Bronchiolitis obliterans murine model induced by nitric acid aerosol inhalation: An economical and reproducible model.

PURPOSE: Bronchiolitis obliterans (BO) is a highly debilitative and fatal syndrome associated with a series of severe lower airway disorders. The pathogenesis of BO is complicated and not entirely understood. An appropriate animal model of BO may aid research into its pathogenesis. Here, we establish a mouse model of BO to provide insight into this disease. MATERIALS AND METHODS: 6-8 week old BABL/c mice were exposed to 5% nitric acid (NA) aerosol through a nebulizer for 3 hours, and controls were exposed to distilled water instead. Symptoms, airway resistance and pathological process were observed dynamically. The levels of matrix metalloproteinase-2 (MMP-2), MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), 8-isoprostane and myeloperoxidase (MPO) in lung tissue and bronchoalveolar lavage fluids (BLAF) were determined by ELISA on day 3, 7, 14, 28 and 56 after the aerosol nebulization. RESULTS: Typical BO lesions were observed in NA nebulized mice characterized histologically by initial necrotizing bronchiolitis and final airway fibrosis at day 28 after the aerosol nebulization. NA nebulized mice also exhibited labored breathing and significantly increased airway resistance. Expression of MMP-2, MMP-9, TIMP-1, 8-isoprostane and MPO were significantly elevated in NA nebulized mice in different time frame. CONCLUSION: A murine BO model was established by NA aerosol inhalation. It provides an easy, economic, and reproducible mice model for BO research.

Effects of sulfuric, nitric, and mixed acid rain on Chinese fir sapling growth in Southern China.

The influence of acid rain on plant growth includes direct effects on foliage as well as indirect soil-mediated effects that cause a reduction in root growth. In addition, the concentration of NO3- in acid rain increases along with the rapid growth of nitrogen deposition. In this study, we investigated the impact of simulated acid rain with different SO42-/NO3- (S/N) ratios, which were 1:0, 5:1, 1:1, 1:5 and 0:1, on Chinese fir sapling growth from March 2015 to April 2016. Results showed that Chinese fir sapling height growth rate (HGR) and basal diameter growth rate (DGR) decreased as acid rain pH decreased, and also decreased as the percentage of NO3- increased in acid rain. Acid rain pH significantly decreased the Chlorophyll a (Chla) and Chlorophyll b (Chlb) content, and Chla and Chlb contents with acid rain S/N 1:5 were significantly lower than those with S/N 1:0 at pH 2.5. The chlorophyll fluorescence parameters, maximal efficiency of Photosystem II photochemistry (Fv/Fm) and non-photochemical quenching coefficient (NPQ), with most acid rain treatments were significantly lower than those with CK treatments. Root activities first increased and then decreased as acid rain pH decreased, when acid rain S/N ratios were 1:1, 1:5 and 0:1. Redundancy discriminant analysis (RDA) showed that the Chinese fir DGR and HGR had positive correlations with Chla, Chlb, Fv/Fm ratio, root activity, catalase and superoxide dismutase activities in roots under the stress of acid rain with different pH and S/N ratios. The structural equation modelling (SEM) results showed that acid rain NO3- concentration and pH had stronger direct effects on Chinese fir sapling HGR and DGR, and the direct effects of acid rain NO3- concentration and pH on HGR were lower than those on DGR. Our results suggest that the ratio of SO42- to NO3- in acid rain is an important factor which could affect the sustainable development of monoculture Chinese fir plantations in southern China.

Corrosive acid injury of the stomach.

Ingestion of corrosives with accidental or suicidal intent is a common problem in Sri Lanka. Management options and outcomes of corrosive injuries on stomach are not well documented in our setting. The clinical presentation, complications and management outcomes of nine patients with corrosive injury to stomach are presented. Gastric outlet obstruction seen in majority, was managed with bypass procedure (n=5) or resection (n=4). The outcomes of management were successful with both methods.

Effects of nitrogen dioxide and its acid mist on reactive oxygen species production and antioxidant enzyme activity in Arabidopsis plants.

