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Biomedical subjects

W W Merrill

Publications and source records attributed to W W Merrill.

At least 37 records · Page 2Linked to original sources
PubMed1989

Chemotactic properties of rat immunoglobulins and immune complexes.

The effect of rat immunoglobulins and immune complexes on the locomotor function of rat polymorphonuclear leukocytes (PMN) was investigated in vitro. Rat immunoglobulin G1 (IgG1), IgG2a, IgG2b, and IgA monoclonal antibodies specific for the dinitrophenyl hapten were used. Both monomeric and polymeric IgA showed chemotactic activity in a dose-dependent manner. IgG1 and IgG2b also induced a dose-dependent locomotor response of PMN, but the nature of the induced migration was chemokinetic (enhancing random migration). IgG2a was chemotactic and induced maximal migration at a relatively low concentration. IgG1- and IgG2b-immune complexes induced stronger migration than antibody alone; however, IgA- and IgG2a-immune complexes did not. IgA was shown to modify the chemotactic movement of PMN induced by N-formylmethionyl-leucyl-phenylalanine (FMLP). In the presence of both IgA and FMLP in the lower chamber, the migration towards suboptimal concentrations of FMLP was enhanced. By contrast, IgA in the upper chamber decreased migration towards the optimal or higher concentrations of FMLP. These findings suggest that IgA may work synergistically with luminal chemoattractants to mobilize PMN to the locus of infection on the mucosal surface. In addition, the intense activity of IgG2a alone and IgG1- or IgG2b-immune complexes in inducing PMN migration may play an important role in inflammatory processes. The data indicate that immunoglobulins have a direct effect on PMN mobility.

Animals↗
PubMed1989

Kinetics of cellular influx and histamine release in normal human bronchi.

Inhalation of certain substances can induce bronchial inflammation followed by bronchoconstriction or bronchial hyperreactivity. We have developed a model of airway inflammation and bronchoconstriction induced by an aqueous extract of cotton bracts (CBE) in which the severity of flow rate reduction correlates with the presence of bronchoalveolar neutrophils. In the current study normal human volunteers underwent local bronchial instillation of CBE. Bronchial lavage histamine concentrations and cellular populations were determined at time intervals after local challenge. In addition, bronchial biopsies were obtained after CBE instillation, and the degree of subepithelial inflammation was quantitated. We report that lavage of bronchi locally exposed to CBE contains 1) greater histamine concentrations 4 min after challenge compared with lavage from saline-challenged bronchi and 2) concentrations of eosinophils and macrophages that are greater than control lavage 8 min after exposure. Bronchial biopsies taken after CBE instillation also demonstrated a variable degree of subepithelial granulocyte infiltration that correlated with the global bronchoconstricting response to CBE assessed on a separate day. These studies suggest that inflammation can develop rapidly in normal human bronchi and may precede significant flow rate reductions by greater than 1 h.

Biopsy↗
PubMed1989

Modulation of endoperoxide product levels and cyclophosphamide-induced injury by glutathione repletion.

Glutathione is a tripeptide important in a number of diverse cellular functions including enzymatic reactions involved in prostaglandin endoperoxide metabolism. We have previously reported that cyclophosphamide administration to rats results in acute lung injury manifested by increased bronchoalveolar lavage albumin concentrations. In the current study we examine whether cyclophosphamide treatment affects pulmonary glutathione stores or bronchoalveolar endoperoxide metabolic product levels and whether these effects may be related to acute lung injury caused by the drug. We show that cyclophosphamide treatment causes a dose-dependent reduction in pulmonary glutathione stores 4 h after drug administration. In addition, acute lung injury as the result of cyclophosphamide can be abrogated by coadministration of oxothiazolidine carboxylate, an intracellular cysteine delivery system that also reverses pulmonary glutathione depletion induced by cyclophosphamide in our study. Finally, cyclophosphamide treatment reduces prostaglandin E2 concentrations in bronchoalveolar lavage and alveolar macrophage culture supernatant in a dose-dependent fashion and increases bronchoalveolar thromboxane concentrations in low dose-treated animals. These effects are reversed to a variable degree by coadministration of oxothiazolidine carboxylate. Our study suggests in vivo pulmonary arachidonic acid metabolism and cyclophosphamide-induced acute lung injury are modulated by cellular glutathione stores. These findings may have important implications for the treatment of acute lung injury.

Animals↗
PubMed1989

Surface IgA and Fc-alpha receptors on human alveolar macrophages from normal subjects and from patients with sarcoidosis.

