The Experts below are selected from a list of 36 Experts worldwide ranked by ideXlab platform
Feiruo Huang - One of the best experts on this subject based on the ideXlab platform.
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Data_Sheet_1_The Variation of Nasal Microbiota Caused by Low Levels of Gaseous Ammonia Exposure in Growing Pigs.pdf
2019Co-Authors: Tongxin Wang, Weilei Yao, Yafei Shao, Feiruo HuangAbstract:Exposure to gaseous ammonia, even at low levels, can be harmful to pigs and human health. However, less is known about the effects of sustained exposure to gaseous ammonia on nasal microbiota colonization in growing pigs. A total of 120 Duroc×Landrace×Yorkshire pigs were housed in 24 separate chambers and continuously exposed to gaseous ammonia at 0,5, 10, 15, 20, and 25 ppm (four groups per exposure level) for 4 weeks. Then, we used high-throughput sequencing to perform 16S rRNA gene analysis in nasal swabs samples from 72 pigs (n = 12). The results of the nasal microbiota analysis showed that an increase in ammonia concentration, especially at 20 and 25 ppm, decreased the alpha diversity and relative abundance of nasal microbiota. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Chloroflexi were the most abundant phyla. In addition, the relative abundances of 24 microbial genera significantly changed as the ammonia level increased. Four microbial genera (Pseudomonas, Lactobacillus, Prevotella, and Bacteroides) were significantly decreased at 25 ppm, while only two genera (Moraxella and Streptococcus) were increased at 25 ppm. PICRUSt analyses showed that the relative abundances of the nasal microbiota involved in cell motility, signal transduction, the nervous system, environmental adaptation, and energy and carbohydrate metabolism were significantly decreased, while genes involved in the immune system, endocrine system, circulatory system, immune system diseases and metabolism of vitamins, lipid, and amino acids were increased with increased ammonia levels. The results of in vivo tests showed that an increase in ammonia levels, especially an ammonia level of 25 ppm, caused Respiratory Tract Injury and increase the number of Moraxella and Streptococcus species, while simultaneously decreasing Respiratory immunity and growth performance, consistent with the increased presence of harmful bacteria identified by nasal microbiota analysis. Herein, this study also indicted that the threshold concentration of ammonia in pig farming is 20 ppm.
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The Variation of Nasal Microbiota Caused by Low Levels of Gaseous Ammonia Exposure in Growing Pigs
Frontiers Media S.A., 2019Co-Authors: Tongxin Wang, Weilei Yao, Yafei Shao, Feiruo HuangAbstract:Exposure to gaseous ammonia, even at low levels, can be harmful to pigs and human health. However, less is known about the effects of sustained exposure to gaseous ammonia on nasal microbiota colonization in growing pigs. A total of 120 Duroc×Landrace×Yorkshire pigs were housed in 24 separate chambers and continuously exposed to gaseous ammonia at 0,5, 10, 15, 20, and 25 ppm (four groups per exposure level) for 4 weeks. Then, we used high-throughput sequencing to perform 16S rRNA gene analysis in nasal swabs samples from 72 pigs (n = 12). The results of the nasal microbiota analysis showed that an increase in ammonia concentration, especially at 20 and 25 ppm, decreased the alpha diversity and relative abundance of nasal microbiota. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Chloroflexi were the most abundant phyla. In addition, the relative abundances of 24 microbial genera significantly changed as the ammonia level increased. Four microbial genera (Pseudomonas, Lactobacillus, Prevotella, and Bacteroides) were significantly decreased at 25 ppm, while only two genera (Moraxella and Streptococcus) were increased at 25 ppm. PICRUSt analyses showed that the relative abundances of the nasal microbiota involved in cell motility, signal transduction, the nervous system, environmental adaptation, and energy and carbohydrate metabolism were significantly decreased, while genes involved in the immune system, endocrine system, circulatory system, immune system diseases and metabolism of vitamins, lipid, and amino acids were increased with increased ammonia levels. The results of in vivo tests showed that an increase in ammonia levels, especially an ammonia level of 25 ppm, caused Respiratory Tract Injury and increase the number of Moraxella and Streptococcus species, while simultaneously decreasing Respiratory immunity and growth performance, consistent with the increased presence of harmful bacteria identified by nasal microbiota analysis. Herein, this study also indicted that the threshold concentration of ammonia in pig farming is 20 ppm
Bruce E Lehnert - One of the best experts on this subject based on the ideXlab platform.
