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Biomedical subjects

J D Fulmer

Publications and source records attributed to J D Fulmer.

At least 19 recordsLinked to original sources
PubMed1989

Lodoxamide tromethamine prevents neutrophil accumulation in reexpansion pulmonary edema.

Reexpansion pulmonary edema (RPE) is an acute, unilateral lung injury initiated by cytotoxic oxygen metabolites and temporally associated with an influx of polymorphonuclear neutrophils (PMNs); these toxic oxygen products appear to result from reoxygenation of chronically collapsed lung. Lodoxamide tromethamine (U-42585E) reduces infarct size after reperfusion of ischemic myocardium. The possible protective effects of lodoxamide in RPE were examined. Right lungs of rabbits were collapsed for 7 days by injection of air into the pleural space. Reexpansion was accomplished by chest tube with negative pressure in spontaneously ventilating rabbits. Twelve pairs of animals received either lodoxamide (20 mg/kg/h intravenously (i.v.) from 30 min before reexpansion until they were killed) or an equivalent volume of sterile saline. After 2 h, animals were killed by i.v. pentobarbital. Right and left lungs of six pairs of animals were lavaged with 25 ml saline each; the remaining six pairs of animals were studied by measurement of lung wet/dry weight ratio. Albumin concentrations in lavage fluid (BAL) of lodoxamide-treated animals were 243 +/- 165 micrograms/ml in right lung and 29 +/- 15 micrograms/ml in left lung (p less than 0.03); albumin concentration in right lung BAL of untreated animals was 1,180 +/- 319 micrograms/ml (p less than 0.02 vs. lodoxamide-treated animals). PMN percentages in right BAL (3.8 +/- 3.1) and left BAL (2.9 +/- 2.2) did not differ in lodoxamide-treated animals (p greater than 0.65); PMN percentage in right BAL of untreated animals was 18.7 +/- 2.9 (p less than 0.001 vs. lodoxamide-treated animals).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1989

Dietary fish oil inhibits bleomycin-induced pulmonary fibrosis in the rat.

Intratracheal bleomycin induces pulmonary fibrosis in experimental animals, but the mechanisms involved are poorly understood. Since altered levels of fatty acid metabolites are associated with bleomycin-induced lung injury, we examined the effects of a change in dietary fat on bleomycin-induced fibrosis. Previously we have shown that an essential fatty acid-deficient diet can reduce the severity of bleomycin-induced pulmonary fibrosis. The present study examined the effect of replacement of usual dietary fat with menhaden oil, rich in eicosapentaenoic acid, on the development of pulmonary fibrosis. Weanling rats were raised on a standard laboratory diet or a diet consisting of a fat-free powder to which was added 25% (w/w) of menhaden oil. After 8 weeks of feeding, the animals received either 1.5 units of bleomycin or an equivalent volume of saline intratracheally. In animals receiving the laboratory diet, bleomycin treatment produced a 44% increase in total lung protein content when compared to saline-treated controls (p less than 0.001) and a 77% increase in total lung hydroxyproline content (p less than 0.01). In contrast, bleomycin-treated animals receiving the menhaden oil diet had only small increases, which did not reach statistical significance, in protein and hydroxyproline content in the lung. Bronchoalveolar lavage cellularity did not differ among the treatment groups, but the percentage of lavage macrophages was slightly diminished in bleomycin-treated animals receiving the laboratory diet. Cellular differentials of lavage fluid did not differ significantly between bleomycin- and saline-treated animals receiving the menhaden oil diet. Bleomycin-induced histologic changes, quantitated by morphometric analysis, were significantly reduced with the menhaden oil diet. We conclude that a diet rich in eicosapentaenoic acid can significantly ameliorate bleomycin-induced pulmonary fibrosis, possibly via alterations in eicosanoid metabolism.

Animals↗
PubMed1988

Modulation of the development of bleomycin-induced fibrosis by deferoxamine.

