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Biomedical subjects

J Lundahl

Publications and source records attributed to J Lundahl.

At least 91 records · Page 5Linked to original sources

Immediate and delayed effects of nitrogen dioxide exposure at an ambient level on bronchial responsiveness to histamine in subjects with asthma.

The time-kinetics of NO2 induced effects on bronchial responsiveness are poorly known as most observations have been made shortly after exposure. The aim of this study was to measure nonspecific bronchial responsiveness, lung function and inflammatory markers at different times after NO2 exposure in asthmatics. Nineteen subjects with mild asthma were exposed to either purified air or 488 micrograms.m-3 (0.26 ppm) NO2 for 30 min during intermittent exercise. Airway responsiveness to histamine, specific airway resistance (sRaw) and thoracic gas volume (TGV) were measured 30 min, 5 h, 27 h and 7 days after exposure. Peripheral blood inflammatory mediators and the expression of an adhesion molecule, (Mac1) on granulocytes, were analysed 30 min and 27 h after exposure. Bronchial responsiveness to histamine was significantly increased 5 h after NO2 exposure when compared to air (median provocative dose of histamine required to cause 100% increase of sRaw ((PDsRaw,100%) 110 micrograms after NO2 exposure vs 203 micrograms on air). There was a tendency for an increase after 30 min, which was nonsignificant (median PDsRaw,100% 100 vs 153 micrograms). NO2 exposure did not affect sRaw, but TGV was significantly reduced after exposure. We found an increased expression of Mac-1 on granulocytes 30 min after NO2 exposure when compared to pre-exposure values. No effect was seen on tryptase, eosinophil cationic protein (ECP), or myeloperoxidase (MPO). These results suggest that exposure to an ambient level of NO2 causes a delayed effect on bronchial responsiveness in asthmatics. The increased expression of an adhesion molecule in peripheral blood may indicate a NO2-induced priming of human granulocytes.

Adult↗

Human blood monocytes, but not alveolar macrophages, reveal increased CD11b/CD18 expression and adhesion properties upon receptor-dependent activation.

The beta 2 integrin receptor CD11b/CD18 mediates adhesion to the endothelial lining as well as to extracellular matrix components. The present study was undertaken to investigate peripheral human blood monocytes (BMs) and alveolar macrophages (AMs) with respect to quantitative levels of CD11b/CD18 and adhesion properties in relation to the state of activation. BMs and AMs were recruited from healthy subjects. Quantitative analysis of the surface expression of CD11b/CD18 by flow cytometric technique and adhesion properties to albumin-coated surfaces were performed both on resting and N-formyl-methionyl-leucyl-phenylalanine (fMLP)-activated cells. Receptor independent stimuli (phorbol-12-myristate-13-acetate (PMA) and ionomycin) were used in additional experiments. Intracellular stored CD11b/CD18 was evaluated by flow cytometry and immunofluorescence microscopy. The surface expression of CD11b/CD18 on resting BMs increased fivefold (p < 0.01) upon fMLP activation. On resting AMs, the surface expression of CD11b/CD18 was significantly higher (p < 0.01) compared to resting BMs but did not increase further upon activation with fMLP, PMA or ionomycin. In contrast to BMs, no evidence for an additional intracellular pool of CD11b/CD18 was found in AMs. The adherence of resting BMs did not significantly differ from the adherence of resting AMs. After fMLP activation, the adherence of BMs, but not AMs, increased significantly (p < 0.05). Our results indicate that in vivo differentiation of human blood monocytes into alveolar macrophages implies reduced responsiveness to fMLP in terms of CD11b/CD18 upregulation and adhesion properties, and that the lack of upregulation of CD11b/CD18 on alveolar macrophages presumably depends on the absence of an additional intracellular pool.

Adolescent↗

Modulation of CD11b/CD18 on monocytes and granulocytes following hemodialysis membrane interaction in vitro.

