamous cell carcinoma and gastric cancer with high prevalence of Helicobacter pylori (H. pylori) in Northern Iran, we performed an endoscopy-room-based validation study. Methods: We measured serum pepsinogens I (PGI) and II (PGII), gastrin 17 (G-17), and antibodies against whole H. pylori, or cytotoxin-associated gene A (CagA) antigen among 309 consecutive patients in two major endoscopy clinics in northeastern Iran. Updated Sydney System was used as histology gold standard. Areas under curves (AUCs), optimal cutoff and predictive values were calculated for serum biomarkers against the histology. Results: 309 persons were recruited (mean age: 63.5 years old, 59.5% female). 84.5% were H. pylori positive and 77.5% were CagA positive. 21 fundic atrophy and 101 nonatrophic pangastritis were diagnosed. The best cutoff values in fundic atrophy assessment were calculated at PGI 40 pmol/l was 81% sensitive and 73.3% specific for diagnosing fundic atrophy. At cutoff concentration of 11.8 μg/l, PGII showed 84.2% sensitivity and 45.4% specificity to distinguish nonatrophic pangastritis. Exclusion of nonatrophic pangastritis enhanced diagnostic ability of PGI/PGII ratio (from AUC = 0.66 to 0.90) but did not affect AUC of PGI. After restricting study samples to those with PGII<11.8, the sensitivity of using PGI<56 to define fundic atrophy increased to 83.3% (95%CI 51.6-97.9) and its specificity decreased to 88.8% (95%CI 80.8-94.3). Conclusions: Among endoscopy clinic patients, PGII is a sensitive marker for extension of nonatrophic gastritis toward the corpus. PGI is a stable biomarker in assessment of fundic atrophy and has similar accuracy to PGI/PGII ratio among populations with prevalent nonatrophic pangastritis. © 2011 Nasrollahzadeh et al.

Prevalence of tick‐borne encephalitis virus in Ixodes ricinus ticks in Finland

Abstract: Approximately 20 cases of tick-borne encephalitis (TBE) occur annually in Finland. The known endemic areas are situated mainly in the archipelago and coastal regions of Finland, with highest incidence in Aland islands. Ixodes ricinus panels collected in 1996–1997 from two endemic areas were screened for the presence of RNA. Two distinct RT-PCR methods were applied, and were shown to have an approximate detection limit of 10 focus forming doses (FFD)/100 μl. One out of 20 pools (a total of 139 ticks) from Helsinki Isosaari Island and one out of 48 pools (a total of 450 ticks) from Aland were positive with both methods, whereas the remaining pools were negative. The observed overall frequency (0.34%) in ticks in endemic areas of Finland, was similar to the low incidence found by virus isolation in mice in the 1960s (0.5%). Viral RNA was detectable in a diluted sample representing 0.005% of a positive pool of ten nymphs suggesting that the viral RNA load within an infected tick pool was approximately equivalent to 20,000–200,000 FFD. Sequence analysis did not show geographical clustering of the Finnish strains, suggesting an independent emergence of different TBE foci from the south. TBE virus RNA positive ticks were not found in I. ricinus panels consisting of 130 pools (726 ticks) from Helsinki city parks or 41 pools (197 ticks) from Vormsi Island in Estonia. J. Med. Virol. 64:21–28, 2001. © 2001 Wiley-Liss, Inc.

Change in quality of life of people with dementia recently admitted to long-term care facilities.

Abstract: AimTo assess which factors are associated with change in quality of life of people with dementia who have recently been admitted to long-term care facilities. BackgroundMany people with dementia will be admitted to long-term care facilities at some point during their disease. It is currently unknown which factors are associated with improvement and/or deterioration of quality of life immediately following admission. DesignAn observational and longitudinal survey. MethodsData on 343 people with dementia who have been recently admitted to long-term care facilities across eight European countries were collected between November 2010-April 2012. Quality of life was assessed by people with dementia and their proxies using the Quality of Life-Alzheimer's Disease scale'. Explanatory variables included cognitive status, comorbidities, activities of daily living, depressive symptoms and neuropsychiatric symptoms. Descriptive and multilevel regression analyses were performed. ResultsBetter cognitive abilities at baseline were associated with a decrease in self-reported quality of life. Greater dependency and more depressive symptoms at baseline were associated with declined proxy-reported quality of life. Furthermore, an increased dependency and an increase of depressive symptoms between baseline and follow-up were associated with a decreased proxy-reported quality of life. On an individual level, three groups were identified, namely people whose quality of life: (1) decreased; (2) stayed the same; and (3) increased. ConclusionCognitive functioning, functional rehabilitation and treatment of depressive symptoms should receive special attention. However, quality of life of people with dementia does not necessarily decrease after institutionalization. (Less)