Nitrogen dioxide (NO2) is one of the most common and harmful air pollutants. To analyze the response of plants to NO2 stress, we investigated the morphological change, reactive oxygen species (ROS) production and antioxidant enzyme activity in Arabidopsis thaliana (Col-0) exposed to 1.7, 4, 8.5, and 18.8 mg/m(3) NO2. The results indicate that NO2 exposure affected plant growth and chlorophyll (Chl) content, and increased oxygen free radical (O2(-)) production rate in Arabidopsis shoots. Furthermore, NO2 elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate (AsA) and glutathione (GSH) contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO2 and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO2/nitric acid mist-caused oxidative damage.

Case report of tracheobronchial injuries after acid ingestion: CT findings with serial follow-up: Airway complication after acid ingestion.

RATIONALE: Tracheobronchial injury from acid ingestion is a less reported clinical presentation than injury of the gastrointestinal tract, but it can occur due to direct exposure from acid aspiration and cause fatal complications. PATIENT CONCERNS: A 43-year-old man presented to the emergency department after ingesting nitric acid complaining of chest pain and dyspnea. DIAGNOSES: The initial chest computed tomography (CT) images revealed an acute lung injury related to acid aspiration. The follow-up chest CT showed acute and late tracheobronchial injures. INTERVENTIONS: Bronchoscopy showed deep caustic airway injuries consisting of hemorrhage, sloughing of the mucosa, and ulceration of the trachea and left-side bronchial tree. OUTCOMES: Progressive narrowing of the left main bronchus with total collapse of the left lung occurred as a late complication of acid ingestion. LESSONS: Tracheobronchial injury should be considered in cases of aspiration pneumonia after acid ingestion; chest CT can be used to detect and assess acute and late complications of tracheobronchial injuries.

Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice.

Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 microg of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 microg LPS. 24 hours later, pulmonary inflammatory responses and cardiac effects were assessed by bronchoalveolar lavage and isolated cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Additional mice were assessed for histological changes in lung and heart. Instillation of 40 microg of AF-SWCNTs, UFCB and AF-UFCB increased percentage of pulmonary neutrophils. No significant effects were observed at the lower particle concentration. Sporadic clumps of particles from each treatment group were observed in the small airways and interstitial areas of the lungs according to particle dose. Patches of cellular infiltration and edema in both the small airways and in the interstitium were also observed in the high dose group. Isolated perfused hearts from mice exposed to 40 microg of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than other particle-exposed animals and controls, and also exhibited signs of focal cardiac myofiber degeneration. No particles were detected in heart tissue under light microscopy. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects only with the AF-carbon nanotubes. Further experiments are needed to understand the physico-chemical processes involved in this phenomenon.

Growth and physiological response of an endangered tree, Horsfieldia hainanensis merr., to simulated sulfuric and nitric acid rain in southern China.

As nitrogen deposition increases, acid rain is gradually shifting from sulfuric acid rain (SAR) to nitric acid rain (NAR). Acid rain can severely affect plant growth, damage ecosystems, and reduce biodiversity. Thus, a shift in acid rain type presents another challenge to the conservation of endangered plant species. We investigated the effect of three acid rain types (SAR, mixed acid rain [MAR], and NAR) and pH on the growth of an endangered Chinese endemic tree, Horsfieldia hainanensis Merr., using simulated rain in a greenhouse environment. Over nine months, growth indices, chlorophyll content, antioxidant enzyme activity, malondialdehyde content, and chlorophyll fluorescence parameters were investigated for treated and control saplings. The results indicated that at a pH of 5.6, H. hainanensis could adapt to SAR and MAR, but NAR inhibited below-ground growth. At a pH of 2.5 and 4.0, SAR inhibited stem and leaf biomass accumulation, whereas NAR inhibited root biomass accumulation and altered root morphology. MAR had intermediary effects between those of SAR and NAR. Adverse effects on leaf physiology were reduced as the rain type shifted from SAR to NAR; however, roots were increasingly adversely affected. Our results suggest that conservation efforts for H. hainanensis should shift from an above-ground to a below-ground focus as acid rain transitions toward NAR.

Comparative effects of sulfuric and nitric acid rain on litter decomposition and soil microbial community in subtropical plantation of Yangtze River Delta region.

