Insights to HIV-1 coreceptor usage by estimating HLA adaptation with Bayesian generalized linear mixed models.

The mechanisms triggering the human immunodeficiency virus type I (HIV-1) to switch the coreceptor usage from CCR5 to CXCR4 during the course of infection are not entirely understood. While low CD4+ T cell counts are associated with CXCR4 usage, a predominance of CXCR4 usage with still high CD4+ T cell counts remains puzzling. Here, we explore the hypothesis that viral adaptation to the human leukocyte antigen (HLA) complex, especially to the HLA class II alleles, contributes to the coreceptor switch.

Alveolar epithelial-like cell differentiation in a dynamic bioreactor: a promising 3D-approach for the high-throughput generation of lung cell types from human induced pluripotent stem cells.

Purpose: Human induced pluripotent stem cell (hiPSC)-derived lung cell types such as alveolar epithelial cells are promising for toxicological and pharmaceutical in vitro screenings. Reproducible differentiation processes are highly demanded, but protocols which are suitable for the high-throughput generation of lung cell types from hiPSCs are lacking.

Methods: In this study, a new approach for the hiPSC-differentiation in alveolar epithelial-like cells type 2 under dynamic 3D-conditions in a suspension bioreactor is presented.

A rabbit model for outer retinal atrophy caused by surgical RPE removal.

Purpose: We aimed to establish a rabbit model with retinal atrophy induced by an iatrogenic retinal pigment epithelium (RPE) removal, for future testing of the efficacy and safety of cell therapy strategies.

Methods: A localized detachment of the retina from the RPE/choroid layer was created in 18 pigmented rabbits. The RPE was removed by scraping with a custom-made extendable loop instrument.

Long-term monitoring of mercury in young German adults: Time trend analyses from the German Environmental Specimen Bank, 1995-2018.

As highlighted in the Minamata Convention, Mercury (Hg) in its various forms poses a substantial risk to human health and the environment. The health relevance of Hg is also recognized by the European Human Biomonitoring Initiative (HBM4EU), which classifies Hg as a priority substance, since considerable knowledge and data gaps on Hg exposure levels and their changes over time still exist in Europe. The German Environmental Specimen Bank (German ESB) provides valuable policy relevant data and long-term trends of substance exposure on a national level for international comparison and evaluation.

A HET-CAM based vascularized intestine tumor model as a screening platform for nano-formulated photosensitizers.

The development of new tumor models for anticancer drug screening is a challenge for preclinical research. Conventional cell-based in vitro models such as 2D monolayer cell cultures or 3D spheroids allow an initial assessment of the efficacy of drugs but they have a limited prediction to the in vivo effectiveness. In contrast, in vivo animal models capture the complexity of systemic distribution, accumulation, and degradation of drugs, but visualization of the individual steps is challenging and extracting quantitative data is usually very difficult.

Novel Cost-Efficient Graphene-Based Impedance Biosensor for the Analysis of Viral Cytopathogenicity and the Effect of Antiviral Drugs.

Biosensors become increasingly relevant for medical diagnostics, pharmaceutical industry, and environmental technology, for example, to test new drugs easily and reliably or to detect cell growth in changing environmental conditions. Novel materials like graphene are promising candidates to produce biosensors on an industrial scale by means of printing processes. To reach this aim, methods for the reliable and automated production of electrode structures and their coating are required.

Influence of Physicochemical Characteristics and Stability of Gold and Silver Nanoparticles on Biological Effects and Translocation across an Intestinal Barrier-A Case Study from In Vitro to In Silico.

A better understanding of their interaction with cell-based tissue is a fundamental prerequisite towards the safe production and application of engineered nanomaterials. Quantitative experimental data on the correlation between physicochemical characteristics and the interaction and transport of engineered nanomaterials across biological barriers, in particular, is still scarce, thus hampering the development of effective predictive non-testing strategies. Against this background, the presented study investigated the translocation of gold and silver nanoparticles across the gastrointestinal barrier along with related biological effects using an in vitro 3D-triple co-culture cell model.

Microfluidic In Vitro Platform for (Nano)Safety and (Nano)Drug Efficiency Screening.