Bleomycin is an antineoplastic compound which produces a time- and dose-dependent pulmonary fibrosis. The mechanisms which cause this fibrosis are not known. The ability of bleomycin to produce oxygen radicals in the presence of iron and molecular oxygen appears to be related to the fibrosis. Previous studies, which have examined single time points utilizing the ferric ion chelator deferoxamine and iron-deficient diets, suggest that iron plays a central role in bleomycin-induced pulmonary fibrosis. Therefore, the present study was designed to determine the effects of deferoxamine on the development of bleomycin-induced pulmonary fibrosis. Deferoxamine pretreatment and daily injections resulted in a significant reduction in lung collagen content and lung lipid peroxidation 21 days after intratracheal bleomycin compared with bleomycin treatment alone. In addition deferoxamine treatment significantly inhibited lung DNA increases at 4, 7, and 14 days after bleomycin treatment compared with bleomycin treatment alone. These data indicate that deferoxamine treatment reduces the development of bleomycin-induced pulmonary fibrosis in the later phase. The mechanism might be by the prevention of iron-catalyzed, free-radical formation and modulation of some cellular functions.

Animals↗
PubMed1988

Neutrophils in reexpansion pulmonary edema.

This study investigated the possible contribution of neutrophils to development of reexpansion pulmonary edema (RPE) in rabbits. Rabbits' right lungs were collapsed for 7 days and then reexpanded with negative intrathoracic pressure for 2 h before study, a model that creates unilateral edema in the reexpanded lungs but not in contralateral left lungs. Two hours after lung reexpansion, significant increases in lavage albumin concentration (17-fold), percent neutrophils (14-fold), and total number of neutrophils (7-fold) recovered occurred in the reexpanded lung but not in the left. After 2 h of reexpansion increased leukotriene B4 was detected in lavage supernatant from right lungs (335 +/- 33 pg/ml) compared with the left (110 +/- 12 pg/mg, P less than 0.01), and right lung lavage acid phosphatase activity similarly increased (6.67 +/- 0.35 U/l) compared with left (4.73 +/- 0.60 U/l, P less than 0.05). Neutropenia induced by nitrogen mustard (17 +/- 14 greater than neutrophils/microliters) did not prevent RPE, because reexpanded lungs from six neutropenic rabbits were edematous (wet-to-dry lung weight ratio 6.34 +/- 0.43) compared with their contralateral lungs (4.97 +/- 0.04, P less than 0.01). An elevated albumin concentration in reexpanded lung lavage from neutropenic rabbits (8-fold) confirmed an increase in permeability. Neutrophil depletion before reexpansion did not prevent unilateral edema, although neutrophils were absent from lung sections and alveolar lavage fluid from neutropenic rabbits.

Acid Phosphatase↗
PubMed1988

Superoxide dismutase and cytochrome oxidase in collapsed lungs: possible role in reexpansion edema.

This study examined the effects of lung collapse, a condition that causes relative hypoxia in lung tissues, on superoxide dismutase (SOD), cytochrome oxidase (cyt ox), and pyruvate kinase (py ki) activities in rabbits. Cyanide-insensitive respiration measurements were done in collapsed and contralateral lungs, as an index of intracellular free radical production. Rabbits' right lungs were collapsed for 7 days after which the animals were killed. We found that control rabbit lungs contained approximately 25 SOD units/mg DNA measured with 10(-5) M KCN (total SOD) and approximately 11 SOD units/mg DNA measured with 10(-3) M KCN (mitochondrial or MnSOD). Right lung collapse caused a 25% decrease in mitochondrial SOD activity after 7 days (P less than 0.05), whereas no significant changes occurred in right or left lungs' total SOD activity. In control rabbits cyt ox activity averaged approximately 0.009 mumol ferrocytochrome c.min-1.mg DNA-1. Right lung collapse caused a greater than 40% decrease in cyt ox activity after 7 days of collapse (P less than 0.05), whereas cyt ox activity in contralateral left lungs did not change. Pyruvate kinase activity, a marker for anaerobic glycolysis resulting from tissue hypoxia, increased 49% in collapsed right lungs (P less than 0.01). Cyanide-insensitive respiration was 83% higher in 7 day-collapsed lungs (2.28 +/- 0.66 microliters O2.min-1.g-1) compared with contralateral lungs (1.24 +/- 0.34, P less than 0.05), indicating increased O2-. and H2O2 production in this tissue after homogenization at normoxic PO2 (approximately 150 Torr).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effect of iron deficiency on bleomycin-induced lung fibrosis in the hamster.

