| 1. |
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| 2. |
- Arvidsson, Åsa, et al.
(författare)
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The cascade of care for pregnant women with latent tuberculosis infection in a high-income country
- 2023
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Ingår i: Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 55:9, s. 635-645
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Tidskriftsartikel (refereegranskat)abstract
- Background: Pregnant women have an increased risk of developing active tuberculosis (TB). The Public Health Agency of Sweden recommends screening of active TB and latent tuberculosis infection (LTBI) among pregnant women from countries with high TB incidence at Maternal Health Care (MHC) clinics. In ostergotland County, Sweden, a screening program has been active since 2013. The aim of this study was to evaluate this screening program and the cascade of care for LTBI among pregnant women in ostergotland county.Methods: Data were obtained from pregnant women screened for TB at MHC clinics and subsequently referred to the pulmonary medicine clinic or the clinic of infectious diseases in ostergotland County between 2013 and 2018. The Public Health Agency of Swedens national database for active TB was used to analyse if any women developed active TB up to two years after the screening process.Results: A total of 439 women were included. Nine cases of active TB were discovered during the screening process and two developed active TB afterward. 177 women were recommended LTBI treatment and variables significantly associated with a decreased likelihood of being recommended treatment were increasing age, time in Sweden, and parity. 137 women received and 112 (82%) completed treatment. 14 women discontinued treatment due to adverse effects.Conclusion: Screening of pregnant women from countries with high TB incidence at MHC clinics led to the discovery of several cases of active TB. The completion rate of LTBI treatment was high and few discontinued due to adverse effects.
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| 3. |
- Das, Jyotirmoy, et al.
(författare)
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DNA methylome-based validation of induced sputum as an effective protocol to study lung immunity : construction of a classifier of pulmonary cell types
- 2022
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Ingår i: Epigenetics. - : Taylor & Francis Inc. - 1559-2294 .- 1559-2308. ; 17:8, s. 882-893
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Tidskriftsartikel (refereegranskat)abstract
- Flow cytometry is a classical approach used to define cell types in peripheral blood. While DNA methylation signatures have been extensively employed in recent years as an alternative to flow cytometry to define cell populations in peripheral blood, this approach has not been tested in lung-derived samples. Here, we compared bronchoalveolar lavage with a more cost-effective and less invasive technique based on sputum induction and developed a DNA methylome-based algorithm that can be used to deconvolute the cell types in such samples. We analysed the DNA methylome profiles of alveolar macrophages and lymphocytes cells isolated from the pulmonary compartment. The cells were isolated using two different methods, sputum induction and bronchoalveolar lavage. A strong positive correlation between the DNA methylome profiles of cells obtained with the two isolation methods was found. We observed the best correlation of the DNA methylomes when both isolation methods captured cells from the lower parts of the lungs. We also identified unique patterns of CpG methylation in DNA obtained from the two cell populations, which can be used as a signature to discriminate between the alveolar macrophages and lymphocytes by means of open-source algorithms. We validated our findings with external data and obtained results consistent with the previous findings. Our analysis opens up a new possibility to identify different cell populations from lung samples and promotes sputum induction as a tool to study immune cell populations from the lung.
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| 4. |
- Eklund, Daniel, 1984-, et al.
(författare)
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Vitamin D enhances IL-1β secretion and restricts growth of Mycobacterium tuberculosis in macrophages from TB patients
- 2013
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Ingår i: International journal of mycobacteriology. - Netherlands : Wolters Kluwer. - 2212-5531. ; 2:1, s. 18-25
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of multidrug-resistant strains of Mycobacterium tuberculosis (MTB), the bacterium responsible for tuberculosis (TB), has rekindled the interest in the role of nutritional supplementation of micronutrients, such as vitamin D, as adjuvant treatment. Here, the growth of virulent MTB in macrophages obtained from the peripheral blood of patients with and without TB was studied. The H37Rv strain genetically modified to express Vibrio harveyi luciferase was used to determine the growth of MTB by luminometry in the human monocyte-derived macrophages (hMDMs) from study subjects. Determination of cytokine levels in culture supernatants was performed using a flow cytometry-based bead array technique. No differences in intracellular growth of MTB were observed between the different study groups. However, stimulation with 100nM 1,25-dihydroxyvitamin D significantly enhanced the capacity of hMDMs isolated from TB patients to control the infection. This effect was not observed in hMDMs from the other groups. The interleukin (IL)-1β and IL-10 release by hMDMs was clearly increased upon stimulation with 1,25-dihydroxyvitamin D. Furthermore, the 1,25-dihydroxyvitamin D stimulation also led to elevated levels of TNF-α (tumor necrosis factor-alpha) and IL-12p40. It was concluded that vitamin D triggers an inflammatory response in human macrophages with enhanced secretion of cytokines, as well as enhancing the capacity of hMDMs from patients with active TB to restrict mycobacterial growth.
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| 5. |
- Ekqvist, David, et al.
(författare)
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Safety and pharmacokinetics-pharmacodynamics of a shorter tuberculosis treatment with high-dose pyrazinamide and rifampicin : a study protocol of a phase II clinical trial (HighShort-RP)
- 2022
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Increased dosing of rifampicin and pyrazinamide seems a viable strategy to shorten treatment and prevent relapse of drug-susceptible tuberculosis (TB), but safety and efficacy remains to be confirmed. This clinical trial aims to explore safety and pharmacokinetics-pharmacodynamics of a high-dose pyrazinamide-rifampicin regimen.Methods and analysis: Adult patients with pulmonary TB admitted to six hospitals in Sweden and subjected to receive first-line treatment are included. Patients are randomised (1:3) to either 6-month standardised TB treatment or a 4-month regimen based on high-dose pyrazinamide (40 mg/kg) and rifampicin (35 mg/kg) along with standard doses of isoniazid and ethambutol. Plasma samples for measurement of drug exposure determined by liquid chromatography tandem-mass spectrometry are obtained at 0, 1, 2, 4, 6, 8, 12 and 24 hours, at day 1 and 14. Maximal drug concentration (C-max) and area under the concentration-time curve (AUC(0-24h)) are estimated by non-compartmental analysis. Conditions for early model-informed precision dosing of high-dose pyrazinamide-rifampicin are pharmacometrically explored. Adverse drug effects are monitored throughout the study and graded according to Common Terminology Criteria for Adverse Events V.5.0. Early bactericidal activity is assessed by time to positivity in BACTEC MGIT 960 of induced sputum collected at day 0, 5, 8, 15 and week 8. Minimum inhibitory concentrations of first-line drugs are determined using broth microdilution. Disease severity is assessed with X-ray grading and a validated clinical scoring tool (TBscore II). Clinical outcome is registered according to WHO definitions (2020) in addition to occurrence of relapse after end of treatment. Primary endpoint is pyrazinamide AUC(0-24h) and main secondary endpoint is safety.Ethics and dissemination: The study is approved by the Swedish Ethical Review Authority and the Swedish Medical Products Agency. Informed written consent is collected before study enrolment. The study results will be submitted to a peer-reviewed journal.
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| 6. |
- Engström, Linda, et al.
