| 1. |
- Alsved, Malin, et al.
(författare)
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Droplet, aerosol and SARS-CoV-2 emissions during singing and talking
- 2021
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Konferensbidrag (refereegranskat)abstract
- IntroductionAs the pandemic continues to spread, more knowledge is needed about the viral transmission routes. Several super spreading events during the Covid-19 pandemic have been linked to singing in choirs and talking loud. However, in the beginning of the pandemic there was only one study about emitted aerosols and droplets from singing, published in 1968, and only a handful on emissions from talking. Therefore, we conducted a study to measure the aerosol and droplet emissions from talking and singing. We also evaluated the emissions from singing when wearing a face mask.We have further developed our setup so that we collect the aerosol particles from Covid-19 infected patients that are talking and singing, and analyze our samples for SARS-CoV-2, the virus causing Covid-19.MethodTwelve healthy singers (7 professionals, 5 amateurs) were included in the first study part on quantifying the amount of emitted aerosols and droplets. The singers were singing or talking a short consonant rich text repeatedly at a constant pitch with their face in the opening of a funnel. The aerosol particle size and concentration was measured from the other end of the funnel using an aerodynamic particle sizer (APS, 3321, TSI Inc). In addition, the amount of un-evaporated droplets were captured with a high-speed camera and quantified using image analysis.During February and March 2021 we will collect aerosol particles from patients with confirmed Covid-19 that are singing and talking into a funnel. We will use a growth tube condensation collector, a BioSpot (Aerosol Devices), operating at 8 L min-1, and a NIOSH BC-251 cyclone sampler operating at 3.5 L min-1 (TISCH Environmental). The BioSpot collects the whole range of exhaled aerosol particles with high (95%) efficiency into liquid, and the NIOSH cyclone sampler collects particles into three size fractions: <1 µm (filter), 1-4 µm (liquid), >4 µm (liquid). The APS is again used to measure size and concentration of the emitted aerosol particles, so that emissions from infected test subjects can be compared with those of the healthy test subjects. Air samples will be analyzed for detection of SARS-CoV-2 genes, and if possible, SARS-CoV-2 infectivity in cell cultures.ResultsAerosol particle emissions from healthy test subjects were significantly higher during normal singing (median 690, range [320–2870] particles/s) than during normal talking (270 [120–1380] particles/s) (Wilcoxon’s signed rank test, p=0.002). Loud singing produced even more aerosol particles (980 [390–2870] particles/s) than normal singing (p=0.002). The amount of non-evaporated droplets detected by the high-speed camera setup showed similar results: more droplets during loud singing or talking. For both aerosol particle concentrations and droplet numbers, the levels were reduced by on average 70-80% when wearing a surgical face mask.ConclusionsSinging and talking give rise to high aerosol and droplet emissions from the respiratory tract. This is likely an important transmission route for Covid-19. In our upcoming part of the study we hope to determine how much SARS-CoV-2 that is emitted during these social activities.
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| 2. |
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| 3. |
- Alsved, Malin, et al.
(författare)
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Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes
- 2023
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Ingår i: Scientific Reports. - 2045-2322. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Exhaled SARS-CoV-2-containing aerosols contributed significantly to the rapid and vast spread of covid-19. However, quantitative experimental data on the infectivity of such aerosols is missing. Here, we quantified emission rates of infectious viruses in exhaled aerosol from individuals within their first days after symptom onset from covid-19. Six aerosol samples from three individuals were culturable, of which five were successfully quantified using TCID50. The source strength of the three individuals was highest during singing, when they exhaled 4, 36, or 127 TCID50/s, respectively. Calculations with an indoor air transmission model showed that if an infected individual with this emission rate entered a room, a susceptible person would inhale an infectious dose within 6 to 37 min in a room with normal ventilation. Thus, our data show that exhaled aerosols from a single person can transmit covid-19 to others within minutes at normal indoor conditions.
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| 4. |
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| 5. |
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| 6. |
- Alsved, Malin, et al.
