Publications by authors named "Stelzer C"

Purpose: This retrospective cohort study assessed semen and testicular tissue quality from adult and adolescent cancer patients who had samples cryopreserved in the Cryobank of Charité-Universitätsmedizin before and/or after cancer treatment.

Methods And Materials: Medical and cryopreservation data for all samples stored between 03/2004 and 05/2019 were collected retrospectively.

Results: We included information on 601 samples cryopreserved from 506 cancer patients for whom oncologic treatment data were available.

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Some selection-based theories propose that genome streamlining, favoring smaller genome sizes, is advantageous in nutritionally limited environments, particularly under P-limitation. To test this prediction, we conducted several experimental evolution trials on clonal populations of a facultatively asexual rotifer that exhibits intraspecific variation in genome size. Most trials showed a rapid decline in clonal diversity, which was accelerated in populations that were initially nonadapted.

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Intraspecific genome size (GS) variation in Eukaryotes is often mediated by additional, nonessential genomic elements. Physically, such additional elements may be represented by supernumerary (B-)chromosomes or by large heterozygous insertions into the regular chromosome set. Here we analyze meiotic transmission patterns of Megabase-sized, independently segregating genomic elements (ISEs) in Brachionus asplanchnoidis, a planktonic rotifer that displays an up to two-fold intraspecific GS variation due to variation in size and number of these elements.

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Objective: To explore the characteristics of cancer patients who cryopreserved sperm/testicular tissue samples in the Cryobank of Charité-Universitätsmedizin Berlin between 2004 and 2019, and the ART utilization rate with associated outcomes.

Methods: Retrospective data were available for 506 cancer patients, of which 46 (9.1%) had used their samples for artificial reproductive technologies (ART).

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Background: Eukaryotic genomes are known to display an enormous variation in size, but the evolutionary causes of this phenomenon are still poorly understood. To obtain mechanistic insights into such variation, previous studies have often employed comparative genomics approaches involving closely related species or geographically isolated populations within a species. Genome comparisons among individuals of the same population remained so far understudied-despite their great potential in providing a microevolutionary perspective to genome size evolution.

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Background: Accumulating evidence indicates that free amino acids (FAA) might be bioactive compounds with potential immunomodulatory capabilities. However, the FAA composition in human milk is still poorly characterized with respect to its correlation to maternal serum levels and its physiological significance for the infant. Studies addressing the relation of human milk FAA to the infants' intestinal microbiota are still missing.

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Article Synopsis
  • Eukaryotic organisms often have more DNA than you'd expect based on their complexity, leading to theories that this excess might have benefits despite not holding more genetic information.
  • In a study of the rotifer species Brachionus asplanchnoidis, researchers found that larger genome sizes were linked to larger body sizes, bigger eggs, and longer embryonic development times.
  • The findings suggest that natural selection can influence genome size in this population, although the effects must be significant enough to outweigh random genetic changes.
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Multi-input logic gene circuits can enable sophisticated control of cell function, yet large-scale synthetic circuitry in mammalian cells has relied on post-transcriptional regulation or recombinase-triggered state transitions. Large-scale transcriptional logic, on the other hand, has been challenging to implement. Inspired by a naturally found regulatory strategy of using multiple alternative promoters, followed by alternative splicing, we developed a scalable and compact platform for transcriptional OR logic using inputs to those promoters.

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The mapping of molecular inputs to their molecular outputs (input/output, I/O mapping) is an important characteristic of gene circuits, both natural and synthetic. Experimental determination of such mappings for synthetic circuits is best performed using stably integrated genetic constructs. In mammalian cells, stable integration of complex circuits is a time-consuming process that hampers rapid characterization of multiple circuit variants.

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This article provides useful information for universities offering forestry programs and facing the growing demand for bioeconomy education. An explorative survey on bioeconomy perception among 1400 students enrolled in 29 universities across nine European countries offering forestry programs was performed. The data have been elaborated via descriptive statistics and cluster analysis.

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Background: Treatment of patients with solid tumors and KRAS mutations remains disappointing. One option is the combined inhibition of pathways involved in RAF-MEK-ERK and PI3K-AKT-mTOR.

Methods: Patients with relapsed solid tumors were treated with escalating doses of everolimus (E) 2.

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The extent of a drug-drug interaction (DDI) mediated by cytochrome P450 (CYP) 3A inhibitors is highly variable during a dosing interval, as it depends on the temporal course of victim and perpetrator drug concentrations at intestinal and hepatic CYP3A expression sites. Capturing the time course of inhibition is therefore difficult using standard DDI studies assessing changes in area under the curve; thus, a novel design was developed. In a 4-period changeover pilot study, 6 healthy men received intraduodenal or intravenous infusions of the CYP3A substrate midazolam (MDZ) at a rate of 0.

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Within-species variation in genome size has been documented in many animals and plants. Despite its importance for understanding eukaryotic genome diversity, there is only sparse knowledge about how individual-level processes mediate genome size variation in populations. Here, we study a natural population of the rotifer Brachionus asplanchnoidis whose members differ up to 1.

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Flatworms can very rapidly attach to and detach from many substrates. In the presented work, we analysed the adhesive system of the marine proseriate flatworm Minona ileanae. We used light-, scanning- and transmission electron microscopy to analyse the morphology of the adhesive organs, which are located at the ventral side of the tail-plate.

