Biomedical subjects

M J Thomassen

Publications and source records attributed to M J Thomassen.

At least 19 recordsLinked to original sources

PubMed1995

Regulation of human alveolar macrophage inflammatory cytokines by tyloxapol: a component of the synthetic surfactant Exosurf.

We previously demonstrated that the synthetic surfactant Exosurf and a modified natural surfactant, Survanta, both down-regulated endotoxin-stimulated production of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6) in human alveolar macrophages. To further characterize the source of the inhibitory effect of surfactant, the three individual components of Exosurf were evaluated. Dipalmitoylphosphatidylcholine had no effect on endotoxin-stimulated cytokine secretion. Cetyl alcohol (spreading agent) compromised macrophage function as measured by adherence. However, at concentrations equivalent to those found in the complete surfactant (Exosurf) preparation, tyloxapol (nonionic dispersing agent) was inhibitory in a dose-dependent manner. The viability of alveolar macrophages as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cleavage assay was not affected by incubation in Exosurf or any of its individual components. Cytokine secretion and mRNA levels of endotoxin-stimulated alveolar macrophages were decreased by tyloxapol. These data suggest that tyloxapol alone, like Exosurf, has an inhibitory effect on cytokine production which may be pretranslationally mediated.

Cells, Cultured↗

PubMed1992

Synthetic surfactant (Exosurf) inhibits endotoxin-stimulated cytokine secretion by human alveolar macrophages.

Tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), interleukin-6 (IL-6), and interleukin-8 (IL-8) are inflammatory cytokines produced by alveolar macrophages (AMs) and implicated in sepsis-related adult respiratory distress syndrome (ARDS). Preliminary findings from clinical trials suggest that aerosolized delivery of the synthetic surfactant Exosurf (Burroughs Wellcome Co.) reduces mortality in patients with sepsis-induced ARDS. The purpose of the present study was to examine the effect of Exosurf on inflammatory cytokine secretion from AMs in vitro. AMs were obtained from normal nonsmoking adult volunteers. Secreted TNF, IL-1, IL-6, and IL-8 were measured by enzyme-linked immunoassays in 24 h culture fluids of AMs. Exosurf inhibited LPS-stimulated TNF, IL-1, and IL-6 secretion in a dose-dependent fashion. IL-8 secretion was not affected by Exosurf under these conditions. However, if AMs were preincubated for 24 h in media and then LPS-stimulated, IL-8 secretion was inhibited by Exosurf. Regulation of IL-8 production may differ from TNF, IL-1, and IL-6. Unstimulated cytokine secretion was not affected by any of the tested concentrations of Exosurf. The inhibitory effect of Exosurf on endotoxin-induced cytokine secretion by human AMs suggests that Exosurf may modulate inflammatory cytokine production in the lung.

Cytokines↗

PubMed1991

Induction of cytokine messenger RNA and secretion in alveolar macrophages and blood monocytes from patients with lung cancer receiving granulocyte-macrophage colony-stimulating factor therapy.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes the proliferation and differentiation of hematopoietic progenitor cells. Although preliminary data are available from clinical trials, the effect of GM-CSF on gene expression of immunocompetent cells in treated patients has not been studied. We previously demonstrated that in vitro treatment with GM-CSF also enhances maturation-related anti-tumor activities in mononuclear phagocytes. The purpose of the present study was to examine the effects of in vivo recombinant GM-CSF therapy on alveolar macrophages and blood monocytes, to determine if these cells demonstrated differential expression of cytokine genes, cytokine production, and tumoricidal activity. Alveolar macrophages and blood monocytes were isolated from 13 patients receiving a range of GM-CSF doses (60-250 micrograms/m2/day) by continuous infusion over a 2-week period. Both monocytes and macrophages were isolated prior to therapy and at day 10 of the infusion. Monocytes, in addition, were isolated on day 3 of infusion. Results indicated that GM-CSF therapy enhanced expression of tumor necrosis factor, interleukin 1, and interleukin 6 mRNA in both monocytes and alveolar macrophages. Differential responses, however, were observed in cytokine secretion; monocytes demonstrated enhanced secretion of all three cytokines by day 3 of treatment, but alveolar macrophages showed only enhanced interleukin 6 secretion at day 10. Monocyte tumoricidal activity after in vitro lipopolysaccharide stimulation was also significantly elevated by day 3 of treatment, but at day 10 activity was not statistically different from pretreatment values in either monocytes or alveolar macrophages. These data indicate that GM-CSF exerts striking time-dependent modulatory effects on gene expression and functional activities of monocytes and alveolar macrophages in vivo, although the responses of the two cell types differ with respect to cytokine secretion.