Human alveolar macrophages (AM) obtained by bronchoalveolar lavage (BAL) were found to bear cytophilic IgA and Fc alpha-receptors (Fc alpha R) on their surface. The cytophilic IgA belongs to the IgA1 subclass, but unoccupied receptors can be saturated with either IgA1 or IgA2 molecules. Although both polymeric and monomeric forms could attach, binding was about 5-fold greater for the polymers. Both cytophilic IgA and Fc alpha R are sensitive to trypsin and disappear after 18 h of AM culture. An increase in cytophilic IgA was observed on AM from untreated patients with pulmonary sarcoidosis, but not on AM from steroid-treated patients. A significant correlation was found between IgA levels in BAL and the percentage of AM with cytophilic IgA in normal subjects and in steroid-treated sarcoid patients. However, no such relationship was seen among untreated patients. These data suggest that multiple factors may modulate AM surface receptors for IgA. Inflammatory events occurring in the lungs could alter receptor expression and perhaps be of significance in the immunophysiopathology of certain pulmonary diseases.

Binding, Competitive↗
PubMed1989

Human alveolar macrophages release a factor that inhibits phagocyte function.

Human alveolar macrophages release in vitro a factor that inhibits both random migration and chemotaxis of human polymorphonuclear neutrophils (PMN). This factor is not cytotoxic and is recovered in culture supernatants of alveolar cells from most nonsmoking normal subjects. The inhibitor can be detected 30 min after cell cultures are established and is still produced after 24 h in culture. Its release was inhibited by cycloheximide. When supernatants are separated by molecular sieving (I-60 Waters HPLC column), most of the inhibitory activity is recovered in the low-molecular-weight fractions of the chromatogram (less than 1,000 D). The inhibitor has a broad spectrum of activity against known chemoattractants in that it reduces significantly the chemotaxis of PMN induced by the formyl peptide FMLP, by the complement fragment C5a, and by leukotriene B4; it also decreases the chemotactic activity associated with a monocyte-derived interleukin 1 preparation and the chemotactic activity derived from alveolar macrophage culture supernatants. The inhibitory factor is partially heat labile, is sensitive to aminopeptidase M, and is nonpolar. Both phorbol myristate acetate (PMA) and FMLP-induced superoxide release by PMN are diminished significantly in the presence of this inhibitory factor (p less than 0.01 for PMA and p less than 0.05 for FMLP). The inhibitor also reduces monocyte chemotaxis but has no effect on monocyte random migration. Finally, studies with [3H]FMLP indicate that this inhibitor does not act at the site of receptor binding on PMN. Thus, human alveolar macrophages can release in vitro both neutrophil chemotactic factors and an apparent neutrophil-inhibiting factor that may modulate positively and negatively the movement and the respiratory burst of neutrophils in the alveolar space.

Cell Movement↗
PubMed1989

Prostaglandins E2 and E2 alpha are elevated in saliva of cystic fibrosis patients.

Several products of arachidonic acid metabolism were assayed in whole saliva of patients with cystic fibrosis, a disease affecting primarily the exocrine glands. The levels of prostaglandins (PG) E2 and F2 alpha were elevated fourfold in patients with cystic fibrosis, compared with a control group (mean +/- SEM for PGE2 1.13 +/- 0.22 vs 0.37 +/- 0.08 ng/ml saliva, p less than 0.005; and for PGE2 alpha 0.84 +/- 0.27 vs 0.17 +/- 0.03 ng/ml saliva, p less than 0.025). The levels of PGI2, hydroxyeicosatetraenoic acids, and leukotrienes showed no significant differences between the two groups. These changes were not present in individuals heterozygous for the cystic fibrosis gene. Study of appropriate control groups suggested that the changes that we observed in patients with cystic fibrosis could not be attributed to their lung disease or to the medications these patients were receiving. Our findings indicate that metabolism of arachidonic acid is abnormal in cystic fibrosis.

Adolescent↗
PubMed1988

Bronchoalveolar cell activation after inhalation of a bronchoconstricting agent.