We studied the generation of CD11b/CD18 mobilizing factors in serum after incubation with dialysis membrane fragments of different chemical composition. We also evaluated the relative importance of the alternative and classical pathways of the complement system in the generation of such factors. Monocytes and granulocytes from healthy blood donors were incubated in normal human serum (NHS) and in NHS that had been preincubated with Cuprophan (CU) membrane (NHS-CU), Hemophan (HE) (NHS-HE) or polysulfone (PS) (NHS-PS). NHS-CU caused the highest up-regulation of the CD11b/CD18 receptor on monocytes and granulocytes. The rank in capacity to mobilize CD11b/CD18 on granulocytes was CU > HE > PS (p < 0.001), CU > HE (p < 0.05) and HE > PS (p < 0.001). The rank in capacity to mobilize CD11b/CD18 on monocytes was CU > HE > PS (p < 0.001), CU > HE (p < 0.05) and HE > PS (p < 0.01). NHS-PS induced a lower up-regulation of CD11b/CD18 compared to NHS which indicates that serum factors with the ability to mobilize the CD11b/CD18 receptor on monocytes and granulocytes are deposited on or absorbed by PS. In order to study the relative contribution of the alternative and classical pathways of the complement system in the generation of CD11b/CD18 mobilizing factors in serum, three different serum preparations (1. both pathways intact. 2. only the alternative intact and 3. only the classical pathway intact) were used. The CU membrane activated the classical pathway to a larger extent than the PS membrane (p < 0.01). When only the alternative pathway was intact no difference in the generation of CD11b/CD18 mobilizing factors between the CU and PS membranes was observed. These studies show that CD11b/CD18 mobilizing serum factors are generated after incubation with CU membranes and that such factors are probably adsorbed by PS. The classical pathway of complement activation seems to contribute to the generation of CD11b/CD18 mobilizing factors in serum.

Biocompatible Materials↗

The degree of natural allergen exposure modifies eosinophil activity markers in the circulation of patients with mild asthma.

We have previously found that CD9, CD11b, and intracellular ECP (EG2) may be used as activity markers for eosinophils in vitro. The main object of the present study was to determine whether these markers can reflect eosinophil activation in vivo in relation to allergen exposure. for this purpose, six patients with a history of allergic rhinitis and occasional asthma symptoms during the pollen season participated. Blood donors served as controls. Peripheral blood eosinophils were analyzed according to the FOG method and flow cytometry, before and during one birch pollen season with high pollen load (HPL) and one with low pollen load (LPL). The CD9 expression on peripheral eosinophils from the patients was significantly increased both before (P < 0.05) and during (P < 0.01) HPL season, and CD11b expression solely during HPL season (P = 0.01) as compared to controls. The intracellular expression of the EG2 epitope was increased before (P < 0.01) and during (P < 0.05) HPL season, and increased significantly (P < 0.05) during season as compared to before. No changes were observed before and during LPL season. The proportion of eosinophils was increased both before (P < 0.05) and during (P < 0.001) the HPL season as compared to controls. The markers CD9, EG2, and, to a lesser extent, CD11b seem to detect activated eosinophils in the circulation, whereas EG2 may also reflect increased antigen exposure during season.

Adult↗

Tumor necrosis factor alpha-308 alleles in multiple sclerosis and optic neuritis.

Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, is believed to play an important role in multiple sclerosis (MS) pathogenesis. A bi-allelic polymorphism in the TNF-alpha promoter region (TNF alpha-308), has been reported to influence levels of TNF-alpha production. In the present study, we investigated the TNF alpha-308 polymorphism in 93 patients with MS, 17 patients with optic neuritis (ON) and 95 healthy individuals using an allele-specific PCR technique. Allelic genotype was compared with TNF-alpha mRNA expression levels and HLA class II phenotypes. No significant difference regarding the TNF alpha-308 polymorphism was observed between MS patients and controls. Specifically, the less common allele, TNF2, which is associated with higher expression levels of TNF-alpha, was somewhat less frequent among MS patients. In fact, analysis of 19 patients homozygous for the MS associated HLA-DR-DQ haplotype HLA-Dw2 showed that this haplotype does not carry the TNF2 allele. In addition, in 47 patients, the TNF-alpha alleles did not correlate with expression levels measured as numbers of TNF-alpha expressing cells. Thus, we found no evidence for an important role of TNF alpha-308 polymorphism for genetic susceptibility to MS.

Alleles↗

Altered expression of CD11b/CD18 and CD62L on human monocytes after cell preparation procedures.

We have investigated the effect of different cell preparation procedures on the surface expression of CD11b/CD18 and CD62L on human monocytes. Both EDTA and heparin anticoagulated blood were used as sources for leukocytes. The monocytes were analysed by flow cytometry in a mixed leukocyte suspensions obtained after ammonium chloride mediated lysis and in mononuclear cell suspension prepared by density gradient centrifugation (Ficoll-Paque) performed both at 4 degrees C and at 20 degrees C. Monocytes from heparinized blood had a higher expression of CD11b/CD18 and a more pronounced inter-individual variation than monocytes from EDTA blood. Monocytes isolated by Ficoll-Paque had a higher degree of ex vivo activation by means of altered expression of CD11b/CD18 and CD62L compared to monocytes prepared by ammonium chloride mediated lysis. This was more pronounced when the isolation procedure was performed at 20 degrees C. Our findings indicate that monocytes prepared by ammonium chloride mediated lysis of EDTA blood and with the cell handling temperature kept at 4 degrees C are exposed to the smallest ex vivo modulation by means of receptor alteration. An awareness of ex vivo modulation by different cell preparation procedures is of importance especially when comparing the expression of functional receptors on leukocytes of disparate origin.

