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Evaluating your Relevance with the Carotid Bifurcation regarding Stenting: Anatomic along with Morphologic Considerations.
In addition to causing acute invasive infections in immunocompromised patients, the mold Aspergillus fumigatus causes chronic infections in patients with chronic pulmonary conditions such as cystic fibrosis. Here we describe a non-lethal model of chronic pulmonary aspergillosis in which immunocompetent mice are endotracheally infected with A. fumigatus conidia embedded in agar beads. This approach results in the establishment of hyphal infection within the airways of mice for up to a 28-day period and is amenable to the study of innate and adaptive antifungal responses, fungal mutant strains, and antifungal agents.Animal models are fundamental to unravel the complex nature of fungal infections in the host context. Here, a versatile murine model of hematopoietic cell transplantation (HCT) is described. This model can be used to investigate the establishment and progression of fungal infections after HCT and to elucidate how different transplant variables affect the recovery of host immunity.Infection tissue microenvironments are dynamic, complex, and play a critical role in host-microbe interaction outcomes. A crucial parameter of the infection site microenvironment is oxygen. Both host and microbial cell physiology is significantly impacted by the availability of oxygen. When oxygen tensions drop to levels that do not meet the metabolic demands of the cell, a hypoxia response ensues. In numerous host-microbe studies, it has now been observed that the host and microbial hypoxia response plays a critical role in disease outcomes. However, in most pathosystems, spatial and temporal oxygen dynamics throughout the infection remain ill defined. Here, we detail a protocol for detecting low oxygen environments in tissue in a murine model of invasive pulmonary aspergillosis. The protocol utilizes mice immune compromised with a high dose of steroid and challenged via the aerosol route with conidia of the major human fungal pathogen Aspergillus fumigatus. Qualitative analysis of oxygen levels at the site of infection in the murine lung is accomplished with pimonidazole-mediated adduct detection via immunohistochemistry. The protocol is adaptable to other host-microbe interaction models.Neutrophil migration to the site of infection is an essential process for the control and clearance of microbial growth within the host. Identifying the molecular factors that mediate neutrophil chemotaxis is therefore critical for our understanding of disease pathogenesis and the mechanisms underlying protective immunity. Here, we describe a protocol that enables analysis of neutrophil recruitment from the blood into fungal-infected organs in vivo, using mixed bone marrow chimeras and flow cytometry. This method directly assesses the relative contribution of a receptor or intracellular molecule in controlling neutrophil chemotaxis during fungal infection and can be adapted to a variety of other non-fungal infection experimental settings.Phagocytosis and cytokine production are important processes by which innate immune cells, especially professional phagocytes such as neutrophils and macrophages, control and regulate immunity to fungi. These cellular responses are initiated when conserved pathogen components, known as pathogen-associated molecular patterns (PAMPs), are recognized by pattern-recognition receptors (PRRs), which include members of the C-type lectin receptor (CLR) family that are able to bind to fungal cell wall-derived carbohydrates. Phagocytosis and cytokine production can be quantitatively examined by flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively, using in vitro based assays with primary-derived murine cells and cell lines. Here, we describe a flow cytometry-based method using transduced cell lines to assess the ability of CLRs to mediate internalization, using A. fumigatus conidia and the β-1,3 glucan receptor, Dectin-1 (CLEC7A), as an example. The use of ELISA-based assays to measure cytokine production by immune cells that are induced in response to fungi and methods for isolating and culturing primary macrophages from various murine tissues are described.Experimental evolution is an experiment class of its own; instead of requiring an a priori hypothesis, the genetic adaptation of microbes to defined environments tells us about the underlying pathways and mechanisms. Such experiments are often deceptively simple in their design, based on a single abiotic stressor and what is in essence a long-term continuous culture. However, they generally provide a starting point to thorough follow-up analyses (which are specific for the organism at hand and not part of this method chapter). In this chapter, we describe a method to use a biotic stressor which is frequently encountered by pathogenic fungi-macrophage-like cells-in a serial passaging regime. Experimental evolution under such conditions can reveal new virulence attributes and mechanisms by selecting for adaptive mutations against the host cell-induced stress.It is important to note that every evolution experiment is different, and these techniques should be taken as a general guideline to be adapted to different organisms and questions. Then, it is a powerful tool with many potential applications in pathobiology research.Microbial interactions with epithelial barriers are important steps preceding disease. Infections with Candida albicans are no exception. This opportunistic fungus, commonly harmlessly residing in close proximity to human epithelia, can shift to a more pathogenic form, can invade tissues, and cause disease. Pathogenesis, in C. albicans as well as in many other microorganisms, is characterized by three important steps adhesion to-, invasion into-, and damage of host