Gene Expression Regulation, Neoplastic↗

PubMed1991

Monocyte tumoricidal activity and tumor necrosis factor production in patients with malignant brain tumors.

Monocyte-mediated tumoricidal activity, tumor necrosis factor alpha (TNF alpha) secretion and gene expression were examined in astrocytoma patients, patients with other types of brain tumors (primary or metastatic), and normal individuals. The spontaneous monocyte-mediated tumoricidal activity of either patient group against an astrocytoma cell line was significantly greater than normal. There was no difference between patient groups. When monocytes were stimulated with lipopolysaccharide in vitro, tumoricidal activity increased in all patient groups. Patient monocyte activity tested shortly (48 h) after surgery was not different from that before surgery. Both spontaneous and stimulated monocyte cytocidal activities were tumor-cell-restricted: melanoma and astrocytoma cells were equally susceptible but non-neoplastic glial cells were not affected. Examination of monocyte TNF alpha secretion and mRNA expression indicated that patient activity was comparable to or greater than normal. These results demonstrate that, despite steroid therapy, circulating monocytes in astrocytoma and other brain tumor patients retain intact functional activity.

Adult↗

PubMed1991

Immunologic changes in renal cell carcinoma patients receiving gamma interferon.

Immunologic changes were monitored in 5 patients with metastatic renal cell carcinoma participating in a phase II trial of recombinant interferon gamma (rIFN gamma). Treatment consisted of a 4-week period of intravenous infusion of either 0.1 mg/m2 given over 4 h on alternate days (3 times/week) or 2 mg/m2 given over 1 h for 5 days every other week. One minor response was seen at the higher dose level and toxicity was minimal (grades I-II). Absolute leukocyte counts and lymphocyte subpopulations did not change significantly. Both natural killer cytolytic activity and spontaneous monocyte-mediated tumoricidal activity increased. Prostaglandin E2 synthesis of patient leukocytes was abnormally high and pretreatment levels dropped during treatment. Data suggest that rIFN gamma may be potentially useful for enhancing immunologic function in renal cell carcinoma.

Aged↗

PubMed1990

Monocytes in cystic fibrosis: responsiveness to microbial stimuli.

Peripheral blood monocytes were obtained from 19 patients with cystic fibrosis (CF) and age-matched paired normal individuals. The oxidative metabolic response of these cells was measured by superoxide anion production before and after stimulation with Salmonella typhimurium or Pseudomonas aeruginosa lipopolysaccharide (LPS). CF monocytes showed slightly greater spontaneous superoxide anion production (14.1 +/- 2.1 SEM nanomoles superoxide anion/10(6) monocytes/180 min; n = 12) than normal monocytes (9.5 +/- 1.4; n = 12), P = 0.009. No differences between CF and normals were found in LPS-stimulated superoxide anion production (CF = 33.5 +/- 4.6, n = 13; normal = 33.8 +/- 4.2, n = 13). Furthermore, CF monocytes responded to both P. aeruginosa and S. typhimurium LPS stimulation as well as to recombinant interferon-gamma. Superoxide anion production of CF monocytes was comparable in autologous serum and in normal serum, and responses of patients colonized with P. aeruginosa and P. cepacia did not differ. We conclude that CF monocytes have a slightly increased metabolic level and, despite chronic infection, are capable of a further response to exogenous microbial stimuli.

