Possibilities of simulation of coronavirus SARS-CoV-2 by using light scattering approach.

Issues related to human coronavirus (SARS CoV-2) are a burning topic of research in present times. Due to its easily contagious nature, real experimentation under laboratory conditions requires a high level of biosafety. A powerful algorithm serves as a potential tool for the analysis of these particles. We attempted to simulate the light scattering from coronavirus (SARS CoV-2) model. Different images were modelled using a modified version of a Monte Carlo code. The results indicate that spikes on the viruses exhibit a significant scattering profile and that the presence of spikes during modelling contributes to the distinctiveness of the scattering profiles.

Sociodemographic and environmental factors influencing acute respiratory infections among under-five children of chars (riverine islands) of Tinsukia District, Assam: A community-based cross-sectional study.

Acute respiratory tract infections (ARIs) are a major cause of morbidity and mortality in under-five children worldwide. Assam has around 2500 river islands (locally called Chars/Chaporis) in the Brahmaputra River with socioeconomically deprived inhabitants lacking access to basic health-care facilities. A community-based cross-sectional study was carried out among 380 under-five children living in the Char areas of Tinsukia District to estimate the prevalence of ARI and determine the associated risk factors. The prevalence of ARI among under-five children was found to be 56.32%. Prevalence was significantly higher among children living in Dibru-Saikhowa island, with families having >2 children, belonging to socioeconomic class 5 (modified BG Prasad scale), having a positive history of smoking or ARI in family members, having homes with attached kitchens or using wood for cooking, inadequate ventilation or overcrowding and residences of katcha ghars.

Inactivation, Clearance, and Functional Effects of Lung-Instilled Short and Long Silver Nanowires in Rats.

There is a potential for silver nanowires (AgNWs) to be inhaled, but there is little information on their health effects and their chemical transformation inside the lungs in vivo. We studied the effects of short (S-AgNWs; 1.5 µm) and long (L-AgNWs; 10 µm) nanowires instilled into the lungs of Sprague-Dawley rats. S- and L-AgNWs were phagocytosed and degraded by macrophages; there was no frustrated phagocytosis. Interestingly, both AgNWs were internalized in alveolar epithelial cells, with precipitation of Ag2S on their surface as secondary Ag2S nanoparticles. Quantitative serial block face three-dimensional scanning electron microscopy showed a small, but significant, reduction of NW lengths inside alveolar epithelial cells. AgNWs were also present in the lung subpleural space where L-AgNWs exposure resulted in more Ag+ve macrophages situated within the pleura and subpleural alveoli, compared with the S-AgNWs exposure. For both AgNWs, there was lung inflammation at day 1, disappearing by day 21, but in bronchoalveolar lavage fluid (BALF), L-AgNWs caused a delayed neutrophilic and macrophagic inflammation, while S-AgNWs caused only acute transient neutrophilia. Surfactant protein D (SP-D) levels in BALF increased after S- and L-AgNWs exposure at day 7. L-AgNWs induced MIP-1α and S-AgNWs induced IL-18 at day 1. Large airway bronchial responsiveness to acetylcholine increased following L-AgNWs, but not S-AgNWs, exposure. The attenuated response to AgNW instillation may be due to silver inactivation after precipitation of Ag2S with limited dissolution. Our findings have important consequences for the safety of silver-based technologies to human health.

Pulmonary effects of inhalation of spark-generated silver nanoparticles in Brown-Norway and Sprague-Dawley rats.

