Publications by authors named "Julia Walther"

25 Publications

  • Page 1 of 1

Does DDI-Predictor Help Pharmacists to Detect Drug-Drug Interactions and Resolve Medication Issues More Effectively?

Metabolites 2021 Mar 17;11(3). Epub 2021 Mar 17.

Institut de Pharmacie, CHU Lille, F-59000 Lille, France.

The characterization of drug-drug interactions (DDIs) may require the use of several different tools, such as the thesaurus issued by our national health agency (i.e., ANSM), the metabolic pathways table from the Geneva University Hospital (GUH), and DDI-Predictor (DDI-P). We sought to (i) compare the three tools' respective abilities to detect DDIs in routine clinical practice and (ii) measure the pharmacist intervention rate (PIR) and physician acceptance rate (PAR) associated with the use of DDI-P. The three tools' respective DDI detection rates (in %) were measured. The PIRs and PARs were compared by using the area under the curve ratio given by DDI-P (R) and applying a chi-squared test. The DDI detection rates differed significantly: 40.0%, 76.5%, and 85.2% for ANSM (The National Agency for the Safety of Medicines and Health Products), GUH and DDI-P, respectively ( < 0.0001). The PIR differed significantly according to the DDI-P's R: 90.0%, 44.2% and 75.0% for R ≤ 0.5; R 0.5-2 and R > 2, respectively ( < 0.001). The overall PAR was 85.1% and did not appear to depend on the R category ( = 0.729). Our results showed that more pharmacist interventions were issued when details of the strength of the DDI were available. The three tools can be used in a complementary manner, with a view to refining medication adjustments.
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http://dx.doi.org/10.3390/metabo11030173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8002594PMC
March 2021

Immunosuppressive agents for rheumatoid arthritis: a systematic review of clinical trials and their current development stage.

Ther Adv Musculoskelet Dis 2020 16;12:1759720X20959971. Epub 2020 Dec 16.

Service de Rhumatologie, Hôpitaux Universitaires de Strasbourg, Centre National de Référence des Maladies Autoimmunes et Systémiques Rares, Hôpital de Hautepierre, 1 Avenue Molière BP 83049, Strasbourg, Cedex, 67098, France.

Aims: With the arrival of conventional synthetic (csDMARDs), biological (bDMARDS) and then targeted synthetic (tsDMARDs) disease-modifying anti-rheumatic drugs, the therapeutic arsenal against rheumatoid arthritis (RA) has recently expanded. However, there are still some unmet needs for patients who do not achieve remission and continue to worsen despite treatments. Of note, most randomized controlled trials show that, for methotrexate-inadequate responders, only 20% of patients are ACR70 responders. With our better understanding of RA pathogenesis, finding new treatments is a necessary challenge. The objective of our study was to analyse the whole pipeline of immunosuppressive and immunomodulating drugs evaluated in RA and describe their mechanisms of action and stage of clinical development.

Methods: We conducted a systematic review of all drugs in clinical development in RA, in 17 online registries of clinical trials.

Results: The search yielded 4652 trials, from which we identified 243 molecules. Those molecules belong to csDMARDs ( = 22), bDMARDs ( = 118), tsDMARDs ( = 103). Twenty-four molecules are already marketed in RA in at least one country: eight csDMARDs, 10 bDMARDs and six tsDMARDs. Molecules under current development are mainly bDMARDs ( = 34) and tsDMARDs ( = 33). Seven of those have reached phase III. A large number of molecules (150/243, 61.7%) have been withdrawn.

Conclusion: Despite the availability of 24 marketed molecules, the development of new targeted molecules is ongoing with a total of 243 molecules in RA. With seven molecules currently reaching phase III, we can expect an increase in the armamentarium in the years to come.
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http://dx.doi.org/10.1177/1759720X20959971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7747097PMC
December 2020

Prescribing practices of lopinavir/ritonavir, hydroxychloroquine and azithromycin during the COVID-19 epidemic crisis and pharmaceutical interventions in a French teaching hospital.

Eur J Hosp Pharm 2020 Nov 25. Epub 2020 Nov 25.

Service de Pharmacie, Hopitaux universitaires de Strasbourg, Strasbourg, Alsace, France

Objective: The aims of this study were to describe prescribing practices of lopinavir/ritonavir, hydroxychloroquine and azithromycin during the COVID-19 epidemic crisis (primary endpoint), then to characterise pharmaceutical interventions (PIs) targeted to these medications and evaluate the impact of these PIs on prescribers' practices (secondary end-points).

Methods: This retrospective observational study was carried out at the University Hospital of Strasbourg (France) from March to April 2020. The analysed population excluded patients from intensive care units but included all other adult patients with COVID-19 who received at least one dose of lopinavir/ritonavir combination, hydroxychloroquine or azithromycin, while inpatients. Analyses were performed by using data extracted from electronic medical records.