Acid rain is mainly caused by dissolution of sulfur dioxide and nitrogen oxides in the atmosphere, and has a significant negative effect on ecosystems. The relative composition of acid rain is changing gradually from sulfuric acid rain (SAR) to nitric acid rain (NAR) with the rapidly growing amount of nitrogen deposition. In this study, we investigated the impact of simulated SAR and NAR on litter decomposition and the soil microbial community over four seasons since March 2015. Results first showed that the effects of acid rain on litter decomposition and soil microbial were positive in the early period of the experiment, except for SAR on soil microbes. Second, soil pH with NAR decreased more rapidly with the amount of acid rain increased in summer than with SAR treatments. Only strongly acid rain (both SAR and NAR) was capable of depressing litter decomposition and its inhibitory effect was stronger on leaf than on fine root litter. Meanwhile, NAR had a higher inhibitory effect on litter decomposition than SAR. Third, in summer, autumn and winter, PLFAs were negatively impacted by the increased acidity level resulting from both SAR and NAR. However, higher acidity level of NAR (pH=2.5) had the strongest inhibitory impact on soil microbial activity, especially in summer. In addition, Gram-negative bacteria (cy19:0) and fungi (18:1ω9) were more sensitive to both SAR and NAR, and actinomycetes was more sensitive to SAR intensity. Finally, soil total carbon, total nitrogen and pH were the most important soil property factors affecting soil microbial activity, and high microbial indices (fungi/bacteria) with high soil pH. Our results suggest that the ratio of SO42- to NO3- in acid rain is an important factor which could affect litter decomposition and soil microbial in subtropical forest of China.

Comparison of systemic and local effects of nitric acid and hydrochloric acid: an experimental study in a rat model.

BACKGROUND: We aimed to determine the local and systemic effects of widely available household cleaners, namely 45% nitric acid (NHO(3)), and 18% hydrochloric acid (HCl), in a rat model. METHODS: This prospective, experimental, placebo-controlled trial was carried out in the Animal Research Laboratory of Akdeniz University hospital. Commonly available solution of 45% NHO(3) and 18% HCl were tested against normal saline. Each solution was administrated orally to groups consisting of ten rats. The metabolic changes were determined by measuring the pH and calcium (Ca) levels before and after the administration of solutions. In addition, the pathological changes and mortality rates were determined for each group. RESULTS: There was a statistically significant increase in the post-ingestion (30 minutes later) Ca levels and a decrease in the post-ingestion pH levels after the administration of test solution in the NHO(3) (p=0.006 for Ca increase, p=0.001 for pH decrease) and HCl (p=0.007 for Ca increase, p=0.023 for pH decrease) groups. There was also a statistically significant difference between groups for Ca increase (p=0.000) and pH decrease (p=0.006). In post hoc analysis, the difference between the groups was found to be originated from the placebo group. In the pathological evaluation of esophagus and stomach, there was a statistically significant difference between groups (p=0.009 (E) and p=0.016 (S)) and the difference was found to be originated from the control group (p=0.543 (E), p=0.244 (S) for NHO(3) and HCl). The 30-minute mortality rates were 0,2 in the NHO(3) group, 0,6 in the HCl group and 0 in the control group. CONCLUSION: Serious metabolic and mild local pathological changes can occur after the ingestion of household NHO3 and HCl solutions. Further studies should be performed to elucidate the causes of death following oral ingestion of these compounds and appropriate public health warnings should be taken.

Photosynthetic and growth responses of Schima superba seedlings to sulfuric and nitric acid depositions.

A continuing rise in acid deposition can cause forest degradation. In China, acid deposition has converted gradually from sulfuric acid deposition (SAD) to nitric acid deposition (NAD). However, the differing responses of photosynthesis and growth to depositions of sulfuric vs. nitric acid have not been well studied. In this study, 1-year-old seedlings of Schima superba, a dominant species in subtropical forests, were treated with two types of acid deposition SO4 (2-)/NO3 (-) ratios (8:1 and 0.7:1) with two applications (foliar spraying and soil drenching) at two pH levels (pH 3.5 and pH 2.5) over a period of 18 months. The results showed that the intensity, acid deposition type, and spraying method had significant effects on the physiological characteristics and growth performance of seedlings. Acid deposition at pH 2.5 via foliar application reduced photosynthesis and growth of S. superba, especially in the first year. Unlike SAD, NAD with high acidity potentially alleviated the negative effects of acidity on physiological properties and growth, probably due to a fertilization effect that improved foliar nitrogen and chlorophyll contents. Our results suggest that trees were damaged mainly by direct acid stress in the short term, whereas in the long term, soil acidification was also likely to be a major risk to forest ecosystems. Our data suggest that the shift in acid deposition type may complicate the ongoing challenge of anthropogenic acid deposition to ecosystem stability.