Airway inflammation is thought to be an important determinant of bronchoconstriction and bronchial hyperreactivity. We have recently demonstrated that bronchoconstriction induced by an aqueous extract of cotton bracts (CBE) is associated with bronchoalveolar complement activation, release of polymorphonuclear neutrophil (PMN) chemoattractants by pulmonary cells, and increased numbers of bronchoalveolar lavage PMN's. In the present study we performed bronchoalveolar lavage (BAL) on subjects after CBE or control (saline) challenge and examined whether BAL cells were activated in vitro to produce other inflammatory agonists. After CBE administration, cultured BAL cells released increased amounts of the reactive O2 species, superoxide (O2-.), and the cyclooxygenase products prostaglandin E2 and thromboxane B2. Although none of these in vitro parameters of BAL cell activation appeared to correlate with the degree of bronchoconstriction induced by CBE, BAL fluid levels of thromboxane B2 were also increased after CBE administration and in vivo amounts of this eicasanoid did correlate with the degree of bronchoconstriction induced by CBE (r = 0.50, P less than 0.04). Finally, although cell culture supernatants were highly chemotactic for PMN's, concentrations of leukotriene B4 were not increased, suggesting other chemotaxins were released by BAL cells in this setting. We conclude that CBE administration activates bronchoalveolar cells to release reactive O2 species and cyclooxygenase products that may be important in the bronchoconstricting response to CBE.

Adult↗
PubMed1987

Limitations of using urea to quantify epithelial lining fluid recovered by bronchoalveolar lavage.

The quantitation of substances in the epithelial lining fluid (ELF) of the lower respiratory tract, as obtained by bronchoalveolar lavage (BAL), is not precise because of the variable dilution of the ELF by the instilled lavage fluid. It has been reported that the absolute concentration of proteins in ELF can be determined by using the ratio of urea concentration in BAL fluid to that in serum as a method to calculate the volume of ELF recovered by BAL. Furthermore, it has been suggested that the error caused by diffusion of urea into the instilled lavage fluid can be minimized by instilling only 100 ml (5 X 20 ml) of saline rather than 300 ml (6 X 50 ml). We tested the validity of this method by collecting and individually analyzing aliquots from 2 different BAL protocols--a 100-ml (5 X 20 ml) BAL and a 300-ml (6 X 50 ml) BAL--performed in 6 healthy, nonsmoking subjects. Total protein, albumin, and urea were measured in each aliquot and in pooled fluid from each BAL procedure, and urea was measured in serum. In the 300-ml BAL, total protein and albumin concentrations tended to decrease progressively from the second to the sixth aliquots. In contrast, the urea concentration increased progressively from the first to the sixth aliquots. The concentration of albumin in ELF, calculated from the concentration of urea and albumin in each BAL aliquot, tended to decrease in each successive aliquot, becoming significant by the fourth aliquot.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1987

Relationship of the ventilatory response to cotton bract extract and the cells and proteins of the lung.

Many healthy subjects who have had no exposure to cotton textile dusts will experience significant reductions in expired flow rate following an inhalational challenge with an aqueous extract of cotton bracts (CBE). Differences noted among individuals in the magnitude of the bronchial response to a standardized preparation of CBE suggest variable airway reactivity. The mechanism of this response and the reasons for its variability among these naive subjects are unknown. We have studied this problem by performing bronchoalveolar lavage on 13 volunteer subjects with no history of textile dust exposure. Two to three months later, a bronchial provocation with aqueous CBE was performed by an investigator blinded to the lavage results. Subjects with greater than 20 percent drop in flow rate at 40 percent of vital capacity during a partial forced expiration (MEF 40 percent [P]) following CBE had a reduction in total recoverable alveolar macrophages, with a resultant increase in the percentage of recoverable lymphocytes. The magnitude of response (MEF 40 percent [P]) correlated directly with the measured lymphocyte percentage (r = 0.69 p less than 0.01) and inversely with the total numbers of recovered cells.

Adult↗
PubMed1987

Neutrophil chemotactic activity produced by normal and activated human bronchoalveolar lavage cells.

Activated macrophages can secrete a number of mediators that can attract inflammatory cells and enhance secretion of phlogistic substances from these cells. The ultimate effect of activated bronchoalveolar lavage (BAL) cells may be fibrotic lung injury. Inasmuch as pulmonary sarcoidosis is a disease associated with spontaneous activation of macrophages and lymphocytes among BAL cells, cells obtained from patients with sarcoidosis were compared with normal cells. We report that adherent BAL cells in culture from patients with sarcoidosis (n = 21) release during a resting period in vitro more chemotactic activity for neutrophils (PMNs) than do BAL cells from normal individuals (n = 14). After density fractionation of the respiratory cells by albumin gradient, cells from high-density fractions in the group with sarcoidosis secrete more chemotactic activity for neutrophils than cells from less dense fractions. The PMN chemotactic activity spontaneously released in vitro by BAL cells from patients with sarcoidosis correlates with the percentage of PMNs recovered by BAL. Immunochemical bioassay and high-performance liquid chromatographic (HPLC) analysis of BAL cell supernatants revealed a complex pattern of chemotactic factors to be present. Generally, three peaks of chemotactic activity were noted on HPLC 1-60 separations at greater than 20 kd, 8 to 10 kd, and less than 1 kd apparent molecular weights. Significantly, interleukin-1 was present in these supernatants, whereas complement components and leukotriene B4 were absent. Sarcoid BAL cells, principally alveolar macrophages, are activated in vivo as manifested by spontaneous secretion of chemotactic factors for PMNs in vitro. Interleukin-1 and other less well characterized molecules were detected. The presence of PMNs among the lavage cells of some patients with sarcoidosis appears to be an in vivo biologic correlate of this activation. These data provide additional criteria of BAL cell activation in patients with pulmonary sarcoidosis and provide further evidence concerning factors that attract inflammatory cells into the lung.

