| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Patterson, Nick, et al.
(författare)
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Large-scale migration into Britain during the Middle to Late Bronze Age
- 2022
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; , s. 588-594
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Tidskriftsartikel (refereegranskat)abstract
- Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000 and 875 BC, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2-6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain's independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period.
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| 4. |
- Wilson, Jeffrey M., et al.
(författare)
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α-Gal specific-IgE prevalence and levels in Ecuador and Kenya : Relation to diet, parasites, and IgG4
- 2021
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 147:4, s. 1393-1401.e7
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Tidskriftsartikel (refereegranskat)abstract
- Background: IgE to α-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate that α-Gal sensitization is prevalent but has been little investigated. Objective: We sought evidence for the cause(s) of α-Gal sensitization and lack of reported meat allergy among children in less developed settings in Ecuador and Kenya. Methods: IgE to α-Gal and total IgE were assessed in children from Ecuador (n = 599) and Kenya (n = 254) and compared with children with (n = 42) and without known (n = 63) mammalian meat allergy from the southeastern United States. Information on diet, potential risk factors, and helminth infections was available for children from Ecuador. IgG4 to α-Gal and antibodies to regionally representative parasites were assessed in a subset of children. Results: In Ecuador (32%) and Kenya (54%), α-Gal specific IgE was prevalent, but levels were lower than in children with meat allergy from the United States. Sensitization was associated with rural living, antibody markers of Ascaris exposure, and total IgE, but not active infections with Ascaris or Trichuris species. In Ecuador, 87.5% reported consuming beef at least once per week, including 83.9% of those who had α-Gal specific IgE. Levels of α-Gal specific IgG4 were not high in Ecuador, but were greater than in children from the United States. Conclusions: These results suggest that in areas of the developing world with endemic parasitism, α-Gal sensitization is (1) common, (2) associated with Ascaris exposure, and (3) distinguished by a low percentage of specific/total IgE compared with individuals with meat allergy in the United States.
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| 5. |
- Commins, Scott P., et al.
(författare)
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The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose-alpha-1,3-galactose
- 2011
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 127:5, s. 1286-1293.e6
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Tidskriftsartikel (refereegranskat)abstract
- Background: In 2009, we reported a novel form of delayed anaphylaxis to red meat that is related to serum IgE antibodies to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Most of these patients had tolerated meat for many years previously. The implication is that some exposure in adult life had stimulated the production of these IgE antibodies. Objectives: We sought to investigate possible causes of this IgE antibody response, focusing on evidence related to tick bites, which are common in the region where these reactions occur.Methods: Serum assays were carried out with biotinylated proteins and extracts bound to a streptavidin ImmunoCAP.Results: Prospective studies on IgE antibodies in 3 subjects after tick bites showed an increase in levels of IgE to alpha-gal of 20fold or greater. Other evidence included (1) a strong correlation between histories of tick bites and levels of IgE to alpha-gal (chi(2) = 26.8, P < .001), (2) evidence that these IgE antibodies are common in areas where the tick Amblyomma americanum is common, and (3) a significant correlation between IgE antibodies to alpha-gal and IgE antibodies to proteins derived from A americanum (r(s) = 0.75, P < .001).Conclusion: The results presented here provide evidence that tick bites are a cause, possibly the only cause, of IgE specific for alpha-gal in this area of the United States. Both the number of subjects becoming sensitized and the titer of IgE antibodies to alpha-gal are striking. Here we report the first example of a response to an ectoparasite giving rise to an important form of food allergy.
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| 6. |
- James, Hayley R, et al.
(författare)
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IgE Antibodies to Mammalian Allergens Are a Major Risk Factor for Prevalence, Severity, and Persistence of Asthma in Northern Sweden
- 2015
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 135:2, s. AB22-AB22
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- IgE to mammalian allergens can contribute significantly to asthma risk. Studying the details of the relationship between animal sensitization and asthma is simpler in an environment where mite, fungal, and cockroach allergens make little or no contribution to asthma risk. Methods: Quantitative assays for IgE to eight allergens were carried out on 963 sera from 19-year-olds in a population-based cohort in northern Sweden, and associations with questionnaire data from ages 7, 12, and 19 on asthma symptoms, diagnosis, and treatment were tested. Results: Overall, 79 (53%) of the students with a physician diagnosis of asthma were positive to one or more of the mammalian allergens (cat, dog, or horse danders) tested. Of the allergens assessed, only mammalian allergens, birch, and timothy grass pollen showed a significant relationship with asthma diagnosis. Multivariate analysis showed that high titer (>17.5 IU/ml) IgE to any mammalian allergen had the strongest relationship with asthma at age 19 (odds ratio 5.1 [3.0-8.6]). Furthermore, IgE to mammalian allergens gave an odds ratio of 8.5 [4.9-15] for asthma that started before age 12 and was still present at age 19. Sensitization to Fel d 1 and Fel d 4 was strongly associated with asthma and significantly reduced in cat owners. Conclusions: Sensitization to cat and dog related allergens, and specifically to the components Fel d 1 and Fel d 4, is a major risk factor for the persistence and severity of asthma in an area where these are the only significant perennial allergens.
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| 7. |
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| 8. |
- Schuyler, Alexander J, et al.