Adolescent↗

PubMed1990

Immunologic studies of alveolar macrophages from patients with metastatic renal cell carcinoma.

Alveolar macrophage function in patients with renal carcinoma, a disease characterized by frequent pulmonary metastases, has not been examined. The purpose of this study was to evaluate tumoricidal responses of alveolar macrophages in renal carcinoma to determine if such activity is compromised. Alveolar macrophages and/or blood monocytes were obtained from 26 normal volunteers and 16 patients with renal carcinoma. Tumoricidal activity of alveolar macrophages and monocytes was assessed against 3H-thymidine-labeled tumor target cells. Patient alveolar macrophages and monocytes exposed to lipopolysaccharide (LPS) or recombinant interferon-gamma expressed tumoricidal activity comparable to those in normal subjects. Activated alveolar macrophages recognized and lysed neoplastic cells (including allogenic renal carcinoma cells), but not nonneoplastic cells. Alveolar macrophage and monocyte tumoricidal responses of patients with pulmonary metastases were not different from those of patients with metastases to other sites. These results indicate that alveolar macrophages from patients with renal carcinoma with or without pulmonary metastases are not compromised in vitro, but respond to immunomodulators with enhanced tumoricidal activity in the same fashion as do alveolar macrophages from normal volunteers.

Adult↗

PubMed1990

Modulation of human alveolar macrophage tumoricidal activity by recombinant macrophage colony-stimulating factor.

Recombinant macrophage colony-stimulating factor (M-CSF) is a hemopoietic growth factor capable of modulating activities of both immature and mature monocytes. The effect of M-CSF on tumoricidal activity of alveolar macrophages and monocytes from nonsmoking normal volunteers was compared using [3H]thymidine-labeled human tumor cells (SK-MEL-28, melanoma) as targets. A dose-response study (500-5,000 U/ml) of recombinant M-CSF indicated that both alveolar macrophages and blood monocytes demonstrated peak cytotoxicity at 1,000 U/ml. Maximal activity occurred 72-96 h after exposure to 1,000 U/ml of M-CSF. To investigate the mechanisms involved in this cytotoxicity, tumor necrosis factor-alpha (TNF) and interleukin-1-beta (IL-1) were measured in supernatant fluids of 24 h M-CSF-treated cells. No significant increase in either cytokine was detected after M-CSF treatment of alveolar macrophages or monocytes. Superoxide anion production of alveolar macrophages was not enhanced by M-CSF. These data suggest that alveolar macrophages tumoricidal activity is induced by M-CSF and is not dependent on oxidative metabolism or secreted forms of IL-1 or TNF.

Adult↗

PubMed1989

Differential effect of recombinant granulocyte macrophage colony-stimulating factor on human monocytes and alveolar macrophages.

The effect of granulocyte-macrophage colony-stimulating factor (GM-CSF), a pluripotent cytokine, on tumoricidal activity of alveolar macrophages and monocytes from nonsmoking normal volunteers was compared using [3H]thymidine-labeled human tumor cells (SK-MEL-28, melanoma) as targets. A dose-response study (500-5000 units/ml) of recombinant GM-CSF indicated dramatic differences between cytotoxicity of alveolar macrophages and blood monocytes. Macrophages exhibited significant (P less than 0.01) tumoricidal activity at all GM-CSF doses tested. In contrast, monocytes showed no significant tumoricidal activity at 500 units/ml and significantly (P less than 0.01) less activity than alveolar macrophages at doses of 1000-5000 units/ml. Maximal activity in alveolar macrophages occurred 72-96 h after exposure to 1000-5000 units/ml GM-CSF. Tumoricidal activity may be related to the state of maturation, because monocytes matured in vitro for 7 days displayed enhanced tumoricidal activity after GM-CSF exposure. Tumor necrosis factor alpha and interleukin 1 beta were measured in supernatant fluids of 24-h GM-CSF-treated cells. No significant increase in either cytokine was detected after GM-CSF treatment of alveolar macrophages. Monocyte interleukin 1 beta secretion was not enhanced by GM-CSF; however, tumor necrosis factor alpha secretion was enhanced in some donors (three of five). Superoxide anion production of alveolar macrophages was not enhanced by GM-CSF. These data suggest that alveolar macrophage tumoricidal activity is induced by GM-CSF and is not dependent on oxidative metabolism or secreted forms of interleukin 1 beta or tumor necrosis factor alpha.