(författare)
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SARS-CoV-2 in aerosol particles exhaled from COVID-19 infected patients during breathing, talking and singing
- 2021
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Konferensbidrag (refereegranskat)abstract
- In the beginning of the COVID-19 pandemic, several super spreader events occurred during singing in choirs, which lead to an increased attention to airborne transmission of SARS-CoV-2, the virus causing COVID-19. Since then, aerosol generation from singing has been studied in more detail, however, only from healthy subjects. In this study, we collected aerosol particles in the exhaled breath of 40 COVID-19 infected patients during breathing, talking and singing, respectively, and analysed the samples for detection of SARS-CoV-2.MethodPatients that were contacted by the COVID-19 testing service due to a positive test result were asked to volunteer for the study. A team of researchers drove a small truck hosting a mobile laboratory to the home address of the patient to perform exhaled breath aerosol collection using a condensational particle collector (BioSpot, Aerosol Devices) and a two-stage cyclone sampler (NIOSH bc-251, Tisch Environmental). Samples were collected for 10 min each when the patient was breathing, talking and singing, respectively.All samples were stored at -80°C until RNA extraction and analysis by reverse transcription quantitative polymerase chain reaction (RT-qPCR) targeting the N-gene.ResultsA first screening of air samples collected with the BioSpot showed that SARS-CoV-2 could be detected in the exhaled aerosols from three of nine patients during singing or talking. Two of these samples contained 103 and 104 viral RNA copies, corresponding to a viral emission rate of approximately 4 and 25 viruses per second, respectively. Samples from the remaining 31 patients are to be analysed during the spring. We hope to contribute to quantifying and understanding the Covid-19 transmission via the airborne route.This study was approved by the Swedish Ethics Review Authority (2020-07103). This work was supported by AFA Insurances and the Swedish Research Council FORMAS.
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| 7. |
- Alsved, Malin, et al.
(författare)
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SARS-CoV-2 in aerosol particles exhaled from COVID-19 infected patients during breathing, talking and singing
- 2021
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Konferensbidrag (refereegranskat)abstract
- In the beginning of the COVID-19 pandemic, several super spreader events occurred during choir singing, which lead to an increased attention to airborne transmission of SARS-CoV-2. Since then, aerosol generation from singing has been studied in detail, however, mainly from healthy subjects. In this study, we collected aerosol particles in the exhaled breath of 38 COVID-19 infected patients during breathing, talking and singing, respectively, and analyzed the samples for detection of SARS-CoV-2.MethodPatients that were contacted by the COVID-19 testing service due to a positive test result early in the phase of their infection (median 2, range: 0-6 days from symptom onset) were asked to volunteer for the study. A team of researchers drove a small truck hosting a mobile laboratory to the home address of the patient to perform exhaled breath aerosol collection using a condensational particle collector (BioSpot, Aerosol Devices) and a two-stage cyclone sampler (NIOSH bc-251, Tisch Environmental). Samples were collected for 10 min each when the patients were breathing, talking and singing, respectively. In addition, patient samples from nasopharynx and saliva were collected, and patients filled out a questionnaire about symptoms. All samples were stored at -80 °C until RNA extraction and analysis by reverse transcription quantitative polymerase chain reaction (RT-qPCR) targeting the N-gene.ResultsA first preliminary screening of air samples collected with the BioSpot showed that SARS-CoV-2 could be detected in the exhaled aerosols from 14 of 38 (37%) patients during respiratory activities. 50% of patients in the early phase of the infection, day 0-1 from symptom onset, emitted detectable levels of airborne SARS-CoV-2 RNA, 35% of patients on day 2-3, and 0% of patients on day 4-6. The highest viral RNA concentrations in aerosol samples were found in those collected during singing. Further analysis is ongoing and we hope that our results will contribute to quantifying and understanding the Covid-19 transmission via the airborne route.This study was approved by the Swedish Ethics Review Authority (2020-07103). This work was supported by AFA Insurances and the Swedish Research Council FORMAS.
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| 8. |
- Alsved, Malin, et al.