Result: During the study period, 278 patients were included. A rapid decrease in lopinavir/ritonavir prescriptions was observed. This was accompanied by an increase in hydroxychloroquine and azithromycin prescriptions until the end of March, followed by a decrease leading to the disappearance of these two medications in April. The pharmaceutical analysis of the prescriptions resulted in 59 PIs of which 21 were associated with lopinavir/ritonavir, 32 with hydroxychloroquine and 6 with azithromycin. Regarding the medication-related problems, the most frequent ones were incorrect treatment durations (n=32 (54.2%)), drug interactions with potential torsadogenic reactions (n=14 (23.7%)) and incorrect dosing (n=6 (10.2%)). From the 59 PIs, 48 (81.4%) were accepted and physicians adjusted the medication regimens in a timely manner.

Conclusion: This study demonstrated the value-even more meaningful in a crisis situation-of a strong synergy between physicians and pharmacists for patient-safety focused practices.
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http://dx.doi.org/10.1136/ejhpharm-2020-002449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7689541PMC
November 2020

In Vivo Endoscopic Optical Coherence Tomography of the Healthy Human Oral Mucosa: Qualitative and Quantitative Image Analysis.

Diagnostics (Basel) 2020 Oct 15;10(10). Epub 2020 Oct 15.

Technische Universitaet Dresden, Department of Medical Physics and Biomedical Engineering, Carl Gustav Carus Faculty of Medicine, Fetscherstraße 74, 01307 Dresden, Germany.

To date, there is still a lack of reliable imaging modalities to improve the quality of consultation, diagnostic and medical examinations of the oral mucosa in dentistry. Even though, optical technologies have become an important element for the detection and treatment of different diseases of soft tissue, for the case of oral screenings the evidence of the benefit in comparison to conventional histopathology is mostly still pending. One promising optical technology for oral diagnostics is optical coherence tomography (OCT). To prove the potential of OCT, even the amount of freely accessible OCT data is not sufficient to describe the variance of healthy human oral soft tissue in vivo. In order to remedy this deficiency, the present study provides in vivo OCT cross sections of the human oral mucosa of the anterior and posterior oral cavity as well as the oropharynx of 47 adult volunteers. A collection of representative OCT cross sections forms the basis for a randomized blinded image analysis by means of seven criteria to assess the main features of the superficial layers of the human oral mucosa and to determine its correlation to regional features known from hematoxylin and eosin (HE) stained histology.
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http://dx.doi.org/10.3390/diagnostics10100827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7602587PMC
October 2020

Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa .

Biomed Opt Express 2019 Apr 22;10(4):1942-1956. Epub 2019 Mar 22.

Optical + Biomedical Engineering Laboratory, Department of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, WA 6009, Australia.

Stromal collagen organization has been identified as a potential prognostic indicator in a variety of cancers and other diseases accompanied by fibrosis. Changes in the connective tissue are increasingly considered for grading dysplasia and progress of oral squamous cell carcinoma, investigated mainly by histopathology. In this study, polarization-sensitive optical coherence tomography (PS-OCT) with local phase retardation imaging is used for the first time to visualize depth-resolved (i.e., local) birefringence of healthy human oral mucosa . Depth-resolved birefringence is shown to reveal the expected local collagen organization. To demonstrate proof-of-principle, 3D image stacks were acquired at labial and lingual locations of the oral mucosa, chosen as those most commonly affected by cancerous alterations. To enable an intuitive evaluation of the birefringence images suitable for clinical application, color depth-encoded projections were generated. Compared to views of intensity or conventional cumulative phase retardation, we show that this novel approach offers improved visualization of the mucosal connective tissue layer in general, and reveals the collagen fiber architecture in particular. This study provides the basis for future prospective pathological and comparative studies non-invasively assessing stromal changes in conspicuous and cancerous oral lesions at different stages.
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http://dx.doi.org/10.1364/BOE.10.001942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6484997PMC
April 2019

Endoscopic optical coherence tomography with wide field-of-view for the morphological and functional assessment of the human tympanic membrane.

J Biomed Opt 2018 12;24(3):1-11

Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Anesthesiology and Critical C, Germany.

An endoscopic optical coherence tomography (OCT) system with a wide field-of-view of 8 mm is presented, which combines the image capability of endoscopic imaging at the middle ear with the advantages of functional OCT imaging, allowing a morphological and functional assessment of the human tympanic membrane. The endoscopic tube has a diameter of 3.5 mm and contains gradient-index optics for simultaneous forward-viewing OCT and video endoscopy. The endoscope allows the three-dimensional visualization of nearly the entire tympanic membrane. In addition, the oscillation of the tympanic membrane is measured spatially resolved and in the frequency range between 500 Hz and 5 kHz with 125 Hz resolution, which is realized by phase-resolved Doppler OCT imaging during acoustical excitation with chirp signals. The applicability of the OCT system is demonstrated in vivo. Due to the fast image acquisition, structural and functional measurements are only slightly affected by motion artifacts.
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http://dx.doi.org/10.1117/1.JBO.24.3.031017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6975278PMC
December 2018

Application of optical and spectroscopic technologies for the characterization of carious lesions in vitro.

