Entire Respiratory Tract Research Articles

Genetic Vaccine for Respiratory Syncytial Virus Provides Protection Without Disease Potentiation

Respiratory syncytial virus (RSV) is a major cause of infectious lower respiratory disease in infants and the elderly. As there is no vaccine for RSV, we developed a genetic vaccine approach that induced protection of the entire respiratory tract from a single parenteral administration. The approach was based on adenovirus vectors derived from newly isolated nonhuman primate viruses with low seroprevalence. We show for the first time that a single intramuscular (IM) injection of the replication-deficient adenovirus vectors expressing the RSV fusion (F0) glycoprotein induced immune responses that protected both the lungs and noses of cotton rats and mice even at low doses and for several months postimmunization. The immune response included high titers of neutralizing antibody that were maintained ≥ 24 weeks and RSV-specific CD8+ and CD4+ T cells. The vectors were as potently immunogenic as a human adenovirus 5 vector in these two key respiratory pathogen animal models. Importantly, there was minimal alveolitis and granulocytic infiltrates in the lung, and type 2 cytokines were not produced after RSV challenge even under conditions of partial protection. Overall, this genetic vaccine is highly effective without potentiating immunopathology, and the results support development of the vaccine candidate for human testing.

Short term inhalation toxicity of a liquid aerosol of glutaraldehyde-coated CdS/Cd(OH)2 core shell quantum dots in rats

Quantum dots exhibit extraordinary optical and mechanical properties, and the number of their applications is increasing. In order to investigate a possible effect of coating on the inhalation toxicity of previously tested non-coated CdS/Cd(OH)2 quantum dots and translocation of these very small particles from the lungs, rats were exposed to coated quantum dots or CdCl2 aerosol (since Cd2+ was present as impurity), 6h/d for 5 consecutive days. Cd content was determined in organs and excreta after the end of exposure and three weeks thereafter. Toxicity was determined by examination of broncho-alveolar lavage fluid and microscopic evaluation of the entire respiratory tract. There was no evidence for translocation of particles from the respiratory tract. Evidence of a minimal inflammatory process was observed by examination of broncho-alveolar lavage fluid. Microscopically, minimal to mild epithelial alteration was seen in the larynx. The effects observed with coated quantum dots, non-coated quantum dots and CdCl2 were comparable, indicating that quantum dots elicited no significant effects beyond the toxicity of the Cd2+ ion itself. Compared to other compounds with larger particle size tested at similarly low concentrations, quantum dots caused much less pronounced toxicological effects. Therefore, the present data show that small particle sizes with corresponding high surfaces are not the only factor triggering the toxic response or translocation.

Nanoparticle Mass Transfer From Lung Airways to Systemic Regions—Part I: Whole-Lung Aerosol Dynamics

This is a two-part paper describing inhaled nanoparticle (NP) transport and deposition in a model of a human respiratory tract (Part I) as well as NP-mass transfer across barriers into systemic regions (Part II). Specifically, combining high-resolution computer simulation results of inhaled NP deposition in the human airways (Part I) with a multicompartmental model for NP-mass transfer (Part II) allows for the prediction of temporal NP accumulation in the blood and lymphatic systems as well as in organs. An understanding of nanoparticle transport and deposition in human respiratory airways is of great importance, as exposure to nanomaterial has been found to cause serious lung diseases, while the use of nanodrugs may have superior therapeutic effects. In Part I, the fluid-particle dynamics of a dilute NP suspension was simulated for the entire respiratory tract, assuming steady inhalation and planar airways. Thus, a realistic airway configuration was considered from nose/mouth to generation 3, and then an idealized triple-bifurcation unit was repeated in series and parallel to cover the remaining generations. Using the current model, the deposition of NPs in distinct regions of the lung, namely extrathoracic, bronchial, bronchiolar, and alveolar, was calculated. The region-specific NP-deposition results for the human lung model were used in Part II to determine the multicompartmental model parameters from experimental retention and clearance data in human lungs. The quantitative, experimentally validated results are useful in diverse fields, such as toxicology for exposure-risk analysis of ubiquitous nanomaterial as well as in pharmacology for nanodrug development and targeting.