(författare)
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SARS-CoV-2 in exhaled aerosol particles from covid-19 cases and its association to household transmission
- 2022
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Ingår i: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 75:1, s. 50-56
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Covid-19 transmission via exhaled aerosol particles has been considered an important route for the spread of infection, especially during super-spreading events involving loud talking or singing. However, no study has previously linked measurements of viral aerosol emissions to transmission rates.METHODS: During Feb-Mar 2021, covid-19 cases that were close to symptom onset were visited with a mobile laboratory for collection of exhaled aerosol particles during breathing, talking and singing, respectively, and of nasopharyngeal and saliva samples. Aerosol samples were collected using a BioSpot-VIVAS and a NIOSH bc-251 two-stage cyclone, and all samples were analyzed by RT-qPCR for SARS-CoV-2 RNA detection. We compared transmission rates between households with aerosol-positive and aerosol-negative index cases.RESULTS: SARS-CoV-2 RNA was detected in at least one aerosol sample from 19 of 38 (50%) included cases. The odds ratio of finding positive aerosol samples decreased with each day from symptom onset (OR 0.55, 95CI 0.30-1.0, p=0.049). The highest number of positive aerosol samples were from singing, 16 (42%), followed by talking, 11 (30%), and the least from breathing, 3 (8%). Index cases were identified for 13 households with 31 exposed contacts. Higher transmission rates were observed in households with aerosol-positive index cases, 10/16 infected (63%), compared to households with aerosol-negative index cases, 4/15 infected (27%) (Chi-square test, p=0.045).CONCLUSIONS: Covid-19 cases were more likely to exhale SARS-CoV-2-containing aerosol particles close to symptom onset and during singing or talking as compared to breathing. This study supports that individuals with SARS-CoV-2 in exhaled aerosols are more likely to transmit covid-19.
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| 9. |
- Alsved, Malin, et al.
(författare)
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Size distribution of exhaled aerosol particles containing SARS-CoV-2 RNA
- 2023
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 55:2, s. 158-163
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Tidskriftsartikel (refereegranskat)abstract
- Background: SARS-CoV-2 in exhaled aerosols is considered an important contributor to the spread of COVID-19. However, characterizing the size distribution of virus-containing aerosol particles has been challenging as high concentrations of SARS-CoV-2 in exhaled air is mainly present close to symptom onset. We present a case study of a person with COVID-19 who was able to participate in extensive measurements of exhaled aerosols already on the day of symptom onset and then for the following three days. Methods: Aerosol collection was performed using an eight-stage impactor while the subject was breathing, talking and singing, for 30 min each, once every day. In addition, nasopharyngeal samples, saliva samples, room air samples and information on symptom manifestations were collected every day. Samples were analyzed by RT-qPCR for detection of SARS-CoV-2 RNA. Results: SARS-CoV-2 RNA was detected in seven of the eight particle size fractions, from 0.34 to >8.1 µm, with the highest concentrations found in 0.94–2.8 µm particles. The concentration of SARS-CoV-2 RNA was highest on the day of symptom onset, and declined for each day thereafter. Conclusion: Our data showed that 90% of the exhaled SARS-CoV-2 RNA was found in aerosol particles <4.5 µm, indicating the importance of small particles for the transmission of COVID-19 close to symptom onset. These results are important for our understanding of airborne transmission, for developing accurate models and for selecting appropriate mitigation strategies.
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| 10. |
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| 11. |
- Hussein, Tareq, et al.
(författare)
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Indoor model simulation for covid-19 transport and exposure
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 18:6
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Tidskriftsartikel (refereegranskat)abstract
- Transmission of respiratory viruses is a complex process involving emission, deposition in the airways, and infection. Inhalation is often the most relevant transmission mode in indoor environments. For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the risk of inhalation transmission is not yet fully understood. Here, we used an indoor aerosol model combined with a regional inhaled deposited dose model to examine the indoor transport of aerosols from an infected person with novel coronavirus disease (COVID-19) to a susceptible person and assess the potential inhaled dose rate of particles. Two scenarios with different ventilation rates were compared, as well as adult female versus male recipients. Assuming a source strength of 10 viruses/s, in a tightly closed room with poor ventilation (0.5 h−1 ), the respiratory tract deposited dose rate was 140–350 and 100–260 inhaled viruses/hour for males and females; respectively. With ventilation at 3 h−1 the dose rate was only 30–90 viruses/hour. Correcting for the half-life of SARS-CoV-2 in air, these numbers are reduced by a factor of 1.2–2.2 for poorly ventilated rooms and 1.1–1.4 for well-ventilated rooms. Combined with future determinations of virus emission rates, the size distribution of aerosols containing the virus, and the infectious dose, these results could play an important role in understanding the full picture of potential inhalation transmission in indoor environments.