(författare)
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Preproenkephalin mRNA expression in rat parabrachial neurons: relation to cells activated by systemic immune challenge
- 2001
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Ingår i: Neuroscience Letters. - : Elsevier Science B.V., Amsterdam.. - 0304-3940 .- 1872-7972. ; 316:3, s. 165-168
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Tidskriftsartikel (refereegranskat)abstract
- By using a dual-labeling immunohistochemical/in situ hybridization technique we examined if enkephalin-expressing neurons in the pontine parabrachial nucleus, a major brain stem relay for ascending visceral and homeostatic information, were activated by systemic immune challenge. While rats subjected to intravenous injection of bacterial wall lipopolysaccharide expressed dense labeling for the immediate-early gene product FOS in parts of the parabrachial nucleus that also demonstrated dense preproenkephalin expression, only a small proportion of the enkephalin-positive neurons were FOS-positive. These data indicate that enkephalins, although implicated in a variety of autonomic responses, are not primarily involved in the transmission of immune-related information from the parabrachial nucleus to its different forebrain and brain stem targets.
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| 7. |
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| 8. |
- Forsman, Lina Davies, et al.
(författare)
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Plasma concentrations of second-line antituberculosis drugs in relation to minimum inhibitory concentrations in multidrug-resistant tuberculosis patients in China : a study protocol of a prospective observational cohort study
- 2018
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 8:9
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Tidskriftsartikel (refereegranskat)abstract
- Individualised treatment through therapeutic drug monitoring (TDM) may improve tuberculosis (TB) treatment outcomes but is not routinely implemented. Prospective clinical studies of drug exposure and minimum inhibitory concentrations (MICs) in multidrug-resistant TB (MDR-TB) are scarce. This translational study aims to characterise the area under the concentration-time curve of individual MDR-TB drugs, divided by the MIC for Mycobacterium tuberculosis isolates, to explore associations with markers of treatment progress and to develop useful strategies for clinical implementation of TDM in MDR-TB.Methods and analysis: Adult patients with pulmonary MDR-TB treated in Xiamen, China, are included. Plasma samples for measure of drug exposure are obtained at 0, 1, 2, 4, 6, 8 and 10 hours after drug intake at week 2 and at 0, 4 and 6 hours during weeks 4 and 8. Sputum samples for evaluating time to culture positivity and MIC determination are collected at days 0, 2 and 7 and at weeks 2, 4, 8 and 12 after treatment initiation. Disease severity are assessed with a clinical scoring tool (TBscore II) and quality of life evaluated using EQ-5D-5L. Drug concentrations of pyrazinamide, ethambutol, levofloxacin, moxifloxacin, cycloserine, prothionamide and para-aminosalicylate are measured by liquid chromatography tandem-mass spectrometry and the levels of amikacin measured by immunoassay. Dried blood spot on filter paper, to facilitate blood sampling for analysis of drug concentrations, is also evaluated. The MICs of the drugs listed above are determined using custom-made broth microdilution plates and MYCOTB plates with Middlebrook 7H9 media. MIC determination of pyrazinamide is performed in BACTEC MGIT 960.Ethics and dissemination: This study has been approved by the ethical review boards of Karolinska Institutet, Sweden and Fudan University, China. Informed written consent is given by participants. The study results will be submitted to a peer-reviewed journal. Trial registration number NCT02816931; Pre-results.
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| 9. |
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| 10. |
- Karlsson, Lovisa, et al.
(författare)
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A differential DNA methylome signature of pulmonary immune cells from individuals converting to latent tuberculosis infection
- 2021
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Ingår i: Scientific Reports. - : Nature Portfolio. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Tuberculosis (TB), caused by Mycobacterium tuberculosis, spreads via aerosols and the first encounter with the immune system is with the pulmonary-resident immune cells. The role of epigenetic regulations in the immune cells is emerging and we have previously shown that macrophages capacity to kill M. tuberculosis is reflected in the DNA methylome. The aim of this study was to investigate epigenetic modifications in alveolar macrophages and T cells in a cohort of medical students with an increased risk of TB exposure, longitudinally. DNA methylome analysis revealed that a unique DNA methylation profile was present in healthy subjects who later developed latent TB during the study. The profile was reflected in a different overall DNA methylation distribution as well as a distinct set of differentially methylated genes (DMGs). The DMGs were over-represented in pathways related to metabolic reprogramming of macrophages and T cell migration and IFN-gamma production, pathways previously reported important in TB control. In conclusion, we identified a unique DNA methylation signature in individuals, with no peripheral immune response to M. tuberculosis antigen who later developed latent TB. Together the study suggests that the DNA methylation status of pulmonary immune cells can reveal who will develop latent TB infection.
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| 11. |
- Moberg, Anna, et al.
(författare)
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C-reactive protein influences the doctors degree of suspicion of pneumonia in primary care: a prospective observational study
- 2020
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Ingår i: European Journal of General Practice. - : TAYLOR & FRANCIS LTD. - 1381-4788 .- 1751-1402. ; 26:1, s. 210-216
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Tidskriftsartikel (refereegranskat)abstract
- Background In primary care, the diagnosis of pneumonia is often based on history and clinical examination alone. However, a previous study showed that the general practitioners degree of suspicion correlates well with findings on chest X-ray, when the C-reactive protein (CRP) value is known. Objectives The present study aimed to investigate to what extent the physicians degree of suspicion is affected by the CRP level when community-acquired pneumonia is suspected in primary care. Methods A prospective observational study was conducted at five primary health care centres in Sweden between October 2015 and December 2017. Adult patients (n = 266) consulting their health care centre with symptoms of lower respiratory tract infection, where the physician suspected pneumonia, were included consecutively. Anamnestic information and findings from clinical examination were documented in a case report form. All patients were tested for CRP. The physicians rated their degree of suspicion as unsure, quite sure, and sure before and after the CRP result. Results The degree of suspicion of pneumonia changed in 69% of the cases; most often to a lower degree (40%). In 28% of the cases, there was no longer any suspicion of pneumonia after CRP. Conclusion Our results indicate that CRP testing highly influences the physicians degree of suspicion of pneumonia in primary care and that it seems to be of most value when not sure of the diagnosis.
