| 1. |
- Cholujová, Dana, et al.
(författare)
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Comparative study of four fluorescent probes for evaluation of natural killer cell cytotoxicity assays
- 2008
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Ingår i: Immunobiology. - : Elsevier. - 0171-2985 .- 1878-3279. ; 213:8, s. 629-640
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Tidskriftsartikel (refereegranskat)abstract
- Cytotoxicity is one of the major defence mechanisms against both virus-infected and tumor cells. Radioactive 51chromium (51Cr) release assay is a “gold standard” for assessment of natural killer (NK) cytolytic activity in vitro. Several disadvantages of this assay led us to design alternative tools based on flow cytometry analysis. Four different fluorescent dyes, calcein acetoxymethyl ester (CAM), carboxyfluorescein succinimidyl ester (CFSE), Vybrant DiO (DiO) and MitoTracker Green (MTG) were tested for labeling of NK target K-562 cells. Target staining stability, spontaneous release of fluorochromes and subsequent accumulation in bystander unstained cells were measured using fluorimetry and flow cytometry. Healthy donor peripheral blood mononuclear cells and affinity column purified NK cells were used as effectors coincubated with target K-562 cells at different E:T ratios for 3h and 90min, respectively. Fluorescent probe 7-amino-actinomycin D was used for live and dead cell discrimination. Bland–Altman statistical method was applied to measure true agreement for all CAM–51Cr, CFSE–51Cr, DiO–51Cr and MTG–51Cr pairs analyzed. Based on the data, none of the four proposed methods can be stated equivalent to the standard 51Cr release assay. Considering linear relationships between data obtained with four fluorochromes and 51Cr release assay as well as linear regression analysis with R2=0.9393 value for CAM–51Cr pair, we found the CAM assay to be the most closely related to the 51Cr assay.
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| 2. |
- Christoffersson, Jonas, 1986-, et al.
(författare)
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A Cardiac Cell Outgrowth Assay for Evaluating Drug Compounds Using a Cardiac Spheroid-on-a-Chip Device
- 2018
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Ingår i: Bioengineering. - : MDPI AG. - 2306-5354. ; 5:2, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D) models with cells arranged in clusters or spheroids have emerged as valuable tools to improve physiological relevance in drug screening. One of the challenges with cells cultured in 3D, especially for high-throughput applications, is to quickly and non-invasively assess the cellular state in vitro. In this article, we show that the number of cells growing out from human induced pluripotent stem cell (hiPSC)-derived cardiac spheroids can be quantified to serve as an indicator of a drug’s effect on spheroids captured in a microfluidic device. Combining this spheroid-on-a-chip with confocal high content imaging reveals easily accessible, quantitative outgrowth data. We found that effects on outgrowing cell numbers correlate to the concentrations of relevant pharmacological compounds and could thus serve as a practical readout to monitor drug effects. Here, we demonstrate the potential of this semi-high-throughput “cardiac cell outgrowth assay” with six compounds at three concentrations applied to spheroids for 48 h. The image-based readout complements end-point assays or may be used as a non-invasive assay for quality control during long-term culture.
