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R A Robbins

Publications and source records attributed to R A Robbins.

140 records · Page 8Linked to original sources
PubMed1987

Antigenic identification of chemotactic factor inactivator in normal human serum and bronchoalveolar lavage fluid.

Several proteins have been described that can modulate the activity of the complement component C5a, a potent chemoattractant for neutrophils. One of these inhibitors has been termed chemotactic factor inactivator (CFI). We hypothesized that CFI was antigenically present in normal human serum and that antigenic levels would correlate with the ability of serum to inhibit C5a. To test this hypothesis, CFI was purified from normal human serum, antibodies to CFI were developed in rabbits, and these reagents were used to develop an enzyme-linked immunoadsorbent assay to measure CFI. Sera from 32 normal volunteers were assayed for CFI and found to contain 77 +/- 29 micrograms/ml (range 17 to 137 micrograms/ml). Partially purified CFI from normal human sera was found to inhibit 61% +/- 9% (range 45% to 75%) of the ability of C5a to attract human neutrophils. Importantly, the ability of CFI to inhibit C5a-induced neutrophil chemotaxis correlated with the antigenic amounts of CFI (r = 0.68, P less than 0.05), suggesting that CFI is a major inhibitor of C5a. This was confirmed by the finding that (1) all C5a inhibitory activity coprecipitated with CFI by ammonium sulfate precipitation (45% to 65% saturation), and (2) depletion of this ammonium sulfate fraction of CFI resulted in a major loss in its ability to inhibit the chemotactic activity of C5a (57% vs. 8% inhibition, P less than 0.01). To determine whether CFI could play a role in the modulation of inflammation at tissue sites, normal bronchoalveolar lavage fluid was evaluated for the presence of CFI. CFI was identified in all fluids (mean 0.50 +/- 0.09 micrograms/mg albumin, range 0.14 to 1.43 micrograms/mg albumin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Role of chemotactic factor inactivator in modulating alveolar macrophage-derived neutrophil chemotactic activity.

The stimulated alveolar macrophage is a potent source of neutrophil chemotactic activity. The release of this chemotactic activity can be inhibited by pretreating alveolar macrophages with anti-C5 antibody. We hypothesized that C5a, a fragment cleaved from C5 when C5 is activated, might activate the alveolar macrophage to release neutrophil chemotactic activity and that chemotactic factor inactivator, a serum inhibitor of C5a, could decrease this release. Activated complement components including C5a were found to stimulate guinea pig macrophages to release chemotactic activity into their culture supernatants at levels that were significantly higher than the chemotactic activity of C5a alone (P less than 0.001). Chemotactic factor inactivator was found to cause a marked reduction in the chemotactic activity released by macrophages stimulated with phagocytic and nonphagocytic stimuli (P less than 0.001, all comparisons). These data indicate that C5a can stimulate alveolar macrophages to release chemotactic activity in vitro, and that chemotactic factor inactivator may play a role in modulating this process.

Aminopeptidases↗
PubMed1986

Complement activation in cystic fibrosis respiratory fluids: in vivo and in vitro generation of C5a and chemotactic activity.

Experiments performed in vitro have demonstrated that leukocyte neutral proteases produce an important mediator of inflammation, C5a, by proteolysis of the C5 component of the complement system. Cystic fibrosis (CF) lung fluids were characterized by high levels of neutrophils (39% of total cells versus 2% in normals) and contained significantly elevated amounts of elastolytic activity (mean 17.7 ng/micrograms total protein) compared to the lung fluids obtained from normal volunteers (0.2 ng elastolytic activity/micrograms protein, p = 0.001). The objective of these studies was to determine if complement activation and complement-derived chemotactic activity are present in CF lung fluids. C3c peptide representing activation of C3 could not be identified in the bronchial-alveolar lung lavage fluids of normal subjects but was readily identified by means of crossed immunoelectrophoresis in CF lung fluids (n = 9, mean 49% of C3); the mean level of C3 was decreased in CF lung specimens. Chemotactic activity was significantly elevated in lung fluids of the CF patients when compared to normal lung fluids. Using gel-filtration chromatography and a sensitive radioimmunoassay the chemotaxin present in CF specimens was identified as the anaphylatoxin C5a. C5a levels in the bronchial-alveolar lavage fluids of CF patients was inversely related to volume in liters expired in 1 s of a forced expiratory maneuver expressed as a percent of vital capacity determined from a forced expiratory maneuver (r = -0.72). Because there was a direct relationship between the total elastolytic activity present in CF airways and the concentration of C5a (r = 0.97, p = 0.03), it was postulated that airway proteases with elastolytic activity also cleave C5, nonimmunologically producing C5a. Detailed inhibition assays revealed that much of the total elastolytic activity had the inhibition profile of a serine proteinase. The levels of the serine proteinases were closely correlated with the numbers of neutrophilic leukocytes present per ml of lavage fluid (r = 0.7, p = 0.05). However, inhibitors of leukocyte serine proteases did not prevent the generation of additional chemotactic activity and the proteolysis of radiolabeled C5 substrate was not prevented by inhibitors of neutrophil elastase. Although the purified metalloelastase of Pseudomonas aeruginosa was active on cell-bound and free C5 yielding C5a, inhibition of this bacterial protease in CF lung fluids only partially blocked cleavage of the alpha- and beta-chains of C5.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1986

