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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the importance of the cytokine tumor necrosis factor-alpha (TNF-alpha) in a mouse model of hypersensitivity pneumonitis (HP). Mice of the C57BL/6 strain were instilled intranasally 3 days/wk for 3 wk with 150 micrograms of the actinomycete Faenia rectivirgula (Micropolyspora faeni) to induce HP as a model of farmer's lung. This experimental model was associated with a progressive inflammation in the lungs of challenged mice, seen histologically as cellular infiltrates of large quantities of macrophages and lymphocytes and some neutrophils. The disease in challenged mice treated with a control rabbit serum was also associated with a substantial release of tumor TNF-alpha (up to 80 U/ml of TNF-alpha in the bronchoalveolar lavage [BAL] at 3 wk after beginning of treatment) and interleukin-1, which peaked at 1 wk (approximately 300 U/ml) and diminished thereafter. A very large increase in BAL cell number (11-fold increase versus saline controls) and an enhanced release potential for TNF-alpha by alveolar macrophages was also seen. Lung fibrosis was also evident in challenged animals, as demonstrated by a 2-fold increase in hydroxyproline levels. Infusion of challenged mice with a rabbit polyclonal antibody against TNF-alpha (2 mg/wk) completely abrogated the disease, as mice so treated had normal lung histology. Anti-TNF-alpha blocked cellular recruitment in the lungs (only a 2-fold increase at week 3); it also completely abolished TNF-alpha secretion in the BAL and drastically reduced interleukin-1 levels in this fluid. Anti-TNF-alpha also abolished lung index increases and lung fibrosis, with both parameters similar to that of saline-instilled mice.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1991 Nov
PMID:Tumor necrosis factor plays an essential role in determining hypersensitivity pneumonitis in a mouse model. 193 Oct 76

Bleomycin damages cellular DNA and is a potent inducer of pulmonary fibrosis. It has been shown to act through a superoxide-mediated mechanism. We are interested in determining the biochemical mechanisms involved in fibrosis and in this preliminary study we have examined the temporal relationship between early biochemical events associated with DNA damage and fibrosis, in lungs of hamsters after administration of 0.75 unit of bleomycin. The activities of poly(ADP-ribose) synthetase, an enzyme associated with DNA repair, inducible superoxide dismutase (SOD) and prolyl hydroxylase as well as the tissue levels of NAD+ and hydroxyproline in the lung were determined. All three enzyme activities expressed as per milligram DNA or per lung, increased upon bleomycin treatment over the saline-administered controls. Lung poly(ADP-ribose) synthetase activity which is sensitive to DNA breaks, increased first (24% over control in 1 day, P less than 0.0001), attained the maximum value on the 5th day (952% over control, P less than 0.0001), and started to decline thereafter and approached near the control value on 14th day. Bleomycin treatment induced a rapid change in the level of lung NAD+. After 1 day the level of NAD+ was reduced by 42% compared to the control (P less than 0.001), further declined to 65% (P less than 0.001) on the 3rd day, and stayed at that level until the 7th day. On the 14th day, however, the NAD+ level was still lower (29%, P less than 0.05) but approaching the value in the control animals. The activity of prolyl hydroxylase showed significant increase on the 3rd day (50% over control, P less than 0.0001) after bleomycin administration. The enzyme activity continued to increase until the end of the experiment (490% of control, P less than 0.0001, on Day 14). The content of undialyzable hydroxyproline, a marker for collagen, was also increased significantly in the lung tissue on the 3rd day (30% over control, P less than 0.05), continued to increase and reached the highest level on the 14th day (71% over control, P less than 0.001). A significant increase in the activity of SOD (19% over control, P less than 0.001) was seen on the 5th day which continued to increase and attained the highest value on Day 14 (115% over control, P less than 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)
Exp Mol Pathol 1985 Oct
PMID:Poly(ADP-ribose) synthetase activity during bleomycin-induced lung fibrosis in hamsters. 241 86