Prior infection of pigs with a recent humanH3N2 influenza virus confers minimal cross‐protection against aEuropean swineH3N2 virus

H3N2 influenza viruses circulating in humans and European pigs originate from the pandemic A/Hong Kong/68 virus. Because of slower antigenic drift in swine, the antigenic divergence between swine and human viruses has been increasing. It remains unknown to what extent this results in a reduced cross-protection between recent human and swine H3N2 influenza viruses. We examined whether prior infection of pigs with an old [A/Victoria/3/75 (A/Vic/75)] or a more recent [A/Wisconsin/67/05 (A/Wis/05)] human H3N2 virus protected against a European swine H3N2 virus [sw/Gent/172/08 (sw/Gent/08)]. Genetic and antigenic relationships between sw/Gent/08 and a selection of human H3N2 viruses were also assessed. After challenge with sw/Gent/08, all challenge controls had high virus titers in the entire respiratory tract at 3days post-challenge and nasal virus excretion for 5-6days. Prior infection with sw/Gent/08 or A/Vic/75 offered complete virological protection against challenge. Pigs previously inoculated with A/Wis/05 showed similar virus titers in the respiratory tract as challenge controls, but the mean duration of nasal shedding was 1·3days shorter. Unlike sw/Gent/08- and A/Vic/75-inoculated pigs, A/Wis/05-inoculated pigs lacked cross-reactive neutralizing antibodies against sw/Gent/08 before challenge, but they showed a more rapid antibody response to sw/Gent/08 than challenge controls after challenge. Cross-protection and serological responses correlated with genetic and antigenic differences. Infection immunity to a recent human H3N2 virus confers minimal cross-protection against a European swine H3N2 virus. We discuss our findings with regard to the recent zoonotic infections of humans in the United States with a swine-origin H3N2 variant virus.

Lipopolysaccharide-induced acute lung injury in rats: Comparative assessment of intratracheal instillation and aerosol inhalation

Acute lung injury (ALI) has many possible etiopathologies and is characterized by acute diffuse lung damage with poor prognosis. Lipopolysaccharide (LPS) is widely used as septic model of ALI in pharmacological research. This study compares intratracheal bolus instillation (IT) with dose-adjusted aerosol inhalation (IH) of LPS in Wistar rats using both non-invasive and terminal endpoints. The former comprised exhaled nitric oxide (NOE) and ‘enhanced pause’ (Penh) both measured in spontaneous breathing conscious rats. Terminal endpoints included lung weights, LDH, protein, total cell counts, and cytodifferentiation in bronchoalveolar lavage (BAL). Measurements were made 1, 3, 7, and 14 days after IT instillation (5mg LPS/kg body weight) or 6-hour directed-flow nose-only inhalation exposure to respirable LPS-aerosol at 100mg/m3 (thoracic dose: 2.6mgLPS/kg body weight). Controls received saline (IT) or air only (IH). LDH and protein were significantly different from the control in the LPS-IH group (days 1 and 3) with a somewhat inconclusive outcome in the LPS-IT group due to the effects occurring in the control. Total cell counts were equally elevated with similar time-course changes in the LPS-IT and -IH groups. Polymorphonuclear neutrophils (PMNs) were indistinguishable amongst LPS-dosed rats. Again, IT-dosed control rats displayed markedly higher background levels than those dosed by inhalation. Similarly NOE was significantly elevated on post-LPS day 1 as was Penh. In summary, the LPS-aerosol dose delivered by nose-only exposure over 6h was equally potent as the 2-times higher LPS-IT bolus dose on post-LPS day 1 with somewhat faster recovery thereafter. The climax and discriminatory power of the non-invasive endpoints matched those determined terminally. This supports the conclusion that the pharmacological efficacy and side effects of inhalation pharmaceuticals designed to mitigate ALI can better be identified by LPS-aerosol than by LPS-IT. Non-invasive time-course measurements may deliver apt information both on the efficacious dose as well as the dosing intervals required to maintain the targeted efficacy using a minimum of experimental animals. The outcome of this comparative study supports the conclusion that the inhalation route produces a more uniform type of injury at lower, more meaningful dosages. When designing studies for screening of effective drugs this mode of delivery appears to better approximate the human condition with less dosimetric uncertainty, less experimental variability and better characterization of what was actually delivered to the entire respiratory tract.