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| 12. |
- Moberg, Anna, 1976-
(författare)
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Diagnosing pneumonia in primary care : Aspects of the value of clinical and laboratory findings and the use of chest X-ray
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is important to identify patients with pneumonia because it is potentially a serious disease, often of bacterial origin, that should be treated with antibiotics. It is equally important to identify those with acute bronchitis, a self-limiting disease, that should not be treated with antibiotics. Because bacterial resistance is increasing, over-prescribing of antibiotics should be avoided. However, it is sometimes difficult to differentiate between the two diagnoses, and guidelines concerning the assessment do not conform. The general aim of this thesis was to investigate if diagnostics of pneumonia in primary care can be improved and whether this could contribute to reduced prescription of antibiotics. As a first step, different anamnestic, clinical and laboratory findings and the doctor’s degree of suspicion of pneumonia in primary care were compared with chest X-ray (CXR) findings. The doctor’s degree of suspicion of pneumonia was shown to be a good predictor. When the physician was sure of the diagnosis, the likelihood for radiographic pneumonia was high and when quite sure, CXR was positive in less than half of the cases. To further improve the diagnostics of pneumonia, and thus reduce antibiotic prescriptions, patients were referred for CXR when the physician was unsure or quite sure of a pneumonia diagnosis. The intervention did not result in any decrease in antibiotic prescriptions compared with a control group. However, it emerged that the physicians did not fully trust the CXR outcome, but prescribed antibiotics even when the results were negative. To gain insight into the contribution of C-reactive protein (CRP) levels to the degree of suspicion, physicians were asked to estimate their degree of suspicion of pneumonia before and after CRP testing. CRP affected the degree of suspicion to a great extent, and most often resulted in a lowered degree of suspicion and thereby in the clinical decision of dismissing the diagnosis of pneumonia. The use of different diagnostic tests and prescription of antibiotics in the assessment of acute bronchitis and pneumonia over time was evaluated in a register-based study. The study showed that the use of diagnostic tests for both diagnoses has increased, and that there has been a reduction in antibiotic prescriptions for acute bronchitis. In conclusion, the doctor’s degree of suspicion of pneumonia seems to be a good predictor of the condition. When the physician is sure of the diagnosis, no further investigation is needed, and antibiotics can be prescribed on reliable grounds. CRP testing affects the degree of suspicion and is most valuable when unsure of the diagnosis where it can be helpful to exclude pneumonia. In contrast, more extensive use of CXR does not contribute to a decrease in antibiotic prescriptions in the diagnostics of pneumonia.
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| 13. |
- Moberg, Anna, et al.
(författare)
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Use of chest X-ray in the assessment of community acquired pneumonia in primary care - an intervention study
- 2020
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Ingår i: Scandinavian Journal of Primary Health Care. - : Taylor & Francis. - 0281-3432 .- 1502-7724. ; 38:3, s. 323-329
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this study was to explore if consequent use of chest X-ray (CXR), when the physician is not sure of the diagnosis of pneumonia after clinical examination and CRP-testing, favors a more restrictive prescribing of antibiotics. Design This was an intervention study conducted between September 2015 and December 2017. Setting Two intervention primary health care centers (PHCCs) and three control PHCCs in the southeast of Sweden. Intervention All patients were referred for CXR when the physician s suspicion of pneumonia was unsure, or quite sure after CRP-testing. Control units managed patients according to their usual routine after clinical examination and CRP-testing. Subjects A total of 104 patients were included in the intervention group and 81 patients in the control group. The inclusion criteria of the study were clinically suspected pneumonia in patients >= 18 years, with respiratory symptoms for more than 24 h. Main outcome measure:Antibiotic prescribing rate. Results In the intervention group, 85% were referred for CXR and 69% were prescribed antibiotics, as compared to 26% and 77% in the control group. The difference in antibiotic prescribing rate was not statistically significant, unadjusted OR 0.68 [0.35-1.3] and adjusted OR 1.1 [CI 0.43-3.0]. A total of 24% of patients with negative CXR were prescribed antibiotics. Conclusion This study could not prove that use of CXR when the physician was not sure of the diagnosis of pneumonia results in lowered antibiotic prescribing rate in primary care. In cases of negative findings on CXR the physicians do not seem to rely on the outcome when it comes to antibiotic prescribing.
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| 14. |
- Niward, Katarina, et al.
(författare)
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Distribution of plasma concentrations of first-line anti-TB drugs and individual MICs: a prospective cohort study in a low endemic setting
- 2018
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Ingår i: Journal of Antimicrobial Chemotherapy. - : OXFORD UNIV PRESS. - 0305-7453 .- 1460-2091. ; 73:10, s. 2838-2845
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Tidskriftsartikel (refereegranskat)abstract
- Background: Therapeutic drug monitoring (TDM) could improve current TB treatment, but few studies have reported pharmacokinetic data together with MICs. Objectives: To investigate plasma concentrations of rifampicin, isoniazid, pyrazinamide and ethambutol along with MICs. Methods: Drug concentrations of rifampicin, isoniazid, pyrazinamide and ethambutol were analysed pre-dose and 2, 4 and 6 h after drug intake at week 2 in 31 TB patients and MICs in BACTEC 960 MGIT were determined at baseline. The highest plasma concentrations at 2, 4 and 6 h post-dose (C-high) were determined, as well as estimates of C-high/MIC and area under the concentration-time curve (AUC(0-6))/MIC including the corresponding ratios based on calculated free-drug concentrations. This trial was registered at www.clinicaltrials.gov (NCT02042261). Results: After 2 weeks of treatment, the median C-high values for rifampicin, isoniazid, pyrazinamide and ethambutol were 10.0, 5.3, 41.1 and 3.3 mg/L respectively. Lower than recommended drug concentrations were detected in 42% of the patients for rifampicin (amp;lt;8 mg/L), 19% for isoniazid (amp;lt;3 mg/L), 27% for pyrazinamide (amp;lt;35 mg/L) and 16% for ethambutol (amp;lt;2 mg/L). The median Chigh/MIC values for rifampicin, isoniazid, pyrazinamide and ethambutol were 164, 128, 1.3 and 2.5, respectively, whereas the AUC(0-6)/MIC was 636 (range 156-2759) for rifampicin and 351 (range 72-895) for isoniazid. Conclusions: We report low levels of first-line TB drugs in 16%-42% of patients, in particular for rifampicin. There was a wide distribution of the ratios between drug exposures and MICs. The future use of MIC determinations in TDM is dependent on the development of a reference method and clinically validated pharmacokinetic/pharmacodynamic targets.
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| 15. |
- Niward, Katarina, 1971-, et al.
(författare)
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Plasma Levels of Rifampin Correlate with the Tuberculosis Drug Activity Assay
- 2018
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Ingår i: Antimicrobial Agents and Chemotherapy. - : AMER SOC MICROBIOLOGY. - 0066-4804 .- 1098-6596. ; 62:5
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Tidskriftsartikel (refereegranskat)abstract
- The plasma tuberculosis drug activity (TDA) assay may be an alternative tool for therapeutic drug monitoring in resource-limited settings. In tuberculosis (TB) patients (n = 30), TDA and plasma levels of first-line drugs were analyzed 2 h post-dose, 2 weeks after treatment initiation. Patients with plasma levels of rifampin lower than 8 mg/liter had a significantly lower median TDA (1.40 versus 1.68, P = 0.0013). TDA may be used to identify TB patients with suboptimal rifampin levels during TB treatment.
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| 16. |
- Niward, Katarina, et al.