Interleukin-2-induced chemotaxis of human T-lymphocytes.

Interleukin-2 (IL-2), a growth factor for T-lymphocytes, has been postulated to cause the accumulation of T-lymphocytes at sites of inflammation by inducing proliferation of these cells. We hypothesized that IL-2 might also serve to attract T-lymphocytes to inflammatory sites. To test this hypothesis, human T-lymphocytes were purified from the peripheral blood of normal volunteers by rosetting with neuraminidase-treated sheep red blood cells and tested for chemotactic activity by using a blind-well chamber technique. Purified IL-2 caused a greater than 20-fold attraction of T-lymphocytes compared with medium alone (P less than 0.001). This attraction was shown to be chemotactic rather than chemokinetic by checkerboard analysis. The T-lymphocyte chemotaxis could be completely inhibited by adsorption of the IL-2 with an IL-2-dependent cell line, and could be neutralized by monoclonal anti-IL-2 antibody. Further specificity of IL-2-directed chemotaxis was demonstrated by using species-specific IL-2. Mouse IL-2 was ineffective at promoting human T-lymphocyte chemotaxis. These data suggest that IL-2 may be responsible for the localized accumulation of T-lymphocytes both by causing attraction of these cells and by modulating their proliferation.

Animals↗
PubMed1985

Ketone body metabolism in the neonate: development and the effect of diet.

In the course of mammalian development milk has evolved with unique characteristics as has the capacity of the neonatal rat to process this nutrient source. The primary carbon source in milk is fat, which provides two readily utilized metabolites, acetoacetate and D(-)-3-hydroxybutyrate (ketone bodies), as well as free fatty acids and glycerol. Carbohydrate provides less than 12% of the caloric content of rat milk and glucose has to be produced by the suckling rat to maintain glucose homeostasis. One would predict that glucose would be used sparingly and in pathways that cannot be satisfied by other readily available metabolites. Studies of the uptake of metabolites and the development of key enzymes for the utilization of glucose and ketone bodies by developing brain support the concept that ketone bodies are preferred substrates for the supply of carbon to respiration and lipogenesis. Astrocytes, oligodendrocytes, and neurons from developing brain all have an excellent capacity to use ketone bodies for respiration. By contrast, glucose is utilized preferentially in the hexose monophosphate shunt by all three cell populations. We are examining the requirement for ketone bodies by developing brain with the application of a system to rear rat pups artificially on a milk substitute that promotes a hypoketonemia.

Animals↗
PubMed1983

Fibronectin mediates cell attachment to C1q: a mechanism for the localization of fibrosis in inflammatory disease.

Chronic inflammatory processes frequently lead to the abnormal replacement of normal tissue elements by increased numbers of fibroblasts and fibrous connective tissue, i.e., fibrosis. Since the growth of fibroblasts requires that these cells be attached to an extracellular support, the current study was designed to determine if the interaction between the fibroblast attachment factor fibronectin and the C1q component of complement could support fibroblast attachment and growth and thus could form a basis for the attachment of fibroblasts in abnormal tissue locations in those inflammatory states where C1q is bound. Fibronectin purified from human plasma supported attachment of both Chinese hamster ovary cells and of normal fetal lung fibroblasts (HFL-1) to C1q coated substrates. The attachment activity was approximately twice that of attachment to collagen, and was specific, as no attachment occurred to albumin coated substrates. Cells attached to C1q substrates demonstrated characteristic 'spreading' similar to those on collagen. Moreover, the C1q substrate resembled collagen in its ability to support fibroblast growth. Further, the ability of the interaction between C1q and fibronectin to mediate attachment of fibroblasts to immune complexes was demonstrated by the formation of fibroblast-red blood cell-immune complex rosettes, a process that was dependent on both fibronectin and C1q. Thus, the interaction between fibronectin and C1q could serve as the basis for fibroblast attachment and growth in abnormal tissue sites where immune complexes are formed and could be a contributing factor to the development of fibrosis.

