Intra-alveolar Exudate Research Articles

Applying vibroacoustic therapy in the treatment of patients with COVID-associated pneumonia

Introduction. Pneumonia is a group of acute infectious (mainly bacterial) diseases of various etiology, pathogenesis, and morphological characteristics characterized by focal lesions of the respiratory tract of the lungs with the obligatory presence of intraalveolar exudation. Currently, a wide range of not only pharmacological, but also physiotherapeutic methods of treatment is available. Vibroacoustic therapy is also used to facilitate the discharge of bronchopulmonary secretions.Aim. To evaluate the effectiveness of vibroacoustic pulmonary therapy using the BARK VibroLUNG device (manufactured by BARK Technology, Kazakhstan) in patients with COVID-19.Materials and methods. 70 patients with PCR-confirmed positive COVID-19 infection were included in the study. The patients were divided into 2 groups, which statistically did not differ from each other. Group 1 (n = 35) underwent vibroacoustic pulmonary therapy (VALT) in combination with basic treatment. Group 2 (n = 35) received only basic treatment. VALT was performed for 7 days, 2 sessions per day for 20 minutes.Results. Against the background of complex therapy in combination with the course of VALT, patients in the study group showed a statistically significant decrease in the duration of hospitalization to 19 (12–29) days, as opposed to 27 (24–34) days (p = 0.003) in the control group. When comparing the changes in the indicators of the surviving patients of the study group, a positive dynamics of the main indicators against the background of VALT was obtained: ∆VAS -2 (-3; -1), р = 0.000; ∆SpO2– 6 (2; 7), р = 0.002; ∆PaO2–13 (2; 19), р= 0.001 in comparison with the dynamics of similar indicators of the control group.Conclusions. The results have shown the effectiveness of vibroacoustic therapy in the treatment of patients with coronavirus pneumonia. This method can optimize healthcare costs for the treatment of COVID-19, as there is a significant decrease of duration of hospitalization.

Features of the cell composition of inflammatory infiltrate in different phases of diffuse alveolar lung damage with COVID-19

Acute respiratory distress syndrome (ARDS) with COVID-19 has a worse prognosis than ARDS with other diseases. Mortality from ARDS with COVID-19 is 26.0 - 61.5%, and due to other causes - 35.3-37.2%. To find of the correlation between polymorphonuclear leukocytes (PMNs), lymphocytes, and macrophages in the cellular composition of the inflammatory infiltrate at different stages and phases of diffuse alveolar damage (DAD) with COVID-19, analyzing the autopsy material. The lung tissue of 25 patients who died from ARDS with COVID-19 without a secondary bacterial or mycotic infection, another thanatologically significant pathology of the lungs, was studied. To study the cellular composition of the inflammatory infiltrate and the dynamics of its changes a double immunohistochemical analysis of the expression of antibodies to CD15, CD3, and CD68 was used. The inflammatory infiltrate and intraalveolar exudate in the exudative phase of DAD was represented by 56.8% of PMNs (CD15-positive cells; hereinafter - the average value of the percentage of positive cells to the total number of cells of the inflammatory infiltrate), 6.9% - lymphocytes (CD3-positive cells) and 19.5% macrophages (CD68-positive cells). In the early stage of the proliferative phase: 14.1% PMNs, 38.7% lymphocytes and 13.5% macrophages. In the late stage of the proliferative phase: 11.3% PMNs, 14.5% lymphocytes and 39.3% macrophages. In the exudative phase of DAD a statistically significant predominance of PMN was revealed, which could determine the main volume of lung damage and the severity of ARDS with COVID-19. In the early stage of the proliferative phase of DAD, a statistically significant change in the composition of the inflammatory infiltrate was revealed to compare with the exudative phase: a significant decrease in the content of PMNs relative to the total number of cells in the inflammatory infiltrate; an increase in the number of lymphocytes, which is probably associated with the start of organization and repair processes. In the late stage of the proliferative phase of DAD, compared with its early stage, was revealed a statistically significant increase in the number of macrophages in ratio.

Histopathologic Changes and SARS-CoV-2 Immunostaining in the Lung of a Patient With COVID-19

Histopathologic Changes and SARS-CoV-2 Immunostaining in the Lung of a Patient With COVID-19

Significant increases in the density and number of lymphatic vessels in pleuroparenchymal fibroelastosis.

