The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Kuy Tae Han - One of the best experts on this subject based on the ideXlab platform.
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Inflammatory and genotoxic responses during 30-day welding-fume Exposure Period.
Toxicology letters, 2004Co-Authors: Kyung Seuk Song, Seung Hee Maeng, Soo Jin Kim, Jae Hyuck Sung, Jeong Hee Han, Yong Hyun Chung, Myung Haing Cho, Kyu Hyuck Chung, Kuy Tae HanAbstract:Welder's pneumoconiosis has generally been determined to be benign and unassociated with respiratory symptoms based on the absence of pulmonary-function abnormalities in welders with marked radiographic abnormalities. In previous studies, the current authors suggested a three-phase lung fibrosis process to study the pathological process of lung fibrosis and found that the critical point for recovery was after 30 days of welding-fume Exposure at a high dose, at which point early and delicate fibrosis was observed in the perivascular and peribronchiolar regions. Accordingly, the current study investigated the inflammatory and genotoxic responses during a 30-day Period of welding-fume Exposure to elucidate the process of fibrosis. As such, rats were exposed to manual metal arc-stainless steel (MMA-SS) welding fumes at concentrations of 65.6 +/- 2.9 (low dose) and 116.8 +/- 3.9 mg/m3 (high dose) total suspended particulate for 2 h per day in an inhalation chamber for 30 days. Animals were sacrificed after the initial 2 h Exposure, and after 15 and 30 days of Exposure. The rats exposed to the welding fumes exhibited a statistically significant (P < 0.05) decrease in body weight when compared to the control during the 30-day Exposure Period, yet an elevated cellular differential count and higher levels of albumin, LDH, and beta-NAG, but not elevated TNF-alpha, and IL-1beta in the acellular bronchoalveolar lavage fluid. In addition, the DNA damage resulting from 30 days of welding-fume Exposure was confirmed by a comet assay and the inmmunohistochemistry for 8-hydroxydeoxyguanine (8-OH-dG). Consequently, the elevated inflammatory and genotoxic indicators confirmed the lung injury and inflammation caused by the MMA-SS welding-fume Exposure.
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Inflammatory and genotoxic responses during 30-day welding-fume Exposure Period
Toxicology Letters, 2004Co-Authors: Kyung Seuk Song, Seung Hee Maeng, Soo Jin Kim, Jae Hyuck Sung, Jeong Hee Han, Yong Hyun Chung, Myung Haing Cho, Kyu Hyuck Chung, Kuy Tae HanAbstract:Abstract Welder’s pneumoconiosis has generally been determined to be benign and unassociated with respiratory symptoms based on the absence of pulmonary-function abnormalities in welders with marked radiographic abnormalities. In previous studies, the current authors suggested a three-phase lung fibrosis process to study the pathological process of lung fibrosis and found that the critical point for recovery was after 30 days of welding-fume Exposure at a high dose, at which point early and delicate fibrosis was observed in the perivascular and peribronchiolar regions. Accordingly, the current study investigated the inflammatory and genotoxic responses during a 30-day Period of welding-fume Exposure to elucidate the process of fibrosis. As such, rats were exposed to manual metal arc-stainless steel (MMA-SS) welding fumes at concentrations of 65.6 ± 2.9 (low dose) and 116.8 ± 3.9 mg/m3 (high dose) total suspended particulate for 2 h per day in an inhalation chamber for 30 days. Animals were sacrificed after the initial 2 h Exposure, and after 15 and 30 days of Exposure. The rats exposed to the welding fumes exhibited a statistically significant (P
Gregory J Daglish - One of the best experts on this subject based on the ideXlab platform.
