SARS-CoV replication and pathogenesis in an in vitro model of the human conducting airway epithelium

SARS coronavirus (SARS-CoV) emerged in 2002 as an important cause of severe lower respiratory tract infection in humans and in vitro models of the lung are needed to elucidate cellular targets and the consequences of viral infection. The severe and sudden onset of symptoms, resulting in an atypical pneumonia with dry cough and persistent high fever in cases of severe acute respiratory virus brought to light the importance of coronaviruses as potentially lethal human pathogens and the identification of several zoonotic reservoirs has made the reemergence of new strains and future epidemics all the more possible. In this chapter, we describe the pathology of SARS-CoV infection in humans and explore the use of two models of the human conducting airway to develop a better understanding of the replication and pathogenesis of SARS-CoV in relevant in vitro systems. The first culture model is a human bronchial epithelial cell line Calu3 that can be inoculated by viruses either as a non-polarized monolayer of cells or polarized cells with tight junctions and microvilli. The second model system, derived from primary cells isolated from human airway epithelium and grown on Transwells, form a pseudostratified mucociliary epithelium that recapitulates the morphological and physiological features of the human conducting airway in vivo. Experimental results using these lung epithelial cell models demonstrate that in contrast to the pathology reported in late stage cases SARS-CoV replicates to high titers in epithelial cells of the conducting airway. The SARS-CoV receptor, human angiotensin 1 converting enzyme 2 (hACE2), was detected exclusively on the apical surface of cells in polarized Calu3 cells and human airway epithelial cultures (HAE), indicating that hACE2 was accessible by SARS-CoV after airway lumenal delivery. Furthermore, in HAE, hACE2 was exclusively localized to ciliated airway epithelial cells. In support of the hACE2 localization data, the most productive route of inoculation and progeny virion egress in both polarized Calu3 and ciliated cells of HAE was the apical surface suggesting mechanisms to release large quantities of virus into the lumen of the human lung. Preincubation of the apical surface of cultures with antisera directed against hACE2 reduced viral titers by 2 logs while antisera against DC-SIGN/DC-SIGNR did not reduce viral replication levels suggesting that hACE2 is the primary receptor for entry of SARS-CoV into the ciliated cells of HAE cultures. To assess infectivity in ciliated airway cultures derived from susceptible animal species we generated a recombinant SARS-CoV by deletion of open reading frame 7a/7b (ORF 7a/b) and insertion of the green fluorescent protein (GFP) resulting in SARS-CoV GFP. SARS-CoV GFP replicated to similar titers as wild type viruses in Vero E6, MA104, and CaCo2 cells. In addition, SARS-CoV replication in airway epithelial cultures generated from Golden Syrian hamster tracheas reached similar titers to the human cultures by 72 hours post infection. Efficient SARS-CoV infection of ciliated cell-types in HAE provides a useful in vitro model of human lung origin to study characteristics of SARS-CoV replication and pathogenesis

Familial Medullary Thyroid Carcinoma Associated with Cutaneous Lichen Amyloidosis

Background: This is a report of a patient with a novel genotype phenotype relationship of a c804 mutation of the RET proto-oncogene manifesting as medullary thyroid carcinoma (MTC) and cutaneous lichen amyloidosis (CLA). Summary: Clinical data were obtained for patient appearance and laboratory results. Analyzed were histopathology of the skin lesion and thyroid gland, genetic mutation, and family pedigree. Skin histology and histochemistry were consistent with CLA. Serum calcitonin levels were moderately elevated. Thyroid histology demonstrated a 4mm focus of MTC. Measurements of serum parathormone, calcium, and plasma metanephrines were normal. DNA analysis demonstrated a mutation in codon 804 of the RET proto-oncogene resulting in a Valine to Methionine (V804M) substitution. Genetic testing in two siblings revealed the same mutation. Conclusions: This is the first description of a patient with CLA not associated with a mutation in codon 634. The patient is one of the few with a V804M mutation in whom the clinical expression did not fully conform to the definition of familial MTC.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78146/1/thy.2009.0021.pd

Equation of state and strength of diamond in high pressure ramp loading

Diamond is used extensively as a component in high energy density experiments, but existing equation of state (EOS) models do not capture its observed response to dynamic loading. In particular, in contrast with first principles theoretical EOS models, no solid-solid phase changes have been detected, and no general-purpose EOS models match the measured ambient isotherm. We have performed density functional theory (DFT) calculations of the diamond phase to ~10TPa, well beyond its predicted range of thermodynamic stability, and used these results as the basis of a Mie-Greuneisen EOS. We also performed DFT calculations of the elastic moduli, and calibrated an algebraic elasticity model for use in simulations. We then estimated the flow stress of diamond by comparison with the stress-density relation measured experimentally in ramp-loading experiments. The resulting constitutive model allows us to place a constraint on the Taylor-Quinney factor (the fraction of plastic work converted to heat) from the observation that diamond does not melt on ramp compression

