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Biomedical subjects

W W Merrill

Publications and source records attributed to W W Merrill.

At least 55 records · Page 3Linked to original sources
PubMed1986

An in vitro model for polymorphonuclear-leukocyte-induced injury to an extracellular matrix. Relative contribution of oxidants and elastase to fibronectin release from amnionic membranes.

Alteration of the extracellular matrix by inflammatory cells is believed to be important in both lung injury and the subsequent restoration of lung architecture. Here we describe the results of the interaction between an acellular human amnionic membrane model and stimulated human polymorphonuclear neutrophils (PMN) in vitro. Polymorphonuclear neutrophil suspensions were placed on one surface of the amnion, and either the chemotactic peptide FMLP or the cell membrane activator phorbol myristate acetate (PMA) was placed on the opposite side of the amnion. Stroma and basement membrane sides of the amnion were separately exposed to the PMN. The PMN suspension was removed and centrifuged, and the supernatant was assayed for superoxide anion (O2-.) and for elastase activity. Injury to the acellular amnion was evaluated by transmission electron microscopy and by measurement of fibronectin (FN) released from the membrane matrix. Although both stimulants cause a concentration-dependent release of O2-., only PMA stimulated elastase release. These effects were similar when either the stroma or the basement membrane side was exposed to PMN. PMA-stimulated cells and supernatants from PMA-stimulated cells caused solubilization of membrane at different incubation times. Electron microscopy confirmed the disruption of the basement membrane of the amnion by PMA-stimulated PMN. Oxidant scavengers (SOD and catalase) did not prevent matrix degradation, and elastase inhibition by a specific chloromethylketone inhibitor diminished FN release on both sides of the amnion by activated PMN supernatants, but only on the basement membrane side by intact PMN. We conclude that in this model, elastase rather than oxygen radicals solubilizes FN from the matrix.

Amnion↗
PubMed1986

The relationship between bronchoalveolar neutrophil recruitment and bronchoconstriction induced by a soluble extract of cotton bracts.

Byssinosis is characterized by an obstructive bronchitis in some workers exposed to cotton dust. Mechanisms of airway alterations induced by cotton dust are unknown. To study mechanisms of these alterations, we administered an aqueous extract of cotton bract (CBE) to normal human subjects. After CBE inhalation, we demonstrated reproducible reductions in flow rates of variable magnitude. The percentage of polymorphonuclear leukocytes (PMN) recovered by bronchoalveolar lavage (BAL) and total PMN per milliliter BAL fluid were increased after challenge with CBE, and these parameters were correlated (r = 0.556 and r = 0.553, respectively) with the degree of bronchoconstriction induced by CBE. In addition, chemotactic factors for PMN were noted in BAL fluid and in supernatant from BAL cell cultures. The degree of BAL fluid chemotactic activity correlated with the degree of bronchoconstriction induced by CBE. Assessment of molecular sieve column effluent demonstrated BAL fluid to have 3 distinct peaks of chemotactic activity (approximate molecular weight, greater than 25,000, 10,000, and less than 1,000 daltons) and cell culture supernatant to contain 1 peak (approximate MW, 10,000 daltons). Complement activation as one source of BAL chemotactic activity was suggested by almost complete inhibition of BAL chemotactic activity after incubation with antibody to the fifth component of complement (C5) and detection of C5a des Arg in BAL fluid from some subjects challenged with CBE. These findings suggest that exposure of volunteer subjects to CBE results in a bronchoalveolar inflammatory response related to both complement activation and chemotactic factor synthesis by luminal cells.

Adult↗
PubMed1986

Biologic activity of purified cotton bract extracts in man and guinea pig.

