Publications by authors named "Sabrina Strobel"

10 Publications

  • Page 1 of 1

Mammary analogue secretory carcinoma of a salivary gland of the hard palate with contralateral cervical lymph node metastases: A case report.

Mol Clin Oncol 2021 Nov 6;15(5):226. Epub 2021 Sep 6.

Department of Maxillofacial and Plastic Surgery of The University of Wuerzburg, D-97070 Wuerzburg, Germany.

Mammary analogue secretory carcinoma (MASC) is a rare malignant tumour of the salivary glands, with only few cases reported in the literature to date. Initial preoperative staging is crucial for all patients with an oral malignancy to visualize the tumour, detect lymph node or distant metastases and plan therapeutic interventions. In the case presented herein, radiological imaging revealed a tumour of the right hard palate with suspected positive contralateral lymph nodes. Therefore, local tumour resection comprising hemimaxillectomy and bilateral neck dissection was performed. The diagnosis of MASC was finally based on characteristic histopathological and immunohistochemical findings, such as S100 protein and mammaglobin positivity. The diagnosis of MASC may be challenging, as such findings lack specificity. To confirm the diagnosis, molecular genetic examinations may be performed to detect a highly specific ETV6-NTRK3 fusion gene. Depending on the results of these examinations, surgery, alone or combined with adjuvant radiation or chemoradiation, is the recommended approach. In summary, MASC should be treated similarly to other low-grade salivary gland tumours, such as acinic cell carcinoma, as they exhibit biological and histopathological similarities.
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http://dx.doi.org/10.3892/mco.2021.2389DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8506652PMC
November 2021

No Metagenomic Evidence of Causative Viral Pathogens in Postencephalitic Parkinsonism Following Encephalitis Lethargica.

Microorganisms 2021 Aug 12;9(8). Epub 2021 Aug 12.

Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany.

Postencephalitic parkinsonism (PEP) is a disease of unknown etiology and pathophysiology following encephalitis lethargica (EL), an acute-onset polioencephalitis of cryptic cause in the 1920s. PEP is a tauopathy with multisystem neuronal loss and gliosis, clinically characterized by bradykinesia, rigidity, rest tremor, and oculogyric crises. Though a viral cause of EL is likely, past polymerase chain reaction-based investigations in the etiology of both PEP and EL were negative. PEP might be caused directly by an unknown viral pathogen or the consequence of a post-infectious immunopathology. The development of metagenomic next-generation sequencing in conjunction with bioinformatic techniques has generated a broad-range tool for the detection of unknown pathogens in the recent past. Retrospective identification and characterization of pathogens responsible for past infectious diseases can be successfully performed with formalin-fixed paraffin-embedded (FFPE) tissue samples. In this study, we analyzed 24 FFPE brain samples from six patients with PEP by unbiased metagenomic next-generation sequencing. Our results show that no evidence for the presence of a specific or putative (novel) viral pathogen was found, suggesting a likely post-infectious immune-mediated etiology of PEP.
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http://dx.doi.org/10.3390/microorganisms9081716DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8398509PMC
August 2021

α-Synuclein in Parkinson's disease: causal or bystander?

J Neural Transm (Vienna) 2019 07 25;126(7):815-840. Epub 2019 Jun 25.

Department of Neuropathology, Institute of Pathology, University of Würzburg, Würzburg, Germany.

Parkinson's disease (PD) comprises a spectrum of disorders with differing subtypes, the vast majority of which share Lewy bodies (LB) as a characteristic pathological hallmark. The process(es) underlying LB generation and its causal trigger molecules are not yet fully understood. α-Synuclein (α-syn) is a major component of LB and SNCA gene missense mutations or duplications/triplications are causal for rare hereditary forms of PD. As typical sporadic PD is associated with LB pathology, a factor of major importance is the study of the α-syn protein and its pathology. α-Syn pathology is, however, also evident in multiple system atrophy (MSA) and Lewy body disease (LBD), making it non-specific for PD. In addition, there is an overlap of these α-synucleinopathies with other protein-misfolding diseases. It has been proven that α-syn, phosphorylated tau protein (pτ), amyloid beta (Aβ) and other proteins show synergistic effects in the underlying pathogenic mechanisms. Multiple cell death mechanisms can induce pathological protein-cascades, but this can also be a reverse process. This holds true for the early phases of the disease process and especially for the progression of PD. In conclusion, while rare SNCA gene mutations are causal for a minority of familial PD patients, in sporadic PD (where common SNCA polymorphisms are the most consistent genetic risk factor across populations worldwide, accounting for 95% of PD patients) α-syn pathology is an important feature. Conversely, with regard to the etiopathogenesis of α-synucleinopathies PD, MSA and LBD, α-syn is rather a bystander contributing to multiple neurodegenerative processes, which overlap in their composition and individual strength. Therapeutic developments aiming to impact on α-syn pathology should take this fact into consideration.
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http://dx.doi.org/10.1007/s00702-019-02025-9DOI Listing
July 2019

Melanin and Neuromelanin Fluorescence Studies Focusing on Parkinson's Disease and Its Inherent Risk for Melanoma.