Some investigators have detected fibrinous exudate or immature organisation in the alveolar spaces prior to the development of subpleural elastofibrosis in patients with pleuroparenchymal fibroelastosis (PPFE). We hypothesised that PPFE progress is associated with an impaired lymphatic drainage system, resulting in the failed resolution of intra-alveolar exudate. The aim of this study is to investigate the pulmonary lymphatic vessels in PPFE, histologically. We retrospectively reviewed our medical records from 1995 to 2017, and selected autopsied or surgically biopsied patients with PPFE (n=18), pulmonary apical cap (n=18), and IPF (n=26). We detected lymphatic endothelial cells by using immunostained specimens, calculating the percentage of lymphatic vessel area in the non-aerated area (lymphatic vessel density) and the number of lymphatic vessels per non-aerated area (per mm2 ) (lymphatic vessel number). These parameters in PPFE were compared with those in apical cap, IPF, and normal lung tissue. The lymphatic vessel density in PPFE patients [2.97%; interquartile range (IQR) 2.61-3.86] was significantly higher than that in normal lung (0.91%; IQR 0.84-1.07), pulmonary apical cap (0.67%; IQR 0.58-0.83), and IPF (0.91%; IQR 0.68-1.25) (P<0.01 in any comparison). The lymphatic vessel number in PPFE was also significantly higher than that in normal lung, pulmonary apical cap, and IPF. Among PPFE patients, the increase in lymphatic vessel density was found to be correlated with the characteristic physiology of PPFE, such as a flattened chest cage on computed tomography and high residual volume/total lung capacity ratio on spirometry. Significant increase in the density and number of lymphatic vessels is a supportive characteristic that enables the differentiation of PPFE from IPF and apical cap.

Chromobacterium violaceum Infection in a Horse

Chromobacterium violaceum is an opportunistic pathogen of mammals that produces characteristic violet pigment in bacterial culture. We report pneumonia and septicaemia caused by C. violaceum in a horse. Necropsy examination was performed on a 3-year-old Quarter Horse stallion with a history of recurrent episodes of pneumonia, fever, dyspnoea and sanguineous nasal discharge. The lungs were not collapsed, but they contained dark red foci mixed with white areas, and multiple nodules of firm consistency. Within the liver and kidney there were randomly distributed, multifocal, white pinpoint lesions (0.1-0.5cm diameter) in the capsule and extending into the parenchyma. The brain and spinal cord contained numerous petechiae. Microscopically, the lung had severe multifocal to coalescing infiltration of degenerate neutrophils within the alveoli and parenchyma associated with extensive areas of necrosis and haemorrhage. Rod-shaped bacteria were often present in the centre of the lesions. There was intense intra-alveolar exudation of fibrin and fibrinoid degeneration of blood vessels associated with thrombosis and ischaemic necrosis adjacent to areas of severe haemorrhage. Similar lesions were present in the liver and kidneys. A pure culture of C. violaceum was obtained from samples of the lung and liver. The identity of the organism was confirmed by amplifying and sequencing the 16S rRNA gene with subsequent analysis of sequence similarity.

Usefulness of Bronchoscopic Probe-Based Confocal Laser Endomicroscopy in the Diagnosis of Pneumocystis jirovecii Pneumonia

Background: Probe-based confocal laser endomicroscopy (pCLE) is a novel technique that provides in vivo microscopic imaging of the distal lung. We hypothesized that the intra-alveolar exudates characterizing Pneumocystis jirovecii pneumonia (PJP) can be identified by pCLE in vivo and help in its diagnosis. Objectives: We aimed to assess the usefulness of pCLE for the in vivo diagnosis of PJP. Methods: Thirty-two human immunodeficiency virus (HIV)-positive patients with new pulmonary infiltrates and fever were studied using pCLE. Real-time alveolar images were recorded during the bronchoscopy for off-line analysis by two independent observers. Bronchoalveolar lavage samples were also obtained and processed for microbiology and cytological evaluation, including Grocott stain for P. jirovecii. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of pCLE for the diagnosis of PJP in these patients were calculated. Results: Fourteen patients (44%) were confirmed to have PJP by cultures/staining. pCLE was well tolerated in all patients. It identified intra-alveolar exudates in 13 of them (41%), where 11 of them (85%) had positive Grocott stain for P. jirovecci, with 93% concordance between observers. Sensitivity, specificity, PPV and NPV of pCLE for the diagnosis of PJP were 79, 89, 85 and 84%, respectively. In smokers, these figures improved to be 92, 88, 85 and 94%. Conclusions: pCLE is a quick and safe procedure for on-site diagnosis of PJP in HIV+ patients with excellent specificity and sensitivity mainly in smokers.