BACKGROUND: The increasing use of silver nanoparticles (AgNPs) in consumer products is concerning. We examined the potential toxic effects when inhaled in Brown-Norway (BN) rats with a pre-inflammatory state compared to Sprague-Dawley (SD) rats. METHODS: We determined the effect of AgNPs generated from a spark generator (mass concentration: 600-800 µg/mm(3); mean diameter: 13-16 nm; total lung doses: 8 [Low] and 26-28 [High] µg) inhaled by the nasal route in both rat strains. Rats were sacrificed at day 1 and day 7 after exposure and measurement of lung function. RESULTS: In both strains, there was an increase in neutrophils in bronchoalveolar lavage (BAL) fluid at 24 h at the high dose, with concomitant eosinophilia in BN rats. While BAL inflammatory cells were mostly normalised by Day 7, lung inflammation scores remained increased although not the tissue eosinophil scores. Total protein levels were elevated at both lung doses in both strains. There was an increase in BAL IL-1ß, KC, IL-17, CCL2 and CCL3 levels in both strains at Day 1, mostly at high dose. Phospholipid levels were increased at the high dose in SD rats at Day 1 and 7, while in BN rats, this was only seen at Day 1; surfactant protein D levels decreased at day 7 at the high dose in SD rats, but was increased at Day 1 at the low dose in BN rats. There was a transient increase in central airway resistance and in tissue elastance in BN rats at Day 1 but not in SD rats. Positive silver-staining was seen particularly in lung tissue macrophages in a dose and time-dependent response in both strains, maximal by day 7. Lung silver levels were relatively higher in BN rat and present at day 7 in both strains. CONCLUSIONS: Presence of cellular inflammation and increasing silver-positive macrophages in lungs at day 7, associated with significant levels of lung silver indicate that lung toxicity is persistent even with the absence of airway luminal inflammation at that time-point. The higher levels and persistence of lung silver in BN rats may be due to the pre-existing inflammatory state of the lungs.

Pulmonary toxicity of instilled silver nanoparticles: influence of size, coating and rat strain.

Particle size and surface chemistry are potential determinants of silver nanoparticle (AgNP) respiratory toxicity that may also depend on the lung inflammatory state. We compared the effects of intratracheally-administered AgNPs (20 nm and 110 nm; polyvinylpyrrolidone (PVP) and citrate-capped; 0.1 mg/Kg) in Brown-Norway (BN) and Sprague-Dawley (SD) rats. In BN rats, there was both a neutrophilic and eosinophilic response, while in SD rats, there was a neutrophilic response at day 1, greatest for the 20 nm citrate-capped AgNPs. Eosinophilic cationic protein was increased in bronchoalveolar lavage (BAL) in BN and SD rats on day 1. BAL protein and malondialdehyde levels were increased in BN rats at 1 and 7 days, and BAL KC, CCL11 and IL-13 levels at day 1, with increased expression of CCL11 in lung tissue. Pulmonary resistance increased and compliance decreased at day 1, with persistence at day 7. The 20 nm, but not the 110 nm, AgNPs increased bronchial hyperresponsiveness on day 1, which continued at day 7 for the citrate-capped AgNPs only. The 20 nm versus the 110 nm size were more proinflammatory in terms of neutrophil influx, but there was little difference between the citrate-capped versus the PVP-capped AgNPs. AgNPs can induce pulmonary eosinophilic and neutrophilic inflammation with bronchial hyperresponsiveness, features characteristic of asthma.

Role of mitogen-activated protein kinase phosphatase-1 in corticosteroid insensitivity of chronic oxidant lung injury.

Oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and in the induction of corticosteroid (CS) insensitivity. Chronic ozone exposure leads to a model of COPD with lung inflammation and emphysema. Mitogen-activated protein kinase phosphatase-1 (MKP-1) may underlie CS insensitivity in COPD. We determined the role played by MKP-1 by studying the effect of corticosteroids in wild-type C57/BL6J and MKP-1(-/-) mice after chronic ozone exposure. Mice were exposed to ozone (3 ppm, 3 h) 12 times over 6 weeks. Dexamethasone (0.1 or 2 mg/kg; intraperitoneally) was administered before each exposure. Mice were studied 24 h after final exposure. In ozone-exposed C57/BL6J mice, bronchial hyperresponsiveness (BHR) was not inhibited by both doses of dexamethasone, but in MKP-1(-/-) mice, there was a small inhibition by high dose dexamethasone (2 mg/kg). There was an increase in mean linear intercept after chronic ozone exposure in both strains which was CS-insensitive. There was lesser inflammation after low dose of dexamethasone in MKP-1(-/-) mice compared to C57/Bl6J mice. Epithelial and collagen areas were modulated in ozone-exposed MKP-1(-/-) mice treated with dexamethasone compared to C57/Bl6J mice. MKP-1 regulated the expression of MMP-12, IL-13 and KC induced by ozone but did not alter dexamethasone׳s effects. Bronchial hyperresponsiveness, lung inflammation and emphySEMa after chronic exposure are CS-insensitive, and the contribution of MKP-1 to CS sensitivity in this model was negligible.

