| 482981. |
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| 482982. |
- Ljungquist-Höddelius, Pia, et al.
(författare)
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Lateral diffusion of PDGF β-receptors in human fibroblasts
- 1991
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Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 11:1, s. 43-52
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Tidskriftsartikel (refereegranskat)abstract
- When platelet-derived growth factor (PDGF) binds to its receptors a number of biochemical reactions are elicited in the cell. Several models have been presented for the effects of ligand-induced receptor conformation and aggregation on signal transduction but little is known about the direct effects on receptor diffusion. This study concerns the lateral mobility of PDGF receptors in fibroblasts. It was assessed with fluorescence recovery after photobleaching (FRAP), using rhodaminated receptor antibodies or Fab-fragments of the antibody as ligands. The aims of the investigation were: (a) to compare the lateral mobility of membrane receptors of human fibroblasts labelled with either antibodies against the PDGF receptor or Fab-fragments of the same antibodies, and (b) to study the effects of serum of PDGF on the mobility of the receptors. Human foreskin fibroblasts (AG 1523) were grown on coverslips either under standard or under serum-free conditions yielding 'normal' and 'starved' cells, respectively. Two parameters of the diffusion were evaluated; the diffusion coefficient (D) and the mobile fraction (R) of the receptors. We found that normal fibroblasts had a smaller diffusion coefficient and a lower mobile fraction compared to starved cells using antibodies for receptor labelling. The addition of PDGF, just before the measurement, increased the D and R for normal cells, while starved cells, showing higher initial values, displayed slightly reduced values of D and R. After the addition of serum, D increased and R remained low for normal cells, whereas for starved cells both D and R increased to upper limits of 11.0 x 10-10 cm2s-1 and >90% respectively. In general, the D and R values, both in normal and starved cells, were higher for cells labelled with Fab-fragments than for antibody-labelled cells. The results are discussed in relation to the natural complexity of the receptor. and how PDGF, serum, antibodies and Fab-fragments might interfere with receptor structure, aggregation state and membrane diffusion characteristics.
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| 482983. |
- Ljungquist, Katarina, et al.
(författare)
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A Probabilistic Approach for Evaluation of Radon Concentration in the Indoor Environment
- 2005
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Ingår i: Indoor + Built Environment. - 1420-326X .- 1423-0070. ; 14:1, s. 17-27
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Tidskriftsartikel (refereegranskat)abstract
- An analytical method based on structural reliability has been developed with the objective to ensure a healthy indoor environment for people in residential buildings. The method has been applied to a model of the foundation of a house, which is principally a concrete slab on the ground, when the hazard to the indoor environment is radon. The reasons why radon is found indoors have been identified using fault tree analysis. Random variables in the model are defined such that resistance is the ability of people to withstand the radon concentration indoors without adverse health effects and the load effect is equal to the top event of the fault tree and is a function of the environmental load and the decisions made in the building process. A quantitative evaluation was made using both Monte Carlo simulation and First-order second-moment theory where the load effect is compared with the resistance defined as the threshold value for radon concentration indoors stated in the Swedish Building Regulations. The objective was to calculate the probability for exceeding the threshold value and to estimate analytically the safety index. Other interesting areas of application of the developed model could be for the environmental impact from moisture causing growth of micro-organisms and release of chemical emissions, or from soil contaminates like, for example, petroleum products.
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| 482984. |
- Ljungquist, Oskar, et al.