Microfluidic technology is a valuable tool for realizing more in vitro models capturing cellular and organ level responses for rapid and animal-free risk assessment of new chemicals and drugs. Microfluidic cell-based devices allow high-throughput screening and flexible automation while lowering costs and reagent consumption due to their miniaturization. There is a growing need for faster and animal-free approaches for drug development and safety assessment of chemicals (Registration, Evaluation, Authorisation and Restriction of Chemical Substances, REACH).

Comparative cytotoxic and antiproliferative profile of methotrexate and fluorouracil on different ocular cells.

Purpose: To analyse the cytotoxic and antiproliferative effect of methotrexate (MTX) and fluorouracil (5-FU) in vitro on fibroblasts, retinal pigment epithelial (RPE) and photoreceptor cells as an adjunct for reducing the incidence of proliferative vitreoretinopathy (PVR) after rhegmatogenous retinal detachment surgery.

Methods: Methotrexate and 5-FU were dissolved separately in balanced salt solution (BSS) with concentrations ranging from 0-8000 µg/ml and 0-4000 µg/ml, respectively. All solutions were analysed in terms of pH and osmolarity and applied for 1 h to fibroblasts (BJ), RPE (ARPE-19) and photoreceptor (661W) cell lines adherently cultivated in 96-well cell culture plates (10 000 cells/well).

Validation of human microRNA target pathways enables evaluation of target prediction tools.

MicroRNAs are regulators of gene expression. A wide-spread, yet not validated, assumption is that the targetome of miRNAs is non-randomly distributed across the transcriptome and that targets share functional pathways. We developed a computational and experimental strategy termed high-throughput miRNA interaction reporter assay (HiTmIR) to facilitate the validation of target pathways.

Long-term time trend of lead exposure in young German adults - Evaluation of more than 35 Years of data of the German Environmental Specimen Bank.

Lead is a ubiquitous pollutant with well-known effects on human health. As there is no lower toxicological threshold for lead in blood and since data gaps on lead exposure still exist in many European countries, HBM data on lead is of high importance. To address this, the European Human Biomonitoring Initiative HBM4EU classified lead as a priority substance.

Towards Harmonized Biobanking for Biomonitoring: A Comparison of Human Biomonitoring-Related and Clinical Biorepositories.

Human biomonitoring (HBM) depends on high-quality human samples to identify status and trends in exposure and ensure comparability of results. In this context, much effort has been put into the development of standardized processes and quality assurance for sampling and chemical analysis, while effects of sample storage and shipment on sample quality have been less thoroughly addressed. To characterize the currently applied storage and shipment procedures within the consortium of the European Human Biomonitoring Initiative (HBM4EU), which aims at harmonization of HBM in Europe, a requirement analysis based on data from an online survey was conducted.

Synthesis and in vitro evaluation of cyclodextrin hyaluronic acid conjugates as a new candidate for intestinal drug carrier for steroid hormones.

Steroid hormones became increasingly interesting as active pharmaceutical ingredients for the treatment of endocrine disorders. However, medical applications of many steroidal drugs are inhibited by their very low aqueous solubilities giving rise to low bioavailabilities. Therefore, the prioritized oral administration of steroidal drugs remains problematic.

Non-pooled Human Platelet Lysate: A Potential Serum Alternative for Cell Culture.

Serum supplementation is crucial in cell culture to provide all the essential nutrients needed for cellular processes. Fetal bovine serum (FBS) is considered the 'gold standard', but its production raises serious ethical concerns. Human-derived alternatives to FBS exist in the form of human platelet lysates (hPLs) or human AB serum (ABS).

Multi-endpoint toxicological assessment of polystyrene nano- and microparticles in different biological models in vitro.

Nanoplastics (NP) and microplastics (MP) accumulate in our environment as a consequence of the massive consumption of plastics. Huge knowledge-gaps exist regarding uptake and fate of plastic particles in micro- and nano-dimensions in humans as well as on their impact on human health. This study investigated the transport and effects of 50 nm and 0.

Age-Related Loss of Human Vitreal Viscoelasticity.

Purpose: To determine the viscoelasticity of human vitreous bodies and its changes with age in order to benefit the understanding and therapy of vitreoretinal diseases.

Methods: In a postmortem study, 190 human vitreous bodies were extracted from 33- to 92-year-old donors, analyzed with regard to their viscoelastic properties via dynamic mechanical analyses, and compared with bovine and porcine vitreous. Postmortem intervals and donor-related parameters were examined as potential parameters influencing vitreous viscoelasticity.