Antigen-Antibody Complex↗
PubMed1981

The effects of erythromycin on the absorption and disposition of kinetics of theophylline.

The effects of erythromycin on the kinetics of theophylline were investigated in eight female patients with documented asthma in a crossover study. Theophylline pharmacokinetics were determined at steady state before and after one-week treatment with erythromycin stearate 250 mg given four times a day. Multiple serum samples were collected for 12 h after an aminophylline dose in the two drug treatment phases and assayed by high performance liquid chromatography. The resultant serum theophylline concentration-time data were analyzed by weighted, nonlinear regression analysis to obtain various pharmacokinetic parameters. In this study, the elimination half-live increased from 7.8 +/- 1.7 h on the control day to 9.5 +/- 1.4 h following treatment with antibiotic (p less than 0.02). The estimated apparent volume of distribution for theophylline (V/F) was also observed to increase from 0.42 +/- 0.09 l/kg before treatment with erythromycin to 0.53 +/- 0.15 l/kg after antibiotic treatment (0.05 less than p less than 0.10). In this study, no difference was demonstrated in the apparent clearance rate (Clapp), apparent first-order absorption rate constant (ka), maximum serum drug concentration (Cmax), time of maximum drug concentration (Tmax) or absorption lag time (tlag) for theophylline before and after treatment with erythromycin. With no apparent alteration in theophylline clearance following erythromycin coadministration, the decrease in the first-order elimination rate constant suggested that the apparent volume of distribution of theophylline is increased in the presence of erythromycin. It is concluded that patients maintained on theophylline derivatives should be closely monitored when erythromycin is coadministered.

Adult↗
PubMedDate not supplied

Elevation of chemotactic factor inactivator in alcoholic liver disease.

Defective regulation of neutrophil chemotaxis occurs in patients with alcoholic liver disease. One potent mediator of neutrophil chemotaxis is the complement-derived neutrophil chemoattractant, C5a, which can be inhibited by a serum protein, chemotactic factor inactivator. We hypothesized that chemotactic factor inactivator elevation might, in part, explain the defective neutrophil chemotaxis seen in patients with alcoholic hepatitis. To test this hypothesis, sera were collected from 22 patients with alcoholic hepatitis and 9 normal controls, and evaluated for the antigenic presence of chemotactic factor inactivator using an ELISA test. Chemotactic factor inactivator levels were found to be markedly elevated in patients with alcoholic hepatitis (162 +/- 24 micrograms per ml) compared to normals (60 +/- 3 micrograms per ml, p less than 0.01). Subdividing the hepatitis patients revealed that the elevation of chemotactic factor inactivator was found to be greatest in those patients with mild alcoholic hepatitis (prothrombin time within normal limits and bilirubin less than or equal to 5 mg per dl, 256 +/- 44 micrograms per ml, p less than 0.001), while the group with the severest hepatic dysfunction (prolonged prothrombin time and bilirubin greater than 5 mg per dl) did not differ significantly from controls (71 +/- 11 micrograms/ml, p less than 0.2). Importantly, the inhibition of C5a-induced chemotactic activity by partially purified chemotactic factor inactivator correlated with antigenic amounts of chemotactic factor inactivator in serum (r = 0.63, p less than 0.05). The C5a inhibitory activity in sera obtained from patients with alcoholic hepatitis coprecipitated with chemotactic factor inactivator when serum was precipitated by ammonium sulfate precipitation (45 to 64% saturation).(ABSTRACT TRUNCATED AT 250 WORDS)

Aminopeptidases↗
PubMedDate not supplied

In vivo and in vitro methods for evaluating airways inflammation: implications for respiratory toxicology.

The lung is frequently the target of injury for toxic exposures. Often these exposures lead to significant disease. Assessment of toxic exposures to the lung, however, may be made using both in vitro and in vivo methods. Recent advances in respiratory cell biology have made possible in vitro analyses of the interactions between airway cells and potential toxins. In addition, the lung can be sampled in vivo using bronchoscopy and bronchoalveolar lavage. This opens up the possibility of assessing potential toxins prior to the development of clinically significant disease. Together, these advancing methodologies promise new potential for the assessment and evaluation of toxic exposures to the lung.

Air Pollutants↗
PubMedDate not supplied

Death competency: a study of hospice volunteers.

Three groups of hospice volunteers, trainees (N = 52), medium-term (2 to 42 months, N = 94), long-term (48 months or more, N = 96), and nonhospice and nonpatient care controls (N = 78) completed Bugen's Coping with Death Scale, the Templer/McMordie Death Anxiety Scale, and a new self-efficacy scale related to hospice and the ability to deal with death in general. The groups did not differ on the Death Anxiety Scale. However, on the Coping with Death Scale, experienced volunteers scored higher than trainees and controls; and on the self-efficacy scale all hospice volunteer groups believed themselves more able to deal with death than controls. In this study, the death competency scales appear more useful than the death anxiety measure in distinguishing hospice patient care volunteers from controls. The potential usefulness of these scales in future efforts at selection and evaluation are noted.