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| 12. |
- Löndahl, Jakob, et al.
(författare)
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Luftvägsvirus vid arbetsplatser - Smittvägar, riskfaktorer och skyddsåtgärder
- 2021
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Ingår i: Arbete och hälsa. - 0346-7821. ; 55:2, s. 1-53
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Tidskriftsartikel (refereegranskat)abstract
- Att spridning av sjukdomsframkallande luftvägsvirus kostar samhället enorma resurser har blivit uppenbart för alla under covid-19, men ovälkomna virus har varit människans följeslagare genom hela historien och ständigt uppkommer nya varianter med särskilt hög smittsamhet eller dödlighet. Riskerna har ökat med befolkningstillväxt och globalisering. Samtidigt har våra förutsättningar att skydda oss också har blivit bättre genom ökad kunskap och framsteg inom medicin och teknik.Syftet med denna kunskapssammanställning är att beskriva smittvägar, riskfaktorer och skyddsåtgärder för infektiös luftvägssjukdom och därmed bidra till en minskad smittrisk vid arbetsplatser. Mycket av innehållet bygger på forskning om influensa och covid-19, men även en rad andra luftvägsinfektioner är inkluderade.Spridning av virus har här delats upp i tre smittvägar: inandning, direkt deponering och kontakt. Risken för smitta via inandning av virus är särskilt stor när avstånden mellan människor är korta och uppehållstiden lång i lokaler med dålig ventilation. Risken ökar om det också pågår aktiviteter som innebär spridning av virusinnehållande aerosolpartiklar till luften, såsom högt tal eller sång eller vissa medicinska procedurer, eller om den inandade luftmängden är förhöjd, som vid tungt arbete. Virusöverföring via direkt deponering sker när stora smittbärande droppar stänker direkt på en mottagare vid exempelvis hosta. Virusspridning via både inandning och direkt deponering sker på olika sätt genom luften, men benämns här inte ”luftsmitta” eftersom detta begrepp åtminstone enligt klassisk medicinsk indelning syftat på (effektiv) smitta via inandning över avstånd mer än enstaka meter och eftersom det främst använts för sjukdomar som är mycket allvarliga och därför kräver extrema skyddsåtgärder. Smitta via kontakt kan ske antingen via direkt beröring eller genom mellanled, som handtag eller andra ytor.Samtliga tre smittvägar är välbelagda för luftvägsvirus i den vetenskapliga litteraturen, men deras relativa betydelse varierar beroende situation, virustyp och interventioner för att minska smitta. För covid-19 pekar mycket forskning mot att inandning är en dominerande smittväg i många miljöer. Vissa yrkesgrupper, särskilt inom vårdsektorn, löper en förhöjd risk att smittas av luftvägsvirus.En lång rad skyddsåtgärder finns tillgängliga för att på olika sätt minska smittrisker: distans, hygien, fysiska barriärer, ventilation, administrativa åtgärder (exempelvis information, regleringar, kontroller, checklistor) och personlig skyddsutrustning. De flesta av dessa åtgärder har starkt stöd av vetenskapliga studier.
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| 13. |
- Marschall, Hanns-Ulrich, et al.