(författare)
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16S rRNA is a valuable tool in finding bacterial aetiology of community-acquired pleural empyema-a population-based observational study in South Sweden
- 2022
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 2374-4235 .- 2374-4243. ; 54:3, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe incidence of community-acquired pleural empyema is increasing. Knowledge of the bacterial aetiology is important in order to base recommendations on empirical antimicrobial treatment. The primary aim of the present study was to describe the bacterial aetiology of adult patients with culture proven and/or 16S rRNA-positive community-acquired pleural infection.MethodsWe performed a retrospective, population-based observational cohort study in Skåne County, south of Sweden. We included all patients with pleural samples obtained between 1st of January 2011 to 31st of December 2017 in Skåne, south of Sweden, with a positive culture and/or 16S rRNA result. Exclusion criteria were patients with culture-negative and/or 16S rRNA-negative pleural samples, age < 18 years, pleural empyema caused by trauma or iatrogenesis, pleural infection caused by tuberculosis or fungi, simultaneous lung- or abscess of the abdomen and bacterial species considered to be contaminants.ResultsA total of 291 patients were included in the study, of which 63% were men and the median age was 69 years. The dominating bacterial aetiology was viridans streptococci (36%), followed by Streptococcus pneumoniae (14%) and anaerobic bacteria (12%). 16S rRNA added information of bacterial aetiology in addition to standard culturing methods in 63% of the patients.ConclusionWe found that the aetiology of adult patients with culture proven and/or 16S rRNA-positive community-acquired pleural empyema is dominated by viridans streptococci, S. pneumoniae and anaerobic bacteria. Our study shows that 16S rRNA is a valuable tool in finding the bacterial aetiology of community-acquired pleural empyema.
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| 482985. |
- Ljungquist, Oskar, et al.
(författare)
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A Cross-Sectional Cohort Study of Extended-Spectrum-Beta-Lactamase-Producing Enterobacterales in Patients with Traveler's Diarrhea
- 2020
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Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596. ; 64:12
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Tidskriftsartikel (refereegranskat)abstract
- Patients with traveler’s diarrhea (TD) can acquire extended-spectrum-beta-lactamase (ESBL)-producing members of the Enterobacterales (EPE) during travel to areas of endemicity. The aim of the present study was to investigate the prevalence and characteristics of EPE carriage in travelers from southern Sweden who were sampled for bacterial diagnostics of TD compared to those of EPE carriage 10 years ago. Clinical samples sent for culture of common causes of bacterial enterocolitis, if the referral stated foreign travel, were included in the study. Antimicrobial susceptibility testing was done according to the EUCAST disk diffusion test method. EPE strains were subjected to whole-genome sequencing (WGS). Eighty-four of 303 patients carried a total of 92 ESBL-producing members of the Enterobacterales. The overall prevalence of EPE in tested samples was thus 28%, compared to 24% 10 years earlier (P = 0.33). Among 86 strains available for WGS, 47 different sequence types (STs) were identified, and there were only 5 ST131 strains. Of the 79 Escherichia coli isolates, 76% carried at least one fim (type 1 fimbria) gene, 29% carried at least one pap (p-fimbriae) gene, and 43% were extraintestinal pathogenic E. coli (ExPEC) or uropathogenic E. coli (UPEC). Over half of the E. coli strains (57%) were intestinal pathogenic E. coli, most commonly enteroaggregative E. coli (EAEC) (33%), and enteroinvasive E. coli EIEC (22%). A relatively high proportion of patients with traveler’s diarrhea carry EPE, but there was no significant increase compared to 10 years ago. Most E. coli strains were intestinal pathogenic strains. A comparatively high proportion of the strains were ExPEC/UPEC, many expressing the virulence genes pap and/or fim. (This project was assigned ClinicalTrials.gov number NCT03866291.)
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| 482986. |
- Ljungquist, Oskar, et al.
(författare)
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A population-based study of the appearances of enteric Campylobacter and non-typhoidal Salmonella infections on computed tomography
- 2024
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Ingår i: Annals of Medicine. - 1365-2060. ; 56:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundSwift identification and diagnosis of gastrointestinal infections are crucial for prompt treatment, prevention of complications, and reduction of the risk of hospital transmission. The radiological appearance on computed tomography could potentially provide important clues to the etiology of gastrointestinal infections. We aimed to describe features based on computed tomography of patients diagnosed with Campylobacter, Salmonella or Shigella infections in South Sweden.MethodsThis was a retrospective observational population-based cohort study conducted between 2019 and 2022 in Skåne, southern Sweden, a region populated by 1.4 million people. Using data from the Department of Clinical Microbiology combined with data from the Department of Radiology, we identified all patients who underwent computed tomography of the abdomen CTA two days before and up to seven days after sampling due to the suspicion of Campylobacter, Salmonella or Shigella during the study period.ResultsA total of 215 CTAs scans performed on 213 patients during the study period were included in the study. The median age of included patients was 45 years (range 11–86 years), and 54% (114/213) of the patients were women. Of the 215 CTAs, 80% (n = 172) had been performed due to Campylobacter and 20% (n = 43) due to Salmonella enteritis. CTA was not performed for any individual diagnosed with Shigella during the study period. There were no statistically significant differences in the radiological presentation of Campylobacter and Salmonella infections.ConclusionThe most common location of Campylobacter and Salmonella infections was the cecum, followed by the ascending colon. Enteric wall edema, contrast loading of the affected mucosa, and enteric fat stranding are typical features of both infections. The CTA characteristics of Campylobacter and Salmonella are similar, and cannot be used to reliably differentiate between different infectious etiologies.