(författare)
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Susceptibility testing breakpoints for Mycobacterium tuberculosis categorize isolates with resistance mutations in gyrA as susceptible to fluoroquinolones : implications for MDR-TB treatment and the definition of XDR-TB
- 2016
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 0305-7453 .- 1460-2091. ; 71:2, s. 333-338
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Tidskriftsartikel (refereegranskat)abstract
- Fluoroquinolones (FQs) are important in the treatment of MDR-TB and in the definition of XDR-TB. Our objective was to investigate how discrepancies in the phenotypic and genotypic methods for antimicrobial susceptibility testing could affect the interpretation of antimicrobial susceptibility test results. We analysed MICs of ofloxacin and levofloxacin in Middlebrook 7H10 broth (7H10) as well as sequencing of the quinolone resistance-determining region of the gyrA gene and the MTBDRsl assay in 75 resistant isolates, including MDR and XDR strains of Mycobacterium tuberculosis. Among 75 resistant isolates, 27 had mutations associated with FQ resistance. Among isolates with resistance mutations in gyrA, 26% (seven of 27) were susceptible to levofloxacin and ofloxacin by phenotypic testing at 1 mg/L and 2 mg/L. The most common mutation was in codon 94 and these isolates had significantly increased MICs of levofloxacin (2-8 mg/L) compared with isolates with mutations in codon 90 (0.25-2 mg/L, PaEuroS < aEuroS0.05). The sensitivity and specificity for the MTBDRsl assay compared with gyrA sequencing were 96% and 98%, respectively. Current critical concentrations may classify up to 26% of isolates with gyrA mutations as susceptible to FQs due to a close relationship between susceptible and resistant populations. These results should be considered while improving clinical breakpoints for M. tuberculosis and may have an impact on the definition of XDR-TB.
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| 17. |
- Niward, Katarina, 1971-
(författare)
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Towards individualised treatment of tuberculosis
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Each year, around 10 million of individuals develop active tuberculosis (TB). Worldwide, TB is the leading cause of death from an infectious agent surpassing both malaria and HIV. Current treatment regimens are long and therefore encompass a risk of nonadherence and development of acquired drug-resistance, reflected in the increase of multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. Indeed, this calls for prudent use of existing TB drugs and improvement of TB treatment strategies. The aim of this thesis was to investigate the current drug susceptibility testing (DST) breakpoints for Mycobacterium tuberculosis (M. tuberculosis), the pharmacokinetics and pharmacodynamics (PK/PD) of TB treatment and to explore the role of therapeutic drug monitoring (TDM) for optimising TB treatment.Drug resistance in M. tuberculosis is expressed over a continuous scale and for some drugs it may be identified as low- and high-level resistance. This has been poorly reflected in currently used binary susceptibility breakpoints for TB drugs. Results from genome sequencing and phenotypic DST of ofloxacin and levofloxacin were compared in study I and current breakpoints were found to misclassify up to 25% of M. tuberculosis isolates with resistance mutations in gyrA as susceptible to fluoroquinolones. This finding may have implications for the classification of XDR-TB, treatment of MDR-TB and the evaluation of fluoroquinolones in clinical studies.Study II was a prospective cohort study of susceptible TB in Sweden, where drug concentrations of first-line TB drugs were measured along with the susceptibility level of the bacteria defined by the minimum inhibitory concentration (MIC) of M. tuberculosis. First-line drug concentrations below the reference range (16-42%) were common and most pronounced for rifampicin (13/31, 42%). An exploratory investigation of PK/PD parameters displayed a wide distribution of ratios between drug exposures and MICs. Rifampicin exhibited higher level of individual fluctuations over time during TB treatment compared with isoniazid. In study III the plasma drug concentrations of rifampicin were compared to the tuberculosis drug activity assay (TDA) and results showed that rifampicin drug levels, but not drug levels of the other first-line drugs, correlated with TDA. Patients with rifampicin drug levels below 8 mg/L had significantly lower median TDA. This finding supports the use of TDA as a potential indicator for low rifampicin exposure in resource-constrained settings without access to drug concentration analysis. The study design in study II has been further developed in study IV, which is a prospective cohort study of MDR-TB in China, where drug exposure will be explored in relation to individual bacterial MIC and measurements of treatment outcome.In summary, the work in this thesis emphasises the importance of reliable DST of M. tuberculosis and the need to re-evaluate the currently used breakpoints. Therapeutic drug monitoring (TDM) based on drug concentrations and MICs is a useful tool to avoid suboptimal drug exposure and to individualise TB treatments. Such strategies may improve treatment regimens and avoid further development of resistance.
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| 18. |
- Paues, Jakob
(författare)
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Brain Stem Involvement in Immune and Aversive Challenge
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Activation of the immune system by e.g. bacteria induces the acute-phase-response and sickness behaviour. The latter encompasses among other things fever, lethargy, anorexia and hyperalgesia. An often used model to study sickness behaviour is the intravenous injection of the gram negative bacterial endotoxin lipopolysaccharide (LPS). LPS induces the production of inflammatory mediators, such as cytokines and prostaglandins, which in turn can interact with the central nervous system (CNS) to affect behaviour. The CNS also memorises substances that have made us sick in the past to avoid future harm, a phenomenon called conditioned taste aversion (CTA). An often used model to study CTA is the intraperitoneal injection of LiCl.The pontine parabrachial nucleus (PB) is an autonomic relay nucleus situated in the rostral brain stem that integrates afferent somatosensory and interoceptive information and forwards this information to the hypothalamus and limbic structures. PB is crucial for the acquisition of CTA and PB neurons are activated by many anorexigenic substances. Further, PB neurons express neuropeptides, among those calcitonin gene related peptide (CGRP) and enkephalin, both of which have been implicated in immune signalling, nociception, food intake, and aversion.By using a dual-labelling immunohistochemical/in situ hybridization technique we investigated if enkephalinergic neurons in PB are activated by systemic immune challenge. While there were many neurons in the external lateral parabrachial subnucleus (PBel) that expressed the immediate early gene fos after intravenous injection of LPS and while a large proportion of the PBel neurons expressed preproenkephalin, there were very few double-labelled cells. The fos-expressing cells were predominantly located to the outer part of the PBel (PBelo), whereas the preproenkephalin-expressing PBel neurons were located closest to the peduncle. Thus we conclude that although enkephalin has been implicated in autonomic and immune signalling, enkephalinergic neurons in PB do not seem to be activated by immune stimulation (paper I). To further characterise the PBelo neurons activated by immune challenge we investigated if these neurons expressed CGRP. Dual-labelling in situ hybridisation showed that PBelo neurons that expressed fos after intravenous injection of LPS to a large extent co-expressed CGRP mRNA, indicating that CGRP may be involved in the regulation of the sickness response in immune challenge (paper II). Using dual-labelling immunohistochemistry we examined if PBel neurons activated by an immune stimulus projected to the amygdala, a limbic structure implicated in the affective response to homeostatic challenge. Animals were injected with the retrograde tracer substance cholera toxin b (CTb) into the amygdala and subsequently subjected to immune challenge. We found that approximately a third of the neurons that expressed fos after the intravenous injection of LPS also were labelled with CTb. Thus PBel neurons activated by immune challenge project to the amygdala. The PBel-amygdala pathway has earlier been suggested to be important in nociceptive signalling. To investigate if amygdala-projecting PBel neurons are activated by nociceptive stimuli we again injected animals with CTb into the amygdala. After recovery the animals were injected with formalin into a hindpaw. Dual-labelling immunohistochemistry against fos and CTb showed that very few noxiously activated PB neurons projected to the amygdala. Thus, the PBel-amygdala projection seems to be important in immune challenge but not in nociceptive signalling (paper III). Many PBel neurons express fos after intraperitoneal injection of LiCl. Melanocortins are neuropeptides that recently have been implicated in metabolism, food intake and aversive mechanisms. The PB is known to express melanocortin receptor-4 (MC4-R) mRNA. Using dual-labelling in situ hybridization we investigated if PB neurons activated by intravenous injection of LPS or intraperitoneal injection of LiCl expressed MC4-R mRNA. We found that many PBelo neurons were activated by either LPS or LiCl and that a large proportion of such activated neurons expressed MC4-R mRNA. Further, using dual-labelling in situ hybridization against MC4-R mRNA and CGRP mRNA, we found that a large proportion of the CGRP positive PBelo neurons also expressed MC4-R mRNA.In summary, this thesis shows that CGRP-expressing neurons in the PBel are activated by peripheral immune challenge, that lipopolysaccharide-activated PBel neurons project to the amygdala, that the amygdala-projecting neurons in the PBel are CGRP-positive, and that PBel neurons activated by immune or aversive challenge express MC4-R. Taken together, these data suggest the presence of a melanocortin-regulated CGRP-positive pathway from the PBel to the amygdala that relays information of importance to certain aspects of sickness behaviour.