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relative acute toxicities of hydrogen fluoride hydrogen chloride and hydrogen bromide in nose and pseudo mouth breathing rats
Toxicological Sciences, 1991Co-Authors: D M Stavert, D C Archuleta, M J Behr, Bruce E LehnertAbstract:AbsTract Hydrogen fluoride (HF), hydrogen bromide (HBr), and hydrogen chloride (HCl) gases can be generated during the pyrolysis of a variety of materials and they may be encountered in numerous industrial settings. Although Injury to the Respiratory Tract has been characterized following the inhalation of halide gases via the nasal route, essentially no experimental information is currently available about their injurious effects when they are inhaled during mouth breathing. In this study, we simulated mouth breathing by using a pseudo-mouth-breathing (MB) rat model in order to: (1) characterize the profiles and magnitudes of Respiratory Tract Injury that result from the acute inhalation of relatively high mass concentrations of the above halides when the upper airway is bypassed, and (2) assess the relative toxicities of HF, HBr, and HCL when inhaled by way of either the nasal or the oral pathways. Tracheal tubes connected to mouthpieces were inserted into temporarily anesthetized rats, i.e., mouth breathers. Awake rats were placed into whole body flow plethysmographs for pulmonary ventilation studies while they were exposed either to air or to 1300 ppm of HF, HBr, or HCl for 30 min. Similarly pretreated rats were also exposed but without the mouthpiece, i.e., nose breathers (NB). The animals were euthanized 24 hr after exposure for histopathologic analyses of their upper and lower Respiratory Tracts and for lung gravimetric measurements. Tissue Injury following NB exposure to the halides was confined to the nasal region, e.g., epithelial and submucosal necrosis, accumulations of inflammatory cells, exudates, and the extravasation of erythrocytes. MB exposure caused higher mortality rates and major tissue disruption in the trachea, including epithelial, submucosal, glandular, and cartilage necrosis, and accumulations of inflammatory cells and exudates. More peripheral lung damage was manifested by lung gravimetric increases and histopathologic changes primarily in the larger conducting airways. The results of this study demonstrate that the injurious response profiles to HF, HBr, and HCl markedly differ as a function of the route by which they are inhaled. Furthermore, examinations of the magnitudes of Injury caused by exposure to the halides during nose or mouth breathing in conjunction with animal ventilatory data obtained during exposure to the halides suggest that HF, HBr, and HCl are quantitatively similar in their toxic effects in the Respiratory Tract.
Tongxin Wang - One of the best experts on this subject based on the ideXlab platform.
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Data_Sheet_1_The Variation of Nasal Microbiota Caused by Low Levels of Gaseous Ammonia Exposure in Growing Pigs.pdf
2019Co-Authors: Tongxin Wang, Weilei Yao, Yafei Shao, Feiruo HuangAbstract:Exposure to gaseous ammonia, even at low levels, can be harmful to pigs and human health. However, less is known about the effects of sustained exposure to gaseous ammonia on nasal microbiota colonization in growing pigs. A total of 120 Duroc×Landrace×Yorkshire pigs were housed in 24 separate chambers and continuously exposed to gaseous ammonia at 0,5, 10, 15, 20, and 25 ppm (four groups per exposure level) for 4 weeks. Then, we used high-throughput sequencing to perform 16S rRNA gene analysis in nasal swabs samples from 72 pigs (n = 12). The results of the nasal microbiota analysis showed that an increase in ammonia concentration, especially at 20 and 25 ppm, decreased the alpha diversity and relative abundance of nasal microbiota. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Chloroflexi were the most abundant phyla. In addition, the relative abundances of 24 microbial genera significantly changed as the ammonia level increased. Four microbial genera (Pseudomonas, Lactobacillus, Prevotella, and Bacteroides) were significantly decreased at 25 ppm, while only two genera (Moraxella and Streptococcus) were increased at 25 ppm. PICRUSt analyses showed that the relative abundances of the nasal microbiota involved in cell motility, signal transduction, the nervous system, environmental adaptation, and energy and carbohydrate metabolism were significantly decreased, while genes involved in the immune system, endocrine system, circulatory system, immune system diseases and metabolism of vitamins, lipid, and amino acids were increased with increased ammonia levels. The results of in vivo tests showed that an increase in ammonia levels, especially an ammonia level of 25 ppm, caused Respiratory Tract Injury and increase the number of Moraxella and Streptococcus species, while simultaneously decreasing Respiratory immunity and growth performance, consistent with the increased presence of harmful bacteria identified by nasal microbiota analysis. Herein, this study also indicted that the threshold concentration of ammonia in pig farming is 20 ppm.