Modeling the airflow in a lung with cystic fibrosis

Cystic fibrosis (CF) is a chronic progressive pulmonary disorder caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. A CF lung is generally characterized by obstructed airflow to an extent that leads to destruction of airway wall support structure. Airway resistance, resulting from both laminar and turbulent flow, is an important mechanical factor contributing to flow of air into and out of the airways. There are numerous research studies focusing on airflow in the respiratory system that assumed flow to be only laminar and steady. The goal of this research is to describe the air flow mathematically by considering the resistance from both laminar and turbulent airflow throughout the entire respiratory tract. Furthermore, we implement a model that includes airway clogging in CF lungs and recalculate the rate of air flow given these obstructions.

Recently Emerged Swine Influenza A Virus (H2N3) Causes Severe Pneumonia in Cynomolgus Macaques

The triple reassortant H2N3 virus isolated from diseased pigs in the United States in 2006 is pathogenic for certain mammals without prior adaptation and transmits among swine and ferrets. Adaptation, in the H2 hemagglutinin derived from an avian virus, includes the ability to bind to the mammalian receptor, a significant prerequisite for infection of mammals, in particular humans, which poses a big concern for public health. Here we investigated the pathogenic potential of swine H2N3 in Cynomolgus macaques, a surrogate model for human influenza infection. In contrast to human H2N2 virus, which served as a control and largely caused mild pneumonia similar to seasonal influenza A viruses, the swine H2N3 virus was more pathogenic causing severe pneumonia in nonhuman primates. Both viruses replicated in the entire respiratory tract, but only swine H2N3 could be isolated from lung tissue on day 6 post infection. All animals cleared the infection whereas swine H2N3 infected macaques still presented with pathologic changes indicative of chronic pneumonia at day 14 post infection. Swine H2N3 virus was also detected to significantly higher titers in nasal and oral swabs indicating the potential for animal-to-animal transmission. Plasma levels of IL-6, IL-8, MCP-1 and IFNγ were significantly increased in swine H2N3 compared to human H2N2 infected animals supporting the previously published notion of increased IL-6 levels being a potential marker for severe influenza infections. In conclusion, the swine H2N3 virus represents a threat to humans with the potential for causing a larger outbreak in a non-immune or partially immune population. Furthermore, surveillance efforts in farmed pig populations need to become an integral part of any epidemic and pandemic influenza preparedness.

Fibrogenesis and carcinoid tumor - a case report

Carcinoid tumors are rare. They may appear in the entire gastrointestinal and respiratory tracts, with single or multiple occurrences. Prognosis is dependent on the size and location. Symptoms may appear in carcinoid syndrome, related to active substances, especially serotonin. One important aspect associated with these tumors and usually ignored is fibrogenesis. This is a case report of a patient with carcinoid tumor of the terminal ileum, treated by laparoscopy, associated with fat and fibrosis infiltration.

Pulmonary manifestations of sarcoidosis

Sarcoidosis affects the lungs in more than 90% of cases. Symptoms include cough, dyspnea, and chest pain. The entire respiratory tract can be involved. The most common areas of involvement are the airways and interstitium. Airway disease can lead to airway obstruction while interstitial lung disease can lead to restrictive disease. Patients may have a mix of these areas of involvement. For the symptomatic patient, the identification of disease involvement can usually be determined by pulmonary function testing and chest imaging. The chest X-ray staging system has been widely used in sarcoidosis, high-resolution computer tomography (HRCT) can provide detailed information regarding lung involvement. Unfortunately the various patterns seen on HRCT have limited the ability to develop a simple scoring system. Special studies such as bronchoscopy can be useful for detecting large airway disease. Other chest manifestations include adenopathy, pulmonary hypertension, and pulmonary muscle weakness. Fibrotic lung disease can lead to bronchiectasis, which can become infected.