Purified aqueous extracts of cotton bract induce acute airway constriction in healthy volunteers never before exposed to cotton bract. The response is similar to that of textile workers who inhale cotton dust. Approximately 60% of volunteers respond to bract extract with significant decreases in lung function, and these volunteers show an increased number of lymphocytes present in their lungs. Following inhalation of bract, the percent of polymorphonuclear leukocytes increases. Macrophages obtained by bronchoalveolar lavage from volunteers pre-challenged with bract extract release increased amounts of chemotactic factor and superoxide anion. Efforts to detect release of histamine and leukotrienes in volunteers following challenge with bract show no increase in urinary histamine and no significant release of leukotrienes in lung lavage fluid. Purified extracts exhibit chemotactic activity in vitro. They also contract guinea pig ileal longitudinal muscle in vitro. This preparation contains mast cells but no basophils, and the H-1 blocker, mepyramine blocks the contraction. Purified bract extracts contain no histamine or endotoxin but other contractors of smooth muscle may be present. The purified extract exhibits spectral, fluorescent, and radioimmune assay properties similar to a leukotriene B-like component. Cotton bract appears to have direct as well as cell-mediated activities.

Adolescent↗
PubMed1986

Interstitial lung diseases in the elderly patient.

In this article we have attempted to review basic aspects of the respiratory immune system and some of what is known about the effects of aging on immunity. We have discussed the more common forms of interstitial lung disease as they relate to the elderly patient and have outlined a general method of approaching interstitial disease in this population. This topic is the focus of considerable ongoing research, and a wealth of information is available for the clinician who desires to delve more deeply into the subject. It is our hope that this article will serve as a background to facilitate further study by those with a particular interest in this area.

Aged↗
PubMed1986

Bacterial adherence to respiratory tract cells. Relationships between in vivo and in vitro pH and bacterial attachment.

Alterations in in vitro pH have been shown to have a significant effect on the bacterial binding capacity of epithelial cells for certain organisms. We investigated the effect of in vivo pH and in vitro changes in pH on the adherence of Pseudomonas aeruginosa to buccal and tracheal cells of 19 chronic tracheostomy patients. In addition, airway pH was measured in 5 normal volunteers. Oropharyngeal and endobronchial pH were measured with a flexible electrode that could be passed through a bronchoscope under direct visualization. In vitro adherence of Pseudomonas to respiratory epithelial cells was determined at pH 6.5 and 7.2. Colonization status of the patients was determined by culture of oropharyngeal and tracheal secretions. The pH value of each site in the respiratory tract and its secretions were different in the tracheostomy patients (buccal pH 6.3; tracheal, 6.9; sputum, 7.5). No difference was noted in pH of the 2 sites in control subjects (buccal, 6.7; tracheal, 6.7). Changes in in vitro pH had a significant effect (p less than 0.004) on bacterial binding to epithelial cells from both sites. The pH had its greatest effect on tracheal cells of patients colonized with Pseudomonas. Increased in vitro binding of these organisms was noted at the more alkaline pH. The magnitude of the effect of in vitro pH alteration on bacterial binding correlated directly with the degree of binding. These results demonstrated that pH has a significant effect on in vitro Pseudomonas adherence and the effect is most marked on cells obtained from the lower respiratory tract of patients colonized with this organism.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Skin testing with an aqueous extract of cotton bract.

Airway challenge with cotton bract extract (CBE) causes reversible bronchospasm in most volunteers never before exposed to CBE or the textile industry. Lung function abnormalities develop slowly after inhalation with a maximum effect reached within 2 hours and lung function slowly improving thereafter. When CBE was injected intradermally in three naive subjects with negligible airway response to CBE, we observed an initial wheal-and-flare reaction within minutes followed by erythema and subsequent induration that persisted for 24 to 48 hours. Microscopic examination of skin biopsy specimens obtained during the course of these reactions revealed edema in the early phase followed by perivascular infiltration of a mixed cellular nature in the subsequent stages of the reaction. Degranulation of mast cells was noted throughout the course of the reaction. These findings indirectly suggest that a nonspecific inflammatory reaction initiated by mast cell-derived mediators and sustained by the presence of infiltrating cells may be responsible for some of the airway effects observed in byssinosis.

Byssinosis↗
PubMed1985

Immunoglobulin G subclass proteins in serum and lavage fluid of normal subjects. Quantitation and comparison with immunoglobulins A and E.