Respiratory tract responses to repeated inhalation of an oxidant and acid gas-particle air pollutant mixture.

The purpose of this study was to examine a broad range of toxicologic responses in rats exposed to a multi-component pollutant atmosphere. Cumulative and adaptive respiratory tract responses to 3 concentrations of an inhaled particle-oxidant mixture were examined in Fisher 344 N rats exposed 4 h/day, 3 days/week for 4 weeks. The mixtures contained O3, NO2, NH4HSO4, carbon particles, and HNO3 vapor. Irritant-induced, rapid-shallow breathing responses were present during the first 4-h exposure to medium and high concentrations. Successive exposures showed diminished responses in medium concentrations and exacerbated responses in high concentrations. At the end of 4 weeks, rats exposed to high concentrations exhibited lung lesions. Lavaged pulmonary macrophages showed dose-dependent depressions of Fc-receptor binding and phagocytosis. Lung tissue macrophages showed dose-dependent increases in acid phosphatase staining density and carbon particles. Respiratory tract clearance of tracer particles was not significantly affected by the exposures. Broncho-alveolar epithelial permeability was increased by the high concentration. Epithelial cell-proliferation labeling showed a dose-dependent increase at all levels of the respiratory tract. Progressively exacerbated breathing-pattern responses at high concentrations were associated with lung lesions and high cell-proliferation labeling in the nose transitional epithelium and terminal bronchioles. Attenuating or adaptive breathing-pattern responses occurred in the presence of smaller, but in many cases still significant, compromise of respiratory functions. Either attenuating or exacerbated breathing-pattern responses can occur in the presence of a significant dose-dependent compromise of other respiratory functions and lung tissue injury.

Chronic inhalation exposure to ozone and nitric acid elevates stress-inducible heat shock protein 70 in the rat lung.

The ability of urban oxidant and acid air pollutants to induce heat shock proteins (HSPs) in the mammalian lung is not known. Such proteins are known to be correlated with environmental stress and pathophysiological conditions. In this study, stress-inducible HSP 70 was assessed by slot-blotting in rat lungs (N=10 per group) following inhalation exposures for 4 h per day, 3 days per week for 40 weeks to the following pollutants: (a) purified air;(b) 0.15 ppm ozone (O3);(c)50 micrograms/m3 nitric acid (HNO3); or(d) a combination of both 0.15 ppm O3 and 50 micrograms/m3 HNO3. At 24 h following the last exposure, samples from the right apical lobe of the lung were obtained for either slot-blotting or gel electrophoretic separation, subsequent protein immunoblotting, and chemiluminescence detection of HSP 70 levels. Experiments demonstrate that stress-inducible HSP 70 was present constitutively in the control lungs and was separable from the constitutive form of HSP 70. Slot-blotting analysis demonstrate that the O3 and HNO3 exposures alone produced significant elevations of HSP70. Specifically, either O3 or HNO3 alone significantly elevated lung stress-inducible HSP 70 levels by 277% and 221% respectively, above control levels. The group exposed to combined O3 and HNO3 showed a 177% elevation in lung stress-inducible HSP 70 that was significantly greater that the group inhaling purified air, but this effect was less than the effects of either pollutant component alone. Moreover, all exposure groups were significantly different from one another. These results indicate that stress-inducible HSP 70 in the rat lung is highly elevated after chronic inhalation exposures to both O3 and HNO3 when administered either alone or in combination within the range of urban ambient concentrations.

Cytotoxicity of retrofill materials.