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| 19. |
- Paues, Jakob, et al.
(författare)
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Expression of melanocortin-4 receptor by rat parabrachial neurons responsive to immune and aversive stimuli
- 2006
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 141:1, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- The pontine parabrachial nucleus is a major relay area for visceral and other interoceptive information, and has been implicated in mechanisms underlying anorexia and food aversion during disease. Thus, physiological studies have shown that peripheral immune stimuli, as well as the administration of aversive substances such as lithium chloride, evoke a prominent Fos-expression in the lateral parabrachial nucleus and behavioral experiments have demonstrated that this structure is critical for the acquisition of conditioned taste aversion. The present study examined in rats the relationship between parabrachial neurons activated by systemic administration of bacterial cell-wall lipopolysaccharide or lithium chloride and the melanocortin system, a major regulator of feeding and energy homeostasis that also has been implicated in aversive behavior. Dual-labeling in situ hybridization showed melanocortin-4 receptor expression on neurons in the external lateral parabrachial subnucleus that displayed lipopolysaccharide- or lithium chloride-induced expression of c-fos mRNA. Melanocortin-4 receptor mRNA was also co-expressed with mRNA for calcitonin gene-related peptide in this subnucleus. Taken together with previous observations showing that calcitonin gene-related peptide expressing neurons in the external lateral parabrachial subnucleus are activated by peripheral immune challenge, that lipopolysaccharide-activated external lateral parabrachial subnucleus neurons project to the amygdala, and that the amygdala-projecting neurons in the external lateral parabrachial subnucleus are calcitonin gene-related peptide-positive, the present findings suggest the presence of a melanocortin-regulated calcitonin gene-related peptide-positive pathway from the external lateral parabrachial subnucleus to the amygdala that relays information of importance to forebrain responses to certain aspects of sickness behavior. These observations may thus help explain how melanocortins can reduce feeding and influence conditioned taste aversion during inflammation and other disease conditions.
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| 20. |
- Paues, Jakob, et al.
(författare)
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Fatal progressive multifocal leukoencephalopathy in a patient with non-Hodgkin lymphoma treated with rituximab
- 2010
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Ingår i: Journal of Clinical Virology. - : Elsevier Science B.V., Amsterdam.. - 1386-6532 .- 1873-5967. ; 48:4, s. 291-293
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Tidskriftsartikel (refereegranskat)abstract
- We report a case of progressive multifocal leukoencephalopathy (PML) in a woman with non-Hodgkin lymphoma treated with chemotherapy in combination with rituximab. She presented with rapid deterioration of vision and subsequently cognitive decline. Magnetic resonance imaging (MRI) of the brain raised the suspicion of PML. The first PCR analysis of the cerebrospinal fluid (CSF) was negative, but a second sample was positive for JC virus DNA. Anti-viral treatment was ineffective and the patient died 7 months after debut of symptoms. Our case emphasizes the importance of the awareness of PML in patients with progressive neurological symptoms treated with antilymphocytic drugs and that consecutive CSF analyses may be needed to detect the JC virus.
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| 21. |
- Paues, Jakob, et al.
(författare)
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Feeding-related immune responsive brain stem neurons : association with CGRP
- 2001
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Ingår i: Neuroreport. - 0959-4965 .- 1473-558X. ; 12:11, s. 2399-2403
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Tidskriftsartikel (refereegranskat)abstract
- Using dual-labeling in situ hybridization histochemistry, the neurotransmitter expression of immune-responsive neurons in the pontine parabrachial nucleus, a major relay for interoceptive information, was investigated. Intravenous injection of bacterial wall lipopolysaccharide resulted in dense c-fos mRNA expression in the external lateral parabrachial nucleus, and a majority of the c-fos expressing cells also expressed calcitonin gene-related peptide (CGRP) mRNA. In contrast CGRP-posi- tive cells in the adjoining external medial subnucleus were c-fos negative. Taken together with previous hodological and behavioral studies, these data suggest that CGRPergic parabrachial neurons may mediate lipopolysaccharide-induced anorexia by means of their projection to central nucleus of the amygdala.
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| 22. |
- Pehrson, Isabelle, et al.
(författare)
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The spectrum of tuberculosis described as differential DNA methylation patterns in alveolar macrophages and alveolar T cells
- 2022
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Ingår i: CLINICAL EPIGENETICS. - : BMC. - 1868-7075 .- 1868-7083. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Host innate immune cells have been identified as key players in the early eradication of Mycobacterium tuberculosis and in the maintenance of an anti-mycobacterial immune memory, which we and others have shown are induced through epigenetic reprogramming. Studies on human tuberculosis immunity are dominated by those using peripheral blood as surrogate markers for immunity. We aimed to investigate DNA methylation patterns in immune cells of the lung compartment by obtaining induced sputum from M. tuberculosis- exposed subjects including symptom-free subjects testing positively and negatively for latent tuberculosis as well as patients diagnosed with active tuberculosis. Alveolar macrophages and alveolar T cells were isolated from the collected sputum and DNA methylome analyses performed (Illumina Infinium Human Methylation 450 k).Results: Multidimensional scaling analysis revealed that DNA methylomes of cells from the tuberculosis-exposed subjects and controls appeared as separate clusters. The numerous genes that were differentially methylated between the groups were functionally connected and overlapped with previous findings of trained immunity and tuberculosis. In addition, analysis of the interferon-gamma release assay (IGRA) status of the subjects demonstrated that the IGRA status was reflected in the DNA methylome by a unique signature.Conclusions: This pilot study suggests that M. tuberculosis induces epigenetic reprogramming in immune cells of the lung compartment, reflected as a specific DNA methylation pattern. The DNA methylation signature emerging from the comparison of IGRA-negative and IGRA-positive subjects revealed a spectrum of signature strength with the TB patients grouping together at one end of the spectrum, both in alveolar macrophages and T cells. DNA methylation-based biosignatures could be considered for further development towards a clinically useful tool for determining tuberculosis infection status and the level of tuberculosis exposure.
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| 23. |
- Perez-Recio, Sandra, et al.