Biomed Tech (Berl) 2018 Oct;63(5):595-602

Technische Universität Dresden, Faculty of Medicine Carl Gustav Carus, Clinic of Operative and Pediatric Dentistry, Dresden, Germany.

The detection of the beginning demineralization process of dental hard tissue remains a challenging task in dentistry. As an alternative to bitewing radiographs, optical and spectroscopic technologies showed promising results for caries diagnosis. The aim of the present work is to give an overview of optical and spectroscopic properties of healthy and carious human teeth in vitro by means of Raman spectroscopy (RS), optical coherence tomography (OCT) and hyperspectral imaging (HSI). OCT was able to represent microstructural changes below the enamel surface and revealed increased scattering for white spot lesions and a white scattering trail for deeper lesions. HSI showed similar absorbance characteristics for healthy and demineralized enamel over the entire spectrum and a characteristic absorbance peak at 550 nm for discolored lesions. Already at early carious stages (white spot), we found a distinct loss of hydroxylapatite-related intensity at 959 cm-1 in demineralized regions with RS. Healthy and demineralized tooth surfaces can be distinguished at different signal levels by means of RS, OCT and HSI. The presented modalities provide additional information to the current clinical diagnosis of caries such as microstructural changes, quantification of the demineralization and imaging of caries-related chemical changes.
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http://dx.doi.org/10.1515/bmt-2017-0133DOI Listing
October 2018

Inhibition of the PI3K but not the MEK/ERK pathway sensitizes human glioma cells to alkylating drugs.

Cancer Cell Int 2018 4;18:69. Epub 2018 May 4.

3Applied Pharmacy, University of Applied Sciences Kaiserslautern, Campus Pirmasens, Carl-Schurz-Str. 10-16, 66953 Pirmasens, Germany.

Background: Intrinsic chemoresistance of glioblastoma (GBM) is frequently owed to activation of the PI3K and MEK/ERK pathways. These signaling cascades are tightly interconnected however the quantitative contribution of both to intrinsic resistance is still not clear. Here, we aimed at determining the activation status of these pathways in human GBM biopsies and cells and investigating the quantitative impact of both pathways to chemoresistance.

Methods: Receptor tyrosine kinase (RTK) pathways in temozolomide (TMZ) treatment naive or TMZ resistant human GBM biopsies and GBM cells were investigated by proteome profiling and immunoblotting of a subset of proteins. Resistance to drugs and RTK pathway inhibitors was assessed by MTT assays. Apoptotic rates were determined by Annexin V staining and DNA damage with comet assays and immunoblotting.

Results: We analyzed activation of RTK pathways by proteome profiling of tumor samples of patients which were diagnosed a secondary GBM and underwent surgery and patients which underwent a second surgery after TMZ treatment due to recurrence of the tumor. We observed substantial activation of the PI3K and MEK/ERK pathways in both groups. However, AKT and CREB phosphorylation was reduced in biopsies of resistant tumors while ERK phosphorylation remained unchanged. Subsequent proteome profiling revealed that multiple RTKs and downstream targets are also activated in three GBM cell lines. We then systematically describe a mechanism of resistance of GBM cell lines and human primary GBM cells to the alkylating drugs TMZ and cisplatin. No specific inhibitor of the upstream RTKs sensitized cells to drug treatment. In contrast, we were able to restore sensitivity to TMZ and cisplatin by inhibiting PI3K in all cell lines and in human primary GBM cells. Interestingly, an opposite effect was observed when we inhibited the MEK/ERK signaling cascade with two different inhibitors.

Conclusions: Temozolomide treatment naive and TMZ resistant GBM biopsies show a distinct activation pattern of the MEK/ERK and PI3K signaling cascades indicating a role of these pathways in resistance development. Both pathways are also activated in GBM cell lines, however, only the PI3K pathway seems to play a crucial role in resistance to alkylating agents and might serve as drug target for chemosensitization.
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http://dx.doi.org/10.1186/s12935-018-0565-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935937PMC
May 2018

In vivo imaging in the oral cavity by endoscopic optical coherence tomography.

J Biomed Opt 2018 03;23(7):1-13

TU Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive Care Medicine, Clini, Germany.