Dentin bonding agents reduce microleakage and enhance marginal adaption of composite resin restorations. These characteristics are advantages for their use as an endodontic retrofilling material. Because these materials will be in direct contact with vital tissues, their cytotoxic potential must be evaluated before clinical use. It was the purpose of this study to evaluate the cell cytotoxicity of amalgam, Caulk Universal Bond, Gluma, 35% HEMA, Morita Clearfil, Scotchbond 2, Super EBA, Tenure, and Tenure 5-4. VERO cells were grown in RPMI-1640 medium and cell monolayers were prepared by incubating 15 ml of the cell suspension in 60-mm culture dishes at 37 degrees C in 5% CO2. Twelve milliliters of a medium-agarose mixture containing 1% neutral red vital stain were overlayed onto the cell layer and allowed to solidify. The materials were directly exposed to the agarose overlays by inverting 6.0-mm diameter polypropylene capsules containing the cured and liquid sample materials either immediately (0 time) or after placement in phosphate-buffered saline with 1% gentamicin for 7, 15, or 30 days. Cytotoxicity was determined by measuring the zone of killed cells around the sample 24 h after placement on the agarose. Cytotoxicity was determined by measuring the zones of cell inhibition at 24 h and at 7, 15, and 30 days. Initially, all of the materials were found to be cytotoxic, except amalgam and the Tenure components. The dentin bonding primers showed a mean zone of inhibition of 13.2 mm and the cleansers a 40.0-mm zone. Amalgam demonstrated increasing cytotoxicity: 0.0 mm at 24 h to 12.0 mm at 30 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentrations, deposition, and effects of nitrogenous pollutants in selected California ecosystems.

Atmospheric deposition of nitrogen (N) in California ecosystems is ecologically significant and highly variable, ranging from about 1 to 45 kg/ha/year. The lowest ambient concentrations and deposition values are found in the eastern and northern parts of the Sierra Nevada Mountains and the highest in parts of the San Bernardino and San Gabriel Mountains that are most exposed to the Los Angeles air pollution plume. In the Sierra Nevada Mountains, N is deposited mostly in precipitation, although dry deposition may also provide substantial amounts of N. On the western slopes of the Sierra Nevada, the majority of airborne N is in reduced forms as ammonia (NH3) and particulate ammonium (NH4+) from agricultural activities in the California Central Valley. In southern California, most of the N air pollution is in oxidized forms as nitrogen oxides (NOx), nitric acid (HNO3), and particulate nitrate (NO3-) resulting from fossil fuel combustion and subsequent complex photochemical reactions. In southern California, dry deposition of gases and particles provides most (up to 95%) of the atmospheric N to forests and other ecosystems. In the mixed-conifer forest zone, elevated deposition of N may initially benefit growth of vegetation, but chronic effects may be expressed as deterioration of forest health and sustainability. HNO3 vapor alone has a potential for toxic effects causing damage of foliar surfaces of pines and oaks. In addition, dry deposition of predominantly HNO3 has lead to changes in vegetation composition and contamination of ground- and stream water where terrestrial N loading is high. Long-term, complex interactions between N deposition and other environmental stresses such as elevated ozone (O3), drought, insect infestations, fire suppression, or intensive land management practices may affect water quality and sustainability of California forests and other ecosystems.

Contrasting physiological responses of ozone-tolerant Phaseolus vulgaris and Nicotiana tobaccum varieties to ozone and nitric acid.

Ozone (O3) and nitric acid (HNO3) are synthesized by the same atmospheric photochemical processes and are almost always co-pollutants. Effects of O3 on plants have been well-elucidated, yet less is known about the effects of HNO3 on plants. We investigated the physiological effects of experimental O3 and HNO3 fumigation on Phaseolus vulgaris (snap bean) and Nicotiana tobaccum (tobacco) varieties with known sensitivity to O3, but unknown responses to HNO3. Responses were measured as leaf absorptance, aboveground plant biomass, and photosynthetic CO2-response curve parameters. Our results demonstrate that O3 reduced absorptance, stomatal conductance and plant biomass in both species, and maximum photosynthetic rate in P. vulgaris, whereas the main effect of HNO3 was an increase in mesophyll conductance. Overall, the results suggest that HNO3 affects mesophyll conductance through increased nitrogen absorbed by leaves during HNO3 deposition which in turn increases photosynthetic demand for CO2, or that damage to epicuticular waxes on leaves increased diffusion of CO2 to sites of carboxylation.

Physiological responses of lichens to factorial fumigations with nitric acid and ozone.

This paper addresses the effects of gaseous nitric acid (HNO(3)) and ozone (O(3)), two important air pollutants, on six lichen species with different morphological, ecological, and biological characteristics. The treatment chambers were set up in a factorial design consisting of control chambers, chambers fumigated with HNO(3), with O(3), and with HNO(3) and O(3), together. Each species showed a different sensitivity to the fumigations, reflecting the physiological variation among species. Our results clearly indicate that HNO(3) is a strong phytotoxin to many lichens, and that O(3) alone has little effect on the measured parameters. The combined fumigation effects of HNO(3) and O(3) were not significantly different from HNO(3) alone.