Cells 2019 06 15;8(6). Epub 2019 Jun 15.

Institute of Pathology, Department of Neuropathology, University of Wuerzburg, Comprehensive Cancer Center (CCC) Mainfranken Wuerzburg, 97080 Wuerzburg, Germany.

Parkinson's disease is associated with an increased risk of melanoma (and vice versa). Several hypotheses underline this link, such as pathways affecting both melanin and neuromelanin. For the first time, the fluorescence of melanin and neuromelanin is selectively accessible using a new method of nonlinear spectroscopy, based on a stepwise two-photon excitation. Cutaneous pigmentation and postmortem neuromelanin of Parkinson patients were characterized by fluorescence spectra and compared with controls. Spectral differences could not be documented, implying that there is neither a Parkinson fingerprint in cutaneous melanin spectra nor a melanin-associated fingerprint indicating an increased melanoma risk. Our measurements suggest that Parkinson's disease occurs without a configuration change of neuromelanin. However, Parkinson patients displayed the same dermatofluorescence spectroscopic fingerprint of a local malignant transformation as controls. This is the first comparative retrospective fluorescence analysis of cutaneous melanin and postmortem neuromelanin based on nonlinear spectroscopy in patients with Parkinson's disease and controls, and this method is a very suitable diagnostic tool for melanoma screening and early detection in Parkinson patients. Our results suggest a non-pigmentary pathway as the main link between Parkinson's disease and melanoma, and they do not rule out the melanocortin-1-receptor gene as an additional bridge between both diseases.
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http://dx.doi.org/10.3390/cells8060592DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627191PMC
June 2019

Astrocyte- and Microglia-Specific Mitochondrial DNA Deletions Levels in Sporadic Alzheimer's Disease.

J Alzheimers Dis 2019 ;67(1):149-157

Institute of Pathology, Department of Neuropathology, University of Wuerzburg, Germany.

Oxidative stress is implicated in the pathogenesis of neurodegenerative diseases, including sporadic Alzheimer's disease (AD). Mitochondrial DNA (mtDNA) deletions are markers of oxidative damage with an age-dependent accumulation. In a previous study, we analyzed mtDNA levels in diverse neuronal cell types in order to unravel the impact of oxidative stress in brains of AD patients. The aim of this study was to identify possible correlations between mtDNA deletion levels of selected astrocytes and microglia from three brain regions with different vulnerability to AD pathology and different stages of disease compared to controls. Our results reflect a higher vulnerability of hippocampal astrocytes and microglia to oxidative stress compared to other brain regions, such as cerebellum and brainstem.
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http://dx.doi.org/10.3233/JAD-180661DOI Listing
March 2020

Comparison of two cone-beam computed tomography systems in the visualization of endodontic structures.

Swiss Dent J 2017 ;127(3):221-229

Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center, University of Freiburg, Freiburg i.Br., Germany

An important part of endodontic diagnosis and treatment is the adequate visualization of root canal anatomy. The objective of the present study was to compare two different three-dimensional cone-beam computed tomography (CBCT) systems, Scanora 3D and 3D Accuitomo 170, with respect to their visualization of endodontic canal systems and potential pathological alterations. Seventy extracted human teeth were investigated with regard to the radiographic detection of number of root canals, lateral canals, root canal fillings and posts, vertical root fractures, and the occurrence of image artifacts. For each evaluation parameter under investigation the radiographic diagnoses obtained by the two different CBCT systems under investigation were similarly accurate, without statistically significant differences. The evaluation of teeth containing highdensity foreign materials was impaired for both CBCT systems because of image artifacts. However, a difference between the CBCT systems was not observed. In conclusion, both CBCT systems were found to be similarly suitable for the visualization of endodontic structures in vitro.
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September 2017

Antimicrobial influence of different root canal filling techniques in experimentally infected human root canals.

Quintessence Int 2017 ;48(4):273-280

Objective: The aim of the present study was to evaluate the antimicrobial influence of different root canal filling techniques using gutta-percha and an epoxy resin-based sealer in experimentally infected root canals of extracted human teeth.