(författare)
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Identification of Recent Tuberculosis Exposure Using QuantiFERON-TB Gold Plus, a Multicenter Study
- 2021
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Ingår i: Microbiology Spectrum. - : American Society for Microbiology. - 2165-0497. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- We investigated whether the difference of antigen tube 2 (TB2) minus antigen tube 1 (TB1) (TB22TB1) of the QuantiFERON-TB gold plus test, which has been postulated as a surrogate for the CD81 T-cell response, could be useful in identifying recent tuberculosis (TB) exposure. We looked at the interferon gamma (IFN-g) responses and differences in TB2 and TB1 tubes for 686 adults with QFT-plus positive test results. These results were compared among groups with high (368 TB contacts), low (229 patients with immune-mediated inflammatory diseases [IMID]), and indeterminate (89 asylum seekers or people from abroad [ASPFA]) risks of recent TB exposure. A TB2-TB1 value.0.6 IU.ml(-1) was deemed to indicate a true difference between tubes. In the whole cohort, 13.6%, 10.9%, and 11.2% of cases had a TB2>TB1 result in the contact, IMID, and ASPFA groups, respectively (P = 0.591). The adjusted odds ratios (aORs) for an association between a TB2-TB1 result of >0.6 IU.ml(-1) and risk of recent exposure versus contacts were 0.71 (95% confidence interval [CI], 0.31 to 1.61) for the IMID group and 0.86 (95% CI, 0.49 to 1.52) for the ASPFA group. In TB contact subgroups, 11.4%, 15.4%, and 17.7% with close, frequent, and sporadic contact had a TB2>TB1 result (P = 0.362). The aORs versus the close subgroup were 1.29 (95% CI, 0.63 to 2.62) for the frequent subgroup and 1.55 (95% CI, 0.67 to 3.60) for the sporadic subgroup. A TB2-TB1 difference of.0.6 IU.ml(-1) was not associated with increased risk of recent TB exposure, which puts into question the clinical potential as a proxy marker for recently acquired TB infection. IMPORTANCE Contact tuberculosis tracing is essential to identify recently infected people, who therefore merit preventive treatment. However, there are no diagnostic tests that can determine whether the infection is a result of a recent exposure or not. It has been suggested that by using the QuantiFERON-TB gold plus, an interferon gamma (IFN-gamma) release assay, a difference in IFN-gamma production between the two antigen tubes (TB2 minus TB1) of.0.6 IU.ml(-1) could serve as a proxy marker for recent infection. In this large multinational study, infected individuals could not be classified according to the risk of recent exposure based on differences in IFN- g in TB1 and TB2 tubes that were higher than 0.6 IU.ml(-1). QuantiFERON-TB gold plus is not able to distinguish between recent and remotely acquired tuberculosis infection, and it should not be used for that purpose in contact tuberculosis tracing.
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| 24. |
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| 25. |
- Persson, Hans Lennart, et al.
(författare)
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Alveolar macrophages from patients with tuberculosis exhibit reduced capacity of restricting growth of Mycobacterium tuberculosis: a pilot study of vitamin D stimulation in vitro
- 2013
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Ingår i: Microbiology Discovery. - United Kingdom : Herbert Publications PVT LTD. - 2052-6180. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The role of vitamin D supplementation as adjuvant treatment of tuberculosis (TB) has lately attracted increasing interest. Our aim was to investigate the capacity of alveolar macrophages (AMs) from patients with or without exposure to TB to control intracellular growth of virulent Mycobacterium tuberculosis (Mtb). Methods: AMs were freshly harvested from the bronchoalveolar lavage fluid of 7 patients with a history of TB (4 patients with previous TB and 3 patients with current TB) and 4 non-TB subjects. The H37Rv strain, genetically modified to express Vibrio harveyi luciferase, was used to determine the growth of Mtb by luminometry in the AMs from study subjects. Cytokine levels in culture supernatants were determined using a flow cytometry-based bead array technique. Results: AMs from patients with a TB history were less efficient in restricting Mtb growth. Stimulation with 100 nM1, 25-dihydroxyvitamin D (1,25D3) did not significantly influence the capacity of AMs from any study subjects to control the infection. Out of the cytokines evaluated (TNF-α, IL-1β, IL-10 and IL-12p40) only TNF-α demonstrated detectable levels in culture supernatants, but did not respond to stimulation with 1,25D3. Conclusions: We conclude that AMs of TB-patients show reduced ability to control mycobacterial growth in vitro, and, that AMs in this pilot study do no respond to 1, 25D3-stimulation. The former observation supports the concept that innate immunity is crucial for the control of TB infection.
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| 26. |
- Richard, Sabine, et al.
(författare)
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Activation of the parabrachio-amygdaloid pathway by immune challenge or spinal nociceptive input : a quantitative study in the rat using Fos immunohistochemistry and retrograde tract tracing
- 2005
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967 .- 1096-9861. ; 481:2, s. 210-219
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral nociceptive stimulation results in activation of neurons in the pontine parabrachial nucleus (PB) of rats. Electrophysiological studies have suggested that noxiously activated PB neurons project to the amygdala, constituting a potential pathway for emotional aspects of pain. In the present study we examined this hypothesis by combining retrograde tract tracing with Fos immunohistochemistry. Cholera toxin subunit B was injected into the amygdala of rats. After a minimum of 48 hours the rats were given a subcutaneous injection of 100 l of 5% formalin into one hindpaw and killed 60-90 minutes later. A dense aggregation of retrogradely labeled neurons was seen in the external lateral PB. Fos-expressing neurons were present preferentially in the central, dorsal, and superior lateral subnuclei as well as in the lateral crescent area, as described previously. There was little overlap between the retrogradely labeled and Fos-expressing populations and double-labeled neurons were rare. In contrast, systemic immune challenge by intravenous injection of bacterial wall lipopolysaccharide resulted in a Fos expression that overlapped the retrograde labeling in the external lateral PB, and many double-labeled neurons were seen. While these data provide direct functional anatomical evidence that nociceptive information from the hindlimb is relayed to the amygdala via the parabrachial nucleus, the number of parabrachio-amygdaloid neurons involved is small. Considering the widespread activation of parabrachio-amygdaloid neurons by a variety of visceral and humoral stimuli, the parabrachio-amygdaloid pathway thus appears to be more involved in the mediation of information related to viscerally and humorally elicited activity than in transmission of spinal nociceptive inputs.
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| 27. |
- Schulman, H., et al.