Metagenomic insights into evolution of a heavy metal-contaminated groundwater microbial community.

Understanding adaptation of biological communities to environmental change is a central issue in ecology and evolution. Metagenomic analysis of a stressed groundwater microbial community reveals that prolonged exposure to high concentrations of heavy metals, nitric acid and organic solvents ( approximately 50 years) has resulted in a massive decrease in species and allelic diversity as well as a significant loss of metabolic diversity. Although the surviving microbial community possesses all metabolic pathways necessary for survival and growth in such an extreme environment, its structure is very simple, primarily composed of clonal denitrifying gamma- and beta-proteobacterial populations. The resulting community is overabundant in key genes conferring resistance to specific stresses including nitrate, heavy metals and acetone. Evolutionary analysis indicates that lateral gene transfer could have a key function in rapid response and adaptation to environmental contamination. The results presented in this study have important implications in understanding, assessing and predicting the impacts of human-induced activities on microbial communities ranging from human health to agriculture to environmental management, and their responses to environmental changes.

[Effects of exogenous NO on the growth and antioxidant enzyme activities of cucumber seedlings under NO3- stress].

In this study, cucumber seedlings were cultivated in nutrient solution added with different concentration (0.05, 0.1, 0.2, and 0.3 mmol x L(-1)) sodium nitroprusside (SNP) as nitric oxide (NO) donor to study the effects of exogenous NO on the growth of cucumber seedlings and the activities of antioxidant enzymes in cucumber leaves under NO3- stress. Under the stress of 140 mmol x L(-1) NO3-, treating with 0.1 mmol x L(-1) of SNP for 1 d or 7 d increased the leaf soluble protein content and superoxidase (SOD), catalase (CAT), and ascorbic acid peroxidase (APX) activities, and decreased the leaf malondialdehyde (MDA) content significantly, suggesting that exogenous NO could enhance the capacity of cucumber seedlings in scavenging active oxygen species, protect the seedlings from the peroxidation of membrane lipids, and promote the seedlings growth and increase their resistance to high concentration NO3- stress. After the cucumber seedlings grew in 0.3 mmol x L(-1) of SNP for 7 d, the activities of leaf SOD, POD, and CAT decreased, and the MDA content increased, resulting in the injury of cucumber seedlings. It was indicated that certain concentration (0.1-0.2 mmol x L(-1)) exogenous NO could alleviate the NO3- stress to cucumber seedlings.

Management of unusually extensive esophagogastric corrosive injuries: emergency measures and gastric reconstruction.

Ingestion of a corrosive substance only rarely presents with life-threatening symptoms because of acute necrosis of the esophagus and/or stomach and necessitates emergency surgery. Once the patient is stabilized, a staged reconstruction of the alimentary tract is planned. The surgeon should be familiar with the various types of gastric reconstruction in conjunction with or without esophageal replacement. The authors report 2 illustrative cases, which presented severe symptoms after corrosive substance ingestion, to emphasize the important aspects of management of this condition. The reconstruction of the gastrointestinal tract in children is managed with a staged approach using various methods, including Hunt-Lawrence J pouch gastric substitution.

Acute lung injury after inhalation of nitric acid.

We report two cases of acute lung injury after the inhalation of nitric acid fumes in an industrial accident. The first patient, who was not using a respirator and standing in close proximity to the site of spillage of concentrated nitric acid, presented within 12 h with worsening dyspnea and required noninvasive ventilation for type 1 respiratory failure. The second case presented 1 day later with similar symptoms, but only required supportive treatment with high-flow oxygen. Both patients' chest radiographs showed widespread bilateral airspace shadows consistent with acute lung injury. Both received treatment with systemic steroids. They were discharged from hospital 5 days postexposure. Initial lung function test showed a restrictive pattern that normalized by 3 weeks postexposure. This case series describes the natural history after acute inhalation of nitric acid fumes, and demonstrates that the severity of lung injury is directly dependent on the exposure level. It also highlights the use of noninvasive ventilatory support in the management of such patients.