Distribution of sialic acid receptors and influenza A virus of avian and swine origin in experimentally infected pigs

BackgroundPigs are considered susceptible to influenza A virus infections from different host origins because earlier studies have shown that they have receptors for both avian (sialic acid-alpha-2,3-terminal saccharides (SA-alpha-2,3)) and swine/human (SA-alpha-2,6) influenza viruses in the upper respiratory tract. Furthermore, experimental and natural infections in pigs have been reported with influenza A virus from avian and human sources.MethodsThis study investigated the receptor distribution in the entire respiratory tract of pigs using specific lectins Maackia Amurensis (MAA) I, and II, and Sambucus Nigra (SNA). Furthermore, the predilection sites of swine influenza virus (SIV) subtypes H1N1 and H1N2 as well as avian influenza virus (AIV) subtype H4N6 were investigated in the respiratory tract of experimentally infected pigs using immunohistochemical methods.ResultsSIV antigen was widely distributed in bronchi, but was also present in epithelial cells of the nose, trachea, bronchioles, and alveolar type I and II epithelial cells in severely affected animals. AIV was found in the lower respiratory tract, especially in alveolar type II epithelial cells and occasionally in bronchiolar epithelial cells. SA-alpha-2,6 was the predominant receptor in all areas of the respiratory tract with an average of 80-100% lining at the epithelial cells. On the contrary, the SA-alpha-2,3 was not present (0%) at epithelial cells of nose, trachea, and most bronchi, but was found in small amounts in bronchioles, and in alveoli reaching an average of 20-40% at the epithelial cells. Interestingly, the receptor expression of both SA-alpha-2,3 and 2,6 was markedly diminished in influenza infected areas compared to non-infected areas.ConclusionsA difference in predilection sites between SIV and AIV virus was found, and this difference was in accordance with the distribution of the SA-alpha-2,6 and SA-alpha-2,3 receptor, respectively. The results indicated that the distribution of influenza A virus receptors in pigs are similar to that of humans and therefore challenge the theory that the pig acts as a mixing vessel between human and avian influenza viruses. Furthermore, it was shown that AIV prefers to infect alveolar type II epithelial cells in pigs. This corresponds with findings in humans emphasising the resemblance between the two species.

Early Target Cells of Measles Virus after Aerosol Infection of Non-Human Primates

Measles virus (MV) is highly infectious, and has long been thought to enter the host by infecting epithelial cells of the respiratory tract. However, epithelial cells do not express signaling lymphocyte activation molecule (CD150), which is the high-affinity cellular receptor for wild-type MV strains. We have generated a new recombinant MV strain expressing enhanced green fluorescent protein (EGFP), based on a wild-type genotype B3 virus isolate from Khartoum, Sudan (KS). Cynomolgus macaques were infected with a high dose of rMVKSEGFP by aerosol inhalation to ensure that the virus could reach the full range of potential target cells throughout the entire respiratory tract. Animals were euthanized 2, 3, 4 or 5 days post-infection (d.p.i., n = 3 per time point) and infected (EGFP+) cells were identified at all four time points, albeit at low levels 2 and 3 d.p.i. At these earliest time points, MV-infected cells were exclusively detected in the lungs by fluorescence microscopy, histopathology and/or virus isolation from broncho-alveolar lavage cells. On 2 d.p.i., EGFP+ cells were phenotypically typed as large mononuclear cells present in the alveolar lumen or lining the alveolar epithelium. One to two days later, larger clusters of MV-infected cells were detected in bronchus-associated lymphoid tissue (BALT) and in the tracheo-bronchial lymph nodes. From 4 d.p.i. onward, MV-infected cells were detected in peripheral blood and various lymphoid tissues. In spite of the possibility for the aerosolized virus to infect cells and lymphoid tissues of the upper respiratory tract, MV-infected cells were not detected in either the tonsils or the adenoids until after onset of viremia. These data strongly suggest that in our model MV entered the host at the alveolar level by infecting macrophages or dendritic cells, which traffic the virus to BALT or regional lymph nodes, resulting in local amplification and subsequent systemic dissemination by viremia.