IL-17A modulates oxidant stress-induced airway hyperresponsiveness but not emphysema.

IL-17A induces the release of pro-inflammatory cytokines and of reactive oxygen species which could lead to neutrophilic inflammation. We determined the role of IL-17 receptor (IL-17R) signalling in oxidant-induced lung emphysema and airway hyperresponsiveness. IL-17R(-/-) and wild-type C57/BL6 mice were exposed to ozone (3 ppm; 3 hours) for 12 times over 6 weeks. Bronchial responsiveness to acetylcholine was measured, and lungs were retrieved. Mean linear intercept (Lm) and isometric contractile responses of intrapulmonary airways to acetylcholine were determined. In wild-type mice but not in IL-17R(-/-), chronic ozone exposure caused airway hyperresponsiveness. The increase in Lm after chronic ozone exposure of wild-type mice was also observed in IL-17R(-/-) mice. The increased maximal contractile response to acetylcholine seen in airways of wild-type mice exposed to ozone was abolished in IL-17R(-/-) mice. p38-mitogen-activated protein kinase (MAPK) and dexamethasone-dependent increase in contractile response was reduced in airways from IL-17R(-/-) ozone-exposed mice. Lung inflammation scores were not altered in IL-17R(-/-) mice exposed to ozone compared to wild-type mice. The increased release of IL-17 and IL-1ß, and the activation of p38 MAPK in the lungs of ozone-exposed mice was reduced in IL-17R(-/-) mice. IL-17R signalling underlies the increase in airway hyperresponsiveness seen after ozone exposure, mediated by the increased contractility of airway smooth muscle. The emphysema and lung inflammation induced by ozone is not dependent on IL-17.

Oxidative stress-induced antibodies to carbonyl-modified protein correlate with severity of chronic obstructive pulmonary disease.

RATIONALE: There is increasing evidence for the presence of autoantibodies in chronic obstructive pulmonary disease (COPD). Chronic oxidative stress is an essential component in COPD pathogenesis and can lead to increased levels of highly reactive carbonyls in the lung, which could result in the formation of highly immunogenic carbonyl adducts on "self" proteins. OBJECTIVES: To determine the presence of autoantibodies to carbonyl-modified protein in patients with COPD and in a murine model of chronic ozone exposure. To assess the extent of activated immune responses toward carbonyl-modified proteins. METHODS: Blood and peripheral lung were taken from patients with COPD, age-matched smokers, and nonsmokers with normal lung function, as well as patients with severe persistent asthma. Mice were exposed to ambient air or ozone for 6 weeks. Antibody titers were measured by ELISA, activated compliment deposition by immunohistochemistry, and cellular activation by ELISA and fluorescence-activated cell sorter. MEASUREMENTS AND MAIN RESULTS: Antibody titer against carbonyl-modified self-protein was significantly increased in patients with Global Initiative for Chronic Obstructive Lung Disease stage III COPD compared with control subjects. Antibody levels inversely correlated with disease severity and showed a prevalence toward an IgG1 isotype. Deposition of activated complement in the vessels of COPD lung as well as autoantibodies against endothelial cells were also observed. Ozone-exposed mice similarly exhibited increased antibody titers to carbonyl-modified protein, as well as activated antigen-presenting cells in lung tissue and splenocytes sensitized to activation by carbonyl-modified protein. CONCLUSIONS: Carbonyl-modified proteins, arising as a result of oxidative stress, promote antibody production, providing a link by which oxidative stress could drive an autoimmune response in COPD.