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effect of Exposure Period on degree of dominance of phosphine resistance in adults of rhyzopertha dominica coleoptera bostrychidae and sitophilus oryzae coleoptera curculionidae
Pest Management Science, 2004Co-Authors: Gregory J DaglishAbstract:Degree of dominance of phosphine resistance was investigated in adults of Rhyzopertha dominica F and Sitophilus oryzae L. Efficacy of the grain fumigant phosphine depends on both concentration and Exposure Period, which raises the possibility that dominance levels vary with Exposure Period. New and published data were used to test this possibility in adults of R dominica and S oryzae fumigated for Periods of up to 144 h. The concentrations required for control of homozygous resistant and susceptible strains and their F1 hybrids decreased with increasing Exposure Period. For both species the response lines for the homozygous resistant and susceptible strains and their F1 hybrids were parallel. Therefore, neither dominance level nor resistance factor was affected by Exposure Period. Resistance was incompletely recessive and the level of dominance, calculated at 50% mortality level, was -0.59 for R dominica and -0.65 for S oryzae. The resistant R dominica strain was 30.9 times more resistant than the susceptible strain, compared with 8.9 times for the resistant S oryzae strain. The results suggest that developing discriminating doses for detecting heterozygote adults of either species will be difficult.
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Effect of Exposure Period on degree of dominance of phosphine resistance in adults of Rhyzopertha dominica (Coleoptera: Bostrychidae) and Sitophilus oryzae (Coleoptera: Curculionidae).
Pest management science, 2004Co-Authors: Gregory J DaglishAbstract:Degree of dominance of phosphine resistance was investigated in adults of Rhyzopertha dominica F and Sitophilus oryzae L. Efficacy of the grain fumigant phosphine depends on both concentration and Exposure Period, which raises the possibility that dominance levels vary with Exposure Period. New and published data were used to test this possibility in adults of R dominica and S oryzae fumigated for Periods of up to 144 h. The concentrations required for control of homozygous resistant and susceptible strains and their F1 hybrids decreased with increasing Exposure Period. For both species the response lines for the homozygous resistant and susceptible strains and their F1 hybrids were parallel. Therefore, neither dominance level nor resistance factor was affected by Exposure Period. Resistance was incompletely recessive and the level of dominance, calculated at 50% mortality level, was -0.59 for R dominica and -0.65 for S oryzae. The resistant R dominica strain was 30.9 times more resistant than the susceptible strain, compared with 8.9 times for the resistant S oryzae strain. The results suggest that developing discriminating doses for detecting heterozygote adults of either species will be difficult.
Jürgen Pauluhn - One of the best experts on this subject based on the ideXlab platform.
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Pulmonary toxicity of multi-walled carbon nanotubes (Baytubes) relative to alpha-quartz following a single 6h inhalation Exposure of rats and a 3 months post-Exposure Period.
Toxicology, 2009Co-Authors: Heidrun Ellinger-ziegelbauer, Jürgen PauluhnAbstract:Manufactured multi-walled carbon nanotubes (MWCNT) have attracted a great deal of attention due to their unique structural, chemical, and physical characteristics. This study utilized a 1x 6h inhalation Exposure protocol followed by a 3 months post-Exposure Period. Wistar rats were nose-only exposed to 11 and 241 mg/m(3) MWCNT (Baytubes) of respirable, solid aerosol. MWCNT depleted of residual metals (depletion from 0.53% to 0.12% Co) were compared at 11 mg/m(3). Rats similarly exposed to air and alpha-quartz (248 mg/m(3)) served as negative and positive controls, respectively. Pulmonary response was characterized by bronchoalveolar lavage (BAL), lung histopathology, organ burden determinations, and gene expression analyses of lung homogenates with emphasis on extracellular matrix components. This acute inhalation Exposure protocol was suitable to characterize and distinguish acute deposition-related effects from the long-term sequelae of retained MWCNT. Subtle differences in acute pulmonary toxic potency due to differences in metal contaminations could be revealed by this protocol. Consistent with the long retention halftime of poorly soluble particles, even short-term inhalation studies may require post-Exposure Periods of at least 3 months to reveal MWCNT-specific dispositional and toxicological characteristics relative to alpha-quartz. Distinct differences in the time course of pulmonary inflammation of MWCNT and alpha-quartz could be demonstrated. Transcriptomics proved to be a useful tool to analyze the etiopathology of collagen detected by BAL and histopathology. In summary, the pulmonary inflammogenicity following Exposure to MWCNT was concentration-dependent with evidence of regression over time. Conversely, alpha-quartz resulted in progressive changes over time. The time course of pulmonary inflammation associated with retained MWCNT was independent on the concentration of residual cobalt. This supports the conclusion that the predominant response to inhaled MWCNT is principally related to the assemblage structure and not catalyst impurities (if in the range of < or = 0.5%).
