Standardized microgel beads as elastic cell mechanical probes

Cell mechanical measurements are gaining increasing interest in biological and biomedical studies. However, there are no standardized calibration particles available that permit the cross-comparison of different measurement techniques operating at different stresses and time-scales. Here we present the rational design, production, and comprehensive characterization of poly-acrylamide (PAAm) microgel beads mimicking size and overall mechanics of biological cells. We produced mono-disperse beads at rates of 20-60 kHz by means of a microfluidic droplet generator, where the pre-gel composition was adjusted to tune the beads' elasticity in the range of cell and tissue relevant mechanical properties. We verified bead homogeneity by optical diffraction tomography and Brillouin microscopy. Consistent elastic behavior of microgel beads at different shear rates was confirmed by AFM-enabled nanoindentation and real-time deformability cytometry (RT-DC). The remaining inherent variability in elastic modulus was rationalized using polymer theory and effectively reduced by sorting based on forward-scattering using conventional flow cytometry. Our results show that PAAm microgel beads can be standardized as mechanical probes, to serve not only for validation and calibration of cell mechanical measurements, but also as cell-scale stress sensors.

Control of primary mouse cytomegalovirus infection in lung nodular inflammatory foci by cooperation of interferon-gamma expressing CD4 and CD8 T cells

Human cytomegalovirus (CMV) and mouse cytomegalovirus (MCMV) infection share many characteristics. Therefore infection of mice with MCMV is an important tool to understand immune responses and to design vaccines and therapies for patients at the risk of severe CMV disease. In this study, we investigated the immune response in the lungs following acute infection with MCMV. We used multi-color fluorescence microscopy to visualize single infected and immune cells in nodular inflammatory foci (NIFs) that formed around infected cells in the lungs. These NIFs consisted mainly of myeloid cells, T cells, and some NK cells. We found that the formation of NIFs was essential to reduce the number of infected cells in the lung tissue, showing that NIFs were sites of infection as well as sites of immune response. Comparing mice deficient for several leukocyte subsets, we identified T cells to be of prime importance for restricting MCMV infection in the lung. Moreover, T cells had to be present in NIFs in high numbers, and CD4 as well as CD8 T cells supported each other to efficiently control virus spread. Additionally, we investigated the effects of perforin and interferon-gamma (IFNγ) on the virus infection and found important roles for both mechanisms. NK cells and T cells were the major source for IFNγ in the lung and in in vitro assays we found that IFNγ had the potential to reduce plaque growth on primary lung stromal cells. Notably, the T cell-mediated control was shown to be perforin-independent but IFNγ-dependent. In total, this study systematically identifies crucial antiviral factors present in lung NIFs for early containment of a local MCMV infection at the single cell level.

Molecular detection of fungal pathogens in clinical specimens by 18S rDNA high-throughput screening in comparison to ITS PCR and culture

The rising incidence of invasive fungal infections and the expanding spectrum of fungal pathogens makes early and accurate identification of the causative pathogen a daunting task. Diagnostics using molecular markers enable rapid identification of fungi, offer new insights into infectious disease dynamics, and open new possibilities for infectious disease control and prevention. We performed a retrospective study using clinical specimens (N = 233) from patients with suspected fungal infection previously subjected to culture and/or internal transcribed spacer (ITS) PCR. We used these specimens to evaluate a high-throughput screening method for fungal detection using automated DNA extraction (QIASymphony), fungal ribosomal small subunit (18S) rDNA RT-PCR and amplicon sequencing. Fungal sequences were compared with sequences from the curated, commercially available SmartGene IDNS database for pathogen identification. Concordance between 18S rDNA RT-PCR and culture results was 91%, and congruence between 18S rDNA RT-PCR and ITS PCR results was 94%. In addition, 18S rDNA RT-PCR and Sanger sequencing detected fungal pathogens in culture negative (N = 13) and ITS PCR negative specimens (N = 12) from patients with a clinically confirmed fungal infection. Our results support the use of the 18S rDNA RT-PCR diagnostic workflow for rapid and accurate identification of fungal pathogens in clinical specimens.

Epiphytic bromeliads in a changing world: the effect of elevated CO2 and varying water supply on growth and nutrient relations

Global climate change is likely to impact all plant life. Vascular epiphytes represent a life form that may be affected more than any other by possible changes in precipitation leading to water shortage, but negative effects of drought may be mitigated through increasing levels of atmospheric CO₂ . We studied the response of three epiphytic Aechmea species to different CO₂ and watering levels in a full-factorial climate chamber study over 100 days. All species use crassulacean acid metabolism (CAM). Response variables were relative growth rate (RGR), nocturnal acidification and foliar nutrient levels (N, P, K, Mg). Both elevated CO₂ and increased water supply stimulated RGR, but the interaction of the two factors was not significant. Nocturnal acidification was not affected by these factors, indicating that the increase in growth in these CAM species was due to higher assimilation in the light. Mass-based foliar nutrient contents were consistently lower under elevated CO₂ , but most differences disappeared when expressed on an area basis. Compared to previous studies with epiphytes, in which doubling of CO₂ increased RGR, on average, by only 14%, these Aechmea species showed a relatively strong growth stimulation of up to +61%. Consistent with earlier findings with other bromeliads, elevated CO₂ did not mitigate the effect of water shortage.