A model of chronic inflammation and pulmonary emphysema after multiple ozone exposures in mice.

Oxidative stress plays a role in the pathophysiology of emphysema through the activation of tissue proteases and apoptosis. We examined the effects of ozone exposure by exposing BALB/c mice to either a single 3-h exposure or multiple exposures over 3 or 6 wk, with two 3-h exposures per week. Compared with air-exposed mice, the increase in neutrophils in bronchoalveolar lavage fluid and lung inflammation index was greatest in mice exposed for 3 and 6 wk. Lung volumes were increased in 3- and 6-wk-exposed mice but not in single-exposed. Alveolar space and mean linear intercept were increased in 6- but not 3-wk-exposed mice. Caspase-3 and apoptosis protease activating factor-1 immunoreactivity was increased in the airway and alveolar epithelium and macrophages of 3- and 6-wk-exposed mice. Interleukin-13, keratinocyte chemoattractant, caspase-3, and IFN-γ mRNA were increased in the 6-wk-exposed group, but heme oxygenase-1 (HO-1) mRNA decreased. matrix metalloproteinase-12 (MMP-12) and caspase-3 protein expression increased in lungs of 6-wk-exposed mice. Collagen area increased and epithelial area decreased in airway wall at 3- and 6-wk exposure. Exposure of mice to ozone for 6 wk induced a chronic inflammatory process, with alveolar enlargement and damage linked to epithelial apoptosis and increased protease expression.

Mice lacking Ly49E show normal NK cell development and provide evidence for probabilistic expression of Ly49E in NK cells and T cells.

Ly49E is an unusual member of the Ly49 family that is expressed on fetal NK cells, epithelial T cells, and NKT cells, but not on resting adult NK cells. Ly49E(bgeo/bgeo) mice in which the Ly49E gene was disrupted by inserting a ß-geo transgene were healthy, fertile, and had normal numbers of NK and T cells in all organs examined. Their NK cells displayed normal expression of Ly49 and other NK cell receptors, killed tumor and MHC class I-deficient cells efficiently, and produced normal levels of IFN-γ. In heterozygous Ly49E(+/bgeo) mice, the proportion of epidermal T cells, NKT cells, and IL-2-activated NK cells that expressed Ly49E was about half that found in wild-type mice. Surprisingly, although splenic T cells rarely expressed Ly49E, IL-2-activated splenic T cells from Ly49E(bgeo/bgeo) mice were as resistant to growth in G418 as NK cells and expressed similar levels of ß-geo transcripts, suggesting that disruption of the Ly49E locus had increased its expression in these cells to the same level as that in NK cells. Importantly, however, the proportion of G418-resistant heterozygous Ly49E(+/bgeo) cells that expressed Ly49E from the wild-type allele was similar to that observed in control cells. Collectively, these findings demonstrate that Ly49E is not required for the development or homeostasis of NK and T cell populations or for the acquisition of functional competence in NK cells and provide compelling evidence that Ly49E is expressed in a probabilistic manner in adult NK cells and T cells.

Assembly of EcoKI DNA methyltransferase requires the C-terminal region of the HsdM modification subunit.

The methyltransferase component of type I DNA restriction and modification systems comprises three subunits, one DNA sequence specificity subunit and two DNA modification subunits. Limited proteolysis of the EcoKI methyltransferase shows that a 55-kDa N-terminal fragment of the 59-kDa modification subunit is resistant to degradation. We have purified this fragment and determined by mass spectrometry that proteolysis removes 43 or 44 amino acids from the C-terminus. The fragment fails to interact with the other subunits even though it still possesses secondary and tertiary structure and the ability to bind the S-adenosylmethionine cofactor. We conclude that the C-terminal region of the modification subunit of EcoKI is essential for the assembly of the EcoKI methyltransferase.