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| 482987. |
- Ljungquist, Oskar, et al.
(författare)
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Agreement and reliability of hepatic transient elastography in patients with chronic hepatitis C : A cross-sectional test-retest study
- 2023
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Ingår i: Health Science Reports. - 2398-8835. ; 6:4, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Transient elastography (TE) has largely replaced liver biopsy to evaluate fibrosis stage and cirrhosis in chronic hepatitis C. Previous studies have reported excellent reliability of TE but agreement metrics have not been reported. This study aimed to assess interrater agreement and reliability of repeated TE measurements.METHODS: Two operators performed TE independently, directly after each other. The primary outcome was disagreement, defined as a difference in TE results between operators of ≥33%, as well as the smallest detectable change, SDC 95 (i.e., the difference between measurements needed to state with 95% certainty that there is a difference in underlying stiffness). Secondary outcomes included reliability, measured as intraclass correlation (ICC), and patient and examination characteristics associated with the agreement. RESULTS: In total, 65 patients were included, with a mean liver stiffness of 9.7 kPa. Of these, 21 (32%) had a disagreement in TE results of ≥33% between the two operators. The SDC 95 on the log scale was 1.97, indicating that an almost twofold increase or decrease in liver stiffness would be required to confidently represent a change in the underlying fibrosis. Reliability, estimated using the ICC, was acceptable at 0.86. In a post hoc analysis, fasting less than 5 h before TE was associated with a higher degree of disagreement (48% vs. 19%, p = 0.03). CONCLUSIONS: In our clinical setting, interrater agreement in directly repeated TE measurements was surprisingly low. It is essential to further investigate the reliability and agreement of TE to determine its validity and usefulness.
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| 482988. |
- Ljungquist, Oskar, et al.
(författare)
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Conservative Management First Strategy in Aortic Vascular Graft and Endograft Infections
- 2023
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1532-2165 .- 1078-5884. ; 65:6, s. 896-904
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to describe and present the outcomes of a specific treatment protocol for aortic vascular graft and endograft infections (VGEIs) without explantation of the infected graft.METHODS: This was a retrospective, observational single centre cohort study carried out between 2012 and 2022 at a tertiary hospital. An aortic VGEI was defined according to the Management of Aortic Graft Infection Collaboration (MAGIC) criteria. Fitness for graft excision was assessed by a multidisciplinary team and included an evaluation of the patient's general condition, septic status, and anatomical complexity. Antimicrobial treatments were individualised. The primary outcome was survival at the last available follow up; secondary outcomes were antimicrobial treatment duration, infection eradication, treatment failure despite antimicrobial treatment, and the development of aortic fistulation.RESULTS: Fifty patients were included in the study, of whom 42 (84%) had previous endovascular repair. Median patient age was 72 years (range 51 - 82 years) and median duration of treatment with antimicrobials was 18 months (range 1 - 164 months). Kaplan-Meier analysis estimated the 30 day survival rate to be 98% (95% confidence interval [CI] 96 - 100), the one year survival rate to be 88% (95% CI 83.4 - 92.6), and the three year survival rate to be 79% (95% CI 72.7 - 84.7). Twenty-four (48%) patients were able to discontinue antibiotic treatment after a median of 16 months (range 4 - 81 months). When categorised according to infected graft location, deaths occurred in four (40%) patients with thoracic, four (40%) with paravisceral, seven (30%) with infrarenal VGEIs, and in one (25%) patient with an aorto-iliac VGEI; no (0%) patient with a thoraco-abdominal VGEI died.CONCLUSION: Identifying the microbiological aetiology in patients with aortic VGEI enables individualised, specific antibiotic treatment, which may be useful in patients with a VGEI excluded from surgery. This single centre retrospective analysis of patients with VGEIs without fistula selected for conservative treatment suggests that conservative management of aortic VGEIs with targeted antibiotic therapy without graft excision is potentially effective, and that antimicrobial treatment will not necessarily be needed indefinitely.