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The Variation of Nasal Microbiota Caused by Low Levels of Gaseous Ammonia Exposure in Growing Pigs
Frontiers Media S.A., 2019Co-Authors: Tongxin Wang, Weilei Yao, Yafei Shao, Feiruo HuangAbstract:Exposure to gaseous ammonia, even at low levels, can be harmful to pigs and human health. However, less is known about the effects of sustained exposure to gaseous ammonia on nasal microbiota colonization in growing pigs. A total of 120 Duroc×Landrace×Yorkshire pigs were housed in 24 separate chambers and continuously exposed to gaseous ammonia at 0,5, 10, 15, 20, and 25 ppm (four groups per exposure level) for 4 weeks. Then, we used high-throughput sequencing to perform 16S rRNA gene analysis in nasal swabs samples from 72 pigs (n = 12). The results of the nasal microbiota analysis showed that an increase in ammonia concentration, especially at 20 and 25 ppm, decreased the alpha diversity and relative abundance of nasal microbiota. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Chloroflexi were the most abundant phyla. In addition, the relative abundances of 24 microbial genera significantly changed as the ammonia level increased. Four microbial genera (Pseudomonas, Lactobacillus, Prevotella, and Bacteroides) were significantly decreased at 25 ppm, while only two genera (Moraxella and Streptococcus) were increased at 25 ppm. PICRUSt analyses showed that the relative abundances of the nasal microbiota involved in cell motility, signal transduction, the nervous system, environmental adaptation, and energy and carbohydrate metabolism were significantly decreased, while genes involved in the immune system, endocrine system, circulatory system, immune system diseases and metabolism of vitamins, lipid, and amino acids were increased with increased ammonia levels. The results of in vivo tests showed that an increase in ammonia levels, especially an ammonia level of 25 ppm, caused Respiratory Tract Injury and increase the number of Moraxella and Streptococcus species, while simultaneously decreasing Respiratory immunity and growth performance, consistent with the increased presence of harmful bacteria identified by nasal microbiota analysis. Herein, this study also indicted that the threshold concentration of ammonia in pig farming is 20 ppm
Susa L Jorda - One of the best experts on this subject based on the ideXlab platform.
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toxicological medical and industrial hygiene aspects of glutaraldehyde with particular reference to its biocidal use in cold sterilization procedures
Journal of Applied Toxicology, 2001Co-Authors: Ya Allantyne, Susa L JordaAbstract:Aqueous solutions of ⩾5% glutaraldehyde (GA) are of moderate acute peroral toxicity and those of ⩽2% are of slight toxicity. By single sustained skin contact, aqueous GA solutions of ⩾45% are of moderate acute percutaneous toxicity, those of 25% are of slight toxicity and those of ⩽15% do not present an acute percutaneous hazard. Vapor generated at ambient temperature may cause sensory irritant effects to the eye and Respiratory Tract, but not acute Respiratory Tract Injury. The 50% decrease in Respiratory rate (rd50) is 13.86 ppm. A 0.1% solution of GA is not irritating to the eye; the threshold for conjunctival irritation is 0.2% and for corneal Injury it is 1.0%. Eye Injury is moderate at 2% and severe at ⩾5%. Primary skin irritation depends on the duration and contact site, occlusion and solvent. By sustained contact, the threshold for skin irritation is 1%, above which erythema and edema are dose related. With 45% and higher, skin corrosion may occur. There is a low incidence of skin sensitizing reactions, with an eliciting threshold of 0.5% aqueous GA. However, GA is neither phototoxic nor photosensitizing. Subchronic repeated exposure studies by the peroral route show only renal physiological compensatory effects, secondary to reduced water consumption. Repeated skin contact shows only minor skin irritant effects without systemic toxicity. By subchronic vapor exposure, effects are limited to the nasal mucosa at 1.0 ppm, with a no-effect concentration generally at 0.1 ppm. There is no evidence for systemic target organ or tissue toxicity by subchronic repeated exposure by any route. A chronic drinking water study showed an apparent increase, in females only, of large granular cell lymphocytic leukemia but this was not dosage related. This is most likely the result of a modifying effect on the factor(s) responsible for the expression of this commonly occurring rat neoplasm. A chronic (2-year) inhalation toxicity/oncogenicity study showed inflammatory changes in the anterior nasal cavity but no