Pneumocystis jiroveciiPneumonia with Granulomatous Reaction in the Lung and the Liver Discovered at Autopsy

We report the case of a 42-year-old woman who died in hospital from severe respiratory failure, 10 days after the onset of symptoms. Autopsy and microscopic examination identified features of diffuse alveolar damage in both lungs including hyaline membranes and intra-alveolar exudate. Gomori's methenamine silver stain of pink frothy materials in these exudates revealed thin-walled and cup-shaped microorganisms and a diagnosis of Pneumocystis jirovecii pneumonia was made. There were small granulomas in the pulmonary interstitium and hepatic lobules representing an unusual inflammatory reaction against Pneumocystis jirovecii. Extrapulmonary involvement with pneumocystis infection is a rare event occurring in 1% to 2% of all pneumocystis cases. Screening and confirmatory tests for human immunodeficiency virus (HIV) detection were positive. There was no information available regarding the patient’s medical history or the possibility of HIV infection prior to the autopsy, because the patient was a foreign worker who arrived in Korea 2 months before her death. Medical examiners often perform autopsies with limited information regarding the deceased person, even when person is a Korean national. Therefore, an awareness of protection protocols during autopsy, as well as of the atypical patterns of critical diseases, is crucial.

Autopsy Findings and Histopathological Corroboration in A Case of Death due to Hornet Bite

We present a rare case of death due to hornet bite in an adult 64 years old patient who died within 6 hours of admission. There were bites on multiple sites and histopathology of Kidney showed acute tubular necrosis. Liver shows fatty changes periportal fibrosis and portal inflammation. Lungs show intra-alveolar exudation, alveolar wall destruction and inflammatory infiltrates. Heart showed deposition of lipofuschin and brain showed focal oedema with dilatation of vessels. These accidents can occur in places of cohabitation of hornets with humans. People who are allergic to wasp venom are also allergic to hornet stings. In severe cases, allergic individuals may go into anaphylactic shock and die unless treated promptly. Clinical criteria for fatal cases can be formulated from this case and especially susceptible individuals like elderly with co morbid conditions and children should be treated early and extensively to avoid fatal complications.

High-Mobility Group Box-1 as a Novel Therapeutic Target for Reducing Pulmonary Ischemia-Reperfusion Injury in CLAWN Miniature Swine

Purpose: Strategies that reduce ischemia-reperfusion injury (IRI) have the potential to expand the use of extended-criteria or donation after cardiac donors and improve both the short and long-term outcomes of transplantation. Because high-mobility group box 1 (HMGB1) has been reported to be a mediator of inflammation and cell injury, blocking of HMGB1 might represent a novel therapeutic strategy against IRI. However, there is limited data to characterize the role of HMGB1 on pulmonary IRI especially in large animals. The aim of this study was to determine the role of HMGB1 on IRI and to evaluate the cytoprotective effects of anti-HMGB1 antibodies as a translational research using our established, in situ porcine lung warm IRI model. Methods: Warm ischemia was induced in 12 CLAWN miniature swine by clamping the left main bronchus, pulmonary artery and veins for 90 minutes. In the control group (n=5), the animals were followed without any additional treatment. In the HMGB1 Ab group (n=4), 1mg/kg of anti-HMGB1 Ab was intravenously injected just before reperfusion. In the isotype Ab group (n=3), control IgY Ab was injected as the same fashion as the HMGB1 Ab group. Lung function and structure were serially accessed via lung biopsy, chest X-ray and blood gas analysis. Serum cytokine levels such as IL-1β and HMGB1 were measured in order to characterize the inflammatory response to IRI and evaluate the effect of the treatment on that response. Results: Serum levels of HMGB1 increased after IRI, peaking 2 days after reperfusion (14 ± 6 ng/ml) in the control group. Anti-HMGB1 Ab treatment resulted in significant reduction of HMGB1 (0.9 ± 0.5 ng/ml). Two hours after reperfusion, the PaO2 of the HMGB1 Ab group was 551 ± 19 mmHg, more than double of the control group (266 ± 60 mmHg). Lung biopsy in the control group showed significant damage to alveolar endothelial cells with intra-alveolar edema, hemorrhage, and fibrin exudates at POD2. In contrast, treatment with anti-HMGB1 Ab resulted in marked improvement of histological findings and less PCNA-positive infiltrating cells and TUNEL-positive apoptotic cells. Systemic IL-1β levels increased after IRI in both the control and HMGB1 groups, peaking 1 day after reperfusion, though there was no difference in the concentration between two groups (control vs. HMGB1 Ab group; 63 ± 26 vs. 62 ± 14 pg/ml). Furthermore, treatment of isotype control IgY Ab showed no effect on improving gas oxygenation or inhibiting lung damage after IRI. Conclusions: In this study, we demonstrated that HMGB1 played a major role in the progression of lung IRI and that reducing systemic HMGB1 by anti-HMGB1 Ab alone could reduce IRI independently of systemic IL-1β concentration using a clinically relevant large animal model. Targeting HMGB1 might represent a novel therapeutic strategy in clinical IRI associated with lung transplantation.