Effect of Dialyzer Membranes on in Vitro Generation of Eicosanoids

Eicosanoids are potent substances released from blood cells after contact with foreign materials. Eicosanoid generation, in addition to complement fragment formation, may be a valuable indicator of the biocompatibility of dialyzer membranes. In the present in vitro study, eicosanoid generation induced by several different flat dialyzer membranes [polyacrylonitrile (PAN), cuprammonium cellulose (CC), and polycarbonate (PC)] was evaluated and compared using blood from non-uremic healthy volunteers.

Generation of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) was greatest with PC followed by PAN and CC. The formation of C3a des arg with PAN was less than with either CC or PC.

Our results suggest that dialyzer membranes affect complement activation and eicosanoid generation differently; biocompatibility as expressed by a low level of complement fragment formation does not necessarily translate into biocompatibility when considering eicosanoid generation.

Modulation of innate immunity of patients with Alzheimer's disease by omega-3 fatty acids

The innate immune system of patients with Alzheimer's disease and mild cognitive impairment (MCI) is deregulated with highly increased or decreased transcription of inflammatory genes and consistently depressed phagocytosis of amyloid-β_1-42 (Aβ) by monocytes and macrophages. Current immune therapies target single mechanisms in the adaptive immune system but not innate immunity. Here, we summarize recent advances in therapy by ω-3, ω-6, and epoxy fatty acids; specialized proresolving mediators; and vitamin D₃ that have proven immune effects and emerging cognitive effects in patients with MCI. The hypothesis of this approach is that macrophages of normal participants, but not those of patients with Alzheimer's disease and MCI, possess effective phagocytosis for Aβ and protect homeostasis of the brain and, furthermore, that defective MCI macrophages recover phagocytic function via ω-3. Recent studies of fish-derived ω-3 supplementation in patients with MCI have shown polarization of Apoε3/ε3 patients' macrophages to an intermediate M1-M2 phenotype that is optimal for Aβ phagocytosis and the stabilization of cognitive decline. Therefore, accumulating preclinical and preliminary clinical evidence indicates that ω-3 supplementation should be tested in a randomized controlled clinical trial and that the analysis should involve the apolipoprotein E genotype and intervening conditions during trial.-Fiala, M., Kooij, G., Wagner, K., Hammock, B., Pellegrini, M. Modulation of innate immunity of patients with Alzheimer's disease by omega-3 fatty acids.

Registration Academy Improves Performance

St. Joseph Health started its curriculum design by asking patient access leaders what a perfect training program would cover.

Soluble epoxide hydrolase inhibition alleviates neuropathy in Akita (Ins2 Akita) mice

The soluble epoxide hydrolase (sEH) is a regulatory enzyme responsible for the metabolism of bioactive lipid epoxides of both omega-6 and omega-3 long chain polyunsaturated fatty acids. These natural epoxides mediate cell signaling in several physiological functions including blocking inflammation, high blood pressure and both inflammatory and neuropathic pain. Inhibition of the sEH maintains the level of endogenous bioactive epoxy-fatty acids (EpFA) and allows them to exert their generally beneficial effects. The Akita (Ins2^Akita or Ins2^C96Y) mice represent a maturity-onset of diabetes of the young (MODY) model in lean, functionally unimpaired animals, with a sexually dimorphic disease phenotype. This allowed for a test of male and female mice in a battery of functional and nociceptive assays to probe the role of sEH in this system. The results demonstrate that inhibiting the sEH is analgesic in diabetic neuropathy and this occurs in a sexually dimorphic manner. Interestingly, sEH activity is also sexually dimorphic in the Akita model, and moreover correlates with disease status particularly in the hearts of male mice. In addition, in vivo levels of oxidized lipid metabolites also correlate with increased sEH expression and the pathogenesis of disease in this model. Thus, sEH is a target to effectively block diabetic neuropathic pain but also demonstrates a potential role in mitigating the progression of this disease.

Inactivation of Gram-Positive Bacteria by Novel Phenolic Branched-Chain Fatty Acids

Novel phenolic branched-chain fatty acids (PBC-FAs) were evaluated for their antimicrobial properties against both gram-positive ( Listeria innocua , Bacillus subtilis , Enterococcus faecium ) and gram-negative ( Escherichia coli , Salmonella Typhimurium, and Pseudomonas tolaasii ) bacteria. In addition, PBC-FA derivatives, such as PBC-FA methyl ester mixture, methyl-branched fatty acid mixtures, and trimethylsilyl-PBC-FA methyl esters, were synthesized to study the structure activity relationship. Results showed that PBC-FAs were a potent antimicrobial against gram-positive bacteria with MICs of 1.8 to 3.6 μg/ml. The compounds were less effective against gram-negative bacteria. Derivatives of PBC-FAs and an equimolar mixture of oleic acid and phenol all had MICs above 233 μg/ml against both gram-positive and gram-negative bacteria. Comparison of antimicrobial activities of the PBC-FAs with those of the derivatives suggests that the carboxylic group in the fatty acid moiety and the hydroxyl group on the phenol moiety were responsible for the antimicrobial efficacy. Growth curves of L. innocua revealed that PBC-FAs prevented bacterial growth, while MBC-FAs only delayed the onset of rapid growth of L. innocua . Our results demonstrated that the novel PBC-FAs have potential for use as antimicrobials against gram-positive bacteria.