Bleomycin produces a dose- and time-dependent interstitial pulmonary fibrosis in humans, and is widely used to produce an animal model for the study of interstitial pulmonary fibrosis. The mechanism(s) for bleomycin-induced pulmonary fibrosis is (are) unknown, but the production of oxygen radicals by a ferrous ion-molecular oxygen pathway might be related to the fibrosis. Therefore, we studied the effect of iron deficiency on the biochemical, inflammatory, and morphologic parameters of bleomycin-induced pulmonary fibrosis in the hamster. Mild iron deficiency was induced in hamsters by bleeding via the retro-orbital sinus and maintenance on an iron-deplete diet. After intratracheal administration of bleomycin (1 U), there was no accumulation of lung collagen in the iron-deficient bleomycin-treated animals. In comparison, iron-replete animals treated with bleomycin exhibited a significant (p less than 0.01) increase in lung collagen. In addition, bleomycin-treated iron-replete animals had increased lung lipid peroxidation (p less than 0.05), whereas bleomycin-treated iron-deficient animals did not (p greater than 0.05). Lung DNA and morphometric estimates of the lesion severity were significantly increased in both iron-replete and iron-deficient bleomycin-treated animals. These data indicate that iron deficiency is associated with a reduction in the severity of bleomycin-induced pulmonary fibrosis, possibly by the prevention of iron-catalyzed oxygen-radical formation and lipid peroxidation.

Animals↗
PubMed1988

Re-expansion pulmonary edema. A potential role for free radicals in its pathogenesis.

Re-expansion pulmonary edema (RPE) has been attributed to decreased lung interstitial pressures from a variety of mechanisms. Because some recent studies have implicated mechanisms that increase microvascular permeability in RPE, we tested whether the edema were due to free radical generation during re-expansion and reoxygenation of the collapsed lung. We used a rabbit model of RPE to test the effects of intracellular (dimethylthiourea) or extracellular (catalase) oxygen metabolite scavengers. Allopurinol was administered separately to determine whether xanthine oxidase was an important source of superoxide in this model. Edema was quantitated both gravimetrically and histologically, and lung xanthine oxidase activity was measured using a sensitive fluorometric assay with pterin as substrate. The results suggest indirectly that OH. or H2O2 (derived from O2-) contribute to the well-documented increase in lung permeability in RPE because dimethylthiourea, dimethylthiourea plus catalase, or catalase alone inhibited the edema to various degrees. Further, we observed histologically that increased numbers of neutrophils were present in re-expanded lungs and that neutrophil infiltration appeared to be diminished by antioxidant administration. Allopurinol did not decrease the edema, because xanthine oxidase activity in rabbit lung tissue is extremely low. We speculate that free radical generation in lung tissue contributes to the pathogenesis of RPE, although reinitiation of lung perfusion and ventilation requires a rapid change in intrathoracic pressure.

Allopurinol↗
PubMed1987

Prostaglandin synthesis and release by subpopulations of rat alveolar macrophages.

Alveolar macrophages are the primary phagocytic cell of lung, but are also capable of a variety of other functions, which include initiating or modulating inflammatory and immune responses through the production of soluble mediators. One such group of mediators is the eicosanoids. Further, recent data indicate that alveolar macrophages are not functionally homogeneous, but are heterogeneous with several subpopulations that differ both morphologically and functionally. Considering the apparent importance of prostaglandin synthesis and release in inflammatory and immune responses, the current study was undertaken to determine whether alveolar macrophage subpopulations differ in their ability to synthesize and release prostaglandin (PG) E, PGI2, and thromboxane A2 after stimulation by calcium ionophore A23187, zymosan, or aggregated IgG. Alveolar macrophages were harvested by bronchoalveolar lavage and were separated into 18 density-defined fractions. Density-defined alveolar macrophages (DD-AM) showed marked heterogeneity in prostaglandin synthesis and release. Maximal PGE synthesis and release was seen as a single peak after calcium ionophore A23187 and zymosan stimulation. In contrast, two peaks in PGE synthesis were seen after aggregated IgG stimulation. PGI2 synthesis was seen as a single peak generated by different DD-AM after calcium ionophore A23187 and zymosan. In contrast, aggregated IgG stimulation of subpopulations exhibited uniform synthesis and release of PGI2. Thromboxane A2 synthesis and release was maximal from a broad range of various DD-AM after calcium ionophore A23187, zymosan, and aggregated IgG stimulation. The results demonstrate that DD-AM are heterogeneous in ability to synthesize and release prostaglandins which is dependent on the stimuli. Therefore, specific subpopulations of alveolar macrophages may be central to the control of the pulmonary inflammatory response through specific eicosanoid synthesis and release.