Although total concentration of immunoglobulin G has been quantitated in the lower respiratory tract of humans, the contribution of the 4 subclass species of IgG to total recoverable IgG protein has not been assessed. We have developed sensitive, micro-ELISA assays specific for the individual subclasses and employed them to measure serum and local intrapulmonary levels of these proteins. We have compared lung lavage and serum concentrations of these proteins (relative to albumin) and also compared these immunoglobulins with IgA and IgE. The results of serum level measurements of subclass proteins are similar to results reported by others; IgG1 and IgG2 are present in lung lavage in concentrations similar to their serum concentration, serum and lavage levels are directly related, and IgG4 is increased in lavage compared with that in serum, suggesting increased local synthesis or accumulation of this protein within the lower respiratory tract. Local intrapulmonary concentrations of both IgA and IgE also are increased compared with those in their serum concentrations. Local IgG3 is variable, with some subjects having increased amounts compared with that in serum, whereas others have concentrations similar to those in serum. These data suggest a preferential accumulation of IgG4 in the lower respiratory tract. It is possible that IgG4, like IgA and IgE, plays a special role in the immune defense of the lung.

Adolescent↗
PubMed1984

Alterations in the antibacterial properties of rabbit pulmonary macrophages exposed to wood smoke.

We studied the local response of the bronchoalveolar cell population after acute exposure to smoke from pyrolysis of Douglas fir wood. Cell viability experiments and function of the pulmonary macrophages were assessed, including adherence to surfaces, bacterial phagocytosis, and the intracellular bactericidal process. The smoke-exposed group (n=23) when compared with control animals (n=15) produced a significantly greater total cell yield (p less than 0.01) on bronchoalveolar lavage. There was no increase in the percentage of polymorphonuclear leukocytes. As carboxyhemoglobin levels increased, macrophage adherence to glass decreased (r = -0.79, p = 0.0001). Pulmonary macrophages from exposed animals were 33% less adherent at 120 min in vitro; however, these nonadherent smoke-exposed macrophages remained viable (55 to 78% viable by trypan blue dye exclusion). Both the phagocytic rate (361 14C cpm/unit time) and the maximal number of bacteria associated (at 60 min) with the exposed macrophages were significantly less than in the sham-exposed animals (uptake = 672 14C cpm/time, p less than 0.002 for each). The antibacterial properties of pulmonary macrophages are adversely affected by exposure to wood pyrolysis.

Animals↗
PubMed1984

Demonstration of a free elastolytic metalloenzyme in human lung lavage fluid and its relationship to alpha 1-antiprotease.

Although the human alveolar macrophage in tissue culture can secrete an elastolytic metalloenzyme that is not inactivated by alpha 1-antiprotease (AAP), levels of this proteolytic activity and its relationship to AAP in human lung lavage fluid ( HLF ) are unknown from previous studies. Therefore, we measured elastolytic activity in concentrated (20- to 30-fold) HLF from 15 smokers and 10 nonsmokers and related results to measurements of AAP in these fluids. Activity (mean +/- SEM) against a C elastin substrate (expressed as nanograms of porcine pancreatic elastase equivalents per milligram of lavage fluid protein) in smokers, 18.9 +/- 6.7, significantly exceeded (p = 0.05) levels present in nonsmokers, 4.4 +/- 1.8. With the synthetic elastin-like chromophore substrate succinyl-trialanine-nitroanilide ( SLAPN ), activity in individual samples was reduced 79% by EDTA, a metalloproteinase inhibitor, whereas activity was reduced by only 29% in the presence of PMSF, a serine proteinase inhibitor. In addition, using a pooled sample of HLF and C elastin substrate, 80% of activity against the elastin substrate was eliminated by EDTA, whereas 51% was eliminated by PMSF. The activity measured with C elastin substrate correlated inversely with antigenic AAP (r = -0.05, p = 0.01), but no correlations were found between this activity and HLF cell number, cell viability, differential count, or subject smoking history. The detection of activity with C elastin in HLF , with primarily a metalloenzyme inhibitor profile, in the presence of antigenically detectable AAP, may have pathogenetic relevance for emphysema in humans.

