The development of an immunohistochemical method to detect the autophagy-associated protein LC3-II in human tumor xenografts

Autophagy is believed to be an important process during tumorgenesis, and in recent years it has been shown to be modulated in response to a number of conventional anticancer agents. Furthermore, the development of targeted small molecule inhibitors, such as those to the PI3K-AKT-mTOR pathway, has presented a molecular link between the disruption of this signalling cascade and the process of autophagy. The cellular consequence of stimulating or inhibiting autophagy in cancer cells is not completely understood, so it is important that this process be monitored, along with antiproliferative and apoptotic biomarkers, in the preclinical setting. The field of autophagy is still evolving, and there is a constantly changing set of criteria for the assessment of the process in cells, tissues, and organs. The gold standard technique for analyzing autophagy in mammalian cells remains transmission electron microscopy, which has many limitations and is often difficult to perform on in vivo tissue including human tumor xenografts. In order to monitor autophagy in human tumor xenogaft tissue, we have taken the approach to develop an immunohistochemical (IHC) method for the detection of the autophagosome-associated protein, microtubule-associated protein 1 light chain 3 (LC3), in human tumor xenografts. After synthesis, LC3 is cleaved to form LC3-I, and upon induction of autophagy, LC3-I is conjugated to the lipid phosphatidylethanolamine to form LC3-II, which is tightly bound to the membrane of the autophagosome. It is thought that detection of endogenous LC3-II by IHC could be difficult because of the relatively low level of expression of the protein. Here we present the validation of an IHC method to detect LC3 in human tumor xenografts that we believe is able to distinguish LC3-I from LC3-II. It is hoped that this assay can become a useful tool for the detection of autophagy in preclinical xenograft models and determine the effects of anticancer therapies on the autophagic process.     

Neuron-glia interactions underlie ALS-like axonal cytoskeletal pathology

Amyotrophic lateral sclerosis (ALS) is a devastating disorder involving loss of movement due to degeneration of motor neurons. Studies suggest that in ALS axonal dysfunction precedes the death of motor neurons. Pathologically, ALS is characterized by neurofilamentous swellings (spheroids) within the axons of motor neurons. However, the causes of this axonopathy and possible resulting axonal dysfunction are not known. Using a novel model of cultured mouse motor neurons, we have determined that these neurons are susceptible to proximal axonopathy, which is related to the glial environment. This axonopathy showed remarkable similarity, both morphologically and neurochemically, to spheroids that develop over months in SOD1_G93A transgenic mice. Focal ubiquitination, as well as perturbations of neurofilaments and microtubules, occurred in the axonal spheroid-like swellings in vitro, and visualization of mitochondrial dynamics demonstrated that axonopathy resulted in impaired axonal transport. These data provide strong evidence for the involvement of non-neuronal cells in axonal dysfunction in ALS. This cell culture model may be of benefit for the development of therapeutic interventions directed at axonal preservation.     

Preliminary safety assessment of a membrane-bound delta 9 desaturase candidate protein for transgenic oilseed crops

A gene encoding delta 9 desaturase (D9DS), an integral membrane protein, is being considered for incorporation into oilseed crops to reduce saturated fatty acids and thus improve human nutritional value. Typically, a safety assessment for transgenic crops involves purifying heterologously produced transgenic proteins in an active form for use in safety studies. Membrane-bound proteins have been very difficult to isolate in an active form due to their inherent physicochemical properties. Described here are methods used to derive enriched preparations of the active D9DS protein for use in early stage safety studies. Results of these studies, in combination with bioinformatic results and knowledge of the mode of action of the protein, along with a history of safe consumption of related proteins, provides a weight of evidence supporting the safety of the D9DS protein in food and feed.     

Interferon-γ , Pulmonary Macrophages and Airway Responsiveness in Asthma

Asthma is increasingly being recognised as involving not only allergic inflammatory mechanisms but also a variety of other cell types and cytokines. While the role of interferon-γ(IFN-γ) in asthma remains controversial, it has been proposed to contribute to the pathogenesis of both chronic stable asthma and acute severe asthma. We have shown that in a model of chronic allergic asthma in mice, airway hyper-responsiveness (AHR) is independent of various Th2 cytokines and their signalling pathways, but is dependent on IFN-γ. In a model of an allergen-induced acute exacerbation of chronic asthma, we have demonstrated that activation of pulmonary macrophages may play a critical role in driving the inflammatory response. Furthermore, we have demonstrated that IFN-γstimulation of macrophages can lead to steroidresistant airway inflammation and AHR via the production of interleukin-27. These findings strengthen the notion that the pathogenesis of the lesions of asthma, and especially of AHR, involves both Th2 and Th1 cytokines, as well as interaction between the allergic response and the innate host defence system. Targeting the effects of IFN-γon pulmonary macrophages may be particularly relevant to the treatment of steroid-resistant acute exacerbations of asthma.     

