Search results for "phage"

Complement and atherogenesis: The unknown connection

1999

The question why low-density lipoprotein (LDL) stranded in the subendothelium of arteries should acquire the proinflammatory properties that initiate and sustain atherogenesis has puzzled researchers for decades. The most popular concept contends that oxidative processes are crucial because oxidized LDL (ox-LDL) produced in vitro has atherogenic properties and small amounts of it are found in atherosclerotic lesions. Recently, a possible role for vascular infections has also been considered because infectious agents, in particular Chlamydia pneumoniae, are sometimes present in the lesions. Here, evidence is summarized for a different concept of atherogenesis, which evolves from the fact tha…

Modulation of dendritic cells and macrophages : implication in cancer and atherosclerosis

2010

During my thesis, I studied the cytotoxic function of dendritic cells (DC) from cancer patients and compared it to DC from healthy donors. Our results indicate that human monocyte-derived DC can acquire strong cytotoxic activity toward tumor cells after activation with low dose of LPS. The cytotoxic potential of DC derived from cancer patients was almost the same as the one generated from healthy donors. We identified the tumor cell killing mechanism which involves peroxynitrite release. After killing of cancer cells, DC are capable of engulfing dead tumor cell fragments and overexpress the costimulatory molecules necessary for T cell proliferation. A second study consisted in an analysis o…

Sensory neuropathy with bone destruction due to a mutation in the membrane-shaping atlastin GTPase 3.

2014

Many neurodegenerative disorders present with sensory loss. In the group of hereditary sensory and autonomic neuropathies loss of nociception is one of the disease hallmarks. To determine underlying factors of sensory neurodegeneration we performed whole-exome sequencing in affected individuals with the disorder. In a family with sensory neuropathy with loss of pain perception and destruction of the pedal skeleton we report a missense mutation in a highly conserved amino acid residue of atlastin GTPase 3 (ATL3), an endoplasmic reticulum-shaping GTPase. The same mutation (p.Tyr192Cys) was identified in a second family with similar clinical outcome by screening a large cohort of 115 patients …

Involvement of purinergic nerves in the NANC inhibitory junction potentials in pigeon oesophageal smooth muscle.

2004

1. Electrical field stimulation (EFS) (0.5 ms in train of 2-32 Hz for 300 ms) in smooth muscle of pigeon oesophagus, in the presence of atropine (1 microm) and guanethidine (1 microm), elicited an inhibitory response consisting of a transient hyperpolarization (inhibitory junction potential, IJP) associated with muscle relaxation. 2. Sodium nitroprusside (SNP, 100 microm) induced hyperpolarization correlated to mechanical relaxation. 3. The nitric oxide (NO) synthase inhibitor N(omega)-nitro-l-arginine (from 0.1 to 100 microm) caused a concentration-dependent reduction of electromechanical response to EFS indicating a role for NO in this response. 4. Apamin (1 microm) reduced both IJP and r…

Dynamic Antigen Presentation Patterns of Listeria monocytogenes-Derived CD8 T Cell Epitopes In Vivo

2001

Abstract Little information exists regarding the presentation of antigenic peptides in infected tissues. In this study the in vivo presentation of four different CD8 T cell epitopes of Listeria monocytogenes was monitored. Peptide presentation was measured by a new, highly sensitive, ex vivo Ag presentation assay that was based on the testing of freshly isolated cells from infected spleens with peptide-specific CD8 T cell lines in an IFN-γ-specific ELISPOT assay. Remarkably, the peptide presentation pattern of splenocytes and that of macrophages purified from spleens of L. monocytogenes-infected mice were different from those of in vitro infected macrophage-like cell lines. The in vivo Ag p…

Polyelectrolyte properties of filamentous biopolymers and their consequences in biological fluids.

2014

Anionic polyelectrolyte filaments are common in biological cells. DNA, RNA, the cytoskeletal filaments F-actin, microtubules, and intermediate filaments, and polysaccharides such as hyaluronan that form the pericellular matrix all have large net negative charge densities distributed over their surfaces. Several filamentous viruses with diameters and stiffnesses similar to those of cytoskeletal polymers also have similar negative charge densities. Extracellular protein filaments such collagen, fibrin and elastin, in contrast, have notably smaller charge densities and do not behave as highly charged polyelectrolytes in solution. This review summarizes data that demonstrate generic counterion-…

Bacteriophage richness reduces bacterial niche overlap in experimental microcosms

2015

Antagonistic interactions such as competition and predation shape the structure and dynamics of ecological communities. Their combined effects can affect the species richness within a particular trophic level. Despite theory linking the complementarity of interactions across trophic levels and ecosystem functioning, there is a shortage of empirical tests of such predictions. We present an experimental investigation of these combined effects within a bacteria-phage interaction network. We measured the biomass yield of combinations of bacterial strains under increasing levels of bacteriophage richness. Our results show an increasing impact of phage on bacteria with increasing phage diversity.…

Top-down effects of a lytic bacteriophage and protozoa on bacteria in aqueous and biofilm phases

2014

Lytic bacteriophages and protozoan predators are the major causes of bacterial mortality in natural microbial communities, which also makes them potential candidates for biological control of bacterial pathogens. However, little is known about the relative impact of bacteriophages and protozoa on the dynamics of bacterial biomass in aqueous and biofilm phases. Here, we studied the temporal and spatial dynamics of bacterial biomass in a microcosm experiment where opportunistic pathogenic bacteria Serratia marcescens was exposed to particle‐feeding ciliates, surface‐feeding amoebas, and lytic bacteriophages for 8 weeks, ca. 1300 generations. We found that ciliates were the most efficient enem…

Indications for Anti-Reflux Surgery in Barrett's Esophagus

2014

Characterization of cells involved in the formation of granuloma. An ultrastructural study on macrophages, epitheloid cells, and giant cells in exper…

1981

In experimental tubulo-interstitial (anti-basement membrane) nephritis of the rat, granulomatous inflammation develops around immunologically altered tubular basement membranes. The present light- and electron microscopic studies indicate that in the course of the granulomatous reaction, tissue monocytes evolve from blood monocytes and pursue two independent pathways of differentation. On the one hand they may differentiate into macrophages ("distant from tubules") or, alternatively, into epitheloid cells ("adjacent to tubules"). The latter, through cell fusion, develop into multinucleated giant cells of the Langhans' type. The cytoplasmic components of the epitheloid cells and the multinuc…