(författare)
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Incidence, prevalence, and outcome of primary biliary cholangitis in a nationwide Swedish population-based cohort
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Available epidemiological data on primary biliary cholangitis (PBC) in Sweden originate from regional studies in the 1980s and may not reflect modern day PBC. We aimed to estimate incidence and prevalence, survival and death causes, and gender differences in PBC. We used international classification of disease (ICD) codes to identify patients with PBC in inpatient and outpatient registries 1987-2014 who were then linked to the Swedish cause of death, cancer and prescribed drug registries. Each PBC patient was matched with 10 reference individuals from the general population. In sensitivity analyses, we examined PBC patients identified through clinical patient records from Karolinska, Sahlgrenska and Orebro University Hospitals. We identified 5,350 adults with PBC. Prevalence of PBC increased steadily from 5.0 (1987) to 34.6 (2014) per 100,000 inhabitants whereas the yearly incidence rate was relatively constant with a median of 2.6 per 100,000 person-years, with a female: male gender ratio of 4:1. Compared to reference individuals, PBC individuals aged 15-39 years at diagnosis had a substantially higher risk of death (Hazard Ratio [HR] 12.7, 95% Confidence Interval [CI] 8.3-19.5) than those diagnosed between 40-59 (HR 4.1, 95% CI 3.7-4.5) and > 60 (HR 3.7, 95% CI 3.5-3.9) years of age. Relative risks of mortality were highest in men. In conclusion, we found that recorded prevalence of PBC in Sweden has increased substantially during the last 30 years although incidence has been stable. Patients diagnosed in young adulthood were at a 12.7-fold increased risk of death, and male PBC patients had worse prognosis.
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| 14. |
- Norrehed, Sara, et al.
(författare)
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Samiska föremål : undersökning av fynd från ett 1700-talstorp i Järvsö
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vid en arkeologisk undersökning av ett s.k. sockenlappsboställe i Järvsö 2017 påträffades ett fyndmaterial med stark samisk koppling som skiljer ut platsen från andra 1700-talstorp. Det framkom ben av björn och häst, en kedja med hänge, som troligen suttit på en samisk trumma, samt en rad andra föremål, däribland ett trådnystan av okänd metall.
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| 15. |
- Nyström, Anna-Maja, et al.
(författare)
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A severe form of Noonan syndrome and autosomal dominant café-au-lait spots : evidence for different genetic origins
- 2009
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 98:4, s. 693-698
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The clinical overlap among Noonan syndrome (NS), cardio-facio-cutaneous (CFC), LEOPARD and Costello syndromes as well as Neurofibromatosis type 1 is extensive, which complicates the process of diagnosis. Further genotype–phenotype correlations are required to facilitate future diagnosis of these patients. Therefore, investigations of the genetic cause of a severe phenotype in a patient with NS and the presence of multiple café-au-lait spots (CAL) spots in the patient and four members of the family were performed. Methods: Mutation analyses of candidate genes, PTPN11, NF1, SPRED1 and SPRED2, associated with these syndromes, were conducted using DNA sequencing. Results: A previously identified de novo mutation, PTPN11 F285L and an inherited NF1 R1809C substitution in the index patient were found. However, neither PTPN11 F285L, NF1 R1809C, SPRED1 nor SPRED2 segregated with CAL spots in the family. The results indicate that the familial CAL spots trait in this family is caused by a mutation in another gene, distinct from previous genes associated with CAL spots in these syndromes. Conclusion: We suggest that the atypical severe symptoms in the index patient may be caused by an additive effect on the F285L mutation in PTPN11 by another mutation, for example the NF1 R1809C or alternatively, the not yet identified gene mutation associated with CAL spots in this family.
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| 16. |
- Nyström, Anna-Maja, et al.
(författare)
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Investigation of gene dosage imbalances in patients with Noonan syndrome using multiplex ligation-dependent probe amplification analysis
- 2010
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Ingår i: European Journal of Medical Genetics. - : Elsevier BV. - 1769-7212 .- 1878-0849. ; 53:3, s. 117-121
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Tidskriftsartikel (refereegranskat)abstract
- The RAS-MAPK syndromes are a group of clinically and genetically related disorders caused by dysregulation of the RAS-MAPK pathway. A member of this group of disorders, Noonan syndrome (NS), is associated with several different genes within the RAS-MAPK pathway. To date, mutations in PTPN11, SOS1, KRAS, RAF1 and SHOC2 are known to cause NS and a small group of patients harbour mutations in BRAF, MEK1 or NRAS. The majority of the mutations are predicted to cause an up-regulation of the pathway; hence they are gain-of-function mutations. Despite recent advances in gene identification in NS, the genetic aetiology is still unknown in about of patients.To investigate the contribution of gene dosage imbalances of RAS-MAPK-related genes to the pathogenesis of NS, a multiplex ligation-dependent probe amplification (MLPA) assaywas developed. Two probe sets were designed for seven RAS-MAPK-syndrome-related candidate genes: PTPN11, SOS1, RAF1, KRAS, BRAF, MEK1 and MEK2. The probe sets were validated in 15 healthy control individuals and in glioma tumour cell lines. Subsequently, 44 NS patients negative for mutations in known NS-associated genes were screened using the two probe sets. The MLPA results for the patients revealed no gene dosage imbalances. In conclusion, the present results exclude copy number variation of PTPN11, SOS1, RAF1, KRAS, BRAF, MEK1 and MEK2 as a common pathogenic mechanism of NS. The validated and optimised RAS-MAPK probe sets presented here enable rapid high throughput screening of further patients with RAS-MAPK syndromes.