Adult↗
PubMed1984

Effects of a series of chloromethyl ketone protease inhibitors on superoxide release and the glutathione system in human polymorphonuclear leukocytes and alveolar macrophages.

Certain chloromethyl ketone (CH2Cl) protease inhibitors diminish PMA-stimulated (phorbol myristate acetate) superoxide (O-2) release by both human alveolar macrophages (HAM) and polymorphonuclear leukocytes (PMN). Additionally, these compounds diminish glutathione reductase activity (GSSR) and intracellular levels of reduced glutathione (GSH). Inhibitory profiles of these molecules were similar for each of the measured cell products, i.e., TPCK = Z Gly-Leu-Phe-CH2Cl greater than TLCK greater than Meo Succ-(Ala)2-Pro-Val-CH2Cl. Because Meo Succ-(Ala)2-Pro-Val inhibited GSSR in cell sonicates but not in intact cells, it appears that all these effects are closely related to the cell penetration by these CH2Cl compounds. We conclude that (1) inhibition of O-2 release in PMN and HAM by CH2Cl does not necessarily implicate a surface protease in O-2 production, (2) some of these compounds certainly impair the intracellular glutathione redox system necessary for the respiratory burst, and (3) only the nonpenetrating inhibitor Meo Succ-(Ala)2-Pro-Val-CH2Cl can be used to distinguish injury caused by extracellular protease (elastase) from that caused by superoxide anion.

Amino Acid Chloromethyl Ketones↗
PubMed1984

Bronchial lavage proteins as correlates of histopathologic airway changes in healthy smokers and patients with pulmonary carcinoma.

Cigarette smoking is known to be an important etiologic factor in several lung diseases; however, the number of smokers who develop these diseases represents a small segment of the smoking population. It is possible that evidence of inhalation-induced injury to bronchial epithelial cells of smokers will be reflected in the proteinaceous products of these cells, thereby identifying a high-risk subgroup. We have tested this hypothesis by analysis of 2 proteins, free secretory component (FSC) and the keratins, in lavage fluids obtained from 4 groups of subjects: 30 normal nonsmokers, 15 asymptomatic smokers, 22 symptomatic smokers, and 40 carcinoma patients. Among symptomatic smokers, FSC relative to total protein (FSC/TP) was depressed compared with that in nonsmokers and asymptomatic smokers. The keratins were detected only in symptomatic smokers and correlated with pack/years of smoking history (p = 0.017). Carcinoma patients had depressed FSC/TP and detectable keratin (33 of 38 patients studied). Lung sections from carcinoma patients studied immunohistochemically revealed an apparent inverse relationship between tissue FSC and keratins. This inverse relationship was borne out by analysis of these proteins in the lavage fluid of cancer patients (r = -0.4, p = 0.04). Thus, in cancer patients, immunohistochemical evidence of airway injury correlates with bronchial lavage levels of mucosal epithelial cell proteins. It is possible that smokers with altered levels of these proteins may be the ones at increased risk of smoking-associated lung disease.

Adolescent↗
PubMed1984

Respiratory infection complicating long-term tracheostomy. The implication of persistent gram-negative tracheobronchial colonization.

Colonization of the lower respiratory tract by enteric Gram-negative bacilli (EGNB) has been a frequent finding in patients with long-term tracheostomies; however, the association of hospitalization and certain features of serious illness with this phenomenon has not been clearly established. Because such factors can render the oropharynx more susceptible to EGNB colonization, we sought to discover whether they can also have this effect on the tracheobronchial tree and its microflora. Thus, we collected serial paired culture samples from these two mucosal sites in 15 subjects with long-term tracheostomies and examined patterns and rates of colonization and related these findings to clinical parameters. In 49 sets of cultures, we found that EGNB (especially Pseudomonas species) were present in significantly fewer upper-airway cultures (36.7 percent) than lower-airway cultures (75.5 percent) (p = 0.009). At the tracheobronchial site, seven subjects had persistent EGNB colonization, all with Pseudomonas species, while only one subject had this finding at the oropharyngeal site (p = 0.015). Patients with persistent tracheobronchial colonization were more ill than those without this finding. They were treated with higher doses of prednisone (p = 0.06), received antibiotics more often, and developed purulent tracheobronchitis more often (100 percent vs 25 percent) than patients without persistent colonization. In addition, in the month following the culture survey, four subjects developed pneumonia, and three of these had previous persistent tracheobronchial colonization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Nutritional status and bacterial binding in the lower respiratory tract in patients with chronic tracheostomy.