Indium Lung Disease

Reports of pulmonary fibrosis, emphysema, and, more recently, pulmonary alveolar proteinosis (PAP) in indium workers suggested that workplace exposure to indium compounds caused several different lung diseases. To better understand the pathogenesis and natural history of indium lung disease, a detailed, systematic, multidisciplinary analysis of clinical, histopathologic, radiologic, and epidemiologic data for all reported cases and workplaces was undertaken. Ten men (median age, 35 years) who produced, used, or reclaimed indium compounds were diagnosed with interstitial lung disease 4-13 years after first exposure (n = 7) or PAP 1-2 years after first exposure (n = 3). Common pulmonary histopathologic features in these patients included intraalveolar exudate typical of alveolar proteinosis (n = 9), cholesterol clefts and granulomas (n = 10), and fibrosis (n = 9). Two patients with interstitial lung disease had pneumothoraces. Lung disease progressed following cessation of exposure in most patients and was fatal in two. Radiographic data revealed that two patients with PAP subsequently developed fibrosis and one also developed emphysematous changes. Epidemiologic investigations demonstrated the potential for exposure to respirable particles and an excess of lung abnormalities among coworkers. Occupational exposure to indium compounds was associated with PAP, cholesterol ester crystals and granulomas, pulmonary fibrosis, emphysema, and pneumothoraces. The available evidence suggests exposure to indium compounds causes a novel lung disease that may begin with PAP and progress to include fibrosis and emphysema, and, in some cases, premature death. Prospective studies are needed to better define the natural history and prognosis of this emerging lung disease and identify effective prevention strategies.

Granulomatous Reaction to Pneumocystis jirovecii

To better characterize the clinical and pathologic features of granulomatous reaction to Pneumocystis jirovecii, we reviewed 20 cases of this uncommon response. Patients included 15 males and 5 females (mean age 52 y). The most common symptom was dyspnea (5 of 14). Primary medical diagnoses included human immunodeficiency virus/acquired immunodeficiency syndrome (7 of 20), hematopoietic (6 of 20), and solid malignancies (4 of 20). Radiology findings included nodular (8 of 16) and diffuse (5 of 16) infiltrates and solitary nodules (3 of 16). Diagnostic procedures with the highest yield were open lung biopsy (13 of 20) and autopsy (5 of 20); false-negative results were most common on bronchial washings/brushings, bronchoalveolar lavage, fine needle aspiration, and transbronchial biopsy. Follow-up showed resolution of disease (6 of 13), death from disease (6 of 13), and death from unknown cause (1 of 13). Histologically, clusters of Gomori methenamine silver-positive (20 of 20) Pneumocystis organisms were identified in all cases. Organisms were identified within well (16 of 20) and poorly (4 of 20) formed necrotizing (16 of 20) and non-necrotizing (4 of 20) granulomas ranging in size from 0.1 to 2.5 cm (mean 0.5 cm); granulomas were multiple (18 of 20) or single (2 of 20). Giant cells (11 of 20), a fibrous rim (8 of 20), and eosinophils (6 of 20) were seen. Foamy eosinophilic exudates were present centrally within some granulomas (5 of 20). Cystic spaces (1 of 20) and calcification (1 of 20) were rare. Only one case demonstrated classic intra-alveolar foamy exudates containing Pneumocystis. Granulomatous P. jirovecii pneumonia occurs most commonly in males with human immunodeficiency virus/acquired immunodeficiency syndrome, hematopoietic, and solid malignancies. The diagnosis may be overlooked as conventional radiologic and pathologic features are absent. When suspected, open lung biopsy is most likely to yield diagnostic material. Attention to organism morphology avoids misdiagnosis as Histoplasma.