Bronchoalveolar Lavage Fluid↗
PubMed1987

Cigarette smoking and respiratory tract infection.

Although not conclusive, several lines of evidence suggest that cigarette smoking alters the respiratory tract's ability to defend itself from infection. Some subjects with chronic bronchitis have colonization of the lower respiratory tract with bacteria. Both patients with chronic respiratory disease and healthy smokers appear to have a higher frequency of respiratory infections and an increased severity of symptoms when infected. Children exposed passively to cigarette smoke have higher rates of respiratory illnesses. Yet the marked variability in the incidence of infection in the smoking population suggests that there are subtle factors that predispose some smokers to more risk of infection than others. Cigarette smoking is associated with alterations in mechanisms of the host defense system, even in asymptomatic individuals (summarized in Table 3). Ciliary function is impaired, mucous volume is increased, humoral response to antigens altered, and quantitative and qualitative changes in cellular components occur. Some of these alterations in host defense mechanisms are dose related; others revert to normal after smoking cessation. Yet, it is unknown if one or all of these alterations cause any significant compromise of host defense or if other factors, as yet unidentified, may be important. Answers to these questions await a more thorough elucidation of normal host defense function.

Antibody Formation↗
PubMed1986

Effect of Fluosol-DA/O2 on the antitumor activity and pulmonary toxicity of bleomycin.

The effect of an oxygen-carrying perfluorochemical emulsion on bleomycin antitumor activity and pulmonary toxicity was examined. Fluosol-DA (0.3 ml/mouse, i.v.), combined with bleomycin (10 or 15 mg/kg, i.p.) and a 2 h exposure to 95% oxygen (BFO) increased by five- to six-fold the tumor growth delay of FSaIIC fibrosarcoma compared to bleomycin alone (B). Only a slight increase in tumor growth delay was noted with the incomplete combinations of bleomycin and O2 (BO) and bleomycin and Fluosol-DA (BF). When bleomycin (10 mg/kg) was co-administered with 0.3 ml Fluosol-DA and 95% O2, cell survival was reduced ten-fold compared to that seen with bleomycin alone. In contrast, the surviving fraction of cells obtained from FSaIIC tumors treated in vivo indicated that 0.3 ml Fluosol-DA per mouse or a 2 h exposure to 95% O2 did not markedly alter the effects of bleomycin alone. The pulmonary effects of the BFO combination were assessed during the course of the therapy by bronchoalveolar lavage (BAL) analysis and pulmonary hydroxyproline (OH-Pro) content. Mice treated with this combination had a 20-fold increase in total numbers of cells obtained in the BAL compared to control animals. An increased cellularity in the lungs was also seen morphologically. The composition of the cells in the lavage fluid was altered after BFO but not BO treatment and reflected a neutrophilic influx. Furthermore, total protein recovered in the BAL fluid was increased 5-fold in the BFO treatment group compared to that in the control mice. Pulmonary OH-Pro, an index of collagen and fibrosis, was unaffected acutely after three treatments of either BFO or BO compared to control mice. Thus, Fluosol-DA and O2 can enhance the antitumor activity of bleomycin. The increased pulmonary cellularity suggests that this combination may also have adverse effects on lung tissue.

Animals↗
PubMed1986

Influence of sputum IgA and elastase on tracheal cell bacterial adherence.

