Karina Hettwer

Dr. Karina Hettwer


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 June 2022 in Diagnostics
Verified
Journal Article
Open access
PDF file
JDJonas Dohmen
Jonas Dohmen
ASAlexander Semaan
Alexander Semaan
MKMakbule Kobilay
Makbule Kobilay
MZMartin Zaleski
Martin Zaleski
VBVittorio Branchi
Vittorio Branchi
Stefan HoldenriederStefan Holdenrieder
Stefan Holdenrieder
Background: Despite the significance of colonoscopy for early diagnosis of colorectal adenocarcinoma (CRC), population-wide screening remains challenging, mainly because of low acceptance rates. Herein, exosomal (exo-miR) and free circulating microRNA (c-miR) may be used as liquid biopsies in CRC to identify individuals at risk. Direct comparison of both compartments has shown inconclusive results, which is why we directly compared a panel of 10 microRNAs in this entity. Methods: Exo-miR and c-miR levels were measured using real-time quantitative PCR after isolation from serum specimens in a cohort of 69 patients. Furthermore, results were compared to established tumor markers CEA and CA 19-9. Results: Direct comparison of exo- and c-miR biopsy results showed significantly higher microRNA levels in the exosomal compartment (p < 0.001). Exo-Let7, exo-miR-16 and exo-miR-23 significantly differed between CRC and healthy controls (all p < 0.05), while no c-miR showed this potential. Sensitivity and specificity can be further enhanced using combinations of multiple exosomal miRNAs. Conclusions: Exosomal microRNA should be considered as a promising biomarker in CRC for future studies. Nonetheless, results may show interference with common comorbidities, which must be taken into account in future studies.

1 May 2014
Verified
Journal Article
Closed access
Stefan HoldenriederStefan Holdenrieder
Stefan Holdenrieder
YDYoganiranjana Dharuman
Yoganiranjana Dharuman
JSJens Standop
Jens Standop
NTNicolai Trimpop
Nicolai Trimpop
MHMarielle Herzog
Marielle Herzog
JMJake Micallef
Jake Micallef

27 December 2022 in Foods
Verified
Journal Article
Open access
PDF file
KNKapil Nichani
Kapil Nichani
SUSteffen Uhlig
Steffen Uhlig
BCBertrand Colson
Bertrand Colson
KHKarina Hettwer
Karina Hettwer
KSKirsten Simon
Kirsten Simon
Harshadrai RawelHarshadrai Rawel
Harshadrai Rawel
Food fraud, even when not in the news, is ubiquitous and demands the development of innovative strategies to combat it. A new non-targeted method (NTM) for distinguishing spelt and wheat is described, which aids in food fraud detection and authenticity testing. A highly resolved fingerprint in the form of spectra is obtained for several cultivars of spelt and wheat using liquid chromatography coupled high-resolution mass spectrometry (LC-HRMS). Convolutional neural network (CNN) models are built using a nested cross validation (NCV) approach by appropriately training them using a calibration set comprising duplicate measurements of eleven cultivars of wheat and spelt, each. The results reveal that the CNNs automatically learn patterns and representations to best discriminate tested samples into spelt or wheat. This is further investigated using an external validation set comprising artificially mixed spectra, samples for processed goods (spelt bread and flour), eleven untypical spelt, and six old wheat cultivars. These cultivars were not part of model building. We introduce a metric called the D score to quantitatively evaluate and compare the classification decisions. Our results demonstrate that NTMs based on NCV and CNNs trained using appropriately chosen spectral data can be reliable enough to be used on a wider range of cultivars and their mixes.

12 February 2022 in Pharmaceuticals
Verified
Journal Article
Open access
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WLWener Li
Wener Li
XLXiaojing Luo
Xiaojing Luo
MPMareike S. Poetsch
Mareike S. Poetsch
ROReinhard Oertel
Reinhard Oertel
KNKapil Nichani
Kapil Nichani
MSMario Schubert
Mario Schubert
Adverse effects of drug combinations and their underlying mechanisms are highly relevant for safety evaluation, but often not fully studied. Hydroxychloroquine (HCQ) and azithromycin (AZM) were used as a combination therapy in the treatment of COVID-19 patients at the beginning of the pandemic, leading to higher complication rates in comparison to respective monotherapies. Here, we used human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) to systematically investigate the effects of HCQ, AZM, and their combination on the structure and functionality of cardiomyocytes, and to better understand the underlying mechanisms. Our results demonstrate synergistic adverse effects of AZM and HCQ on electrophysiological and contractile function of iPSC-CMs. HCQ-induced prolongation of field potential duration (FPDc) was gradually increased during 7-day treatment period and was strongly enhanced by combination with AZM, although AZM alone slightly shortened FPDc in iPSC-CMs. Combined treatment with AZM and HCQ leads to higher cardiotoxicity, more severe structural disarrangement, more pronounced contractile dysfunctions, and more elevated conduction velocity, compared to respective monotreatments. Mechanistic insights underlying the synergistic effects of AZM and HCQ on iPSC-CM functionality are provided based on increased cellular accumulation of HCQ and AZM as well as increased Cx43- and Nav1.5-protein levels.

12 April 2025 in Polymers
Verified
Journal Article
Open access
PDF file
MSMarius Stieglitz
Marius Stieglitz
SASonja Adomeit
Sonja Adomeit
Marisa MüllerMarisa Müller
Marisa Müller
KHKarina Hettwer
Karina Hettwer
ASAnja Schlierf
Anja Schlierf
LLLisa Leuchtenberger
Lisa Leuchtenberger
This study investigates the potential of data-driven modeling to monitor and predict mechanical properties of extruded film using recyclates. The first step is to investigate whether a process parameter can indicate the input material quality of the material, which can vary significantly due to the use of recyclate. The die pressure was shown to be a key indicator due to its strong correlation with viscosity and material degradation. The second step is to explore the ability of machine learning models—Generalized Additive Models, Linear Regression, and Random Forest—to predict film tensile strength and modulus based on extrusion process and material parameters. The results demonstrate that including Melt Flow Rate and shear viscosity in addition to pressure and feedstock type (Virgin, PIR, and PCR) significantly improves model accuracy, with Generalized Additive Models achieving the highest R2 of 85.7% for tensile strength prediction. Additionally, the observed variability between different recyclate streams highlights the need for a more detailed classification of recyclates to better predict and optimize the mechanical performance of the film. While data-driven approaches for predicting properties show promise, their effectiveness remains limited by data availability and feedstock variability. Expanding datasets and improving process stability will be critical to refining predictive models for industrial application.

19 January 2015 in Biosensors
Verified
Journal Article
Open access
PDF file
AHAnja Henseleit
Anja Henseleit
CPCarolin Pohl
Carolin Pohl
HKHans-Michael Kaltenbach
Hans-Michael Kaltenbach
KHKarina Hettwer
Karina Hettwer
KSKirsten Simon
Kirsten Simon
EBElke Boschke
Elke Boschke
We used the interaction between human serum albumin (HSA) and a high-affinity antibody to evaluate binding affinity measurements by the bench-top liSPR system (capitalis technology GmbH). HSA was immobilized directly onto a carboxylated sensor layer, and the mechanism of interaction between the antibody and HSA was investigated. The bivalence and heterogeneity of the antibody caused a complex binding mechanism. Three different interaction models (1:1 binding, heterogeneous analyte, bivalent analyte) were compared, and the bivalent analyte model best fit the curves obtained from the assay. This model describes the interaction of a bivalent analyte with one or two ligands (A + L ↔ LA + L ↔ LLA). The apparent binding affinity for this model measured 37 pM for the first reaction step, and 20 pM for the second step.