Dyspnea on Exertion and Ground-Glass Infiltrates in an Ex-Smoker

Dyspnea on Exertion and Ground-Glass Infiltrates in an Ex-Smoker

Hypoxia and chronic lung disease

The lung is both the conduit for oxygen uptake and is also affected by hypoxia and hypoxia signaling. Decreased ventilatory drive, airway obstructive processes, intra-alveolar exudates, septal thickening by edema, inflammation, fibrosis, or damage to alveolar capillaries will all interpose a significant and potentially life-threatening barrier to proper oxygenation, therefore enhancing the alveolar/arterial pO2 gradient. These processes result in decreased blood and tissue oxygenation. This review addresses the relationship of hypoxia with lung development and with lung diseases. We particularly focus on molecular mechanisms underlying hypoxia-driven physiological and pathophysiological lung processes, specifically in the infant lung, pulmonary hypertension, and chronic obstructive pulmonary disease.

Malnutrition causes a reduction in alveolar epithelial sodium and chloride transport which predisposes to death from lung injury

All forms of malnutrition have been associated with increased severity of pneumonia, an increased pneumonia associated mortality and an increased risk of pulmonary fluid overload. Malnutrition was found to be associated with increased sweat sodium and chloride concentrations. A reduction of systemic sodium and chloride transport reflected in sweat sodium and chloride levels has been linked to increased severity of pulmonary edema in children with septicemia. Malnutrition causes a reduction in alveolar epithelial sodium and chloride transport which predisposes to death from lung injury. SUPPORTING EVIDENCE FOR THE HYPOTHESIS: Malnutrition caused reduced pulmonary fluid clearance in the rat model. Amiloride insensitive pulmonary fluid clearance in malnourished rats was reduced. The reduction in fluid clearance was reversible by beta agonists which increases epithelial sodium and chloride transport. Reduction of alveolar ion and fluid transport capacity explains the predisposition to death from pulmonary edema associated with intravenous fluids and blood transfusions in inpatients with malnutrition. Reduced alveolar epithelial ion transport impairs absorption of intra-alveolar inflammatory exudate in pneumonia leading to a increased severity of respiratory compromise and increased mortality. MEANS TO TEST THE HYPOTHESIS: Nasal potential difference measurements could compare airway epithelial sodium and chloride transport in patients with and without malnutrition and malnutrition associated lung disease. Sweat sodium and chloride concentrations could be compared in patients with and without respiratory disease associated with malnutrition and correlated with the severity of respiratory compromise.

An aetiopathological study of chronic bronchopneumonia in lambs in Ireland

Chronic bronchopneumonia in lambs, also known as ‘atypical’ or ‘chronic, non-progressive’ pneumonia is a common, frequently sub-clinical disease affecting animals under 12-months-old in intensive production systems. Infection with both Mycoplasma ovipneumoniae and Mannheimia haemolytica have been implicated in the aetiology of this condition and a variety of pulmonary lesions can result. In this study, detailed laboratory examination of 30 abattoir-derived lungs with the characteristic gross features of atypical pneumonia (AP) was carried out with a view to refining and correlating the histopathological and microbiological criteria required for the diagnosis of this disease. For the first time a broad range of laboratory detection techniques including bacterial and virus isolation, fluorescent antibody tests and immunohistochemistry were used in parallel to identify potential causative pathogens such as M. ovipneumoniae, M. haemolytica, parainfluenza type-3 (PI3) virus and respiratory syncytial virus (RSV) in AP lesions. The most consistent finding was the association of gross AP lesions with M. ovipneumoniae, identified by either culture or immunohistochemistry in 27 (90%) of the 30 cases. However the presence M. ovipneumoniae organisms or antigen did not consistently correlate with particular histopathological changes. Furthermore, peri-airway lymphoid hyperplasia, intra-alveolar exudation and nodular ‘hyaline scars’, which are all previously reported microscopic lesions of AP, were not identified in 12 (40%) of the cases and isolation of M. haemolytica was over-represented in lungs exhibiting suppurative lesions. These findings illustrate the complex aetiopathogenesis of this disease and highlight the requirement to use a combination of diagnostic criteria in its laboratory diagnosis.