Expression of taste receptors in Solitary Chemosensory Cells of rodent airways

BackgroundChemical irritation of airway mucosa elicits a variety of reflex responses such as coughing, apnea, and laryngeal closure. Inhaled irritants can activate either chemosensitive free nerve endings, laryngeal taste buds or solitary chemosensory cells (SCCs). The SCC population lies in the nasal respiratory epithelium, vomeronasal organ, and larynx, as well as deeper in the airway. The objective of this study is to map the distribution of SCCs within the airways and to determine the elements of the chemosensory transduction cascade expressed in these SCCs.MethodsWe utilized a combination of immunohistochemistry and molecular techniques (rtPCR and in situ hybridization) on rats and transgenic mice where the Tas1R3 or TRPM5 promoter drives expression of green fluorescent protein (GFP).ResultsEpithelial SCCs specialized for chemoreception are distributed throughout much of the respiratory tree of rodents. These cells express elements of the taste transduction cascade, including Tas1R and Tas2R receptor molecules, α-gustducin, PLCβ2 and TrpM5. The Tas2R bitter taste receptors are present throughout the entire respiratory tract. In contrast, the Tas1R sweet/umami taste receptors are expressed by numerous SCCs in the nasal cavity, but decrease in prevalence in the trachea, and are absent in the lower airways.ConclusionsElements of the taste transduction cascade including taste receptors are expressed by SCCs distributed throughout the airways. In the nasal cavity, SCCs, expressing Tas1R and Tas2R taste receptors, mediate detection of irritants and foreign substances which trigger trigeminally-mediated protective airway reflexes. Lower in the respiratory tract, similar chemosensory cells are not related to the trigeminal nerve but may still trigger local epithelial responses to irritants. In total, SCCs should be considered chemoreceptor cells that help in preventing damage to the respiratory tract caused by inhaled irritants and pathogens.

Pulmonary manifestations of Sjögren's syndrome

Sjögren's syndrome is a chronic inflammatory disorder characterized by lymphocytic infiltration of exocrine glands, mainly the lacrimal and salivary glands. However, extraglandular organ systems may frequently be involved, including the lungs. Although subclinical pulmonary inflammation exists in more than 50% of patients, clinically significant pulmonary involvement affects approximately 10% of patients and may be the first manifestation of the disease. The entire respiratory tract may be involved, with a wide spectrum of manifestations including xerotrachea and bronchial sicca, obstructive small airway disease, various patterns of interstitial lung disease, lymphoinfiltrative or lymphoproliferative lung disease, such as lymphoma (usually of MALT type), pulmonary hypertension, pleural involvement, lung cysts, and pulmonary amyloidosis.

Breath‐taking complexity of vagal C‐fibre nociceptors: implications for inflammatory pulmonary disease, dyspnoea and cough

Breath‐taking complexity of vagal C‐fibre nociceptors: implications for inflammatory pulmonary disease, dyspnoea and cough

Cross‐protection between antigenically distinct H1N1 swine influenza viruses from Europe and North America

Please cite this paper as: De Vleeschauwer et al. (2011) Cross‐protection between antigenically distinct H1N1 swine influenza viruses from Europe and North America. Influenza and Other Respiratory Viruses 5(2), 115–122. Background An avian‐like H1N1 swine influenza virus (SIV) is enzootic in swine populations of Western Europe. The virus is antigenically distinct from H1N1 SIVs in North America that have a classical swine virus‐lineage H1 hemagglutinin, as does the pandemic (H1N1) 2009 virus. However, the significance of this antigenic difference for cross‐protection among pigs remains unknown. Objectives We examined protection against infection with a North American triple reassortant H1N1 SIV [A/swine/Iowa/H04YS2/04 (sw/IA/04)] in pigs infected with a European avian‐like SIV [A/swine/Belgium/1/98 (sw/B/98)] 4 weeks earlier. We also examined the genetic relationships and serologic cross‐reactivity between both SIVs and with a pandemic (H1N1) 2009 virus [A/California/04/09 (Calif/09)]. Results After intranasal inoculation with sw/IA/04, all previously uninfected control pigs showed nasal virus excretion, high virus titers in the entire respiratory tract at 4 days post‐challenge (DPCh) and macroscopic lung lesions. Most pigs previously infected with sw/B/98 tested negative for sw/IA/04 in nasal swabs and respiratory tissues, and none had lung lesions. At challenge, these pigs had low levels of cross‐reactive virus neutralizing and neuraminidase inhibiting (NI) antibodies to sw/IA/04, but no hemagglutination‐inhibiting antibodies. They showed similar antibody profiles when tested against Calif/09, but NI antibody titers were higher against Calif/09 than sw/IA/04, reflecting the higher genetic homology of the sw/B/98 neuraminidase with Calif/09. Conclusions Our data indicate that immunity induced by infection with European avian‐like H1N1 SIV affords protection for pigs against North American H1N1 SIVs with a classical H1, and they suggest cross‐protection against the pandemic (H1N1) 2009 virus.