Animals↗
PubMed1987

Amiodarone pulmonary toxicity. Clinical, radiologic, and pathologic correlations.

We have studied 15 patients with amiodarone pulmonary toxicity and compared them with five amiodarone patients without evidence of toxic effect. Six of 15 patients who had toxic reactions presented with an acute illness that resembled an infectious disease. While diffuse interstitial disease was frequent on chest roentgenogram, seven of 15 had airspace opacities, and five had well-localized infiltrates. Physiologic changes were not uniformly found. An interstitial pneumonia with foamy alveolar macrophages was the most common pathologic finding. Foamy macrophages were also present in three of five nontoxic patients. Three of three patients who had toxic reactions, and two of five patients without toxic reactions had lamellated inclusion bodies by electron microscopy. We conclude that all features of amiodarone toxicity are protean, and it may mimic infectious diseases. While pathologic changes are often characteristic, neither foamy alveolar macrophages nor lamellated cytoplasmic inclusions reliably distinguish toxic from nontoxic patients.

Adult↗
PubMed1987

Effects of dietary fats on bleomycin-induced pulmonary fibrosis.

Bleomycin treatment has been used for the experimental induction of pulmonary fibrosis, but the mechanisms involved are poorly understood. Since alterations in the levels of certain fatty acid metabolites have been associated with bleomycin-induced lung injury, we examined the effects of different dietary fats on the development of bleomycin-induced pulmonary fibrosis. Weanling rats were raised on standard laboratory feed or a diet consisting of a fat-free powder to which was added either coconut oil or beef tallow (25% w/w). After 8 weeks of feeding, animals received either 1.5 units bleomycin or an equivalent volume of saline intratracheally. Bleomycin treatment resulted in significant increases in total lung hydroxyproline content in the groups fed the standard lab diet (p less than 0.001) and beef tallow diet (p less than 0.001), but not in the group receiving the coconut oil diet. Furthermore, the lung hydroxyproline content in bleomycin-treated animals was less with the beef tallow diet compared with standard lab feed (p less than 0.05). Bleomycin treatment resulted in an increase in thiobarbituric acid-reactive products, an index of lipid peroxidation, in lungs from animals fed the standard lab diet, but not in the other diet groups. The percentage of diseased lung, as determined by morphometric analysis, was increased in bleomycin-treated animals from all diet groups (p less than 0.05). We conclude that alterations in dietary fats can reduce the severity of pulmonary fibrosis resulting from bleomycin treatment. Possible mechanisms for this effect include alterations in eicosanoid metabolism or changes in immune or effector cell function.

Animals↗
PubMed1986

Fractionation of rat alveolar macrophages by isopycnic centrifugation: morphological, cytochemical, biochemical, and functional properties.

Studies on alveolar macrophages have usually been performed on a single cell suspension obtained by lung lavage. However, recent evidence on the diversity of functions of the alveolar macrophage suggests that the macrophage is not a single population, but one composed of several subpopulations of macrophages. One approach toward determining if alveolar macrophages are heterogeneous would be to separate subpopulations based on density. To accomplish this, we developed a continuous gradient of iso-osmotic colloidal silica (Percoll) that separated alveolar macrophages from Fischer 344 rats into 18 density-defined subpopulations. The density-defined alveolar macrophage subpopulations were then characterized and were shown to be significantly different based on morphological, cytochemical, biochemical, and functional analysis. The results of this study suggest that alveolar macrophages are heterogeneous and that a continuous iso-osmotic gradient of colloidal silica is an efficient and reproducible method for separating subpopulations.