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Pulmonary toxicity of multi-walled carbon nanotubes (Baytubes®) relative to α-quartz following a single 6 h inhalation Exposure of rats and a 3 months post-Exposure Period
Toxicology, 2009Co-Authors: Heidrun Ellinger-ziegelbauer, Jürgen PauluhnAbstract:Manufactured multi-walled carbon nanotubes (MWCNT) have attracted a great deal of attention due to their unique structural, chemical, and physical characteristics. This study utilized a 1x 6h inhalation Exposure protocol followed by a 3 months post-Exposure Period. Wistar rats were nose-only exposed to 11 and 241 mg/m(3) MWCNT (Baytubes) of respirable, solid aerosol. MWCNT depleted of residual metals (depletion from 0.53% to 0.12% Co) were compared at 11 mg/m(3). Rats similarly exposed to air and alpha-quartz (248 mg/m(3)) served as negative and positive controls, respectively. Pulmonary response was characterized by bronchoalveolar lavage (BAL), lung histopathology, organ burden determinations, and gene expression analyses of lung homogenates with emphasis on extracellular matrix components. This acute inhalation Exposure protocol was suitable to characterize and distinguish acute deposition-related effects from the long-term sequelae of retained MWCNT. Subtle differences in acute pulmonary toxic potency due to differences in metal contaminations could be revealed by this protocol. Consistent with the long retention halftime of poorly soluble particles, even short-term inhalation studies may require post-Exposure Periods of at least 3 months to reveal MWCNT-specific dispositional and toxicological characteristics relative to alpha-quartz. Distinct differences in the time course of pulmonary inflammation of MWCNT and alpha-quartz could be demonstrated. Transcriptomics proved to be a useful tool to analyze the etiopathology of collagen detected by BAL and histopathology. In summary, the pulmonary inflammogenicity following Exposure to MWCNT was concentration-dependent with evidence of regression over time. Conversely, alpha-quartz resulted in progressive changes over time. The time course of pulmonary inflammation associated with retained MWCNT was independent on the concentration of residual cobalt. This supports the conclusion that the predominant response to inhaled MWCNT is principally related to the assemblage structure and not catalyst impurities (if in the range of < or = 0.5%).
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Phenyl Isocyanate-Induced Asthma in Rats Following a 2-Week Exposure Period
Fundamental and applied toxicology : official journal of the Society of Toxicology, 1995Co-Authors: Jürgen Pauluhn, W. Rüngeler, U. MohrAbstract:Abstract Phenyl Isocyanate-Induced Asthma in Rats Following a 2-Week Exposure Period. Pauluhn, J., Rungeler, W., and Mohr, U. (1995). Fundam. Appl. Toxicol. 24, 217-228. This study was conducted to assess the toxic effects of repeated inhalation Exposures to phenyl isocyanate vapor in male Wistar rats. Rats were exposed to design concentrations of 0, 1, 4, 7, or 10 mg/m 3 phenyl isocyanate air for 2 weeks (6 hr/day, 5 days/week). The rats were assessed for normal toxicologic parameters, and pulmonary function tests, blood gas measurements, and analysis of bronchoalveolar lavage fluid (BALF) parameters were utilized shortly after Exposures as well as 2 months postExposure. The results indicated that rats exposed to 7 and 10 mg/m 3 experienced decreased body weights, hypoactivity, hypothermia, signs of respiratory tract irritation, delayed onset of mortality, and changes in organ weights. In addition, pulmonary function tests demonstrated decreased forced expiratory flow rates and quasistatic lung compliance. Arterial blood gases showed an arterial hypoxemia and changes consistent with a pronounced venous-admixture-like perfusion, suggesting severe mismatch of the ventilation/perfusion relationship. Delayed onset of mortality appeared to be associated with respiratory acidosis and hypoxemia. Biochemical and cellular components in BALF complemented the results of the functional alterations. Remarkable changes were indicated by increased activities of the BALF parameters, γ-GPT, protein, and sialic acid. Histopathological findings provided evidence of increased secretory cell activity and a concentration-dependent increase in goblet cell hyperplasia at concentrations of 4 mg/m 3 and above. In rats exposed to 7 mg/m 3 further findings consisted of intraluminal inflammation of airways, hypertrophia of bronchial smooth muscle, epithelial desquamation, and eosinophilia of the airways. A complete regression of morphological lesions was not found in the animals exposed to 4 mg/m 3 and above at the 2-month postExposure time Period. In conclusion, the damage to the airways comprise most of the features characteristic of chronic airway inflammation or asthma.