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| 17. |
- Petersson Sjögren, Madeleine, et al.
(författare)
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Sensitive methods for assessment of lung health in welders and controls
- 2023
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Ingår i: Respiratory Medicine. - : W.B. Saunders Ltd. - 0954-6111 .- 1532-3064. ; 212
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Tidskriftsartikel (refereegranskat)abstract
- Background: Welders are exposed to gas and particle emissions that can cause severe lung disease, such as chronic obstructive pulmonary disease (COPD), a leading cause of mortality and morbidity worldwide. It is difficult to detect COPD early and therefore mitigating measures may be delayed. The aim of this study was to investigate lung health in welders and evaluate new sensitive methods with potential to assess early onset pulmonary changes in occupational settings. Methods: This study assessed the lung health and symptoms in active welders (n = 28) and controls (n = 17). Lung measurements were performed with standard spirometry and new methods: airspace dimension assessment (AiDA), oscillometry, blood serum biomarkers (club cell secretory protein 16, surfactant protein D, matrix metalloproteinases, fibroblast, hepatocyte growth factor, interleukins), and one urine biomarker (desmosine). Results: According to spirometry measurements, all participants had normal lung function. However, prevalence of cough was significantly higher among welders compared with controls and lung changes were found in welders with the novel methods. Welders had significantly higher respiratory system resistance assessed with oscillometry, serum levels of metalloproteinases 9 and hepatocyte growth factor, compared with controls. Airspace dimensions were on average higher among welders compared with controls, but the difference was not significant. The number of welding years correlated with decreased respiratory system reactance and increased serum levels of matrix metalloproteinases 9, interleukin 6, and hepatocyte growth factor. Airspace dimension assessment indices were correlated with increasing levels of inflammatory markers and matrix metalloproteinases. Conclusions: This study indicated the potential to use new and more sensitive methods for identification of changes in lungs when standard spirometry failed to do so. © 2023 The Authors
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| 18. |
- Thuresson, Hanna, 1972-
(författare)
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Yngre barns meningsskapande om läsande och skrivande i förskolans literacypraktik
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines the youngest (one- to -three-year-old) preschool children's literacy meaning making practices in preschool. Preschool is the first formal educational setting that children attend, and preschool teachers' actions, teaching, and choice of materials and places for reading and writing activities affect the ways in which children make meaning of literacy. The research focuses on preschool as a specific educational and cultural context and on children’s interaction with their peers and the literacy tools used. The aim of the study is to contribute to the understanding of preschool as an educational as well as a cultural practice for young children by studying how they make meaning of literacy.The theoretical framework for this study is based on a social approach to literacy, drawing from Multimodality and New Literacy Studies. Observations of literacy practices were documented by camera and fieldnotes. The observations took place in four different preschool settings and focused on one- to three-year-old children’s actions.The study identifies eight different meaning making methods in children’s use of different social, material, and bodily resources. These different meaning making methods that children use lead to the conclusion that the norms of literacy in the literacy practices clearly shape children’s literacy meaning making. Despite the children’s relatively minimal experiences of literacy in educational settings they already make meaning of how, where, and with what material literacy is enacted. An important finding for educational settings, therefore, is that literacy is not only a skill, but also a way of learning how to handle objects in different places and to move your body in the setting. Second, children’s meaning making of literacy also contains aspects of breaking with the norms that surround meaning making of literacy. Children challenge and question the literacy habits entailed in educational literacy practices.