Adaptation, Psychological↗
PubMedDate not supplied

Antiproteases attenuate the release of neutrophil chemotactic activity from bronchial epithelial cells induced by smoke.

The released neutrophil chemotactic activity (NCA) from bronchial epithelial cells (BECs) in response to smoke extract was evaluated by reverse-phase, high-performance liquid chromatography (RP-HPLC) and the involvement of proteolytic activity was assessed for the release of NCA from BECs. Smoke extract stimulated the release of NCA (55.3 +/- 5.2 vs. 17.3 +/- 4.1 cells per high-power field [HPF], p < .001). The released activity determined by RP-HPLC analysis was 15-hydroxyeicosatetraenoic acid and leukotriene B4. Several structurally and functionally different serine protease inhibitors, including alpha-1-protease inhibitor (alpha-1-PI), chloromethyl ketone (CK) derivatives, N-tosyl-L-lysine CK (TLCK), methoxysuccinyl-Ala-Ala-Pro-Val CK (SPCK), N-alpha-tosyl-L-phenylalanine CK (TPCK), and N-alpha-p-tosyl-L-arginine methyl ester hydrochloride (TAME), attenuated the release of NCA (P < .01) in a dose-dependent fashion. Leupeptin, a cysteine protease inhibitor, has only a small effect on the release of NCA (p < .05), and phosphoramidon, a neutral endopeptidase inhibitor, had no effect. The measurement of proteolytic enzyme activity using synthetic substrate S-2288 revealed that smoke extract significantly (p < .05) augmented the serine protease activity in BEC layers. Culture supernatant fluids and cell lysates of BECs in response to smoke extract solubilized 14C-labeled casein. These results suggest that BECs may release lipoxygenase-derived NCA in response to smoke extract and that the release of NCA may involve the activation of proteolytic activity of BECs which was inhibited by serine protease inhibitors.

Albumins↗
PubMedDate not supplied

Bronchoalveolar lavage fluid processing. Effect of membrane filtration preparation on neutrophil recovery.

Two common methods for the preparation of bronchoalveolar lavage (BAL) fluid for cytologic examination, cytocentrifugation and membrane filtration, have been found to yield different results in the quantitation of lymphocytes. To compare these two methods for the quantitation of neutrophils, the differential counts from 640 consecutive clinical specimens were analyzed retrospectively. The percentage of neutrophils resulting from the preparation of the BAL fluids by the two methods were highly correlated (r2 = .72). However, cytocentrifugation yielded consistently higher neutrophil percentages than did membrane filtration (means for all samples: 18.5 +/- 1.0% vs. 14.7 +/- 0.9%; P less than .001). To investigate the source of the variation in neutrophil quantitation by the two methods, two series of mixing experiments were performed in which neutrophil-rich cell suspensions were added to BAL fluids. Determination of the cellular differentials before and after mixing the cell suspensions demonstrated that membrane filtration preparation tends to lose neutrophils while cytocentrifugation accurately recovers neutrophils. Thus, accurate quantitation of the two cells recovered by BAL may require use of both cytocentrifugation and membrane filtration.

Adult↗
PubMedDate not supplied

Bronchoalveolar lavage in the cytologic diagnosis of carcinoma of the lung.

To assess the utility of bronchoalveolar lavage as a technique for diagnosing lung cancer, 850 lavages from 421 patients were reviewed. Biopsy-proven lung carcinoma was present in 35 cases. Of these, 24 (68.6%) had cells diagnostic of malignancy on cytologic preparations of the bronchoalveolar lavage fluid. Agreement between cancer subtypes determined by lavage and by tissue biopsy was 79.1%; variation usually occurred between large cell undifferentiated carcinoma and adenocarcinoma, not with small cell anaplastic carcinoma. The subtype of tumors was most accurately determined by examination of Papanicolaou-stained slides. Reactive bronchial epithelium often mimicked carcinoma, but could be correctly identified by its characteristic cytomorphology. No false-positive diagnoses of lung cancer occurred in 386 patients. The sensitivity of bronchoalveolar lavage for the diagnosis of lung carcinoma is similar to that of transbronchial biopsy and Wang needle biopsy. Because bronchoalveolar lavage may detect opportunistic infections, interstitial lung diseases and malignant cells with a low morbidity, it is a useful tool to assess patients with pulmonary infiltrates.

Bronchi↗