Adult↗

PubMed1988

Induction of in vitro tumoricidal activity in alveolar macrophages and monocytes from patients with lung cancer.

Human alveolar macrophages (AMs) and blood monocytes were obtained from 65 smoking and nonsmoking normal volunteers and 29 patients with lung cancer. The oxidative metabolic response of these cells was measured by superoxide anion production after incubation with lipopolysaccharide. In addition, tumoricidal activity of AMs and monocytes was assessed against [3H]thymidine-labeled tumor target cells. Smoking was associated with depressed AM superoxide anion responses in normals but not in patients. In contrast, smoking appeared to slightly elevate monocyte superoxide anion activity. AMs and monocytes exposed to lipopolysaccharide or recombinant gamma-interferon showed tumoricidal activity in all groups. Mean cytotoxicity values of smoking patients versus smoking normals and exsmoking patients versus nonsmoking normals were not significantly different. Smoking, however, in both patients and normals was associated with significantly (P less than 0.005) depressed AM cytotoxicity levels (less than 40%) compared to nonsmoking volunteers and exsmoking patients. Activated AMs from cancer patients and normals were cytotoxic against three different tumorigenic cell lines but not against a nontumorigenic line. No correlation between monocyte and AM cytotoxic activity within single individuals was found. We conclude that AM and monocytes from smoking and exsmoking patients can be activated after exposure to immunomodulators; however, smoking may be slightly suppressive to cytotoxic responses. These studies provide a rationale for clinical trials of immunomodulators in patients with lung cancer.

Adult↗

PubMed1988

Human alveolar macrophage function: differences between smokers and nonsmokers.

Human alveolar macrophages and peripheral blood monocytes were obtained from smoking and nonsmoking normal volunteers. The macrophages and monocytes were incubated in vitro with bacterial lipopolysaccharide (LPS). The oxidative metabolic response of these cells was measured by superoxide anion production. Macrophages from smokers were suppressed in their superoxide anion response to LPS activation as compared to macrophages from nonsmokers. Monocytes from smokers and nonsmokers were not different. The cytotoxic properties of these macrophages and monocytes were assessed by an in vitro 3H-thymidine release assay against various allogeneic target cells. Macrophages and monocytes exposed to LPS were rendered tumoricidal. Macrophages from nonsmokers appeared to generate greater cytotoxic activity than macrophages from smokers. Macrophages from both smokers and nonsmokers were cytotoxic for three different tumorigenic cell lines but not for a nontumorigenic cell line. Monocytes from smokers and nonsmokers were not different in cytotoxic activity. We conclude that macrophages from both smokers and nonsmokers can be activated after exposure to LPS; however, macrophages from smokers may be slightly suppressed in their responses.

Adult↗

PubMed1988

Modulation of human alveolar macrophage tumoricidal activity by C-reactive protein.

In previous reports, we have shown that purified human C-reactive protein (CRP) enhances tumoricidal activity of murine macrophages and human blood monocytes. In the present study, we wished to determine whether CRP induced similar activity in human macrophages. We evaluated the effect of CRP on the generation of in vitro tumoricidal activity in alveolar macrophages from 24 normal volunteers, among whom 10 were smokers and 14 were nonsmokers. CRP, in concentrations comparable with those found in blood during acute inflammation, induced dose-dependent cytotoxicity in nonsmoker alveolar macrophages against tritiated thymidine-labeled human tumor cells. Tumoricidal responses of smoker and nonsmoker macrophages did not significantly differ after exposure to lipopolysaccharide although smoker responses tended to be lower. Responses to CRP, however, were significantly (p less than 0.01) depressed in smokers. These findings suggest that during acute inflammation, CRP may enhance the tumoricidal properties of human alveolar macrophages. Macrophage responsiveness to CRP, however, appears to be detrimentally affected by smoking.