Changes in sensory perception of sports drinks when consumed pre, during and post exercise

The aim of this study was to examine sensory perceptions towards different formulations of sports drinks when consumed before, at various points during, and following exercise. Following familiarisation 14 recreational runners underwent four trials in a single blind counterbalanced design. Each trial utilised one of four different solutions: 7.5% carbohydrate, 421 mg L^− 1 electrolyte (HiC-HiE); 7.5% carbohydrate, 140 mg L^− 1 electrolyte (HiC-LoE); 1.3% carbohydrate, 421 mg L^− 1 electrolyte (LoC-HiE) and water. Subjects were provided with 50-ml samples to ingest and then rate (using a 100-mm line scale) the intensity of sweetness, saltiness, thirst-quenching ability and overall liking before (− 30 min), during (0, 30 and 60 min) and following (90 and 120 min) treadmill running exercise. Ratings of sweetness for all energy-containing drinks were higher during exercise relative to pre- and post-exercise conditions (P < 0.05); ratings also increased with duration of exercise (P < 0.001). Sweetness ratings for LoC-HiE increased during exercise (P < 0.05) but remained the same for other beverages. Ratings of saltiness decreased for all energy-containing drinks during exercise relative to pre-exercise (P < 0.05); ratings decreased with duration of exercise in these drinks (P < 0.05). Ratings of thirst-quenching ability (P = 0.039) and overall liking (P = 0.013) increased with duration of exercise with all beverages. Significant changes in sensory perception occur when consuming sports drinks during exercise relative to non-exercise conditions. Temporal changes also occur during exercise itself which leads to enhanced liking of all beverages.     

Pericardial myxoid liposarcoma in a common eland (Taurotragus oryx)

A pericardial myxoid liposarcoma was diagnosed in a common eland (Taurotragus oryx) based on gross, microscopical and immunohistochemical findings. The pericardial and epicardial tissues were soft and uniformly thickened. Microscopically, the neoplastic mass consisted of stellate cells embedded in a myxoid matrix. These cells contained cytoplasmic vacuoles stained by oil red O. Immunohistochemical analysis showed the neoplastic cells to express vimentin and S-100.     

Prevalence and risk factor analysis for methicillin-resistant Staphylococcus aureus nasal colonization in children attending child care centers

Children attending child care centers (CCCs) are at increased risk for infections, including those caused by methicillin-resistant Staphylococcus aureus (MRSA). Nasal colonization often precedes infection, and MRSA colonization has been associated with increased infection risk. Community-associated MRSA (CA-MRSA) has caused increased MRSA infections in the general population, including children. Little is known about the frequency of MRSA nasal colonization in young children, particularly in those attending CCCs where disease transmission is common. We sampled the nares of 1,163 children in 200 classrooms from 24 CCCs in North Carolina and Virginia to assess S. aureus colonization. MRSA strains were molecularly analyzed for staphylococcal cassette chromosome mec (SCCmec) type, Panton-Valentine leukocidin status, and multilocus sequence type. A case-control study was performed to identify risk factors for MRSA colonization. We found that 18.1% children were colonized with S. aureus and 1.3% with MRSA. Molecular analysis of the MRSA strains identified 47% as CA-MRSA and 53% as health care-associated MRSA (HA-MRSA). Although two centers had multiple children colonized with MRSA, genotyping indicated that no transmission had occurred within classrooms. The case-control study did not detect statistically significant risk factors for MRSA colonization. However, MRSA-colonized children were more likely to be nonwhite and to have increased exposure to antibiotics and skin infections in the home. Both CA-MRSA and HA-MRSA strains were found colonizing the nares of children attending CCCs. The low frequency of colonization observed highlights the need for a large multicenter study to determine risk factors for MRSA colonization and subsequent infection in this highly susceptible population.     

Intrapelvic cementless component extraction with immediate triflange acetabular reconstruction using the retroperitoneal approach

Use of the retroperitoneal approach has been well documented and used for intrapelvic cemented components or cement masses. We report on a single stage revision hip arthroplasty that incorporates a retroperitoneal approach for safe removal of an extensively entrapped porous-coated acetabular component and modular femoral head followed by an immediate reconstruction using a triflange acetabular prosthesis via a posterior approach.