Optical Microscopy in the Nano-World

Scanning near-field optical microscopy (SNOM) is an optical microscopy whose resolution is not bound to the diffraction limit. It provides chemical information based upon spectral, polarization and/or fluorescence contrast images. Details as small as 20 nm can be recognized. Photophysical and photochemical effects can be studied with SNOM on a similar scale. This article reviews a good deal of the experimental and theoretical work on SNOM in Switzerland

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression

Dietary antioxidants protect gut epithelial cells from oxidant-induced apoptosis

BACKGROUND: The potential of ascorbic acid and two botanical decoctions, green tea and cat's claw, to limit cell death in response to oxidants were evaluated in vitro. METHODS: Cultured human gastric epithelial cells (AGS) or murine small intestinal epithelial cells (IEC-18) were exposed to oxidants – DPPH (3 μM), H(2)O(2) (50 μM), peroxynitrite (300 μM) – followed by incubation for 24 hours, with antioxidants (10 μg/ml) administered as a 1 hour pretreatment. Cell number (MTT assay) and death via apoptosis or necrosis (ELISA, LDH release) was determined. The direct interactions between antioxidants and DPPH (100 μM) or H(2)O(2) (50 μM) were evaluated by spectroscopy. RESULTS: The decoctions did not interact with H(2)O(2), but quenched DPPH although less effectively than vitamin C. In contrast, vitamin C was significantly less effective in protecting human gastric epithelial cells (AGS) from apoptosis induced by DPPH, peroxynitrite and H(2)O(2) (P < 0.001). Green tea and cat's claw were equally protective against peroxynitrite and H(2)O(2), but green tea was more effective than cat's claw in reducing DPPH-induced apoptosis (P < 0.01). Necrotic cell death was marginally evident at these low concentrations of peroxynitrite and H(2)O(2), and was attenuated both by cat's claw and green tea (P < 0.01). In IEC-18 cells, all antioxidants were equally effective as anti-apoptotic agents. CONCLUSIONS: These results indicate that dietary antioxidants can limit epithelial cell death in response to oxidant stress. In the case of green tea and cat's claw, the cytoprotective response exceed their inherent ability to interact with the injurious oxidant, suggestive of actions on intracellular pathways regulating cell death

Chronic ethanol feeding modulates inflammatory mediators, activation of nuclear factor-κB, and responsiveness to endotoxin in murine Kupffer cells and circulating leukocytes

Chronic ethanol abuse is known to increase susceptibility to infections after injury, in part, by modification of macrophage function. Several intracellular signalling mechanisms are involved in the initiation of inflammatory responses, including the nuclear factor-κB (NF-κB) pathway. In this study, we investigated the systemic and hepatic effect of chronic ethanol feeding on in vivo activation of NF-κB in NF-κB(EGFP) reporter gene mice. Specifically, the study focused on Kupffer cell proinflammatory cytokines IL-6 and TNF-α and activation of NF-κB after chronic ethanol feeding followed by in vitro stimulation with lipopolysaccharide (LPS). We found that chronic ethanol upregulated NF-κB activation and increased hepatic and systemic proinflammatory cytokine levels. Similarly, LPS-stimulated IL-1 β release from whole blood was significantly enhanced in ethanol-fed mice. However, LPS significantly increased IL-6 and TNF-α levels. These results demonstrate that chronic ethanol feeding can improve the responsiveness of macrophage LPS-stimulated IL-6 and TNF-α production and indicate that this effect may result from ethanol-induced alterations in intracellular signalling through NF-κB. Furthermore, LPS and TNF-α stimulated the gene expression of different inflammatory mediators, in part, in a NF-κB-dependent manner

Multiplex PCR assay to detect high risk lineages of Salmonella Typhi and Paratyphi A.

Funder: National Institute for Health Research (NIHR)Funder: Bill and Melinda Gates FoundationEnteric fever infections remain a significant public health issue, with up to 20 million infections per year. Increasing rates of antibiotic resistant strains have rendered many first-line antibiotics potentially ineffective. Genotype 4.3.1 (H58) is the main circulating lineage of S. Typhi in many South Asian countries and is associated with high levels of antibiotic resistance. The emergence and spread of extensively drug resistant (XDR) typhoid strains has increased the need for a rapid molecular test to identify and track these high-risk lineages for surveillance and vaccine prioritisation. Current methods require samples to be cultured for several days, followed by DNA extraction and sequencing to determine the specific lineage. We designed and evaluated the performance of a new multiplex PCR assay, targeting S. Paratyphi A as well as the H58 and XDR lineages of S. Typhi on a collection of bacterial strains. Our assay was 100% specific for the identification of lineage specific S. Typhi and S. Paratyphi A, when tested with a mix of non-Typhi Salmonella and non-Salmonella strains. With additional testing on clinical and environmental samples, this assay will allow rapid lineage level detection of typhoid of clinical significance, at a significantly lower cost to whole-genome sequencing. To our knowledge, this is the first report of a SNP-based multiplex PCR assay for the detection of lineage specific serovars of Salmonella Typhi

Plasma IL-6 levels (Fig 4A) and TNF-alpha (Fig 4B) levels following hemorrhagic shock and resuscitation (H/R) in pair-fed mice with ethanol (EtOH) or control (ctrl) chow.

<p>Sham operated animals underwent the same surgical procedures but H/R was not carried out. D-JNKI-1 denotes treatment with the D-JNKI-1 peptide, veh represents vehicle treatment (*: p <0.05 <i>vs</i>. corresponding sham group, #: p <0.05 <i>vs</i>. corresponding H/R group, sham groups: n = 4–8, H/R groups: n = 7–12).</p

Hepatic ICAM-1 (Fig 5A) and MMP9 (Fig 5B) gene expression at 2 h after resuscitation in pair-fed mice with ethanol (EtOH) or control (ctrl) chow.

<p>Sham operated animals underwent the surgical procedures but hemorrhagic shock with resuscitation (H/R) was not carried out. D-JNKI-1 denotes treatment with the D-JNKI-1 peptide, veh represents vehicle treatment. After normalization as described in material and methods, gene expression was measured as % increase compared to 100% of the corresponding sham operated group. (*: p <0.05 <i>vs</i>. corresponding sham group, #: p <0.05 <i>vs</i>. corresponding H/R group, sham groups: n = 4–8, H/R groups: n = 7–12).</p

Histological liver necrosis after pair-feeding with ethanol (EtOH) or control (ctrl) chow 2 h after resuscitation.

<p>Sham operated animals underwent the same surgical procedures but hemorrhagic shock with resuscitation (H/R) was not carried out. Representative hematoxylin and eosin stained liver lobes from vehicle (veh) or D-JNKI-1-treated mice are shown (Fig 3A: ctrl-fed veh-treated mice, Fig 3B: ctrl-fed D-JNKI-1-treated mice, Fig 3C: EtOH-fed veh-treated mice, Fig 3D: EtOH-fed D-JNKI-1-treated mice after sham operation; Fig 3E: ctrl-fed veh-treated mice, Fig 3F: ctrl-fed D-JNKI-1-treated mice, Fig 3G: EtOH-fed veh-treated mice, Fig 3H: EtOH-fed D-JNKI-1-treated mice after H/R). Bar is 200 μm.</p