Adult↗

PubMed1988

Pseudomonas cepacia-associated pneumonia in cystic fibrosis. Relation of clinical features to histopathologic patterns of pneumonia.

We studied lungs at autopsy from 40 patients with cystic fibrosis (CF) to determine the structural and clinicopathologic features of pneumonia associated with Pseudomonas cepacia respiratory tract colonization. Three clinical groups were identified: group A included 11 patients exhibiting a fulminant course following P cepacia colonization; group B included 20 patients who declined slowly following colonization; and group C included nine patients without P cepacia colonization. Acute pneumonia occurred in all groups but was most extensive and necrotizing in group A. Chronic lobular pneumonia involved all groups equally, whereas interstitial pneumonia predominated in group B. Diffuse alveolar damage occurred infrequently in all groups. Combinations of structural patterns were frequently seen. We conclude that, although there is great overlap in the structural appearance of pneumonia among patients with CF with different bacterial colonization histories, the evidence suggests that P cepacia is a cause of necrotizing pneumonia in some patients. Factors that predispose to this fulminant lung infection are poorly understood.

Acute Disease↗

PubMed1987

Colonization of the respiratory tract with Pseudomonas cepacia in cystic fibrosis. Risk factors and outcomes.

Between 1981 and 1983, some 85 patients with cystic fibrosis at Rainbow Babies and Childrens Hospital, Cleveland, developed colonization or infection of the respiratory tract with Pseudomonas cepacia. Twenty-nine (34 percent) of the colonized patients died; four were female patients with fulminant bacteremia with P cepacia prior to death. Case-control studies showed that increasing severity of underlying cystic fibrosis, increasing age, having a sibling with cystic fibrosis who was colonized with P cepacia, and previous hospitalizations were associated with increased risk of colonization. In patients with mild cystic fibrosis, no differences in clinical outcome were seen during the period of study; however, patients colonized with P cepacia who had moderate or advanced cystic fibrosis were hospitalized longer and died sooner after colonization, compared with control subjects with similar severity of cystic fibrosis. The excess mortality associated with such colonization varied in magnitude and trend according to the patient's sex and severity of underlying cystic fibrosis, reflecting the combined influence of colonization with P cepacia, sex, and severity of cystic fibrosis on the mortality of the patients. The source and mode of transmission of P cepacia were not determined, but the data suggest a possible nosocomial source. The results of this investigation showed that colonization with P cepacia most often affected patients with moderate or advanced cystic fibrosis and was associated with an adverse clinical outcome in these patients.

Adolescent↗

PubMed1986

Association with phagocytic inhibition of anti-Pseudomonas aeruginosa immunoglobulin G antibody subclass levels in serum from patients with cystic fibrosis.

Serum from cystic fibrosis patients colonized with Pseudomonas aeruginosa specifically inhibits phagocytosis of P. aeruginosa by alveolar macrophages. Serum was examined for P. aeruginosa lipopolysaccharide-specific immunoglobulin G (IgG) subclass levels (by enzyme-linked immunosorbent assay) and for the effect on macrophage phagocytosis (by radiolabeled P. aeruginosa uptake). Sera from cystic fibrosis patients with no known P. aeruginosa colonization history had negligible amounts of lipopolysaccharide-specific IgG and a mean phagocytic enhancement of 5%. The sera of normal volunteers also had negligible amounts of lipopolysaccharide-specific IgG. Serum from cystic fibrosis patients with P. aeruginosa respiratory tract infections had substantial titers (range, 1:20 to 1:1,280) of lipopolysaccharide-specific IgG2, IgG3, and IgG4 and a mean phagocytic inhibition of 56%. However, these patients had low or absent titers of lipopolysaccharide-specific IgG1. No consistent variation in the level of individual IgG subclasses in the sera of colonized patients was observed, as determined by radial immunodiffusion. The results suggest that during P. aeruginosa infection phagocytosis-inhibitory activity develops coincident with production of lipopolysaccharide-specific IgG subclasses.