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| 3. |
- Cros, Olivier
(författare)
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Structural properties of the mastoid using image analysis and visualization
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The mastoid, located in the temporal bone, houses an air cell system whose cells have a variation in size that can go far below current conventional clinical CT scanner resolution. Therefore, the mastoid air cell system is only partially represented in a CT scan. Where the conventional clinical CT scanner lacks level of minute details, micro-CT scanning provides an overwhelming amount of ne details. The temporal bone being one of the most complex in the human body, visualization of micro-CT scanning of this boneawakens the curiosity of the experimenter, especially with the correct visualization settings.This thesis first presents a statistical analysis determining the surface area to volume ratio of the mastoid air cell system of human temporal bone, from micro-CT scanning using methods previously applied for conventional clinical CT scans. The study compared current results with previous studies, with successive downsampling the data down to a resolution found in conventional clinical CT scanning. The results from the statistical analysis showed that all the small mastoid air cells, that cannot be detected in conventional clinical CT scans, do heavily contribute to the estimation of the surface area, and in consequence to the estimation of the surface area to volume ratio by a factor of about 2.6. Such a result further strengthens the idea of the mastoid to play an active role in pressure regulation and gas exchange.Discovery of micro-channels through specific use of a non-traditional transfer function was then reported, where a qualitative and a quantitative pre-analysis were performed and reported. To gain more knowledge about these micro-channels, a local structure tensor analysis was applied where structures are described in terms of planar, tubular, or isotropic structures. The results from this structural tensor analysis suggest these microchannels to potentially be part of a more complex framework, which hypothetically would provide a separate blood supply for the mucosa lining the mastoid air cell system.The knowledge gained from analysing the micro-channels as locally providing blood to the mucosa, led to the consideration of how inflammation of the mucosa could impact the pneumatization of the mastoid air cell system. Though very primitive, a 3D shape analysis of the mastoid air cell system was carried out. The mastoid air cell system was first represented in a compact form through a medial axis, from which medial balls could be used. The medial balls, representative of how large the mastoid air cells can be locally, were used in two complementary clustering methods, one based on the size diameter of the medial balls and one based on their location within the mastoid air cell system. From both quantitative and qualitative statistics, it was possible to map the clusters based on pre-defined regions already described in the literature, which opened the door for new hypotheses concerning the effect of mucosal inflammation on the mastoid pneumatization.Last but not least, discovery of other structures, previously unreported in the literature, were also visually observed and briefly discussed in this thesis. Further analysis of these unknown structures is needed.
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| 4. |
- Zenlander, Robin, et al.
(författare)
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A wide scan of plasma proteins demonstrates thioredoxin reductase 1 as a potential new diagnostic biomarker for hepatocellular carcinoma
- 2023
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 58:9, s. 998-1008
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with liver cirrhosis are recommended ultrasonography screening for early detection of hepatocellular carcinoma to increase the chances of curative treatment. However, ultrasonography alone lacks in sensitivity. Adding plasma biomarkers may increase the detection rate. We performed a broad exploratory analysis to find new plasma proteins with potential applicability for HCC screening in patients with cirrhosis. Methods: In a protein discovery cohort of 172 patients with cirrhosis or HCC, we screened for 481 proteins with suspension bead array or proximity extension assay. From these, 24 proteins were selected for further analysis in a protein verification cohort (n = 160), using ELISA, Luminex or an electrochemiluminescence platform. A cut-off model and a stepwise logistic regression model were used to find combinations of proteins with the best discriminatory performance between HCC and cirrhosis. Results: Stepwise logistic regression revealed alpha-fetoprotein (AFP), decarboxy-prothrombin (DCP), thioredoxin reductase 1 (TXNRD1), and fibroblast growth factor 21 (FGF21) as the proteins with the best discriminatory performance between HCC and cirrhosis. Adding TXNRD1 to DCP and AFP increased the AUC from 0.844 to 0.878, and combining AFP, DCP and TXNRD1 with age and sex resulted in an AUC of 0.920. FGF21, however, did not further increase the performance when including age and sex. Conclusion: In the present study, TXNRD1 improves the sensitivity and specificity of AFP and DCP as HCC screening tools in patients with cirrhosis. We suggest that TXNRD1 should be validated in prospective settings as a new complementary HCC biomarker together with AFP and DCP.
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| 5. |
- Gharehbaghi, Arash, et al.