cells. In this book chapter, we describe three well-established protocols that allow us to differentially stain C. albicans cells adhering to and invading into host cells, therefore allowing quantifications of such processes. We also describe a common host cell cytotoxicity assay that employs a commercial kit, adapted to C. albicans.Fluorescence-based techniques enable researchers to monitor physiologic processes, specifically fungal cell viability and death, during cellular encounters with the mammalian immune system with single event resolution. By incorporating two independent fluorescent probes in fungal organisms either prior to, or ensuing experimental infection in mice or in cultured leukocytes, it is possible to distinguish and quantify live and killed fungal cells to interrogate genetic, pharmacologic, and cellular determinants that shape host-fungal cell outcomes. This chapter reviews the techniques and applications of fluorescent fungal reporters of viability, with emphasis on the filamentous mold Aspergillus fumigatus.Fluorescence-based techniques enable researchers to monitor physiologic processes, specifically fungal cell viability and death, during cellular encounters with the mammalian immune system with single event resolution. By incorporating two independent fluorescent probes in fungal organisms either prior to, or ensuing experimental infection in mice or in cultured leukocytes, it is possible to distinguish and quantify live and killed fungal cells to interrogate genetic, pharmacologic, and cellular determinants that shape host-fungal cell outcomes. This chapter reviews the techniques and applications of fluorescent fungal reporters of viability, with emphasis on the North American endemic dimorphic fungus, Blastomyces dermatitidis.The respiratory epithelium is the initial point of host contact for inhaled particles, leading to orchestrated, but highly heterogeneous, responses. Human airway epithelial cells (AECs) play a crucial role in host defense by promoting uptake and killing of inhaled microorganisms and concomitant cytokine production in order to recruit professional phagocytes to the site of infection. However, inhaled pathogens can also reside and replicate intracellularly to evade host immune defenses or circulating antimicrobial drugs, ultimately causing apoptosis or cell death of the infected AECs. Imaging flow cytometry (IFC) combines flow cytometry, fluorescent microscopy, and advanced data-processing algorithms to dissect the heterogeneity of the interaction of AECs and inhaled microorganisms and its outcomes at the single-cell level. Here, we describe a novel single-cell approach based on differential fluorescent staining and state-of-the-art IFC to identify, quantify, and analyze individual host-pathogen complexes from cultured AECs infected with spores of the major human fungal pathogen Aspergillus fumigatus.The epithelial cell is usually the first host cell that interacts with the microbiota present at mucosal surfaces. Although initially thought of as "bystander" cells with barrier function, the epithelial cell is now known to be a sentinel cell in the recognition and discrimination of commensal and pathogenic microorganisms and a key cell in initiating subsequent innate and adaptive immune responses. Here, we describe the main assays utilized in analyzing the activation of epithelial cell signaling (western blotting), transcription factors (TransAm), gene expression (quantitative reverse transcription PCR (qRT-PCR)), cytokine responses (ELISA, Luminex), and damage induction (lactate dehydrogenase (LDH) release). find more While our laboratory focuses on the epithelial response to Candida pathogens, these assays can be applied universally to analyze the activation of epithelial cells in response to any microbial pathogen.CRISPR/Cas9 technology enables rapid and efficient genome editing in a variety of experimental systems. Genome editing using CRISPR/Cas9 has become an increasingly popular genetic engineering tool due to (1) an extensive array of commercial ready-to-use CRIPSR/Cas9 systems, (2) improved efficiency of cell delivery, and (3) the possibility to do multigene editing. Here, we describe a method to introduce single gene disruption in lung bronchial epithelial cells. This approach can be used to study host factors important for pathogen interaction or to identify and study genetic markers determining susceptibility to fungal disease.Receptors on endothelial and epithelial cells often recognize molecules that are expressed by fungi, and only a limited number of these receptors have been identified to date. Here, we describe a method for identifying novel host cell receptors for fungi that uses intact organisms to precipitate biotin-labelled host cell membrane proteins, which are then detected by immunoblotting with an anti-biotin antibody. Presented here is the method to use for identification of membrane proteins that bind to C. albicans.Defining the humoral immune response to infectious agents is important for gaining insights into infectious diseases and the response of the immune system. It can further aid development of serodiagnostic tests, discovery of vaccine antigen candidates, and immuno-epidemiological research. During the last three decades, serological proteome analyses (SERPAs) have played a significant role in characterizing the antibody response of humans or animals to fungal pathogens. SERPA combines 2D-gel electrophoresis with Western blotting. The introduction of multiplexing approaches by means of fluorescent dyes has greatly improved the reliability of the 2D technique and has boosted also the qualitative capabilities of the SERPA approach. In this chapter, we detail a SERPA protocol using fungal extracellular proteins from a fungal culture, here as an example the mold Aspergillus fumigatus.
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