(författare)
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Quantitative Binding Assay for Measuring Specific IgG Antibodies to Alpha-Gal Using the Neoglycoprotein Gal-alpha-1,3-Gal-beta-1,4-Glcnac-Human Serum Albumin
- 2015
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 135:2, s. AB188-AB188
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Tick bites are known to induce IgE production to alpha-gal. Elevated alpha-gal IgG1 compared to natural alpha-gal IgG2 production has been reported in alpha-gal IgE+ subjects. We here report further investigation of the relationship between alpha-gal IgG and both reactions to red meat and exposure to ticks. Methods: IgG from serum was absorbed onto recombinant Protein G-Sepharose and incubated with radiolabeled allergen. The radioactivity of bound allergen was measured using a gamma counter. A control curve was generated in parallel to assign unitage. Additional testing of serum immunoglobulins was performed via ImmunoCAP and nephelometry. Results: Alpha-gal IgG was measured in a Northern Sweden cohort and in subjects presenting to allergy clinics in Virginia with delayed reactions to red meat. Alpha-gal IgG was significantly higher in alpha-gal IgE+ subjects versus alpha-gal IgE- subjects, and longitudinal serology in several alpha-gal IgE+ subjects demonstrates parallel alpha-gal IgE and IgG response trends. Among the alpha-gal IgE+ subjects, alpha-gal IgG was higher in those with alpha-gal IgE:total IgE ratios >25%, but was not related to reported severity to red meat. Compared to the alpha-gal IgE- subjects in Virginia, alpha-gal IgG was lower in the group from Northern Sweden, where alpha-gal IgE-mediated hypersensitivity is absent and ticks are rare. Conclusions: Alpha-gal IgG is strongly related to alpha-gal IgE and is significantly lower in prevalence and titer in subjects without tick exposure. The absence of a relationship between alpha-gal IgG and severity of reactions to red meat suggests that the alpha-gal syndrome may not be a suitable candidate for conventional immunotherapy.
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| 9. |
- Wilson, Jeffrey M., et al.
(författare)
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A dynamic relationship between two regional causes of IgE-mediated anaphylaxis : alpha-Gal syndrome and imported fire ant
- 2021
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 147:2, s. 643-652.e7
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Tidskriftsartikel (refereegranskat)abstract
- Background: A syndrome of mammalian meat allergy relating to IgE specific for galactose-alpha-1,3-galactose (alpha-Gal) was first reported 10 years ago in the southeastern United States and has been related to bites of the lone star tick (Amblyomma americanum).Objective: Here we investigated the epidemiology of the "alpha-Gal syndrome'' in the United States and sought additional evidence for the connection to tick bites.Methods: A survey of allergists was conducted by using a snowball approach. A second tier of the survey included questions about anaphylaxis to imported fire ants (IFAs). History of tick bites and tick-related febrile illness were assessed as part of a case-control study in Virginia. Antibody assays were conducted on sera from subjects reporting allergic reactions to mammalian meat or IFA.Results: In North America the alpha-Gal syndrome is recognized across the Southeast, Midwest, and Atlantic Coast, with many providers in this area managing more than 100 patients each. The distribution of cases generally conformed to the reported range of A americanum, although within this range there was an inverse relationship between alpha-Gal cases and cases of IFA anaphylaxis that were closely related to the territory of IFA. The connection between tick bites and alpha-Gal sensitization was further supported by patients' responses to a questionnaire and the results of serologic tests.Conclusions: The alpha-Gal syndrome is commonly acquired in adulthood as a consequence of tick bites and has a regional distribution that largely conforms to the territory of the lone star tick. The epidemiology of the syndrome is expected to be dynamic and shifting north because of climate change and ecologic competition from IFA.
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| 10. |
- Lawrence, Monica G, et al.
(författare)
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Undetectable Serum IgE Is a Sensitive and Specific Marker of Common Variable Immunodeficiency (CVID)
- 2015
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 135:2, s. AB275-AB275
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Common variable immunodeficiency (CVID) is characterized by antibody deficiency and recurrent infections as well as autoimmunity, lymphoproliferation, and hematologic malignancy. The current diagnostic criteria for CVID include reduction in serum immunoglobulin (Ig)G and either IgA or IgM and failure of antibody production. Serum IgE level is not currently considered in establishing the diagnosis of CVID. Methods: A cohort of 123 subjects from the University of Virginia Health Systems, Medical College of Wisconsin and Mount Sinai School of Medicine were diagnosed with CVID by an experienced immunologist on the basis of currently accepted diagnostic criteria, including clinical history, serum IgG, IgA and IgM, and antibody response to vaccinations. Serum IgE was measured in all of these subjects using the Phadia ImmunoCap system. Serum IgE was also measured in an unbiased control cohort of 963 healthy 17-18 year olds from northern Sweden. Results: The prevalence of undetectable (<2 IU/ml) total serum IgE in our cohort of 123 subjects with CVID was 84.6% and the prevalence of IgE <10 IU/ml was 97.6%. In comparison, IgE <2 IU/ml was found in only 3.8% of controls, in agreement with other published population estimates. Conclusions: The finding of an undetectable (<2 IU/ml) serum IgE has both a high sensitivity of 84.6% and a high specificity of 96.2% for the diagnosis of CVID. Based on this observation, measurement of serum IgE should be included as a part of the routine laboratory work-up for CVID, and an undetectable serum IgE included as a component of the diagnostic criteria.
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