The common way to diagnose hard and soft tissue irregularities in the oral cavity is initially the visual inspection by an experienced dentist followed by further medical examinations, such as radiological imaging and/or histopathological investigation. For the diagnosis of oral hard and soft tissues, the detection of early transformations is mostly hampered by poor visual access, low specificity of the diagnosis techniques, and/or limited feasibility of frequent screenings. Therefore, optical noninvasive diagnosis of oral tissue is promising to improve the accuracy of oral screening. Considering this demand, a rigid handheld endoscopic scanner was developed for optical coherence tomography (OCT). The novelty is the usage of a commercially near-infrared endoscope with fitting optics in combination with an established spectral-domain OCT system of our workgroup. By reaching a high spatial resolution, in vivo images of anterior and especially posterior dental and mucosal tissues were obtained from the oral cavity of two volunteers. The convincing image quality of the endoscopic OCT device is particularly obvious for the imaging of different regions of the human soft palate with highly scattering fibrous layer and capillary network within the lamina propria.
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http://dx.doi.org/10.1117/1.JBO.23.7.071207DOI Listing
March 2018

Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography.

J Biomed Opt 2018 01;23(7):1-8

Technische Universität Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive, Germany.

As dental caries is one of the most common diseases, the early and noninvasive detection of carious lesions plays an important role in public health care. Optical coherence tomography (OCT) with its ability of depth-resolved, high-resolution, noninvasive, fast imaging has been previously recognized as a promising tool in dentistry. Additionally, polarization sensitive imaging provides quantitative measures on the birefringent tissue properties and can be utilized for imaging dental tissue, especially enamel and dentin. By imaging three exemplary tooth samples ex vivo with proximal white spot, brown spot, and cavity, we show that the combination of polarization sensitive OCT and the degree of polarization uniformity (DOPU) algorithm is a promising approach for the detection of proximal carious lesions due to the depolarization contrast of demineralized tissue. Furthermore, we investigate different sizes of the DOPU evaluation kernel on the resulting contrast and conclude a suitable value for this application. We propose that DOPU provides an easy to interpret image representation and appropriate contrast for possible future screening applications in early caries diagnostics.
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http://dx.doi.org/10.1117/1.JBO.23.7.071203DOI Listing
January 2018

In vivo imaging of human oral hard and soft tissues by polarization-sensitive optical coherence tomography.

J Biomed Opt 2017 Dec;22(12):1-17

TU Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive Care Medicine, Clini, Germany.

Since optical coherence tomography (OCT) provides three-dimensional high-resolution images of biological tissue, the benefit of polarization contrast in the field of dentistry is highlighted in this study. Polarization-sensitive OCT (PS OCT) with phase-sensitive recording is used for imaging dental and mucosal tissues in the human oral cavity in vivo. An enhanced polarization contrast of oral structures is reached by analyzing the signals of the co- and crosspolarized channels of the swept source PS OCT system quantitatively with respect to reflectivity, retardation, optic axis orientation, and depolarization. The calculation of these polarization parameters enables a high tissue-specific contrast imaging for the detailed physical interpretation of human oral hard and soft tissues. For the proof-of-principle, imaging of composite restorations and mineralization defects at premolars as well as gingival, lingual, and labial oral mucosa was performed in vivo within the anterior oral cavity. The achieved contrast-enhanced results of the investigated human oral tissues by means of polarization-sensitive imaging are evaluated by the comparison with conventional intensity-based OCT.
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http://dx.doi.org/10.1117/1.JBO.22.12.121717DOI Listing
December 2017

In vivo imaging of murine vasodynamics analyzing different mouse strains by optical coherence tomography.

Atheroscler Suppl 2017 Nov 31;30:311-318. Epub 2017 May 31.

Division of Vascular Endothelium and Microcirculation, Department of Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany. Electronic address:

Background And Aims: We tried to circumvent the limitations of standard organ chamber experiments using in vivo optical coherence tomography (OCT) to analyze the vascular function of small arteries in different mouse strains.

Methods: OCT images were acquired with a two-axis galvanometer scanner head. Time series (3 frames per second, 300 × 512 pixel per frame) of cross-sectional images were analyzed with image processing software measuring the time course of vessel lumen dynamics. Vascular function of murine saphenous artery of male C57BL/6 (wild-type) and hypercholesterolemic LDLR knockout (LDLR) mice was analyzed at 6 weeks and after 14 weeks feeding a control or high-fat diet containing 21.2% butter fat and 2.1 mg/kg cholesterol. Vasoconstriction and vasodilation was analyzed by OCT in response to 80 mM K and 1 mM SNP.

Results: The OCT technique allowed determination of inner diameter, flow resistance, maximal velocity of diameter change and time to half-maximal diameter change in murine saphenous arteries of wild-type and LDLR mice. LDLR had impaired vasodilation and changes in vasodynamics after 14 weeks on control or high-fat diet, compared to wild-type mice. The diameter of the saphenous artery of LDLR mice was reduced after vasoconstriction (38 ± 7 μm vs 12 ± 6 μm) and vasodilation (245 ± 8 μm vs 220 ± 10 μm) (P < 0.05 vs C57BL/6).