(författare)
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Sedimentation rate and suPAR in relation to disease activity and mortality in patients with tuberculosis
- 2019
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Ingår i: The International Journal of Tuberculosis and Lung Disease. - : INT UNION AGAINST TUBERCULOSIS LUNG DISEASE (I U A T L D). - 1027-3719 .- 1815-7920. ; 23:11, s. 1155-1161
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE : To investigate how levels of the soluble urokinase plasminogen activator receptor (suPAR) and erythrocyte sedimentation rate (ESR) correlate with disease activity and prognosis in pulmonary tuberculosis (PTB). DESIGN: This was a retrospective analysis of patients with active PTB (n = 500) in Gondar, Ethiopia, for whom the suPAR (n = 301) and ESR (n = 330) were analysed at the start of treatment. Both biomarkers were available for 176 patients. Human immunodeficiency virus (HIV) status, chest X-ray (CXR) findings, classification according to the clinical TBscore and treatment outcome were all recorded. RESULTS : In a multivariable logistic regression analysis adjusted for age, sex and HIV status, surrogate markers of disease activity such as advanced CXR patterns correlated with increased levels of suPAR (adjusted OR [aOR] 8.24, Pamp;lt; 0.001) and of ESR (aOR 1.63, P = 0.030), whereas ESR only correlated significantly with a TBscore amp;gt;6 points. Increased levels of both suPAR and ESR were associated with unsuccessful treatment outcomes (aOR 2.93, P = 0.013; aOR 2.52, P = 0.025). The highest quartile of suPAR (aOR 13.3, P = 0.029) but not ESR levels correlated independently with increased mortality. CONCLUSION: SuPAR and ESR levels correlate with disease activity in PTB; however, the clinical role of these potentially prognostic biomarkers needs to be verified in prospective studies.
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| 28. |
- Shao, Ge, et al.
(författare)
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Population pharmacokinetics and model-based dosing evaluation of bedaquiline in multidrug-resistant tuberculosis patients
- 2023
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Ingår i: Frontiers in Pharmacology. - : FRONTIERS MEDIA SA. - 1663-9812. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Bedaquiline is now recommended to all patients in the treatment of multidrug-resistant tuberculosis (MDR-TB) using standard dosing regimens. As the ability to measure blood drug concentrations is very limited, little is known about drug exposure and treatment outcome. Thus, this study aimed to model the population pharmacokinetics as well as to evaluate the currently recommended dosage.Methodology: A bedaquiline population pharmacokinetic (PK) model was developed based on samples collected from the development cohort before and 1, 2, 3, 4, 5, 6, 8, 12, 18, and 24 h after drug intake on week 2 and week 4 of treatment. In a prospective validation cohort of patients with MDR-TB, treated with bedaquiline-containing standardized regimen, drug exposure was assessed using the developed population PK model and thresholds were identified by relating to 2-month and 6-month sputum culture conversion and final treatment outcome using classification and regression tree analysis. In an exploratory analysis by the probability of target attainment (PTA) analysis, we evaluated the recommended dosage at different MIC levels by Middlebrook 7H11 agar dilution (7H11).Results: Bedaquiline pharmacokinetic data from 55 patients with MDR-TB were best described by a three-compartment model with dual zero-order input. Body weight was a covariate of the clearance and the central volume of distribution, albumin was a covariate of the clearance. In the validation cohort, we enrolled 159 patients with MDR-TB. The 7H11 MIC mode (range) of bedaquiline was 0.06 mg (0.008-0.25 mg/L). The study participants with AUC(0-24h)/MIC above 175.5 had a higher probability of culture conversion after 2-month treatment (adjusted relative risk, aRR:16.4; 95%CI: 5.3-50.4). Similarly, those with AUC(0-24h)/MIC above 118.2 had a higher probability of culture conversion after 6-month treatment (aRR:20.1; 95%CI: 2.9-139.4), and those with AUC(0-24h)/MIC above 74.6 had a higher probability of successful treatment outcome (aRR:9.7; 95%CI: 1.5-64.8). Based on the identified thresholds, simulations showed that the WHO recommended dosage (400 mg once daily for 14 days followed by 200 mg thrice weekly) resulted in PTA >90% for the majority of isolates (94%; MICs =0.125 mg/L).Conclusion: We established a population PK model for bedaquiline in patients with MDR-TB in China. Based on the thresholds and MIC distribution derived in a clinical study, the recommended dosage of bedaquiline is sufficient for the treatment of MDR-TB.
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| 29. |
- Sundén, Birgitta, et al.
(författare)
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Real-time PCR detection of Human Herpesvirus 1-5 in patients lacking clinical signs of a viral CNS infection
- 2011
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Ingår i: BMC Infectious Diseases. - : BioMed Central. - 1471-2334. ; 11:220
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Infections of the central nervous system (CNS) with herpes- or enterovirus can be self-limiting and benign, but occasionally result in severe and fatal disease. The polymerase chain reaction (PCR) has revolutionized the diagnostics of viral pathogens, and by multiple displacement amplification (MDA) prior to real-time PCR the sensitivity might be further enhanced. The aim of this study was to investigate if herpes- or enterovirus can be detected in cerebrospinal fluid (CSF) from patients without symptoms.METHODS:Cerebrospinal fluid (CSF) samples from 373 patients lacking typical symptoms of viral CNS infection were analysed by real-time PCR targeting herpesviruses or enteroviruses with or without prior MDA.RESULTS:In total, virus was detected in 17 patients (4%). Epstein-Barr virus (EBV) was most commonly detected, in general from patients with other conditions (e.g. infections, cerebral hemorrhage). MDA satisfactorily amplified viral DNA in the absence of human nucleic acids, but showed poor amplification capacity for viral DNA in CSF samples, and did not increase the sensitivity for herpes virus-detection with our methodology.CONCLUSIONS:Viral pathogens are rarely detected in CSF from patients without signs of CNS infection, supporting the view that real-time PCR is a highly specific method to detect symptomatic CNS-infection caused by these viruses. However, EBV may be subclinically reactivated due to other pathological conditions in the CNS.
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| 30. |
- Svensson, Robin J., et al.
(författare)
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Individualised dosing algorithm and personalised treatment of high‐dose rifampicin for tuberculosis
- 2019
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 85:10, s. 2341-2350
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Tidskriftsartikel (refereegranskat)abstract
- AimsTo propose new exposure targets for Bayesian dose optimisation suited for high‐dose rifampicin and to apply them using measured plasma concentrations coupled with a Bayesian forecasting algorithm allowing predictions of future doses, considering rifampicin's auto‐induction, saturable pharmacokinetics and high interoccasion variability.MethodsRifampicin exposure targets for Bayesian dose optimisation were defined based on literature data on safety and anti‐mycobacterial activity in relation to rifampicin's pharmacokinetics i.e. highest plasma concentration up to 24 hours and area under the plasma concentration–time curve up to 24 hours (AUC0–24h). Targets were suggested with and without considering minimum inhibitory concentration (MIC) information. Individual optimal doses were predicted for patients treated with rifampicin (10 mg/kg) using the targets with Bayesian forecasting together with sparse measurements of rifampicin plasma concentrations and baseline rifampicin MIC.ResultsThe suggested exposure target for Bayesian dose optimisation was a steady state AUC0–24h of 181–214 h × mg/L. The observed MICs ranged from 0.016–0.125 mg/L (mode: 0.064 mg/L). The predicted optimal dose in patients using the suggested target ranged from 1200–3000 mg (20–50 mg/kg) with a mode of 1800 mg (30 mg/kg, n = 24). The predicted optimal doses when taking MIC into account were highly dependent on the known technical variability of measured individual MIC and the dose was substantially lower compared to when using the AUC0–24h‐only target.ConclusionsA new up‐to‐date exposure target for Bayesian dose optimisation suited for high‐dose rifampicin was derived. Using measured plasma concentrations coupled with Bayesian forecasting allowed prediction of the future dose whilst accounting for the auto‐induction, saturable pharmacokinetics and high between‐occasion variability of rifampicin.