(författare)
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A pattern recognition framework for detecting dynamic changes on cyclic time series
- 2015
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Ingår i: Pattern Recognition. - : Elsevier. - 0031-3203 .- 1873-5142. ; 48:3, s. 696-708
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a framework for binary classification of the time series with cyclic characteristics. The framework presents an iterative algorithm for learning the cyclic characteristics by introducing the discriminative frequency bands (DFBs) using the discriminant analysis along with k-means clustering method. The DFBs are employed by a hybrid model for learning dynamic characteristics of the time series within the cycles, using statistical and structural machine learning techniques. The framework offers a systematic procedure for finding the optimal design parameters associated with the hybrid model. The proposed model is optimized to detect the changes of the heart sound recordings (HSRs) related to aortic stenosis. Experimental results show that the proposed framework provides efficient tools for classification of the HSRs based on the heart murmurs. It is also evidenced that the hybrid model, proposed by the framework, substantially improves the classification performance when it comes to detection of the heart disease.
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| 6. |
- Gharehbaghi, Arash, et al.
(författare)
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An Automatic Tool for Pediatric Heart Sounds Segmentation
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, we present a novel algorithm for pediatric heart sound segmentation, incorporated into a graphical user interface. The algorithm employs both the Electrocardiogram (ECG) and Phonocardiogram (PCG) signals for an efficient segmentation under pathological circumstances.First, the ECG signal is invoked in order to determine the beginning and end points of each cardiac cycle by using wavelet transform technique. Then, first and second heart sounds within the cycles are identified over the PCG signal by paying attention to the spectral properties of the sounds. The algorithm is applied on 120 recordings of normal and pathological children, totally containing 1976 cardiac cycles. The accuracy of the segmentation algorithm is 97% for S1 and 94% for S2 identification while all the cardiac cycles are correctly determined.
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| 7. |
- Gharehbaghi, Arash, et al.
(författare)
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Severity assessments of aortic stenosis using intelligent phonocardiography
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objectives: To study capabilities of the intelligent phonocardiography (IPCG) in automatic grading severity of the aortic stenosis (AS).Methods: Phonocardiogram signals were recorded from the patients with AS, as diagnosed by echocardiography. The patient group is comprised of signals, recorded from 5 patients (2 recordings from each), mostly elderly referrals (>60 years) with mild to severe AS. An advanced processing algorithm, consisted of the wavelet transform and the stepwise regression analysis, characterizes the systolic murmur caused by the AS in order to predict the 5 indicators; mean pressure gradient over the aortic valve (MPG), maximum jet velocity (MJV), aortic valve area (AVA), velocity time integral and the ejection period. The automatic assessment is performed by an artificial neural network using the predicted values of the indicators as the input data. Reliability of the IPCG is validated by applying repeated random sub-sampling (RRSS) with 70%/30% of the training/testing data, and calculating the accuracy. The RRSS is also employed to validate reproducibility of the IPCG by using 70% of the signals for training and the second recording of the same individuals for testing.Results: Accuracy of the IPCG is estimated to be and (95% confidence interval) for the reliability and the reproducibility, respectively. Linear correlation between the characterized systolic murmur and the MPG (r>0.81), the MJV (r>0.82) and the AVA (r>0.85) is observed.Conclusions: The IPCG has the potential to objectively serve as a clinical tool for grading severity of the aortic stenosis.