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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Thuresson, Sara, et al.
(författare)
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Airborne SARS-CoV-2 during childbirth
- 2023
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Konferensbidrag (refereegranskat)abstract
- Airborne SARS CoV 2 is considered to play a major role in covid 19 transmission, and has been found in several hospital environments. There is a need to investigate the presence of airborne SARS CoV 2 in other hospital areas than traditional infectious disease wards. The results from the present study can contribute to a better understanding of the risk of covid 19 transmission by aerosols at delivery wards.
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| 23. |
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| 24. |
- Thuresson, Sara, et al.
(författare)
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Airborne SARS-CoV-2 RNA collected during childbirth and autopsy
- 2023
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Konferensbidrag (refereegranskat)abstract
- Airborne SARS-CoV-2 is considered to play a major role in covid-19 transmission, and several studies have reported its presence in hospital environments, including corridors, patient rooms, cohort rooms and ICUs (Dinoi et al., 2022). The risk of airborne virus have been associated with a number of factors, such as low ventilation, high patient viral load and in some cases, certain medical procedures.However, specific medical situations still deserve further investigation. One such situation of interest is childbirth, as respiratory emissions, which could contain virus, are increased due to heavy breathing during labor. Another situation with potential risk for airborne SARS-CoV-2 is autopsy.The aim of the current study was to further explore the presence of airborne SARS-CoV-2 RNA during childbirth and autopsy.The results in this study can increase our understanding about the risk of covid-19 transmission by aerosols at delivery wards and during autopsy, even though the sample material is small. Reports of airborne SARS-CoV-2 in hospital environments contribute to improving guidelines for protective equipment for healthcare personnel working with such patients.
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| 25. |
- Thuresson, Sara, et al.
(författare)
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Airborne Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Hospitals : Effects of Aerosol-Generating Procedures, HEPA-Filtration Units, Patient Viral Load, and Physical Distance
- 2022
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Ingår i: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 75:1, s. 89-96
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Transmission of coronavirus disease 2019 (COVID-19) can occur through inhalation of fine droplets or aerosols containing infectious virus. The objective of this study was to identify situations, patient characteristics, environmental parameters, and aerosol-generating procedures (AGPs) associated with airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus.METHODS: Air samples were collected near hospitalized COVID-19 patients and analyzed by RT-qPCR. Results were related to distance to the patient, most recent patient diagnostic PCR cycle threshold (Ct) value, room ventilation, and ongoing potential AGPs.RESULTS: In total, 310 air samples were collected; of these, 26 (8%) were positive for SARS-CoV-2. Of the 231 samples from patient rooms, 22 (10%) were positive for SARS-CoV-2. Positive air samples were associated with a low patient Ct value (OR, 5.0 for Ct <25 vs >25; P = .01; 95% CI: 1.18-29.5) and a shorter physical distance to the patient (OR, 2.0 for every meter closer to the patient; P = .05; 95% CI: 1.0-3.8). A mobile HEPA-filtration unit in the room decreased the proportion of positive samples (OR, .3; P = .02; 95% CI: .12-.98). No association was observed between SARS-CoV-2-positive air samples and mechanical ventilation, high-flow nasal cannula, nebulizer treatment, or noninvasive ventilation. An association was found with positive expiratory pressure training (P < .01) and a trend towards an association for airway manipulation, including bronchoscopies and in- and extubations.CONCLUSIONS: Our results show that major risk factors for airborne SARS-CoV-2 include short physical distance, high patient viral load, and poor room ventilation. AGPs, as traditionally defined, seem to be of secondary importance.
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| 26. |
- Thuresson, Sara, et al.
(författare)
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Characteristics of SARS-CoV-2-containing aerosols in hospital corridors
- 2022
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Ingår i: ; , s. 1-1
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Konferensbidrag (refereegranskat)abstract
- The aim of this work is to investigate the presence of airborne SARS-CoV-2 in corridors of infection wards, and gain more detailed size information of SARS-CoV-2-containing aerosols. Associations between SARS-CoV-2 presence and relative humidity and/or temperature in the facilities is also explored.