The concomitant treatment of rats with bleomycin and hyperoxia results in synergistic development of pulmonary injury. We exposed rats to 70% oxygen for 72 hr following an intratracheal instillation of bleomycin (0.2 U/kg body wt). Animals were killed 15, 30, 60 and 90 days after treatment for hydroxyproline, cell kinetics, and histopathologic analysis. A 16% increase in hydroxyproline over controls was seen 15 days after treatment which was manifested by the proliferation phase of diffuse alveolar damage and an increase in cell labeling by tritiated thymidine. Thirty days after treatment the hydroxyproline remained elevated while lung injury appeared to be healing with a residual focal interstitial pneumonitis and a drop in cell labeling. Between 60 and 90 days, there was an additional significant increase in hydroxyproline to 44% over controls. Diffuse interstitial pneumonitis with fibrosis was observed. Cell labeling remained constant between 60 and 90 days. We conclude that the treatment of rats with bleomycin and hyperoxia results in slowly progressive pulmonary fibrosis. The increase in hydroxyproline in the chronic phase was not accompanied by an increase in cell proliferation, and therefore may have resulted from an increase in cellular production of hydroxyproline rather than increased number of cells producing collagen.
Exp Mol Pathol 1985 Dec
PMID:Progressive pulmonary fibrosis in rats: a biochemical, cell kinetic, and morphologic analysis. 241 89

We have produced experimental diffuse interstitial pulmonary fibrosis in rats with a combination of low and repeated doses of paraquat plus continuous exposure to normobaric 74% O2 in the breathing air for several weeks. Pulmonary fibrosis was evaluated histologically and biochemically, through the determination of total collagen content in the lung. Our procedure is characterized by low initial mortality, the development of extensive distortion of the pulmonary architecture, and the presence of severe and diffuse interstitial fibrosis. The model was compared with bleomycin-induced pulmonary fibrosis in the same rat strain, in which the process is focal and leaves most of the lung unaffected. We conclude that lung damage produced by the combination of low doses of paraquat plus normobaric 74% O2 concentration in the breathing air is an adequate experimental model of diffuse interstitial pulmonary fibrosis as it occurs in many of the human cases of this condition.
Exp Mol Pathol 1985 Dec
PMID:A new model of diffuse interstitial pulmonary fibrosis in the rat. 241 90

Pulmonary fibrosis is the major toxic effect of bleomycin chemotherapy; however, the molecular mechanisms of the pathological process are unknown. Since alveolar macrophages produce toxic oxygen metabolites and these can damage lung cells, the effect of bleomycin on superoxide anion production was investigated in subpopulations of pig alveolar macrophages. Cells were lavaged from the lung and separated into three subpopulations according to their density. Their capacity to generate superoxide anions increased the more distally they were located. Bleomycin (5.0 milliunits/ml) increased the rate of superoxide production by 75 +/- 24% in dense alveolar macrophages located in the lung periphery. Hydrocortisone (10.0 micrograms/ml) inhibited this superoxide production by 33 +/- 10%. Results from this study suggest that an excess production of superoxide anions by alveolar macrophages may be the underlying cause of bleomycin pulmonary toxicity.
Mol Pharmacol 1986 Jul
PMID:Bleomycin increases superoxide anion generation by pig peripheral alveolar macrophages. 242 42