Update on Macrophage Clearance of Inhaled Micro- and Nanoparticles

Lung macrophages, that is, the intravascular, interstitial, pleural, and surface macrophages, are part of the mononuclear phagocyte system. They are derived from the hematopoietic stem cell in the bone marrow with the monocytes as their putative precursors. Macrophages residing on the inner surfaces of the lungs and immersed within the lung lining layer, that is, the alveolar and the airway macrophages, are constantly exposed to the environment; it is those cells that are recognized as first line of cellular host defense. Phagocytic uptake of inhaled and deposited particles is the main mechanism to remove insoluble micrometer-sized particles from the lung surfaces, where mucociliary transport, cough, or sneezing fail or are absent. Phagocytosis requires an intact cytoskeleton and is most efficient when mediated by Fc-receptors, but complement and scavenger receptors like MARCO and CD206 are just as important. The main pathway for the clearance of macrophage-associated particles is by mucociliary transport; to a lesser degree and species specific, particle-containing macrophages may reenter into the interstitium and go from there to the lymphatics. Inhaled nanometer-sized particles that deposit along the entire respiratory tract, however, are not efficiently phagocytosed by surface macrophages. Uptake by spontaneous or stimulated (macro-) pinocytosis or electrokinetic's phenomena may become more important. In addition, translocation of nanometer-sized particles into the interstitium and to the blood circulation brings them into contact with other fluids; altered particle properties may influence particle uptake. Moreover, translocated particles may interact with lung macrophage populations that were previously not considered of great significance for the clearance of inhaled particles.

Replication of avian, human and swine influenza viruses in porcine respiratory explants and association with sialic acid distribution

BackgroundThroughout the history of human influenza pandemics, pigs have been considered the most likely "mixing vessel" for reassortment between human and avian influenza viruses (AIVs). However, the replication efficiencies of influenza viruses from various hosts, as well as the expression of sialic acid (Sia) receptor variants in the entire porcine respiratory tract have never been studied in detail. Therefore, we established porcine nasal, tracheal, bronchial and lung explants, which cover the entire porcine respiratory tract with maximal similarity to the in vivo situation. Subsequently, we assessed virus yields of three porcine, two human and six AIVs in these explants. Since our results on virus replication were in disagreement with the previously reported presence of putative avian virus receptors in the trachea, we additionally studied the distribution of sialic acid receptors by means of lectin histochemistry. Human (Siaα2-6Gal) and avian virus receptors (Siaα2-3Gal) were identified with Sambucus Nigra and Maackia amurensis lectins respectively.ResultsCompared to swine and human influenza viruses, replication of the AIVs was limited in all cultures but most strikingly in nasal and tracheal explants. Results of virus titrations were confirmed by quantification of infected cells using immunohistochemistry. By lectin histochemistry we found moderate to abundant expression of the human-like virus receptors in all explant systems but minimal binding of the lectins that identify avian-like receptors, especially in the nasal, tracheal and bronchial epithelium.ConclusionsThe species barrier that restricts the transmission of influenza viruses from one host to another remains preserved in our porcine respiratory explants. Therefore this system offers a valuable alternative to study virus and/or host properties required for adaptation or reassortment of influenza viruses. Our results indicate that, based on the expression of Sia receptors alone, the pig is unlikely to be a more appropriate mixing vessel for influenza viruses than humans. We conclude that too little is known on the exact mechanism and on predisposing factors for reassortment to assess the true role of the pig in the emergence of novel influenza viruses.