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| 8. |
- Iredahl, Fredrik, 1988-
(författare)
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Assessment of microvascular and metabolic responses in the skin
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this project was to develop experimental in vivo models that allow for minimally invasive investigations of responses in the skin to microvascular and metabolic provocations. The cutaneous microvasculature has emerged as a valuable model and been proposed to mirror the microcirculation in other organs. Dysfunction in the cutaneous microcirculation has thus been linked to systemic diseases such as hypertension and diabetes mellitus. Models for investigating skin responses could facilitate the understanding of pathophysiological mechanisms as well as effects of drugs.In the first study, three optical measurement techniques (laser Doppler flowmetry (LDF), laser speckle contrast imaging (LSCI) and tissue viability imaging (TiVi)) were compared against each other and showed differences in their ability to detect microvascular responses to provocations in the skin. TiVi was found more sensitive for measurement of noradrenaline-induced vasoconstriction, while LSCI was more sensitive for measurement of vascular occlusion. In the second study, microvascular responses in the skin to iontophoresis of vasoactive drugs were found to depend on the drug delivery protocol. Perfusion half-life was defined and used to describe the decay in the microvascular response to a drug after iontophoresis. In the third study, the role of nitric oxide (NO) was assessed during iontophoresis of insulin. The results showed a NO-dependent vasodilation in the skin by insulin. In the fourth study the vasoactive and metabolic effects of insulin were studied after both local and endogenous administration. Local delivery of insulin increased skin blood flow, paralleled by increased skin concentrations of interstitial pyruvate and lactate, although no change in glucose concentration was observed. An oral glucose load resulted in an increased insulin concentration in the skin paralleled by an increase in blood flow, as measured using the microdialysis urea clearance technique, although no changes in perfusion was measured by LSCI.The thesis concludes that when studying skin microvascular responses, the choice of measurement technique and the drug delivery protocol has an impact on the measurement results, and should therefore be carefully considered. The thesis also concludes that insulin has metabolic and vasodilatory effects in the skin both when administered locally and as an endogenous response to an oral glucose load. The vasodilatory effect of insulin in the skin is mediated by nitric oxide.
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| 9. |
- Boiso, Samuel, et al.
(författare)
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RapidHIT for the purpose of stain analyses – An interrupted implementation
- 2017
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Ingår i: Forensic Science International. - : Elsevier. - 1875-1768 .- 1875-175X. ; 6:Supplement C, s. e589-e590
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Tidskriftsartikel (refereegranskat)abstract
- Rapid DNA instruments have in recent years been developed, enabling analysis of forensic samples with a minimum of human intervention. Initially intended for fast handling of reference samples, such as samples from suspects in booking suites, attention shifted to include crime scene samples. The aim of this study was to determine whether or not the RapidHIT System (IntegenX) is fit for crime scene samples. The first runs gave very poor results, which was found to be due to an incorrect firmware setting leading to no or just minute amounts of amplicons being injected for electrophoresis. After solving this problem, 28 full runs (seven samples each) applying NGM SElect Express were performed comprising various amounts of blood on cotton swabs. Six of the runs failed completely, four due to cartridge leakage and in two runs the PCR mix was not injected. For 155 samples with 1–5ΌL blood (volumes for which complete DNA profiles are expected), 119 samples (77%) gave complete DNA profiles. Among the most serious failures were incorrect allele calling and leakage of DNA extract or PCR product. Other general issues were failure to export results, anode motor breakdown and broken capillary array. Due to the encountered problems with software, hardware and cartridges, together with the low success rate, it was decided not to continue towards implementation of the RapidHIT System in casework.
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| 10. |
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Bioengineered Nanomaterials
- 2013
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- "This book focuses on the novel methodologies and strategies adopted during recent research and development of bioengineered nanomaterials for biomedical applications. It provides comprehensive and updated information on developments in this emerging area. The chapters discuss topics such as nanoemulsions as a vaccine adjuvant, bio-ceramic nanomaterials in medical applications, the potential of nanoparticles for the treatment of solid tumors and metastasis, natural and synthetic nanoporous membranes for cell encapsulation therapy, silver nanoparticles, nanotoxcity testing and bioapplications, inorganic nanoparticle materials for controlled release of drugs, and more"--Provided by publisher.Many varieties of new, complex diseases are constantly being discovered, which leaves scientists with little choice but to embrace innovative methods for controlling the invasion of life-threatening problems. The use of nanotechnology has given scientists an opportunity to create nanomaterials that could help medical professionals in diagnosing and treating problems quickly and effectively. Bioengineered Nanomaterials presents in-depth information on bioengineered nanomaterials currently being developed in leading research laboratories around the world. In particular, the book focuses on nanom.
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