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| 31. |
- Zhang, Haoyue, et al.
(författare)
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Population pharmacokinetics and dose evaluations of linezolid in the treatment of multidrug-resistant tuberculosis
- 2023
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Ingår i: Frontiers in Pharmacology. - : FRONTIERS MEDIA SA. - 1663-9812. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: The pharmacokinetic/pharmacodynamics (PK/PD) target derived from the hollow-fiber system model for linezolid for treatment of the multidrug-resistant tuberculosis (MDR-TB) requires clinical validation. Therefore, this study aimed to develop a population PK model for linezolid when administered as part of a standardized treatment regimen, to identify the PK/PD threshold associated with successful treatment outcomes and to evaluate currently recommended linezolid doses. Method: This prospective multi-center cohort study of participants with laboratory-confirmed MDR-TB was conducted in five TB designated hospitals. The population PK model for linezolid was built using nonlinear mixed-effects modeling using data from 168 participants. Boosted classification and regression tree analyses (CART) were used to identify the ratio of 0- to 24-h area under the concentration-time curve (AUC(0-24h)) to the minimal inhibitory concentration (MIC) threshold using the BACTEC MGIT 960 method associated with successful treatment outcome and validated in multivariate analysis using data from a different and prospective cohort of 159 participants with MDR-TB. Furthermore, based on the identified thresholds, the recommended doses were evaluated by the probability of target attainment (PTA) analysis. Result: Linezolid plasma concentrations (1008 samples) from 168 subjects treated with linezolid, were best described by a 2-compartment model with first-order absorption and elimination. An AUC(0-24h)/MIC > 125 was identified as a threshold for successful treatment outcome. Median time to sputum culture conversion between the group with AUC(0-24h)/MIC above and below 125 was 2 versus 24 months; adjusted hazard ratio (aHR), 21.7; 95% confidence interval (CI), (6.4, 72.8). The boosted CART-derived threshold and its relevance to the final treatment outcome was comparable to the previously suggested target of AUC(0-24h)/MIC (119) using MGIT MICs in a hollow fiber infection model. Based on the threshold from the present study, at a standard linezolid dose of 600 mg daily, PTA was simulated to achieve 100% at MGIT MICs of <=.25 mg which included the majority (81.1%) of isolates in the study. Conclusion: We validated an AUC(0-24h)/MIC threshold which may serve as a target for dose adjustment to improve efficacy of linezolid in a bedaquiline-containing treatment. Linezolid exposures with the WHO-recommended dose (600 mg daily) was sufficient for all the M. tb isolates with MIC <= .25 mg/L.
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| 32. |
- Zheng, Xubin, et al.
(författare)
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Development and validation of a simple LC-MS/MS method for simultaneous determination of moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol in human plasma
- 2020
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Ingår i: Journal of chromatography. B. - : ELSEVIER. - 1570-0232 .- 1873-376X. ; 1158
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging due to high treatment failure rate and adverse drug events. This study aimed to develop and validate a simple LC-MS/MS method for simultaneous measurement of five TB drugs in human plasma and to facilitate therapeutic drug monitoring (TDM) in MDR-TB treatment to increase efficacy and reduce toxicity. Moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol were prepared in blank plasma from healthy volunteers and extracted using protein precipitation reagent containing trichloroacetic acid. Separation was achieved on an Atlantis T3 column with gradient of 0.1% formic acid in water and acetonitrile. Drug concentrations were determined by dynamic multiple reaction monitoring in positive ion mode on a LC-MS/MS system. The method was validated according to the United States Food and Drug Administration (FDA) guideline for bioanalytical method validation. The calibration curves for moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol were linear, with the correlation coefficient values above 0.993, over a range of 0.1-5, 0.4-40, 0.2-10, 2-100 and 0.2-10 mg/L, respectively. Validation showed the method to be accurate and precise with bias from 6.5% to 18.3% for lower limit of quantification and -5.8% to 14.6% for LOW, medium (MED) and HIGH drug levels, and with coefficient of variations within 11.4% for all levels. Regarding dilution integrity, the bias was within 7.2% and the coefficient of variation was within 14.9%. Matrix effect (95.7%-112.5%) and recovery (91.4%-109.7%) for all drugs could be well compensated by their isotope-labelled internal standards. A benchtop stability test showed that the degradation of prothionamide was over 15% after placement at room temperature for 72 h. Clinical samples (n = 224) from a cohort study were analyzed and all concentrations were within the analytical range. The signal of prothionamide was suppressed in samples with hemolysis which was solved by sample dilution. As the method is robust and sample preparation is simple, it can easily be implemented to facilitate TDM in programmatic MDR-TB treatment.
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| 33. |
- Zhu, Yue, et al.
(författare)
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Population Pharmacokinetics and Dose Evaluation of Cycloserine among Patients with Multidrug-Resistant Tuberculosis under Standardized Treatment Regimens
- 2023
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Ingår i: Antimicrobial Agents and Chemotherapy. - : AMER SOC MICROBIOLOGY. - 0066-4804 .- 1098-6596. ; 67:5
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Tidskriftsartikel (refereegranskat)abstract
- Although cycloserine is a recommended drug for the treatment of multidrug-resistant tuberculosis (MDR-TB) according to World Health Organization (WHO), few studies have reported on pharmacokinetics (PK) and/or pharmacodynamics (PD) data of cycloserine in patients with standardized MDR-TB treatment. This study aimed to estimate the population PK parameters for cycloserine and to identify clinically relevant PK/PD thresholds, as well as to evaluate the current recommended dosage. Although cycloserine is a recommended drug for the treatment of multidrug-resistant tuberculosis (MDR-TB) according to World Health Organization (WHO), few studies have reported on pharmacokinetics (PK) and/or pharmacodynamics (PD) data of cycloserine in patients with standardized MDR-TB treatment. This study aimed to estimate the population PK parameters for cycloserine and to identify clinically relevant PK/PD thresholds, as well as to evaluate the current recommended dosage. Data from a large cohort with full PK curves was used to develop a population PK model. This model was used to estimate drug exposure in patients with MDR-TB from a multicentre prospective study in China. The classification and regression tree was used to identify the clinically relevant PK/PD thresholds. Probability of target attainment was analyzed to evaluate the currently recommended dosing strategy. Cycloserine was best described by a two-compartment disposition model. A percentage of time concentration above MICs (T->MIC) of 30% and a ratio of area under drug concentration-time curve (AUC(0-24h)) over MIC of 36 were the valid predictors for 6-month sputum culture conversion and final treatment outcome. Simulations showed that with WHO-recommended doses (500 mg and 750 mg for patients weighing <45 kg and >= 45 kg), the probability of target attainment exceeded 90% at MIC <= 16 mg/L in MGIT for both T->MIC of 30% and AUC(0-24h)/MIC of 36. New clinically relevant PK/PD thresholds for cycloserine were identified in patients with standardized MDR-TB treatment. WHO-recommended doses were considered adequate for the MGIT MIC distribution in our cohort of Chinese patients with MDR-TB.
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