Patients with chronic tracheostomy often develop tracheobronchial colonization with enteric gram-negative bacilli, especially Pseudomonas aeruginosa, but pathogenic mechanisms are largely unknown. To examine this problem, we measured in-vitro bacterial adherence to airway epithelial cells from the tracheal surfaces of 15 patients with chronic tracheostomy and 18 healthy, noncolonized controls without tracheostomy. Patients with tracheostomy had more tracheal cell adherence (7.3 +/- 0.4 [SE] bacteria/cell) than controls (4.8 +/- 0.7 bacteria/cell; p = 0.008), but patients colonized by Pseudomonas species had even more binding (9.0 +/- 0.06 bacteria/cell) than those without this finding (5.8 +/- 0.8 bacteria/cell; p = 0.008). Differences between patients in lower airway cell binding of bacteria were largely related to a multifactorial assessment of patient nutritional status, the prognostic nutritional index (r = 0.67, p = 0.005). Thus, nutritional status may account in part for the common problem of tracheobronchial colonization with gram-negative bacteria in patients with chronic tracheostomy.

Adhesiveness↗
PubMed1984

Bleomycin hydrolase activity in pulmonary cells.

The metabolism of bleomycin (BLM) A2 by BLM hydrolase in the 105,000 X g supernatant fraction of homogenates obtained from freshly isolated and cultured pulmonary cells was assayed by high-pressure liquid chromatography. BLM A2 was converted solely to the less toxic desamido metabolite by the cytosol from isolated rabbit and bovine alveolar and interstitial macrophages, cultured rabbit and bovine pulmonary fibroblasts and cultured rabbit pulmonary artery endothelial cells. The BLM hydrolase activity in the cytosol from cultured rabbit fibroblasts had an apparent Km of 700 microM and Vmax of 33 nmol/hr/mg protein. The rate of BLM dA2 formation found with the cytosol of cultured rabbit pulmonary artery endothelial cells and pulmonary fibroblasts was 3 to 5 times greater per cell than that from the cytosol of rabbit alveolar and interstitial macrophages. Freshly isolated rabbit type II pneumocytes and bovine pulmonary artery endothelial cells grown in culture had undetectable levels of this inactivating enzyme activity. The expression of BLM hydrolase activity in rabbit pulmonary fibroblasts was stable for at least five passages in culture and was not significantly different over wide cell densities in culture. These data suggest that heterogeneity in the cellular distribution of BLM hydrolase activity exists in lungs. High levels of BLM hydrolase activity in the pulmonary endothelium or fibroblasts of some species may have an important role in determining the toxicity of BLM to the lungs.

Animals↗
PubMed1984

IgE immune complexes induce immediate and prolonged release of leukotriene C4 (LTC4) from rat alveolar macrophages.