neoplasms or systemic toxicity. In vitro genotoxicity studies—bacterial mutagenicity, forward gene mutation (HGPRT and TK loci), sister chromatid exchange, chromosome aberration, UDS and DNA repair tests—have given variable results, ranging from no effect through to weak positive. In vivo genotoxicity studies—micronucleus, chromosome aberration, dominant lethal and Drosophila tests—generally have shown no activity but one mouse intraperitoneal study showed bone marrow cell chromosome aberrations. Developmental toxicity studies show GA not to be teratogenic, and a two-generation study showed no adverse reproductive effects. Percutaneous pharmacokinetic studies showed low skin penetration, with lowest values measured in vitro in rats and human skin. Overexposure of humans produces typical sensory irritant effects on the eye, skin and Respiratory Tract. Some reports have described an asthmatic-like reaction by overexposure to GA vapor. In most cases this resembles reactive airways dysfunction syndrome, and the role of immune mechanisms is uncertain. Local mucosal effects may occur if medical instruments or endoscopes are not adequately decontaminated. Protection of individuals from the potential adverse effects of GA exposure requires that there be adequate protection of the skin, eyes and Respiratory Tract. The airborne concentration of GA vapor should be kept below the recommended safe exposure level (e.g. the threshold limit value) by the use of engineering controls. Those who work with GA should, through a training program, be aware of the properties of GA, its potential adverse effects, how to handle the material safely and how to deal with accidental situations involving GA. If effects develop in exposed workers, the reasons should be determined immediately and corrective methods initiated. Copyright © 2001 John Wiley & Sons, Ltd.
D M Stavert - One of the best experts on this subject based on the ideXlab platform.
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relative acute toxicities of hydrogen fluoride hydrogen chloride and hydrogen bromide in nose and pseudo mouth breathing rats
Toxicological Sciences, 1991Co-Authors: D M Stavert, D C Archuleta, M J Behr, Bruce E LehnertAbstract:AbsTract Hydrogen fluoride (HF), hydrogen bromide (HBr), and hydrogen chloride (HCl) gases can be generated during the pyrolysis of a variety of materials and they may be encountered in numerous industrial settings. Although Injury to the Respiratory Tract has been characterized following the inhalation of halide gases via the nasal route, essentially no experimental information is currently available about their injurious effects when they are inhaled during mouth breathing. In this study, we simulated mouth breathing by using a pseudo-mouth-breathing (MB) rat model in order to: (1) characterize the profiles and magnitudes of Respiratory Tract Injury that result from the acute inhalation of relatively high mass concentrations of the above halides when the upper airway is bypassed, and (2) assess the relative toxicities of HF, HBr, and HCL when inhaled by way of either the nasal or the oral pathways. Tracheal tubes connected to mouthpieces were inserted into temporarily anesthetized rats, i.e., mouth breathers. Awake rats were placed into whole body flow plethysmographs for pulmonary ventilation studies while they were exposed either to air or to 1300 ppm of HF, HBr, or HCl for 30 min. Similarly pretreated rats were also exposed but without the mouthpiece, i.e., nose breathers (NB). The animals were euthanized 24 hr after exposure for histopathologic analyses of their upper and lower Respiratory Tracts and for lung gravimetric measurements. Tissue Injury following NB exposure to the halides was confined to the nasal region, e.g., epithelial and submucosal necrosis, accumulations of inflammatory cells, exudates, and the extravasation of erythrocytes. MB exposure caused higher mortality rates and major tissue disruption in the trachea, including epithelial, submucosal, glandular, and cartilage necrosis, and accumulations of inflammatory cells and exudates. More peripheral lung damage was manifested by lung gravimetric increases and histopathologic changes primarily in the larger conducting airways. The results of this study demonstrate that the injurious response profiles to HF, HBr, and HCl markedly differ as a function of the route by which they are inhaled. Furthermore, examinations of the magnitudes of Injury caused by exposure to the halides during nose or mouth breathing in conjunction with animal ventilatory data obtained during exposure to the halides suggest that HF, HBr, and HCl are quantitatively similar in their toxic effects in the Respiratory Tract.