Conclusion: OCT was used as an innovative method to image vascular function of small arteries of wild-type and hypercholesterolemic LDLR mice after high-fat diet. The method offers the ability to display differences in the vasodynamics at early stages of endothelial dysfunction in vivo.
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http://dx.doi.org/10.1016/j.atherosclerosissup.2017.05.023DOI Listing
November 2017

Impact of a detector dead time in phase-resolved Doppler analysis using spectral domain optical coherence tomography.

J Opt Soc Am A Opt Image Sci Vis 2017 Feb;34(2):241-251

For any oblique sample movement containing a transverse velocity component, the commonly used linear relationship between the phase shift and the axial velocity component is erroneous for spectrometer-based optical coherence tomography (spectral domain OCT, SD-OCT). We recently proposed a new Doppler model that assumes a continuous integration of the photocurrent. In this research, we extend the model for detectors with a shutter control by taking detector dead time into account. We present the new relation between phase shift and oblique sample displacement as well as the correlation of the phases of consecutive depth scans, in dependency on the detector dead times ranging from 5% to 90%, as numerically calculated universal contour plots, which are valid for any center wavelength and sample beam size. We found that detector dead time is recommended, especially for oblique sample motion. The reason for this recommendation is the achieved linear relation between the phase shift and the axial velocity component in the velocity range relevant for in vivo measurements, despite the signal damping due to shorter exposure time of the line detector. The theoretical Doppler model is verified using a 1% Intralipid flow phantom model. Because of the results of this research, we believe future measurements in Doppler SD-OCT can be more simple and more accurate by setting a shutter control for the line detector used.
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http://dx.doi.org/10.1364/JOSAA.34.000241DOI Listing
February 2017

Imaging of nanoparticle-labeled stem cells using magnetomotive optical coherence tomography, laser speckle reflectometry, and light microscopy.

J Biomed Opt 2015 03;20(3):036018

Technische Universität Dresden, Faculty of Medicine Carl Gustav Carus, Department of Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Fetscherstrasse 74, 01307 Dresden, Germany.

Cell transplantation and stem cell therapy are promising approaches for regenerative medicine and are of interest to researchers and clinicians worldwide. However, currently, no imaging technique that allows three-dimensional in vivo inspection of therapeutically administered cells in host tissues is available. Therefore, we investigate magnetomotive optical coherence tomography (MM-OCT) of cells labeled with magnetic particles as a potential noninvasive cell tracking method. We develop magnetomotive imaging of mesenchymal stem cells for future cell therapy monitoring. Cells were labeled with fluorescent iron oxide nanoparticles, embedded in tissue-mimicking agar scaffolds, and imaged using a microscope setup with an integrated MM-OCT probe. Magnetic particle-induced motion in response to a pulsed magnetic field of 0.2 T was successfully detected by OCT speckle variance analysis, and cross-sectional and volumetric OCT scans with highlighted labeled cells were obtained. In parallel, fluorescence microscopy and laser speckle reflectometry were applied as two-dimensional reference modalities to image particle distribution and magnetically induced motion inside the sample, respectively. All three optical imaging modalities were in good agreement with each other. Thus, magnetomotive imaging using iron oxide nanoparticles as cellular contrast agents is a potential technique for enhanced visualization of selected cells in OCT.
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http://dx.doi.org/10.1117/1.JBO.20.3.036018DOI Listing
March 2015

Relation of joint spectral and time domain optical coherence tomography (jSTdOCT) and phase-resolved Doppler OCT.

Opt Express 2014 Sep;22(19):23129-46

A variety of promising approaches for quantitative flow velocity measurement in OCT have been proposed in recent years. The question is: Which method gets the most precise flow velocity out of the interference signals detected. We have compared the promising joint spectral and time domain optical coherence tomography (jSTdOCT) and the commonly used phase-resolved Doppler OCT (DOCT) and describe the link between these two proven methods for OCT in the Fourier domain (FD OCT). First, we show that jSTdOCT can be significantly improved by calculating the center of gravity via an unbiased complex algorithm instead of detecting the maximum intensity signal of the broadened Doppler frequency spectrum. Secondly, we introduce a unified mathematical description for DOCT and jSTdOCT that differs only in one exponent and call it enhjSTdOCT. Third, we present that enhjSTdOCT has the potential to significantly reduce the noise of the velocity measurement by choosing an exponent depending on the transverse sample velocity component and the signal-to-noise ratio. EnhjSTdOCT is verified numerically and experimentally to find the optimal parameters for maximal velocity noise reduction.
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http://dx.doi.org/10.1364/OE.22.023129DOI Listing
September 2014

Nutrition, lifestyle factors, and mental health in adolescents and young adults living in Austria.

Int J Adolesc Med Health 2014 ;26(3):377-86

Background: Due to an alarming trend of overweight and obesity in children and adolescents, along with the sparse data on dietary habits and lifestyle factors, the present study aims to analyze the current nutritional behavior as well as the lifestyle and mental health of adolescents and young adults living in Austria.

Materials And Methods: In this cross-sectional study, a total of 500 respondents (aged between 14 and 24 years) completed an anonymous questionnaire on nutrition behavior, mental health, and lifestyle factors by Internet survey.