The severity of bleomycin (BLM)-induced pulmonary fibrosis in mice varies markedly among several different murine strains. We have examined the DNA from lungs of sensitive (i.e., C57BL/6N) and resistant (i.e., BALB/c) strains of mice using a nucleoid sedimentation technique to detect early in vivo changes in the integrity of DNA after intravenous BLM. Mice received intravenous injections of BLM (80 mg/kg) or vehicle; lung nucleoids were prepared 15 min to 6 hr later. BLM produced striking decreases in nucleoid sedimentation distance versus paired controls in both strains within 15 min after injection, indicating extensive DNA scission. Repair of DNA strand breaks was complete in the resistant (BALB/c) mice by 5 hr; in contrast, only partial repair occurred in the sensitive (C57BL/6N) strain during that time. We then examined lungs for subsequent changes in steady state poly-(A)+ RNA levels and mRNA levels for lung matrix proteins (type I procollagen, type III procollagen, and fibronectin). Steady state levels of poly-(A)+ RNA were depressed to 50% of control 1 through 6 days after BLM injection in the lungs of sensitive mice. Resistant mice had pulmonary poly-(A)+ RNA levels similar to those of C57BL/6N mice, except for a 2-fold elevation 1 day after BLM injection. BLM injection affected the steady state levels of mRNA encoding lung matrix proteins differently than total poly-(A)+ RNA. Fibronectin mRNA/poly(A)+ RNA was elevated 2-fold 1 day after BLM treatment only in the sensitive strain and remained elevated at 3 and 6 days. In contrast, alpha 2I procollagen mRNA increased in both murine strains and alpha 1III procollagen mRNA decreased in both strains. Thus, a 7-fold or greater increase in the type I: type III procollagen mRNA ratio was seen in both strains 3 to 6 days after BLM injection. These data demonstrate that BLM treatment rapidly produces extensive pulmonary DNA damage in vivo, that persistence of DNA damage rather than the initial level of strand scission is associated with sensitivity to BLM lung disease in these mice, and that changes in the levels of mRNA encoding pulmonary matrix proteins occur in vivo within 1 to 3 days after intravenous BLM treatment.
Mol Pharmacol 1989 Aug
PMID:Acute pulmonary toxicity of bleomycin: DNA scission and matrix protein mRNA levels in bleomycin-sensitive and -resistant strains of mice. 247 58

Rats were injected intraperitoneally with 1 mCi (each) of [3H]lysine at Day 11 of neonatal life to label their lung collagen. Five weeks later, half of the animals were given an intratracheal injection of 1.5 U of bleomycin sulfate via a tracheostomy; control animals received saline intratracheally by the same technique. Age-matched groups of control and bleomycin-treated rats were killed, and their lung collagen was analyzed at zero (control animals only), 1, 2, 4, 6, and 10 wk after bleomycin administration, a time course appropriate for development of pulmonary fibrosis in this animal model. We measured radioactivity in hydroxylysine and in the difunctional collagen crosslinks hydroxylysinonorleucine and dihydroxylysinonorleucine at each time point. No evidence of breakdown of this pool of mature, preformed collagen was observed in lungs of either the control or the bleomycin-treated rats. We also measured the total lung content of hydroxypyridinium, a trifunctional collagen crosslink, by its intrinsic fluorescence. There was no evidence of collagen degradation in lungs of either group of rats by this criterion either. We conclude that there is no biochemically detectable turnover of mature lung collagen, defined as that pool of lung collagen that is obligatorily extracellular (i.e., crosslinked and containing labeled hydroxylysine from an injection of precursor 5 to 15 wk earlier), in either normal rat lungs or lungs of rats made fibrotic with bleomycin. Statistical analysis of the data suggests that our methodology was sensitive and precise enough to have detected turnover of less than 0.5% of lung collagen per day, some 20-fold less than estimates of lung collagen turnover that have been suggested to be occurring in vivo by others using different techniques and presumably studying different pools of lung collagen.
Am J Respir Cell Mol Biol 1989 Aug
PMID:Biosynthesis of collagen crosslinks. III. In vivo labeling and stability of lung collagen in rats with bleomycin-induced pulmonary fibrosis. 248 79