Bacterial adherence is an important pathogenetic mechanism for airway colonization, but the influence of airway proteins on this phenomenon is largely unknown. We measured tracheal cell bacterial binding in 13 subjects with chronic tracheostomy and related these results to measurements of sputum IgA, elastase activity, and total protein from the same subjects. Tracheal cell adherence was related directly to sputum elastase activity (r = 0.61, p = 0.02); and elastase activity, primarily a serine protease, was higher in subjects colonized by Pseudomonas aeruginosa than in those without this finding (p = 0.02). Sputum levels of IgA/mg protein were related inversely to tracheal cell adherence (r = 0.64, p = 0.02). Sputum IgA concentrations, in turn, were affected by host nutritional status and airway elastase activity. Evidence that elastase can degrade sputum IgA was provided by an inverse relationship observed between these 2 proteins (r = 0.56, p = 0.04) and by in vitro mixing experiments showing fragmentation of IgA by purified neutrophil elastase. In addition, sucrose density gradient separation indicated IgA fragmentation to have occurred in vivo. These data suggest that, once adherence leads to airway colonization, the resulting inflammatory response may foster microbial growth by an elastase-dependent IgA cleavage and hence enhanced tracheal cell adherence.

Adult↗
PubMed1986

Immunoglobulin-G subclasses in cystic fibrosis. IgG2 response to Pseudomonas aeruginosa lipopolysaccharide.

Pulmonary macrophage phagocytosis of Pseudomonas aeruginosa is defective when this pathogen is opsonized with IgG antibodies isolated from serum samples from patients with cystic fibrosis (CF). To evaluate this defect further, IgG subclasses in the serum and lung fluids of patients with CF were quantitated. The pattern of IgG subclasses in serum specimens from patients with CF (n = 15) and in patients without CF but with chronic obstructive airway disease and recurrent P. aeruginosa infection (n = 4) was significantly altered from that found in normal subjects (n = 31). Immunoglobulin-G2 and IgG3 expressed as percentages of total IgG subclasses or in micrograms per milliliter of serum were significantly elevated in the serum specimens of these patients (p less than 0.05), and IgG1 was significantly decreased (p less than 0.01). It appears that the increase in IgG2 in the serum of patients with CF and those without CF but with chronic P. aeruginosa infection may be in response to chronic antigenic stimulation by P. aeruginosa lipopolysaccharide. Evidence presented to support this includes: (1) IgG2 is not increased in CF serum if a history of P. aeruginosa infection is absent, (2) IgG2 levels expressed as percentages of total IgG subclasses in CF lung fluids were positively correlated (r = 0.73) with the number of colony-forming units of P. aeruginosa present in CF sputum specimens, and (3) IgG antibodies specifically eluted from P. aeruginosa lipopolysaccharide ligands on affinity gels were largely restricted to IgG2. The opsonic index, ([IgG3] + [IgG1]) divided by ([IgG2] + [IgG4]), is inverted in CF lung fluids (0.73:1; normal, 2:1). Because pulmonary macrophages show surface receptors binding primarily with IgG3 and IgG1, it may be that such an alteration in IgG subclasses in the respiratory secretions of patients with CF further inhibits opsonin-mediated clearance of P. aeruginosa.

Adolescent↗
PubMed1986

Cyclophosphamide modulation of bronchoalveolar cellular populations and macrophage oxidative metabolism. Possible mechanisms of pulmonary pharmacotoxicity.

Cyclophosphamide, an immunosuppressive alkylating agent, has been reported to cause acute and chronic pulmonary injury in both humans and animals. Cyclophosphamide is also a common component of multi-drug regimens that show high pulmonary toxic potential. Although mechanisms of pulmonary damage caused by cyclophosphamide or other cytotoxic agents are unknown, possibilities include direct toxicity to pulmonary tissue or indirect toxicity through activation of pulmonary inflammatory cells. We report here a model system for the study of acute effects of cyclophosphamide on pulmonary immune cells in rats. Our findings show that 16 h after 1 intraperitoneal dose of cyclophosphamide there is: a dose dependent release of locally produced low molecular weight chemotactic factors for blood monocytes into bronchoalveolar lavage (BAL) fluid, a pulmonary influx of immature myeloperoxidase positive macrophages in low dose cyclophosphamide treated animals, an enhancement of oxidant generation by pulmonary macrophages from low dose treated animals that correlates with the presence of myeloperoxidase positive macrophages, the presence of factors in BAL fluid of treated rats that modulate oxidant release by normal rat pulmonary macrophages, a dose dependent reduction in the percentage of BAL lymphocytes, and evidence for pulmonary injury as manifested by elevated BAL fluid albumin concentrations in low dose cyclophosphamide treated animals. These findings suggest that cyclophosphamide may induce pulmonary injury through activation of pulmonary immunocompetent cells and subsequent attraction of systemic inflammatory cells.

Albumins↗