Results: Only 50% of the participants ate breakfast daily and 10% did not eat breakfast at all. About 47% of the respondents consumed milk and milk products daily. Furthermore, only 31% ate fruit and 21% ate vegetables at least once a day, and 46% ate fish seldom or never. Nearly 28% of young people liked to eat fast food twice or thrice a week and more, with males more often replacing a meal with a fast food product (36%) than females (21%). About 46% of the respondents engaged in physical activity only once a week (or more rarely). A fifth of our respondents (23%) spent more than 2 h a day using various social networks, with Facebook being the most popular social network among the respondents. Around 27% claimed to be smokers, with more female (33%) than male (20%) smoker. In terms of sleeping habits, 19% slept <6 h a day. Regarding well-being, 44% were more likely to feel stressed, 35% stated that they were tense, and 43% felt tired and listless. Eating together, physical activity, and sleep patterns showed positive effects on well-being, whereas higher consumption of fast food/snacks/soft drinks and alcoholic drinks/energy drinks was associated with relatively lower well-being.

Conclusions: Unhealthy eating habits, suboptimal physical activity, and smoking are still prominent in a sample of Austrian adolescents and young people. In addition, stress and tiredness are also relevant problems in this collective.
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http://dx.doi.org/10.1515/ijamh-2013-0310DOI Listing
May 2015

Endoscopic optical coherence tomography device for forward imaging with broad field of view.

J Biomed Opt 2012 Jul;17(7):071302

Dresden University of Technology, Faculty of Medicine Carl Gustav Carus, Department of Clinical Sensoring and Monitoring, Fetscherstr. 74, 01307 Dresden, Germany.

One current challenge of studying human tympanic membranes (TM) with optical coherence tomography (OCT) is the implementation of optics that avoid direct contact with the inflamed tissue. At the moment, no commercial device is available. We report an optics design for contactless forward imaging endoscopic optical coherence tomography (EOCT) with a large working distance (WD) and a broad field of view (FOV) by restricting the overall diameter of the probe to be small (3.5 mm), ensuring a sufficient numerical aperture. Our system uses a gradient-index (GRIN) relay lens and a GRIN objective lens, and executes a fan-shaped optical scanning pattern. The WD and FOV can be adjusted by manually changing the distance between the triplet and the GRIN relay lens. The measured lateral resolution is ∼28  μm at a WD of 10 mm with a FOV of 10 mm. Additionally, a camera and an illumination beam path were implemented within the probe for image guidance during investigations of the TM. We demonstrated the performance of the EOCT design by 3-D imaging of a human TM ex vivo and in vivo with a k-linear spectral domain OCT system.
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http://dx.doi.org/10.1117/1.JBO.17.7.071302DOI Listing
July 2012

Shear flow-induced optical inhomogeneity of blood assessed in vivo and in vitro by spectral domain optical coherence tomography in the 1.3 μm wavelength range.

J Biomed Opt 2011 Nov;16(11):116020

Dresden University of Technology, Clinical Sensoring and Monitoring, Faculty of Medicine Carl Gustav Carus, Dresden, Germany.

The optical inhomogeneity of flowing blood, which appears as a waisted double fan-shaped intensity pattern inside vessels in cross-sectional optical coherence tomography (OCT) images, was investigated for the first time. High resolution spectral domain OCT in the 1.3 μm wavelength region is used to assess this inhomogeneous intravascular backscattering of light in an in vivo mouse model and flow phantom measurements. Based on a predicted alignment of the red blood cells toward laminar shear flow, an angular modulation of the corresponding backscattering cross-section inside the vessels is assumed. In combination with the signal attenuation in depth by absorption and scattering, a simple model of the intravascular intensity modulation is derived. The suitability of the model is successfully demonstrated in the in vivo experiments and confirmed by the in vitro measurements. The observed effect appears in flowing blood only and shows a strong dependency on the shear rate. In conclusion, the shear-induced red blood cell alignment in conjunction with the vessel geometry is responsible for the observed intensity distribution. This inherent effect of blood imaging has to be considered in attenuation measurements performed with OCT. Furthermore, the analysis of the intravascular intensity pattern might be useful to evaluate flow characteristics.
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http://dx.doi.org/10.1117/1.3653235DOI Listing
November 2011

Optical coherence tomography in biomedical research.

Anal Bioanal Chem 2011 Jul 12;400(9):2721-43. Epub 2011 May 12.

Dresden University of Technology, Faculty of Medicine Carl Gustav Carus, Clinical Sensoring and Monitoring, Germany.