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Background: The causes and consequences of genome size variation across Eukaryotes, which spans five orders of magnitude, have been hotly debated since before the advent of genome sequencing. Previous studies have mostly examined variation among larger taxonomic units (e.g.

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Article Synopsis
  • Many organisms experience fluctuations in population sizes due to predator-prey interactions, which are well-studied in model systems like rotifer-algae communities.
  • The research focused on how different sexual propensities among cyclical parthenogens (CPs) and obligate parthenogens (OPs) influence these population dynamics.
  • Findings revealed that OPs had larger population cycle amplitudes at low nutrient levels, indicating that reproductive modes may play a crucial role in understanding population oscillations.
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  • The study investigates how two drugs, hydrochlorothiazide (HCT) and ramiprilate, might contribute to central nervous system (CNS) adverse effects like headaches and drowsiness by examining their concentrations in cerebrospinal fluid (CSF) and serum.
  • Samples were taken from neurological patients who were treated with either drug, and sophisticated methods were used to measure drug levels in both CSF and serum.
  • The findings revealed that the amounts of HCT and ramiprilate in CSF were significantly lower than those in serum, suggesting that the CNS adverse effects are probably not caused by direct action in the brain from these drugs.
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Background: Bisoprolol and metoprolol are moderately lipophilic, beta(1)-selective betablockers reported to cause adverse effects in the central nervous system (CNS), such as sleep disturbance, suggesting that both drugs may reach relevant concentrations in the brain. CNS beta(2)-receptor blockade has been suspected to be related to such effects. The higher molecular size of bisoprolol (325 Dalton) and the higher beta(1)-selectivity compared to metoprolol (267 Dalton) would suggest a lower rate of CNS effects.

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  • Genome size in the rotifer species complex varies widely (205-407 Mbp), raising questions about potential reproductive barriers and speciation due to genetic differences.
  • To investigate this, researchers tested clones from three geographic populations for reproductive isolation and analyzed population structures using AFLPs.
  • Their findings showed that while the populations were genetically distinct, successful interbreeding occurred between clones with large genome size differences, leading to viable hybrids without negative impacts on fitness or reproduction.
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  • Current theory suggests that sex can enhance genetic variation and fitness if allele associations are non-random, particularly in regard to beneficial and harmful alleles.
  • In a study on Brachionus calyciflorus rotifers, it was found that recombination of beneficial alleles was the most effective mechanism during the initial stages of adaptive evolution.
  • Results indicate that sexual reproduction may accelerate adaptation through beneficial allele recombination, especially in early evolutionary stages, and the advantages of sex could evolve over time.
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The tyrosine kinase inhibitor sunitinib is used as first-line therapy in patients with metastasized renal cell carcinoma (mRCC), given in fixed-dose regimens despite its high variability in pharmacokinetics (PKs). Interindividual variability of drug exposure may be responsible for differences in response. Therefore, dosing strategies based on pharmacokinetic/pharmacodynamic (PK/PD) models may be useful to optimize treatment.

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  • The optimal dosing of antibiotics is still not well understood, despite advances in pharmacokinetic-pharmacodynamic (PK-PD) relationships used for patients.
  • The effectiveness of antibiotics like betalactams, aminoglycosides, and vancomycin depends on specific dosing strategies related to their concentration levels in the blood compared to the minimum inhibitory concentration (MIC).
  • More extensive studies, especially involving critically ill patients, are necessary to validate these dosing concepts, and implementing therapeutic drug monitoring (TDM) in ICUs is recommended to better manage antibiotic levels.
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  • Facultative sex allows individuals to reproduce both sexually and asexually, creating diverse life-history strategies uniquely tailored to environmental conditions.
  • The study uses a matrix modeling approach to analyze the costs and benefits of facultative sex in varying environments, emphasizing findings from the rotifer Brachionus calyciflorus, where sexual reproduction is linked to a dormant stage called diapause.
  • Results indicate that in stable environments, asexual reproduction is more advantageous due to high costs associated with sexual reproduction, while in unpredictable (stochastic) environments, facultative sex is favored, particularly when asexuals struggle to adapt to poor conditions.
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Background: Pantoprazole is a proton pump inhibitor drug mainly used for treating peptic diseases. Adverse effects of pantoprazole in the occasional central nervous system (CNS) include headache, vertigo and sleep disturbances. Data in rats suggest that proton pumps are expressed in the inner ear and in the epithelium of the choroid plexus, which would be a potential target to mediate such proton pump inhibitor effects.

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Aim: The aim of this study was to investigate if biomarkers of individual drug metabolism, respectively, the erlotinib/O-desmethyl-erlotinib metabolic ratio, may be a predictive factor for the severity of erlotinib-mediated skin rash in epidermal growth factor receptor (EGFR) inhibitor-treated patients suffering from epithelial cancers. This is especially important since it is known that the severity of skin rash has a prognostic value on outcome and survival in cancer patients experiencing skin rash under treatment with EGFR inhibitors.

Methods: From 2008 to 2014, 96 patients, n = 63 suffering from histologically confirmed non-small-cell lung cancer and n = 33 from pancreatic adenocarcinoma were observed for the occurrence and severity of skin rash after the onset of treatment with erlotinib.

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