Adolescent↗

Relationship between time of intake of grapefruit juice and its effect on pharmacokinetics and pharmacodynamics of felodipine in healthy subjects.

In this randomised, cross-over study, in nine healthy males given felodipine ER 10 mg PO 200 ml grapefruit juice was found to increase the plasma levels of felodipine even when the juice was taken 24 hours before the drug. Grapefruit juice drunk simultaneously with and 1, 4, 10 or 24 hours before the drug administration resulted in a 32-99% increase in mean Cmax values of felodipine, relative to concomitant water and felodipine intake. The effect on AUC was also significant when juice was taken up to 10 h before the drug. The effect of the interaction decreased with increasing time between juice and drug intake. All treatments produced a significant decrease in diastolic blood pressure and an increase in heart rate in comparison with morning basal values. The change in haemodynamic variables was approximately the same after all treatment combinations. Headache was reported more frequently after treatments including grapefruit juice.

Adult↗

Transient endotoxemia during burn wound revision causes leukocyte beta 2 integrin up-regulation and cytokine release.

After severe burns, a wound revision is often done to remove devitalized tissue and minimize bacterial growth. After such revision, the patient may show signs of sepsis. In a group of burned patients we found a transient endotoxemia, and a subsequent leukocyte activation, monitored as increased expression of the beta 2-integrin CD11b, after such wound revision. In most patients we could detect elevated levels of plasma TNF-alpha before the operation, with no increases in these levels after the operation. Plasma levels of IL-6 were elevated in all patients and increased after the wound revision in all patients. They also had elevated plasma levels of soluble E-selectin, indicating systemic inflammation. The close relation between endotoxin levels and CD11b expression, and lack of evidence for additional production of TNF-alpha, suggests that up-regulation of the beta 2 adhesion protein during wound revision is mainly caused by endotoxin interaction with the leukocyte.

Adolescent↗

Up-regulation of antigens on alveolar macrophages in quartz exposed rats.

We have analysed the expression of the OX-6 and OX-42 antigens on alveolar macrophages in rats after intratracheal exposure to quartz. Eight female Sprague Dawley rats were included in the study. Four were exposed to physiological saline and four to quartz dust. The rats were sacrificed after 58 +/- 2 weeks and alveolar macrophages were harvested and analysed by flow cytometry. We found a significant higher amount of both antigens on alveolar macrophages harvested from quartz exposed rats. However, we did not find any significant difference in the percentage positive labeled cells between the two groups. We conclude that quartz dust induces up-regulation of functional receptors on alveolar macrophages in rats and that quantitative analysis of these receptors may serve as inflammatory markers in the bronchoalveolar space.

Animals↗

Serum protects against azurophil granule dependent down-regulation of complement receptor type 1 (CR1) on human neutrophils.

We have investigated the effect of gradual degranulation on the expression of functional receptors (CR1 and CR3) on human neutrophils. Incubation with increasing concentrations of fMLP (10(-10) - 10(-7) M) translocated CR1 and CR3 to the cell surface in a similar kinetic pattern. When reaching maximal expression of receptors (10(-7) M fMLP), 78 +/- 10% and 87 +/- 9% of the total pool of CR1 and CR3, respectively, were translocated to the cell surface. To drive the mobilization process further, cytochalasin B was introduced to increase the stimulatory effect of fMLP. No further increase in CR1 surface expression was obtained. However, we found a characteristic time course of surface appearance of CR1 and CR3 with a maximal surface expression within 1 minute, followed by a time-related down-regulation of CR1 but not CR3. In addition, the total pool of CR1 in cytochalasin B treated neutrophils was reduced after 15 minutes stimulation with fMLP measured by flow cytometry and immunoblotting, indicating degradation of CR1. The down-regulation of CR1 was concomitant with a translocation of azurophil granules, in terms of upregulation of CD63. Azurophil, but not specific nor secretory, granule fractions caused a down-regulation of CR1 on fMLP activated neutrophils. The presence of human sera and serine protease inhibitor protected CR1 from down-regulation. Together, these findings indicate that intracellular stored proteases, released in the late part of the sequential mobilization process, alters the expression of functional receptors mobilized in the early part of the mobilization process. The findings also focus on the importance of the microenvironment for the net outcome of neutrophil activation in terms of functional receptor expression.

Adolescent↗

Intracellular and surface distribution of CD9 in human eosinophils.