Lycium barbarum Extracts Protect the Brain from Blood-Brain Barrier Disruption and Cerebral Edema in Experimental Stroke

BACKGROUND AND PURPOSE: Ischemic stroke is a destructive cerebrovascular disease and a leading cause of death. Yet, no ideal neuroprotective agents are available, leaving prevention an attractive alternative. The extracts from the fruits of Lycium barbarum (LBP), a Chinese anti-aging medicine and food supplement, showed neuroprotective function in the retina when given prophylactically. We aim to evaluate the protective effects of LBP pre-treatment in an experimental stroke model. METHODS: C57BL/6N male mice were first fed with either vehicle (PBS) or LBP (1 or 10 mg/kg) daily for 7 days. Mice were then subjected to 2-hour transient middle cerebral artery occlusion (MCAO) by the intraluminal method followed by 22-hour reperfusion upon filament removal. Mice were evaluated for neurological deficits just before sacrifice. Brains were harvested for infarct size estimation, water content measurement, immunohistochemical analysis, and Western blot experiments. Evans blue (EB) extravasation was determined to assess blood-brain barrier (BBB) disruption after MCAO. RESULTS: LBP pre-treatment significantly improved neurological deficits as well as decreased infarct size, hemispheric swelling, and water content. Fewer apoptotic cells were identified in LBP-treated brains by TUNEL assay. Reduced EB extravasation, fewer IgG-leaky vessels, and up-regulation of occludin expression were also observed in LBP-treated brains. Moreover, immunoreactivity for aquaporin-4 and glial fibrillary acidic protein were significantly decreased in LBP-treated brains. CONCLUSIONS: Seven-day oral LBP pre-treatment effectively improved neurological deficits, decreased infarct size and cerebral edema as well as protected the brain from BBB disruption, aquaporin-4 up-regulation, and glial activation. The present study suggests that LBP may be used as a prophylactic neuroprotectant in patients at high risk for ischemic stroke.published_or_final_versio

Crystal structures from the Plasmodium peroxiredoxins: new insights into oligomerization and product binding

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium falciparum </it>is the protozoan parasite primarily responsible for more than one million malarial deaths, annually, and is developing resistance to current therapies. Throughout its lifespan, the parasite is subjected to oxidative attack, so <it>Plasmodium </it>antioxidant defences are essential for its survival and are targets for disease control.</p> <p>Results</p> <p>To further understand the molecular aspects of the <it>Plasmodium </it>redox system, we solved 4 structures of <it>Plasmodium </it>peroxiredoxins (Prx). Our study has confirmed <it>Pv</it>Trx-Px1 to be a hydrogen peroxide (H₂O₂)-sensitive peroxiredoxin. We have identified and characterized the novel toroid octameric oligomer of <it>Py</it>Trx-Px1, which may be attributed to the interplay of several factors including: (1) the orientation of the conserved surface/buried arginine of the NNLA(I/L)GRS-loop; and (2) the <it>C</it>-terminal tail positioning (also associated with the aforementioned conserved loop) which facilitates the intermolecular hydrogen bond between dimers (in an A-C fashion). In addition, a notable feature of the disulfide bonds in some of the Prx crystal structures is discussed. Finally, insight into the latter stages of the peroxiredoxin reaction coordinate is gained. Our structure of <it>Py</it>Prx6 is not only in the sulfinic acid (RSO₂H) form, but it is also with glycerol bound in a way (not previously observed) indicative of product binding.</p> <p>Conclusions</p> <p>The structural characterization of <it>Plasmodium </it>peroxiredoxins provided herein provides insight into their oligomerization and product binding which may facilitate the targeting of these antioxidant defences. Although the structural basis for the octameric oligomerization is further understood, the results yield more questions about the biological implications of the peroxiredoxin oligomerization, as multiple toroid configurations are now known. The crystal structure depicting the product bound active site gives insight into the overoxidation of the active site and allows further characterization of the leaving group chemistry.</p