Pulmonary alveolar proteinosis mimicking idiopathic pulmonary fibrosis

Pulmonary alveolar proteinosis (PAP) is a rare disorder of unknown etiology. While most biopsies from patients with PAP disclose a prominent positive periodic acid-Schiff, diastase-resistant intra-alveolar exudate, and minimal interstitial thickening, interstitial fibrosis and honeycombing can be the predominant histologic findings. We recently identified two patients with PAP who initially were thought to have idiopathic pulmonary fibrosis, but whose biopsies ultimately disclosed PAP with considerable interstitial fibrosis. Because the clinical and radiographic presentation of PAP can overlap with other interstitial lung disorders, it should be considered in the differential diagnosis of unexplained idiopathic interstitial pneumonias in young patients. Ann Diagn Pathol 7: 82-86, 2003.

Focal organizing pneumonia: CT and pathologic findings.

The purpose of this study was to describe the CT findings of focal organizing pneumonia and to compare the findings with pathology. CT findings of histologically proven focal organizing pneumonias in 26 consecutive patients were analyzed. In 17 patients who had undergone surgical resections, the findings were correlated with pathology. Focal organizing pneumonias appeared as a nodule (n= 13) or a mass (n=13), ranging from 9 mm to 66 mm in diameter. Ground-glass opacity was seen in 6/13 (46%) nodules and 6.5/13 (50%) masses (k=.48) with an extent ranging from 5% to 75% (mean, 16%). In 4/26 (15%) patients, the extent was more than 50% of the lesion. They showed smooth (n=4), lobulated (n=8), spiculated (n=1), or lobulated and spiculated margin (n=13). On correlative analysis, nodule or mass on CT consisted histologically of intraalveolar exudate or microabscess, chronic inflammatory cell infiltration, fibrotic nodules, and polypoid granulation tissue in the alveolar or bronchiolar spaces. Ground-glass opacity consisted of interstitial fibrosis and chronic inflammatory cell infiltration and intraalveolar polypoid granulation tissue. Focal organizing pneumonia may simulate a lung cancer with variable appearances on CT and the findings reflect underlying histopathology of the disease.

Protein oxidation biomarkers in hyperoxic lung injury in rats: effects of U-74389

Hyperoxia, used therapeutically in the treatment of respiratory insufficiencies, can cause lung injury, probably through the actions of reactive oxygen species. The present studies were designed to test the hypothesis that oxidation of specific proteins would provide useful biomarkers of the onset of tissue injury, and thereby provide clues as to the mechanisms responsible. We exposed adult male Sprague-Dawley rats to room air or to greater than 95% O 2 for 60 h and examined proteins in pleural effusion and broncho-alveolar lavage (BAL) fluids, and in lung tissue homogenates and subfractions. Oxidation of protein thiols was assessed by derivatization with monobromobimane, separation by electrophoresis, and visualization of the fluorescent thioether derivatives. Derivatization with 2,4-dinitrophenylhydrazine (DNPH), electrophoresis, and western analysis was employed to assess a different class of oxidative modifications, frequently termed `protein carbonyls'. In addition, we investigated the effects of the 21-aminosteroid U-74389G, 10 mg/kg, given intraperitoneally every 12 h, on biomarkers of protein oxidation and on manifestations of lung injury. Hyperoxia caused lung injury evidenced by pleural effusions, increases in BAL protein concentrations, and pulmonary edema; U-74389G attenuated the first two indices of lung injury, but did not alter edema. Protein thiol status of the fractions studied were not affected notably by hyperoxia, or by the aminosteroid. The formation of DNPH-reactive sites on a limited number of proteins by hyperoxia was observed, and some of these effects were attenuated in the animals given U-74389G. Histological examination of lung tissues showed accumulation of intra-alveolar protein exudates in hyperoxic rats, and a significant attenuation of this effect was observed in the animals treated with U-74389G. In conclusion, studies of shifts in protein thiol status that may be caused by hyperoxia will require increasingly specific methods of analysis, and characterization of the specific DNPH-reactive proteins formed in hyperoxia may provide critical insights into the mechanisms of lung injury. Administration of U-74389G offers some degree of protection against hyperoxia and attenuation of these biomarkers of oxidation, but the precise mechanisms by which this protection is effected will require additional study.