Kyung Seuk Song - One of the best experts on this subject based on the ideXlab platform.
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Inflammatory and genotoxic responses during 30-day welding-fume Exposure Period.
Toxicology letters, 2004Co-Authors: Kyung Seuk Song, Seung Hee Maeng, Soo Jin Kim, Jae Hyuck Sung, Jeong Hee Han, Yong Hyun Chung, Myung Haing Cho, Kyu Hyuck Chung, Kuy Tae HanAbstract:Welder's pneumoconiosis has generally been determined to be benign and unassociated with respiratory symptoms based on the absence of pulmonary-function abnormalities in welders with marked radiographic abnormalities. In previous studies, the current authors suggested a three-phase lung fibrosis process to study the pathological process of lung fibrosis and found that the critical point for recovery was after 30 days of welding-fume Exposure at a high dose, at which point early and delicate fibrosis was observed in the perivascular and peribronchiolar regions. Accordingly, the current study investigated the inflammatory and genotoxic responses during a 30-day Period of welding-fume Exposure to elucidate the process of fibrosis. As such, rats were exposed to manual metal arc-stainless steel (MMA-SS) welding fumes at concentrations of 65.6 +/- 2.9 (low dose) and 116.8 +/- 3.9 mg/m3 (high dose) total suspended particulate for 2 h per day in an inhalation chamber for 30 days. Animals were sacrificed after the initial 2 h Exposure, and after 15 and 30 days of Exposure. The rats exposed to the welding fumes exhibited a statistically significant (P < 0.05) decrease in body weight when compared to the control during the 30-day Exposure Period, yet an elevated cellular differential count and higher levels of albumin, LDH, and beta-NAG, but not elevated TNF-alpha, and IL-1beta in the acellular bronchoalveolar lavage fluid. In addition, the DNA damage resulting from 30 days of welding-fume Exposure was confirmed by a comet assay and the inmmunohistochemistry for 8-hydroxydeoxyguanine (8-OH-dG). Consequently, the elevated inflammatory and genotoxic indicators confirmed the lung injury and inflammation caused by the MMA-SS welding-fume Exposure.
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Inflammatory and genotoxic responses during 30-day welding-fume Exposure Period
Toxicology Letters, 2004Co-Authors: Kyung Seuk Song, Seung Hee Maeng, Soo Jin Kim, Jae Hyuck Sung, Jeong Hee Han, Yong Hyun Chung, Myung Haing Cho, Kyu Hyuck Chung, Kuy Tae HanAbstract:Abstract Welder’s pneumoconiosis has generally been determined to be benign and unassociated with respiratory symptoms based on the absence of pulmonary-function abnormalities in welders with marked radiographic abnormalities. In previous studies, the current authors suggested a three-phase lung fibrosis process to study the pathological process of lung fibrosis and found that the critical point for recovery was after 30 days of welding-fume Exposure at a high dose, at which point early and delicate fibrosis was observed in the perivascular and peribronchiolar regions. Accordingly, the current study investigated the inflammatory and genotoxic responses during a 30-day Period of welding-fume Exposure to elucidate the process of fibrosis. As such, rats were exposed to manual metal arc-stainless steel (MMA-SS) welding fumes at concentrations of 65.6 ± 2.9 (low dose) and 116.8 ± 3.9 mg/m3 (high dose) total suspended particulate for 2 h per day in an inhalation chamber for 30 days. Animals were sacrificed after the initial 2 h Exposure, and after 15 and 30 days of Exposure. The rats exposed to the welding fumes exhibited a statistically significant (P
Heidrun Ellinger-ziegelbauer - One of the best experts on this subject based on the ideXlab platform.
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Pulmonary toxicity of multi-walled carbon nanotubes (Baytubes) relative to alpha-quartz following a single 6h inhalation Exposure of rats and a 3 months post-Exposure Period.