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| 482989. |
- Ljungquist, Oskar, et al.
(författare)
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Convalescent plasma treatment in severely immunosuppressed patients hospitalized with COVID-19 : an observational study of 28 cases
- 2022
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Ingår i: Infectious Diseases. - : Taylor & Francis Group. - 2374-4235 .- 2374-4243 .- 1651-1980. ; 54:4, s. 283-291
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Tidskriftsartikel (refereegranskat)abstract
- Background: Immunosuppressed patients are particularly vulnerable to severe infection from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), risking prolonged viremia and symptom duration. In this study we describe clinical and virological treatment outcomes in a heterogeneous group of patients with severe immunosuppression due to various causes suffering from COVID-19 infection, who were all treated with convalescent plasma (CCP) along with standard treatment.Methods: We performed an observational, retrospective case series between May 2020 to March 2021 at three sites in Skåne, Sweden, with a population of nearly 1.4 million people. All patients hospitalized for COVID-19 who received CCP with the indication severe immunosuppression as defined by the treating physician were included in the study (n = 28).Results: In total, 28 severely immunocompromised patients, half of which previously had been treated with rituximab, who had received in-hospital convalescent plasma treatment of COVID-19 were identified. One week after CCP treatment, 13 of 28 (46%) patients had improved clinically defined as a decrease of at least one point at the WHO-scale. Three patients had increased score points of whom two had died. For 12 patients, the WHO-scale was unchanged.Conclusion: As one of only few studies on CCP treatment of COVID-19 in hospitalized patients with severe immunosuppression, this study adds descriptive data. The study design prohibits conclusions on safety and efficacy, and the results should be interpreted with caution. Prospective, randomized trials are needed to investigate this further.
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| 482990. |
- Ljungquist, Oskar, et al.
(författare)
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Guided Aspiration for Determining the Microbiological Aetiology of Aortic Vascular Graft and Endograft Infections
- 2021
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1532-2165 .- 1078-5884. ; 62:6, s. 935-943
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveOpen and endovascular aortic repair may be complicated by aortic vascular graft or endograft infection (VGEI). Confirming the microbiological aetiology is a key element in providing the best available treatment to patients with a VGEI. The primary aim of this study was to describe the technique of direct aneurysm sac guided aspiration (DASGA) in determining the microbiological aetiology in a cohort of patients with VGEIs, and to report its diagnostic value.MethodsThis was a retrospective observational single centre study performed between the years 2011 to 2020 in Malmö, Sweden. Patients with a suspected aortic VGEI, where a DASGA was performed at the Vascular Centre, were included in the study.ResultsIn total, 31 guided aspirations were performed in 27 patients (25 male [93%]; median age 77 years [range 57 – 82 years]). The combination of culture and 16S rRNA/18S rRNA gave a microbial aetiology in 25/31 (81%) DASGAs. Importantly, excluding three cases where infection was ruled out, this rate increases up to 89%. A polymicrobial aetiology was found in six (24 %) cases. The most common bacteria found were Cutibacterium spp. (n = 8) and Listeria monocytogenes (n = 4). In total, the dominant aetiology could be further characterised into normal gut flora (n = 12; 48%) or skin commensals (n = 8; 32%). No patients had persistent morbidity related to the DASGA.ConclusionDASGA can be used successfully to determine the microbiological aetiology of open and endovascular graft infections. This method appears to be safe, with a high success rate for confirming the microbiological aetiology of VGEIs, particularly if standard culturing methods are combined with 16S rRNA/18S rRNA. Finding the causative microbial aetiology is crucial, and in the vast majority of cases translumbar puncture can be used without serious complications.
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