Adolescent↗

PubMed1986

Pseudomonas cepacia: decrease in colonization in patients with cystic fibrosis.

The incidence and prevalence of Pseudomonas cepacia pulmonary colonization were noted to be increasing in patients with cystic fibrosis (CF). Previous work had indicated a greater prevalence of P. cepacia among siblings (with CF) of patients colonized by P. cepacia as well as an association of initial positive P. cepacia cultures with a hospitalization. Because of uncertainty regarding the source and mode of transmission, limited precautionary measures were instituted in 1983, including physical separation of hospitalized patients colonized with P. cepacia from non-colonized patients, reeducation of staff concerning basic infection control procedures, explanation to families regarding these precautionary efforts, and institution of separate summer camp sessions. Repeated environmental cultures throughout the hospital were negative for P. cepacia. Coincident with the institution of control measures, a sharp decline in incidence occurred (8.2% in 1983 versus 1.7% in 1984). These results are suggestive of patient-to-patient transmission. Because P. cepacia infections have been associated with shorter survival in some patients with CF, we will continue our current segregation measures.

Anti-Bacterial Agents↗

PubMed1985

Occurrence and antimicrobial susceptibility of gram-negative nonfermentative bacilli in cystic fibrosis patients.

Isolation of nonfermentative gram-negative bacilli (other than Pseudomonas aeruginosa) from respiratory tract cultures of cystic fibrosis (CF) patients has increased in recent years. Species recovered include Pseudomonas cepacia, P. maltophilia, P. fluorescens/putida, P. alcaligenes, P. pseudoalcaligenes, P. stutzeri, Acinetobacter spp., Achromobacter xylosoxidans, Flavobacterium spp., and CDC groups IVe and Ve. Although colonization with most of these organisms is sporadic, P. cepacia (and to a lesser extent, P. maltophilia) is usually isolated consistently, and can be associated with significant clinical deterioration. Occurrence of P. cepacia in CF respiratory tract cultures obtained close to the time of death rose nearly ten-fold from 1979 to 1982. Strains representing all nonfermentative gram-negative species encountered were assayed for susceptibility to 17 newer antimicrobial agents. Ceftazidime, n-formimidoyl thienamycin, and aztreonam were most active; cefsulodin, ceforanide, and ceftriaxone were not active against these isolates.

Adolescent↗

PubMed1985

Flagella and motility alterations in Pseudomonas aeruginosa strains from patients with cystic fibrosis: relationship to patient clinical condition.

Selected physiological parameters of 31 classic and rough Pseudomonas aeruginosa strains from respiratory tract cultures of patients with cystic fibrosis were examined. An association of a patient's clinical condition (good or poor) with strain physiology was made. Rough strains from patients in poor clinical condition demonstrated severe alterations in motility when compared with M-2, a highly motile and chemotactic burn strain. Of the 10 rough strains from patients in poor clinical condition, 70% lacked flagella, as determined by electron microscopy. The remaining few flagellated strains from this group exhibited weak motility both in soft agar and by the capillary assay. Their chemotactic response to three amino acids, when compared with that of strain M-2, was reduced approximately 30 to 90%. Classic strains from patients in poor clinical condition were less chemotactic than those from patients in good clinical condition. A majority of classic and rough strains from patients in good clinical condition were comparable to M-2 in both chemotaxis and motility. Changes in other physiological characteristics indicated by reduced growth rates, or auxotrophy, were seldom observed in the cystic fibrosis strains studied. The data suggest that host-selective pressures, associated primarily with patients with cystic fibrosis that are in poor clinical condition, result in the loss of factors related to invasiveness such as motility and chemotaxis. We propose that these results may reflect that there is a more general alteration in the cell envelope of cystic fibrosis strains.

Cell Movement↗