Toxicology, 2009Co-Authors: Heidrun Ellinger-ziegelbauer, Jürgen PauluhnAbstract:Manufactured multi-walled carbon nanotubes (MWCNT) have attracted a great deal of attention due to their unique structural, chemical, and physical characteristics. This study utilized a 1x 6h inhalation Exposure protocol followed by a 3 months post-Exposure Period. Wistar rats were nose-only exposed to 11 and 241 mg/m(3) MWCNT (Baytubes) of respirable, solid aerosol. MWCNT depleted of residual metals (depletion from 0.53% to 0.12% Co) were compared at 11 mg/m(3). Rats similarly exposed to air and alpha-quartz (248 mg/m(3)) served as negative and positive controls, respectively. Pulmonary response was characterized by bronchoalveolar lavage (BAL), lung histopathology, organ burden determinations, and gene expression analyses of lung homogenates with emphasis on extracellular matrix components. This acute inhalation Exposure protocol was suitable to characterize and distinguish acute deposition-related effects from the long-term sequelae of retained MWCNT. Subtle differences in acute pulmonary toxic potency due to differences in metal contaminations could be revealed by this protocol. Consistent with the long retention halftime of poorly soluble particles, even short-term inhalation studies may require post-Exposure Periods of at least 3 months to reveal MWCNT-specific dispositional and toxicological characteristics relative to alpha-quartz. Distinct differences in the time course of pulmonary inflammation of MWCNT and alpha-quartz could be demonstrated. Transcriptomics proved to be a useful tool to analyze the etiopathology of collagen detected by BAL and histopathology. In summary, the pulmonary inflammogenicity following Exposure to MWCNT was concentration-dependent with evidence of regression over time. Conversely, alpha-quartz resulted in progressive changes over time. The time course of pulmonary inflammation associated with retained MWCNT was independent on the concentration of residual cobalt. This supports the conclusion that the predominant response to inhaled MWCNT is principally related to the assemblage structure and not catalyst impurities (if in the range of < or = 0.5%).
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Pulmonary toxicity of multi-walled carbon nanotubes (Baytubes®) relative to α-quartz following a single 6 h inhalation Exposure of rats and a 3 months post-Exposure Period
Toxicology, 2009Co-Authors: Heidrun Ellinger-ziegelbauer, Jürgen PauluhnAbstract:Manufactured multi-walled carbon nanotubes (MWCNT) have attracted a great deal of attention due to their unique structural, chemical, and physical characteristics. This study utilized a 1x 6h inhalation Exposure protocol followed by a 3 months post-Exposure Period. Wistar rats were nose-only exposed to 11 and 241 mg/m(3) MWCNT (Baytubes) of respirable, solid aerosol. MWCNT depleted of residual metals (depletion from 0.53% to 0.12% Co) were compared at 11 mg/m(3). Rats similarly exposed to air and alpha-quartz (248 mg/m(3)) served as negative and positive controls, respectively. Pulmonary response was characterized by bronchoalveolar lavage (BAL), lung histopathology, organ burden determinations, and gene expression analyses of lung homogenates with emphasis on extracellular matrix components. This acute inhalation Exposure protocol was suitable to characterize and distinguish acute deposition-related effects from the long-term sequelae of retained MWCNT. Subtle differences in acute pulmonary toxic potency due to differences in metal contaminations could be revealed by this protocol. Consistent with the long retention halftime of poorly soluble particles, even short-term inhalation studies may require post-Exposure Periods of at least 3 months to reveal MWCNT-specific dispositional and toxicological characteristics relative to alpha-quartz. Distinct differences in the time course of pulmonary inflammation of MWCNT and alpha-quartz could be demonstrated. Transcriptomics proved to be a useful tool to analyze the etiopathology of collagen detected by BAL and histopathology. In summary, the pulmonary inflammogenicity following Exposure to MWCNT was concentration-dependent with evidence of regression over time. Conversely, alpha-quartz resulted in progressive changes over time. The time course of pulmonary inflammation associated with retained MWCNT was independent on the concentration of residual cobalt. This supports the conclusion that the predominant response to inhaled MWCNT is principally related to the assemblage structure and not catalyst impurities (if in the range of < or = 0.5%).