Animals↗
PubMed1986

Production of arachidonic acid metabolites by endothelial cells in hyperoxia.

This study investigated the response of bovine pulmonary artery endothelial cells to incubation in hyperoxia (95% O2-5% CO2). Changes in cell number and morphology, release of lactate dehydrogenase, and production of arachidonic acid metabolites were assessed during continuous exposure of confluent endothelial monolayers to air (air-5% CO2, "controls") or O2 (95% O2-5% CO2, "O2-exposed") for periods of 12-72 h. Control monolayer cell numbers remained constant (approximately 2,000,000 cells/flask), whereas the number of cells in O2-exposed monolayers decreased progressively to 30% of controls (P less than 0.01) by 72 h. As assessed by radioimmunoassay, both control and O2-exposed cells produced the prostacyclin metabolite, 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), and prostaglandin F2 alpha (PGF2 alpha), but no thromboxane metabolite (TxB2) was detected. The O2-exposed cells released significantly more 6-keto-PGF1 alpha and PGF2 alpha than control cells when apparent net production rates over the entire 72-h period were compared. In addition, both control and O2-exposed (48 h) endothelial monolayers released immunoreactive leukotriene B4 (LTB4) on stimulation with calcium ionophore (10 microM A23187). As with the cyclooxygenase products, O2-exposed cells released more immunoreactive LTB4 than did controls. Both cyclooxygenase and lipoxygenase metabolites of arachidonic acid are released by cultured endothelial cells during the development of O2 toxicity.

Animals↗
PubMed1986

Studies of membrane receptors and phagocytosis in subpopulations of rat alveolar macrophages.

Recent data suggest that alveolar macrophages may be a heterogeneous group of cells with several subpopulations. This study was undertaken to determine if there is heterogeneity among rat alveolar macrophages with respect to receptors for zymosan, immunoglobulin, and complement. In addition, avidity for the immunoglobulin IgG was defined by opsonizing sheep red blood cells (SRBC) with different amounts of IgG. Alveolar macrophages were harvested by bronchoalveolar lavage and separated into 18 density-defined fractions by centrifugation through a continuous isosmotic gradient of colloidal silica. All density-defined alveolar macrophages exhibited similar abilities to attach zymosan and SRBC opsonized with a high level of IgG. In contrast, macrophages of a density of 1.046 g/ml to 1.075 g/ml exhibited high receptor activity capable of attaching and phagocytizing SRBC opsonized with small amounts of IgG. Similarly, attachment indices for complement-coated SRBC exhibited a peak activity among fractions exhibiting similar high avidity receptors for IgG. These results demonstrate the functional heterogeneity with respect to IgG and complement receptors among density-defined rat alveolar macrophage subpopulations.

Animals↗
PubMed1986

Studies of membrane receptors, phagocytosis, and morphology of subpopulations of rat lung interstitial macrophages.

Recent data suggest that pulmonary macrophages may be heterogeneous. Several studies have demonstrated that alveolar macrophages are functionally and biochemically heterogeneous. In addition, interstitial macrophages, which are believed to be the precursors to alveolar macrophages, have been suggested to be heterogeneous. Therefore, this study was undertaken to determine if density-defined interstitial macrophages (DD-IM) are heterogeneous with respect to receptors for zymosan, immunoglobulin, and complement as well as morphologically. Furthermore, avidity for IgG was defined by opsonizing sheep red blood cells (SRBC) with different amounts of IgG. Interstitial macrophages were harvested and separated into 18 DD-IM subpopulations by centrifugation through a continuous iso-osmotic gradient of colloidal silica. Interstitial macrophages showed marked heterogeneity in cellular volume. Furthermore, macrophages of density 1.046 to 1.075 g/ml exhibited higher receptor activity capability of attaching and phagocytizing SRBC opsonized with small amounts of IgG and towards zymosan. All DD-IM exhibited similar abilities to attach complement-coated SRBC. These results demonstrate the functional heterogeneity of interstitial macrophages with respect to IgG and zymosan.

Animals↗