Optical coherence tomography (OCT) is a noninvasive, high-resolution, interferometric imaging modality using near-infrared light to acquire cross-sections and three-dimensional images of the subsurface microstructure of biological specimens. Because of rapid improvement of the acquisition speed and axial resolution of OCT over recent years, OCT is becoming increasingly attractive for applications in biomedical research. Therefore, OCT is no longer used solely for structural investigations of biological samples but also for functional examination, making it potentially useful in bioanalytical science. The combination of in vivo structural and functional findings makes it possible to obtain thorough knowledge on basic physiological and pathological processes. Advanced applications, for example, optical biopsy in visceral cavities, have been enabled by combining OCT with established imaging modalities. This report gives an outline of the state of the art and novel trends of innovative OCT approaches in biomedical research in which the main focus is on applications in fundamental research and pre-clinical utilization.
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http://dx.doi.org/10.1007/s00216-011-5052-xDOI Listing
July 2011

Signal power decrease due to fringe washout as an extension of the limited Doppler flow measurement range in spectral domain optical coherence tomography.

J Biomed Opt 2010 Jul-Aug;15(4):041511

Dresden University of Technology, Faculty of Medicine Carl Gustav Carus, Clinical Sensoring and Monitoring, Dresden, Saxony, Germany.

The recently introduced new phase-dependent Doppler model for spectral domain optical coherence tomography (SD OCT) has shown that the simple linear relation between the Doppler phase shift and the axial velocity component of an obliquely moving sample is not valid. Additionally, for nearly transverse sample motion with high velocities the phase shift will approach a constant value. Consequently, for small Doppler angles the velocity measurement range of the phase-resolved Doppler analysis is limited in SD OCT. Since these undesirable small Doppler angles can not be prevented, for example, in the in vivo 3-D measurement, we introduce a novel method extending the limited velocity detection range taking the signal power decrease due to fringe washout in SD OCT into account. The signal damping of an obliquely moving sample is presented as a function of the axial and transverse displacement by a universally valid contour plot and does not correspond simply to the sum of the axial and transverse effect. A quantitative combination of the Doppler analysis and the signal-damping method is presented with a flow phantom model. The practicability of this new combined method is presented for the blood flow of the saphenous artery in the in vivo mouse model.
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http://dx.doi.org/10.1117/1.3466578DOI Listing
January 2011

Transverse motion as a source of noise and reduced correlation of the Doppler phase shift in spectral domain OCT.

Opt Express 2009 Oct;17(22):19698-713

Department of Clinical Sensoring and Monitoring, Medical Faculty Carl Gustav Carus, University of Technology Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.

Recently, a new phase-resolved Doppler model was presented for spectral domain optical coherence tomography (SD OCT) showing that the linear relation between the axial velocity component of the obliquely moving sample and the phase difference of consecutive A-Scans does not hold true in the presence of a transverse velocity component which is neglected in the widely-used classic Doppler analysis. Besides taking note of the new non-proportional relationship of phase shift and oblique sample motion, it is essential to consider the correlation of the phase shift and its specific characteristic at certain Doppler angles for designing Doppler experiments with SD OCT. A correlation quotient is introduced to quantify the correlation of the backscattering signal in consecutive A-Scans as a function of the oblique sample motion. It was found that at certain velocities and Doppler angles no correlation of the phases of sequential A-Scans exists, even though the signal does not vanish. To indicate how the noise of the Doppler phase shift behaves for oblique movement, the standard deviation is determined as a function of the correlation quotient and the number of complex Doppler data averaged. The detailed theoretical model is validated by using a flow phantom model consisting of a 1% Intralipid flow through a 310 microm capillary. Finally, a short discussion of the presented results and the consequence for performing Doppler experiments is given.
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http://dx.doi.org/10.1364/OE.17.019698DOI Listing
October 2009

Simultaneous dual-band optical coherence tomography in the spectral domain for high resolution in vivo imaging.

Opt Express 2009 Oct;17(22):19486-500

Department of Clinical Sensoring and Monitoring, Medical Faculty Carl Gustav Carus, University of Technology Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.

Optical coherence tomography (OCT) in the spectral domain is demonstrated simultaneously at two wavelength bands centered at 800 nm and 1250 nm. A novel commercial supercontinuum laser is applied as a single low coherence broadband light source. The emission spectrum of the source is shaped by optical and spatial filtering in order to achieve an adequate double peak spectrum containing the wavelength bands 700 - 900 nm and 1100 - 1400 nm for dual-band OCT imaging and thus reducing the radiation exposure of the sample. Each wavelength band is analyzed with an individual spectrometer at an A-scan rate of about 12 kHz which enables real-time imaging for the examination of moving samples. A common path optical setup optimized for both spectral regions with a separate single fiber-based scanning unit was realized which facilitates flexible handling and easy access to the measurement area. The free-space axial resolutions were measured to be less than 4.5 microm and 7 microm at 800 nm and 1250 nm, respectively. Three-dimensional imaging ten times faster than previously reported with a signal-to-noise-ratio of above 90 dB is achieved simultaneously in both wavelength bands. Spectral domain dual-band OCT combines real-time imaging with high resolution at 800 nm and enhanced penetration depth at 1250 nm and therefore provides a well suited tool for in vivo vasodynamic measurements. Further, spatially resolved spectral features of the sample are obtained by means of comparing the backscattering properties at two different wavelength bands. The ability of dual-band OCT to enhance tissue contrast and the sensitivity of this imaging modality to wavelength-dependent sample birefringence is demonstrated.
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http://dx.doi.org/10.1364/OE.17.019486DOI Listing
October 2009

In-vivo Fourier domain optical coherence tomography as a new tool for investigation of vasodynamics in the mouse model.