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| 31. |
- Thuresson, Sara, et al.
(författare)
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One year weekly size-resolved air sampling of SARS-CoV-2 in hospital corridors and relations to the indoor environment
- 2024
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Ingår i: Indoor Air. - 0905-6947. ; 2024
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Tidskriftsartikel (refereegranskat)abstract
- Background. Airborne SARS-CoV-2 plays a prominent role in COVID-19 transmission. Numerous studies have sampled air from patient rooms, but airborne spread to other hospital areas such as corridors is less investigated. Methods. Size-fractionated aerosol particles were collected weekly, with 12 hours of sampling time daily, in corridors at two infectious disease wards in southern Sweden between March 2020 and May 2021. Samples were analysed with real-time reverse transcription polymerase chain reaction (RT-qPCR) for detection of SARS-CoV-2 RNA. Indoor temperature, relative humidity, and CO2 concentration were monitored during the sampling period. Results. 20 of the 784 collected samples contained SARS-CoV-2 RNA, although in low concentrations. Positive air samples were found in sizes between 0.14 and 8.1 μm, but none >8.1 μm. 45% were found in submicron particles. No clear seasonal pattern was observed among the positive samples. There was no significant difference in the positivity rate of the samples between the two wards. Conclusions. SARS-CoV-2 was only detected in 2.6% of the aerosol samples, which indicates that the spread of airborne virus from patient rooms to the corridor was limited.
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| 35. |
- Thuresson, Sara
(författare)
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When the air went viral: Exploring SARS-CoV-2 in aerosols during the covid-19 pandemic
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite the enormous economic and health-related burdens caused by respiratory infectious diseases globally, there are significant knowledge gaps regarding how these are spread by aerosols. The covid-19 pandemic made it clear that understanding airborne transmission is especially important in healthcare, where workers and patients are highly exposed to sources of virus. This thesis aims to advance the knowledge about airborne transmission of infectious diseases, mainly in hospital settings. More specifically, the objectives were to identify sources and risk factors for airborne virus, evaluate prevention strategies and explore the dynamics of infection via inhalation. In total, we collected over 1100 air samples at hospitals during the covid-19 pandemic, both close to covid-19-patients and in other areas, such as ward corridors. The samples were analysed for SARS-CoV-2 RNA content to investigate presence and risk factors for airborne virus. Overall, SARS-CoV-2 RNA was detected in around 10% of the samples collected close to patients. In corridors and anterooms, less than 5% of the air samples contained SARS-CoV-2. Interestingly, almost half of the aerosols containing SARS-CoV-2 in corridors were of submicron size. SARS-CoV-2 was also found on surfaces that are less likely contaminated by touch, but rather by airborne transport. A number of factors significantly increased the risk of detecting airborne virus in patient rooms: smaller distance to the patient, lower ventilation rates in the room, and higher viral load of the patient, which correlated with the number of days since symptom onset. Certain medical procedures, called aerosol-generating procedures, were hypothesized to spread more aerosols. Our results indicated that aerosol-generating procedures are of lesser importance, although with a few exceptions. SARS-CoV-2 was found during both childbirth and autopsy, but with no clear risk factors. To further understand aerosol transmission dynamics, exhaled virus from newly infected subjects was analysed for viability. This allowed us to model the emissions of infectious virus from a source in a typical office size room. The simulations showed that a susceptible person can inhale one infectious dose within minutes upon entering a room with an infected individual. The time until infection varied strongly with the individual emission rate of the source. When modelling a scenario of a patient room with a higher ventilation rate, it was found that ventilation rate had some effect on the time, especially for lower emission rates, but again the most important factor was the individual emission rate. This underlines the large individual variations and how important they are for disease spread. In conclusion, this work contributes to increased knowledge about sources of airborne virus, risk factors and prevention strategies. Our results support the importance of airborne SARS-CoV-2 in transmission of covid-19, but also highlight the challenges of predicting risk situations and designing effective mitigation strategies. Importantly for indoor environments, the risk of infection is smaller with increased ventilation and distancing to the source. Moreover, transmission dynamics are likely highly dependent on individual variations in viral emissions.
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