Method And Materials: In total, 96 intact sterilized, permanent human anterior teeth and premolars with single patent root canals were prepared and infected with a clinical isolate of Enterococcus faecalis. After 72 hours, all root canals were sampled using three sterile paper points. The tooth specimens were randomly divided into three groups and a control of 24 specimens each, according to the respective obturation techniques: lateral condensation (LC group), ProTaper Thermafil (PT group), and vertical compaction technique (VC group). AH Plus was used as sealer. The control group was left untreated (without root canal filling). After 7 days root canal fillings were removed and collected. The root canals were sampled using three sterile paper points and dentin chips were obtained from the root canal walls. The samples were cultured on blood agar, and colony forming units were counted.

Results: All root canal filling techniques significantly reduced bacterial viability, eliminating more than 99.9% of E faecalis. In the LC group, three (13%) root canals were culture negative. In the PT group, 21 (88%) root canals and in the VC group 15 (54%) were culture negative.

Conclusion: All root canal filling techniques significantly reduced E faecalis in root canals. In cases where warm filling techniques can be applied, these should be preferred to cold obturation.
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http://dx.doi.org/10.3290/j.qi.a37129DOI Listing
October 2018

The effects of matrix-metallo- proteinases and chlorhexidine on the adhesive bond.

Swiss Dent J 2015 ;125(2):134-45

Department of Operative Dentistry and Periodontology, University Medical Center, Freiburg, Germany.

The bond stability between dentin and filling material is the major challenge in modern adhesive techniques. A resin-dentin bond created by the etch-and-rinse technique considerably loses strength within 0.5 to 5 years. This may lead to secondary caries, hypersensitivity and finally loss of restorations. The decrease in bond strength is mainly due to two factors which are related to the collagen network of dentin and its constituent matrix-metalloproteinases (MMPs). Firstly, the collagen fibres exposed by the etching process using 37% phosphoric acid may not be completely infiltrated by subsequently applied adhesive bonding agents. In consequence, a thin layer of exposed, but non-infiltrated collagen remains at the bottom of the hybrid layer, resulting in nanoleakage. Secondly, this non-infiltrated collagen contains active MMPs that may degrade collagen by hydrolysis. Within dentin, these enzymes physiologically are inactive, but they become activated by phosphoric acid and acidic components of bonding agents. As a result, the hybrid layer disintegrates and the bond strength gradually diminishes. However, when chlorhexidine is used as a therapeutic primer following the etching process using 37% phosphoric acid, MMPs are inhibited in a non-specific manner, such that both the hybrid layer and the dentin bond strength are supposed to be preserved for a lon- ger time period. Based on the studies included in this literature review, the use of a pure aqueous solution of 0.2% chlorhexidine as an additional therapeutic primer can be recommended for etch-and-rinse systems.
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May 2015

Melatonin as a candidate therapeutic drug for protecting bone cells from chlorhexidine-induced damage.

J Periodontol 2014 Dec;85(12):e379-89

Department of Operative Dentistry and Periodontology, Center for Dental Medicine, University Medical Center Freiburg, Freiburg, Germany.

Background: Melatonin was proposed for use in periodontitis and peri-implantitis therapy due to its bone-supportive effects. This issue is of interest because standard adjuvant antiseptics, namely chlorhexidine (CHX), prove damaging for osteoblasts. Thus, the aim of this study is to investigate if melatonin is suitable as an auxiliary agent for protecting osteoblasts from CHX damage.

Methods: MC3T3 osteoblast response was determined following administration of various CHX concentrations in the absence or presence of melatonin. Osteoblast morphology was evaluated, total reactive oxygen species (ROS) and superoxide levels were quantified, ratios of apoptotic and necrotic cells were identified by flow cytometry, metabolic activity of remaining cells was assessed, and effects were calculated with repeated measures analysis and post hoc P value adjustment.

Results: CHX led to poor morphology, increased total ROS and superoxide levels, and rigorously diminished the number of vital and metabolic active osteoblasts in a concentration-dependent manner. However, simultaneous melatonin supply supported cell morphogenesis and growth, reduced ROS and superoxide generation, shifted the percentage of CHX-damaged cells from necrotic/late to early apoptotic events, and modulated metabolic activity in osteoblasts.

Conclusion: These data reveal that melatonin protects osteoblasts in the CHX context, thereby implicating melatonin as a promising drug in periodontitis and peri-implantitis treatment.
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http://dx.doi.org/10.1902/jop.2014.140279DOI Listing
December 2014
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