The interaction of chrysotile asbestos with alveolar macrophages in vitro is known to stimulate cellular superoxide anion production. However, it is likely that particulates in the respiratory tract are present together with components of the pulmonary surfactant, and it is not known how these components may alter the bioactivity of the particulate. We now show that guinea pig immunoglobulin G, a surfactant protein, causes a significant, dose-dependent enhancement of superoxide anion production by nonadherent guinea pig alveolar macrophages in response to chrysotile asbestos. This enhancement could not be mimicked by other particulates or proteins, including IgG fragments, implying that the interaction between IgG, cell, and chrysotile is relatively specific. The enhancing effect of IgG in solution could be reproduced by pretreating the chrysotile asbestos with IgG. The fact that IgG specifically enhances chrysotile asbestos-stimulated superoxide anion production, in turn, leads to a proposal for a molecular mechanism by which asbestos may stimulate the guinea pig macrophage, namely, by crosslinking cell-surface immunoglobulin Fc receptors. In view of the submicromolar concentrations at which IgG was effective in enhancing macrophage stimulation by chrysotile asbestos in vitro, these results also suggest that IgG adsorption may play a role in the progression of asbestos-induced pulmonary fibrosis.
Am J Respir Cell Mol Biol 1989 Oct
PMID:IgG specifically enhances chrysotile asbestos-stimulated superoxide anion production by the alveolar macrophage. 256 Mar 95

"Alveolitis", as opposed to "pneumonia" sensu strictiori, is a term used to denote diffuse inflammatory changes of the pulmonary parenchyma, excluding those that result from local bacterial, fungal or other extracellular microbial growth. The various types of alveolitis are classified according to their histological characteristics and range from "luminal phagocytic" or "mural lymphoplasmacellular" and "exudative" to "fibrosing" alveolitis. In this overview, various exogenous and endogenous causes of different types of alveolitis, and the cellular events in their pathogenesis are briefly discussed to illustrate the complex mechanisms involved. Particular emphasis is placed on the possible transition from diffuse exudative to fibrosing alveolitis. It appears that pulmonary fibrosis, which is usually patchy rather than truly diffuse, does not have a uniform pathogenesis. Besides the possibility of a certain degree of a diffuse fibrosis three major pathways are evident: (1) granulation tissue budding into alveolar lumina (luminal fibrosis) (2) exudate incorporation into alveolar walls (mural fibrosis) and--at least equally important--(3) so-called collapse (atelectatic) induration (obliterative-interseptal fibrosis), a process that has largely been neglected so far.
Virchows Arch B Cell Pathol Incl Mol Pathol 1989
PMID:Cellular events in alveolitis and the evolution of pulmonary fibrosis. 257 13

Tissue eosinophilia has been reported to occur in pulmonary fibrosis, a disease characterized by chronic inflammation and lung fibroblast proliferation. We have examined the in vitro interaction of these two cell types by determining the in vitro survival of human peripheral blood eosinophils co-cultured with human lung fibroblasts. Survival of eosinophils cultured alone was 10% at day 3 and less than 1% at day 7. In contrast, survival of eosinophils that had been co-cultured with fibroblasts was 98, 90, 73, and 69% at days 3, 7, 10, and 14, respectively. Fibroblast-conditioned medium (CM) elicited a similar result in a dose-dependent fashion. Survival of eosinophils cultured with CM which had been preincubated with a monoclonal-neutralizing antibody to human GM-CSF was inhibited in a dose-dependent manner. Human recombinant-derived GM-CSF supported eosinophil survival in the dose-dependent fashion. Survival at day 7 of eosinophils treated with one single dose of GM-CSF (10 U/ml) was 64%. The effect of fibroblast-CM on eosinophils likely represents true survival since eosinophil proliferation as determined by [3H]thymidine incorporation did not occur. We also report that freshly isolated eosinophils had normal ultrastructural, scanning and transmission electron microscopy characteristics, and were normodense. In contrast, eosinophils co-cultured for 7 days with fibroblasts acquired irregular shapes and became hypodense and partially degranulated. Thus, our results indicate that human lung fibroblast-derived GM-CSF mediates the in vitro survival of human eosinophils.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1989 Oct
PMID:Human lung fibroblast-derived granulocyte-macrophage colony stimulating factor (GM-CSF) mediates eosinophil survival in vitro. 269 15


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