Amelioration of ischemia-reperfusion injury by human thioredoxin in rabbit lung

Human thioredoxin is a polypeptide with thiol groups, possessing reducing activity, which is proved to have the ability to reduce active oxygens. This study evaluated the effect of human thioredoxin on the ischemia-reperfusion lung injury and the roles of human thioredoxin on active oxygens by chemiluminescence examination. The left hilum of the lung of Japanese white rabbits was occluded for 110 minutes and then reperfused for 90 minutes. Ten, 30, 60, and 90 minutes after reperfusion the right hilum was occluded for 5 minutes and the pulmonary functions of the left lung were examined. The animals were divided into four groups, three ischemia groups and a sham group (without occlusion; n = 6). The ischemia groups received human thioredoxin, 60 mg/kg ( n = 10), N-acetylcysteine, 150 mg/kg ( n = 7), or saline solution (control, n = 10) during reperfusion. Three rabbits in the human thioredoxin group and the control group were used to measure active oxygens with a cypridina luciferin analog. An additional group of reperfused lungs ( n = 3) that were given superoxide dismutase after 110 minutes of ischemia was established to identify chemiluminescence examination. Compared with the sham group, reperfusion after 110 minutes of ischemia produced a significant lung injury in the control group. Among the ischemia groups, the human thioredoxin group showed significantly higher arterial oxygen tension at 30, 60, and 90 minutes after reperfusion than the control group, although there was no significant difference between the N-acetylcysteine and control groups. Histologically, intraalveolar exudation, interstitial thickening, and cellular infiltration were seen in the control group, whereas in the thioredoxin group alveolar structure was well preserved. In the measurement of active oxygens the chemiluminescence in the human thioredoxin group was less than that in the control group and as little as that in the group administered superoxide dismutase. We concluded human thioredoxin attenuated ischemia-reperfusion injury by involving active oxygens in rabbit lungs. (J Thorac Cardiovasc Surg 1997;113:1-9)

Pathogenesis of influenza virus-induced pneumonia: involvement of both nitric oxide and oxygen radicals.

The role of nitric oxide (NO) in the pathogenesis of influenza virus-induced pneumonia in mice was investigated. Experimental influenza virus pneumonia was produced with influenza virus A/Kumamoto/Y5/67(H2N2). Both the enzyme activity of NO synthase (NOS) and mRNA expression of the inducible NOS were greatly increased in the mouse lungs; increases were mediated by interferon gamma. Excessive production of NO in the virus-infected lung was studied further by using electron spin resonance (ESR) spectroscopy. In vivo spin trapping with dithiocarbamate-iron complexes indicated that a significant amount of NO was generated in the virus-infected lung. Furthermore, an NO-hemoglobin ESR signal appeared in the virus-infected lung, and formation of NO-hemoglobin was significantly increased by treatment with superoxide dismutase and was inhibited by N(omega)-monomethyl-L-arginine (L-NMMA) administration. Immunohistochemistry with a specific anti-nitrotyrosine antibody showed intense staining of alveolar phagocytic cells such as macrophages and neutrophils and of intraalveolar exudate in the virus-infected lung. These results strongly suggest formation of peroxynitrite in the lung through the reaction of NO with O2-, which is generated by alveolar phagocytic cells and xanthine oxidase. In addition, administration of L-NMMA resulted in significant improvement in the survival rate of virus-infected mice without appreciable suppression of their antiviral defenses. On the basis of these data, we conclude that NO together with O2- which forms more reactive peroxynitrite may be the most important pathogenic factors in influenza virus-induced pneumonia in mice.