Alveolar macrophages obtained by lung lavage from rats were incubated with monoclonal mouse anti-DNP IgE and specific antigen (DNP-HSA) and were found to release a slow reacting substance (SRS), which was characterized by high performance liquid chromatography as leukotriene C4 (LTC)4. Alveolar macrophages incubated with 1 microM A23187 (calcium ionophore) released similar amounts of SRS (6.0 +/- 2.2 and 5.7 +/- 3.7 X 10(-10) mol of LTC4 per 5 X 10(6) alveolar macrophages, respectively). The optimal conditions and mechanism of LTC release by IgE and antigen were examined. LTC4 release was maximal when freshly retrieved alveolar macrophages were incubated for 20 min with 10 micrograms/ml IgE and then for 20 min with 100 ng/ml antigen or for 20 min with IgE and antigen that had been preincubated together for 30 min at room temperature. In addition, LTC4 release was maximal when cells were challenged with IgE and antigen in a protein-free balanced salt solution and when the cells were tumbled to prevent adherence. Dose response experiments revealed that macrophages released LTC4 when stimulated with as little as 10 ng IgE and 100 ng DNP-HSA. Alveolar macrophages did not release LTC when challenged with IgE or DNP-HSA alone. Activation of LTC4 release by IgE and antigen was rapid in onset (2.5 to 5 min), and washing to remove fluid phase IgE and antigen revealed that once activated, alveolar macrophages were capable of prolonged and continuous release of LTC4. Peritoneal lavage cells stimulated with IgE and antigen did not release SRS but could release SRS when incubated with A23187 (5.7 +/- 1.3 X 10(-10) mol LTC4/5 X 10(6) macrophages). A large variability existed between individual rats in the ability of their alveolar macrophages to be activated by IgE and antigen to release LTC4. DNP-HSA labeled with 125I was used to show formation of immune complexes of IgE and antigen when IgE and antigen were incubated together before macrophage challenge. IgE immune complexes containing as little as 2 ng of antigen elicited the release of LTC4 from alveolar macrophages. These data indicate that rat alveolar macrophages release primarily LTC4 when challenged with IgE immune complexes, and that the alveolar macrophage may differ in this respect from peritoneal macrophages that do not release detectable quantities of LTC4 when challenged under identical conditions.

Animals↗
PubMed1983

Comparison of bacterial adherence to ciliated and squamous epithelial cells obtained from the human respiratory tract.

Previous in vitro studies have suggested that bacterial adherence to buccal squamous epithelial cells may be a mechanism involved in postoperative colonization of the oropharynx. However, the relationship between bacterial binding to oral epithelial and ciliated respiratory cells is unknown. To investigate bacterial binding to other cells in the human respiratory tract, we measured adherence of Pseudomonas seruginosa to ciliated cells (from nose and trachea) and compared this to squamous cells (from buccal mucosa), Cell samples were collected from 16 noncolonized individuals undergoing either elective surgery or volunteer bronchoscopy. Adherence (mean +/- SEM) to tracheal cells (4.6 +/- 0.8 bacteria per cell) and to nasal cells (4.7 +/- 0.6 bacteria per cell) was similar. These values significantly (p less than 0.001) exceeded buccal cell adherence (0.9 +/- 0.2 bacteria per cell). Because cells from ciliated surfaces bind more bacteria than cells from squamous surfaces, bacterial adherence at these respiratory sites may involve different mechanisms. The enhanced bacterial attachment to ciliated cells may assume pathogenic importance when mucociliary function is impaired.

Acetylcysteine↗
PubMed1983

Immunologic alterations in bronchoalveolar lavage fluid in the acquired immunodeficiency syndrome (AIDS).

The association of Pneumocystis carinii pneumonia and cytomegalovirus infection in apparently healthy intravenous drug abusers or homosexual males recently has been described. Two patients with this syndrome were seen recently at our institution. Bronchoalveolar lavage samples from these two patients, taken at the time of bronchoscopy, were analyzed. In both patients a significant increase in inflammatory cells (polymorphonuclear cells) and evidence for polyclonal B cell activation, as measured by a reverse hemolytic plaque assay was seen compared to normal persons (p less than 0.01 both comparisons). IgM and IgG anti-Pneumocystis carinii antibody titers were elevated in the lavage fluid of one patient each. One patient, originally diagnosed as having "Hamman-Rich Syndrome," demonstrated unequivocal chest X-ray improvement with prednisone therapy alone. These observations suggest that the lungs of these two patients were the site of an intense inflammatory response, which was not reflected in studies with peripheral blood.

Acquired Immunodeficiency Syndrome↗