J Biomed Opt 2009 May-Jun;14(3):034027

University of Technology, Dresden, Clinical Sensoring and Monitoring, Faculty of Medicine Carl Gustav Carus, Fetscherstrasse 74, Dresden 01307, Germany.

In-vivo imaging of the vascular system can provide novel insight into the dynamics of vasoconstriction and vasodilation. Fourier domain optical coherence tomography (FD-OCT) is an optical, noncontact imaging technique based on interferometry of short-coherent near-infrared light with axial resolution of less than 10 microm. In this study, we apply FD-OCT as an in-vivo imaging technique to investigate blood vessels in their anatomical context using temporally resolved image stacks. Our chosen model system is the murine saphenous artery and vein, due to their small inner vessel diameters, sensitive response to vasoactive stimuli, and advantageous anatomical position. The vascular function of male wild-type mice (C57BL/6) is determined at the ages of 6 and 20 weeks. Vasoconstriction is analyzed in response to dermal application of potassium (K(+)), and vasodilation in response to sodium nitroprusside (SNP). Vasodynamics are quantified from time series (75 sec, 4 frames per sec, 330 x 512 pixels per frame) of cross sectional images that are analyzed by semiautomated image processing software. The morphology of the saphenous artery and vein is determined by 3-D image stacks of 512 x 512 x 512 pixels. Using the FD-OCT technique, we are able to demonstrate age-dependent differences in vascular function and vasodynamics.
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http://dx.doi.org/10.1117/1.3149865DOI Listing
September 2009

Effects of axial, transverse, and oblique sample motion in FD OCT in systems with global or rolling shutter line detector.

J Opt Soc Am A Opt Image Sci Vis 2008 Nov;25(11):2791-802

Department of Clinical Sensoring and Monitoring, University of Technology, Dresden, Germany.

This study deals with effects on the interference signal caused by axial, transverse, and oblique motion in spectrometer-based Fourier-domain optical coherence tomography (FD OCT). Two different systems are compared-one with a global shutter line detector and the other with a rolling shutter. We present theoretical and experimental investigations of motion artifacts. Regarding axial motion, fringe washout is observed in both systems, and an additional Doppler frequency shift is seen in the system using a rolling shutter. In addition, both systems show the same SNR decrease as a result of a transversely and obliquely moving sample. The possibility of flow measurement by using the decrease in signal power was demonstrated by imaging 1% Intralipid emulsion flowing through a glass capillary. This research provides an understanding of the SNR degradation caused by sample motion and demonstrates the importance of fast data acquisition in medical imaging.
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http://dx.doi.org/10.1364/josaa.25.002791DOI Listing
November 2008

Anakinra (IL-1R antagonist) lowers pulmonary artery pressure in a neonatal surfactant depleted piglet model.

Pediatr Pulmonol 2008 Sep;43(9):851-7

Kinder- und Jugendklinik, Universitätsklinikum Erlangen, Erlangen, Germany.

In acute respiratory distress syndrome (ARDS) with pulmonary hypertension, interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) are involved in the pulmonary inflammatory reaction. The purpose of this study was to determine whether systemic and aerosolized administered IL-1 receptor antagonist (IL-1Ra) Anakinra (Kineret) improves lung mechanics and pulmonary artery pressure in surfactant depleted newborn piglets. After induction of acute lung injury by lung lavage, neonatal piglets received repetitive treatment of either aerosolized IL-1Ra (IL-1Ra-Aerosol) or intravenous IL-1Ra (IL-1Ra-i.v.), or saline solution as control. IL-1Ra given as aerosol or intravenously significantly reduced mean pulmonary artery pressure (MPAP) but did not influence mean systemic arterial pressure (MAP) compared with the control group. IL-1 beta and IL-8 mRNA expressions normalized to beta-actin and hypoxanthine-guanine-phosphoribosyl transferase were significantly reduced in the IL-1Ra-Aerosol group but not in IL-1Ra-i.v. group compared to the control group. The lung injury score was not significantly different between IL-1Ra groups and the control group. Application of aerosolized IL-1Ra reduced MPAP without affecting MAP in a piglet model of surfactant depletion with pulmonary hypertension. Furthermore, there is evidence for reduction of early pro-inflammatory pulmonary reaction.
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http://dx.doi.org/10.1002/ppul.20851DOI Listing
September 2008