Trends in characteristics of 24-h urine samples and their relevance for human biomonitoring studies - 20 years of experience in the German Environmental Specimen Bank.

To document trends in human exposure to environmental pollutants, the German Environmental Specimen Bank (ESB) has been routinely collecting and archiving 24-h urine samples from young adults at four sampling sites in Germany on an annual basis. For the purpose of normalizing measured analyte concentrations, urinary creatinine (UC), specific gravity (SG), conductivity (CON), and total urine volume (UV) of 24-h urine samples have also been recorded. These parameters are however susceptible to variation over time, as well as within/among participants and normalization against them can thus affect the interpretation of data regarding exposure to environmental pollutants.

Peptide Assembly on the Membrane Determines the HIV-1 Inhibitory Activity of Dual-Targeting Fusion Inhibitor Peptides.

Novel strategies in the design of HIV-1 fusion/entry inhibitors are based on the construction of dual-targeting fusion proteins and peptides with synergistic antiviral effects. In this work we describe the design of dual-targeting peptides composed of peptide domains of E2 and E1 envelope proteins from Human Pegivirus with the aim of targeting both the loop region and the fusion peptide domains of HIV-1 gp41. In a previous work, we described the inhibitory role of a highly conserved fragment of the E1 protein (domain 139-156) which interacts with the HIV-1 fusion peptide at the membrane level.

Tyramine-conjugated alginate hydrogels as a platform for bioactive scaffolds.

Alginate-based hydrogels represent promising microenvironments for cell culture and tissue engineering, as their mechanical and porous characteristics are adjustable toward in vivo conditions. However, alginate scaffolds are bioinert and thus inhibit cellular interactions. To overcome this disadvantage, bioactive alginate surfaces were produced by conjugating tyramine molecules to high-molecular-weight alginates using the carbodiimide chemistry.

Poly(amidoamine)-alginate hydrogels: directing the behavior of mesenchymal stem cells with charged hydrogel surfaces.

The surface charge of a biomaterial represents a promising tool to direct cellular behavior, which is crucial for therapeutic approaches in regenerative medicine. To expand the understanding of how the material surface charge affects protein adsorption and mesenchymal stem cell behavior, differently charged surfaces with zeta potentials spanning from -25 mV to +15 mV were fabricated by the conjugation of poly(amidoamine) to alginate-based hydrogels. We showed that the increase of the biomaterials surface charge resulted in enhanced quantities of biologically available, surface-attached proteins.

Validation of an automated system for aliquoting of HIV-1 Env-pseudotyped virus stocks.

The standardized assessments of HIV-specific immune responses are of main interest in the preclinical and clinical stage of HIV-1 vaccine development. In this regard, HIV-1 Env-pseudotyped viruses play a central role for the evaluation of neutralizing antibody profiles and are produced according to Good Clinical Laboratory Practice- (GCLP-) compliant manual and automated procedures. To further improve and complete the automated production cycle an automated system for aliquoting HIV-1 pseudovirus stocks has been implemented.

Selection of nanobodies with broad neutralizing potential against primary HIV-1 strains using soluble subtype C gp140 envelope trimers.

Broadly neutralizing antibodies (bnAbs) against HIV-1 protect from infection and reduce viral load upon therapeutic applications. However no vaccine was able so far to induce bnAbs demanding their expensive biotechnological production. For clinical applications, nanobodies (VHH) derived from heavy chain only antibodies from Camelidae, may be better suited due to their small size, high solubility/stability and extensive homology to human VH3 genes.

Community-Associated Staphylococcus aureus from Sub-Saharan Africa and Germany: A Cross-Sectional Geographic Correlation Study.

Clonal clusters and gene repertoires of Staphylococcus aureus are essential to understand disease and are well characterized in industrialized countries but poorly analysed in developing regions. The objective of this study was to compare the molecular-epidemiologic profiles of S. aureus isolates from Sub-Saharan Africa and Germany.

Toward Optimal Cryopreservation and Storage for Achievement of High Cell Recovery and Maintenance of Cell Viability and T Cell Functionality.

Cryopreservation of biological materials such as cells, tissues, and organs is a prevailing topic of high importance. It is employed not only in many research fields but also in the clinical area. Cryopreservation is of great importance for reproductive medicine and clinical studies, as well as for the development of vaccines.