Chromosomal numerical aberrations in apparently normal oral mucosa of heavy smokers affected by lung cancer

Cigarette smoke creates a field of injury in the epithelial lining of the entire respiratory tract causing an increased risk for the development of malignant lesions. It is conceivable, therefore, that early genetic alterations, can be detected in oral mucosa of heavy smokers mainly those affected by lung cancer. As aneuploidy was shown to be an early event in oral carcinogenesis, we aimed to investigate the prevalence of aneuploid cells (ACs) in samples obtained from apparently normal looking oral mucosa of heavy smokers affected by lung cancer (LC). Two brush samples were collected from the oral mucosa of 152 subjects; 31 heavy smokers with LC, 59 heavy smokers without LC and 62 never-smokers. The samples were simultaneously analyzed for morphology and fluorescent in situ hybridization (FISH) using chromosomes 2 and 8 centromeric probes. Over 2% ACs were found in 23% of heavy smokers with LC compared to 12% in heavy smokers without LC and 5% of the never-smokers group (P=0.015). A trend was also noticed when comparing the group of heavy smokers without LC with the never-smokers (P=0.198). We conclude that heavy smokers harbour detectable chromosomal numerical aberrations in oral epithelial cells of normal looking mucosa. These aberrations are more frequently found in heavy smokers affected by LC.

Comparative Pathogenesis of an Avian H5N2 and a Swine H1N1 Influenza Virus in Pigs

Pigs are considered intermediate hosts for the transmission of avian influenza viruses (AIVs) to humans but the basic organ pathogenesis of AIVs in pigs has been barely studied. We have used 42 four-week-old influenza naive pigs and two different inoculation routes (intranasal and intratracheal) to compare the pathogenesis of a low pathogenic (LP) H5N2 AIV with that of an H1N1 swine influenza virus. The respiratory tract and selected extra-respiratory tissues were examined for virus replication by titration, immunofluorescence and RT-PCR throughout the course of infection. Both viruses caused a productive infection of the entire respiratory tract and epithelial cells in the lungs were the major target. Compared to the swine virus, the AIV produced lower virus titers and fewer antigen positive cells at all levels of the respiratory tract. The respiratory part of the nasal mucosa in particular showed only rare AIV positive cells and this was associated with reduced nasal shedding of the avian compared to the swine virus. The titers and distribution of the AIV varied extremely between individual pigs and were strongly affected by the route of inoculation. Gross lung lesions and clinical signs were milder with the avian than with the swine virus, corresponding with lower viral loads in the lungs. The brainstem was the single extra-respiratory tissue found positive for virus and viral RNA with both viruses. Our data do not reject the theory of the pig as an intermediate host for AIVs, but they suggest that AIVs need to undergo genetic changes to establish full replication potential in pigs. From a biomedical perspective, experimental LP H5 AIV infection of pigs may be useful to examine heterologous protection provided by H5 vaccines or other immunization strategies, as well as for further studies on the molecular pathogenesis and neurotropism of AIVs in mammals.

Effects of Chronic Exposure to Crack Cocaine on the Respiratory Tract of Mice

Smoked cocaine (crack cocaine) causes several forms of injury to the respiratory tract, including asthma exacerbations, lung edema and hemorrhage, and nasal mucosal alterations. Few studies, however, have assessed respiratory tract pathology in habitual users of crack cocaine. Here, we describe the histological alterations in the respiratory tract of mice caused by chronic inhalation of crack cocaine. Twenty 2-month-old BALB/c mice were exposed to the smoke of 5 g crack cocaine in an inhalation chamber once a day for two months and compared to controls (n = 10). We then morphometrically analyzed nose and bronchiolar epithelial alterations, bronchiolar and alveolar macrophage cell density, alveolar hemosiderin content, and in addition determined the vasoconstriction index and the wall thickness of pulmonary arteries. The serum cocaine level was 212.5 ng/mL after a single inhalation. The mucus content of the nasal epithelium increased in crack-exposed animals, and the nasal and bronchial epithelium thickness decreased significantly. The alveolar hemosiderin content and the alveolar and bronchiolar macrophage cell density increased in animals exposed to crack. The vasoconstriction index increased in the pulmonary arteries of the exposed group. Chronic crack cocaine inhalation causes extensive histological changes along the entire respiratory tract.