Modulation of let-7 miRNAs controls the differentiation of effector CD8 T cells

The differentiation of naive CD8 T cells into effector cytotoxic T lymphocytes upon antigen stimulation is necessary for successful antiviral, and antitumor immune responses. Here, using a mouse model, we describe a dual role for the let-7 microRNAs in the regulation of CD8 T cell responses, where maintenance of the naive phenotype in CD8 T cells requires high levels of let-7 expression, while generation of cytotoxic T lymphocytes depends upon T cell receptor-mediated let-7 downregulation. Decrease of let-7 expression in activated T cells enhances clonal expansion and the acquisition of effector function through derepression of the let-7 targets, including Myc and Eomesodermin. Ultimately, we have identified a novel let-7-mediated mechanism, which acts as a molecular brake controlling the magnitude of CD8 T cell responses

Comparison of host immune responses to homologous and heterologous type II porcine reproductive and respiratory syndrome virus (PRRSV) challenge in vaccinated and unvaccinated pigs

Porcine reproductive and respiratory syndrome (PRRS) is a high-consequence animal disease with current vaccines providing limited protection from infection due to the high degree of genetic variation of field PRRS virus. Therefore, understanding host immune responses elicited by different PRRSV strains will facilitate the development of more effective vaccines. Using IngelVac modified live PRRSV vaccine (MLV), its parental strain VR-2332, and the heterologous KS-06-72109 strain (a Kansas isolate of PRRSV), we compared immune responses induced by vaccination and/or PRRSV infection. Our results showed that MLV can provide complete protection from homologous virus (VR-2332) and partial protection from heterologous (KS-06) challenge. The protection was associated with the levels of PRRSV neutralizing antibodies at the time of challenge, with vaccinated pigs having higher titers to VR-2332 compared to KS-06 strain. Challenge strain did not alter the cytokine expression profiles in the serum of vaccinated pigs or subpopulations of T cells. However, higher frequencies of IFN-γ-secreting PBMCs were generated from pigs challenged with heterologous PRRSV in a recall response when PBMCs were re-stimulated with PRRSV. Thus, this study indicates that serum neutralizing antibody titers are associated with PRRSV vaccination-induced protection against homologous and heterologous challenge

Irinotecan or FOLFIRI for 2nd line colorectal

Background Second-line treatment with irinotecan for advanced or metastatic colorectal cancer prolongs survival. It is uncertain whether irinotecan is better administered with 5- fluorouracil or alone in patients previously treated with a fluoropyrimidine. We compared toxicity (particularly diarrhoea), quality of life, and efficacy of combination chemotherapy and irinotecan in these patients. Methods In DaVINCI, a randomised phase II trial, patients with advanced colorectal cancer were randomly allocated to: combination therapy (FOLFIRI), irinotecan (180 mg/m2 IV over 90 min, day 1), 5-fluorouracil (400 mg/m2 IV bolus and 2400 mg/m2 by 46-hour infusion from day 1) and folinic acid (20 mg/m2 IV bolus, day 1), 2-weekly; or single-agent, irinotecan (350 mg/m2 IV over 90 min), 3-weekly. Toxicity was evaluated every treatment cycle; QOL and response 6 weekly. Analysis was by intention to treat. Results were also combined with those of other trials. Findings We randomised 44 patients to combination and 45 to single-agent. The most common toxicity was complete alopecia (single-agent 37%, combination 14%, P<0.02). Eight patients in the irinotecan arm and 4 in the combination arm had grade 3–4 diarrhoea (P=0.24). The treatment groups did not differ significantly in overall QOL changes, response rate, or progression free or overall survival. In a systematic review of 29 trials of second-line irinotecan-based treatment, single-agent irinotecan was associated with more diarrhoea and alopecia than the combination, but efficacy was similar. Interpretation Combination treatment compared with single-agent irinotecan appears to reduce the rateof complete alopecia and diarrhoea without compromising efficacy on clinical outcomes.Australasian Gastro-Intestinal Trials Grou

A Case of Thoracic Spondylosis Deformans and Multilevel Instrumented Spinal Fusion in an 84-Year-Old Male.

Spondylosis deformans is a type of spinal claw osteophytosis which can be found on the anterolateral vertebral bodies of any region, and which consists of protrusions of intervertebral disc tissue covered by a bony shell. We report here a case of thoracic spondylosis deformans and multilevel instrumented fusion found during routine dissection of a cadaver. Theories of the etiology of this condition are reviewed in general, and with respect to this specific case and the potential interaction of the presenting comorbidities. The clinical implications of these osteophytes, including musculoskeletal and visceral sequelae, are also discussed