Expression of CD9 is a feature of both eosinophils and platelets. We have investigated the CD9 expression on resting and activated eosinophils with regard to possibly interacting platelets. Mixed leukocytes were obtained from the platelet-containing (PC) and platelet-depleted (PD) peripheral blood of healthy donors. A cell membrane permeabilization technique, the FOG method, enabled us to detect the eosinophils as a separate population and permitted flow cytometric analysis of both surface and intracellular antigens. Monoclonal antibodies against CD61 were used to identify platelets. The CD9/CD61 ratio indicated that CD9 on resting eosinophils originates mainly from eosinophils and not from adhered platelets. No difference in CD9 expression was obtained between resting eosinophils in PC and PD blood. However, the expression of CD9 was decreased (p < 0.05) on eosinophils in PMA-activated PD blood but increased (p = 0.001) in PC blood, probably due to interacting platelets since CD61 increased simultaneously. In addition, we were able to detect an intracellularly stored pool of CD9 in eosinophils which decreased after activation with PMA. Together these results indicate a translocation of intracellularly stored CD9 to the cell membrane upon activation, probably followed by a subsequent shedding.

Antigens, CD↗

Cell surface receptor modulation on monocytes and granulocytes during clinical and experimental hemodialysis.

We studied the modulation of cell surface receptors related to cell adhesion (L-selectin and Mac-1) on monocytes and granulocytes during clinical (7 patients treated with cuprophan, Cu, and polysulfone, PS, membranes, n = 14) and experimental Cu and PS hemodialysis (n = 14). The objective was to compare cell surface receptor modulation in vivo when large subpopulations of cells are withdrawn from the circulating pool with the experimental model when cells are not sequestrated. The expression of Mac-1 and L-selectin on monocytes increased during clinical Cu dialysis (p = 0.024 and p = 0.0096, respectively) but remained stable during PS dialysis. On granulocytes, an inverse receptor modulation of Mac-1 and L-selectin was observed during clinical Cu dialysis but not during PS dialysis. Mac-1 was significantly higher and L-selectin lower on granulocytes after 15 min of clinical Cu as compared to PS dialysis (p = 0.001 and p = 0.0093, respectively). During experimental Cu dialysis, Mac-1 expression increased and L-selectin decreased markedly and continuously on both monocytes and granulocytes. The L-selectin/Mac-1 ratio on monocytes and granulocytes may be used as an index of the ability of leukocytes to adhere and to be recruited to an inflammatory focus. This ratio was significantly lower during clinical Cu as compared to PS dialysis (p = 0.0008 and p = 0.0015 respectively) indicating that the recruitment of leukocytes to infection foci may be precluded in patients on Cu membranes. Both monocytes and granulocytes showed significantly lower L-selectin/Mac-1 ratio during and after experimental Cu as compared to PS dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Different functional and morphological characteristics in a nonadherent subpopulation of human macrophages recovered by bronchoalveolar lavage.

The alveolar macrophages (AMs) constitute a morphologically and functionally heterogenous cell population. The adhesive properties of these cells are important for their role in host defence. To focus on the heterogeneity, a population of nonadherent macrophages were characterized functionally and morphologically. These cells were then compared with the total alveolar macrophage population. Alveolar cells (> 95% alveolar macrophages), were recovered by bronchoalveolar lavage (BAL) from healthy smokers. Nonadherent macrophages were separated by adhesion. The phagocytic capacity and the autofluorescent properties of the cell populations were determined in flow cytofluorometric assays. In addition, electron microscopic evaluation was performed. The alveolar macrophage adhesion to wells coated with albumin increased in a time-dependent manner. After 15 min, median 47%, interquartile range 42-52% (uncoated wells 68%, 67-72%) of the alveolar macrophages were attached; and after 60 min, 56%, 51-58% (uncoated wells 73%, 71-76%) of the alveolar macrophages were attached. The nonadherent alveolar macrophage population had less phagocytic capacity. The cell autofluorescence increased with increasing cell size and cell complexity/granularity in both populations. The nonadherent cells were more autofluorescent, indicating an increased granularity/complexity. These findings were confirmed with electron microscopy. Thus, the nonadherent alveolar macrophages had more cytoplasmic inclusions than the total alveolar macrophage population (volume density median 0.39, interquartile range 0.35-0.46 and 0.31, 0.26-0.34, respectively), but less surface protusions. We conclude that in lavage fluid from human smokers there is an ultrastructurally specific subpopulation of alveolar macrophages, showing less adhesive properties and impaired phagocytic capacity in vitro. These macrophages may be older alveolar cells or, alternatively, airway macrophages. Since only alveolar macrophages from smokers were investigated, we cannot draw any conclusions regarding alveolar cells from nonsmokers. Nevertheless, the heterogeneity of the lavaged cells should be taken into consideration when the functional ability of the alveolar macrophages are evaluated.

Adult↗

Eosinophil activity reflects clinical status in patients with asthma before and during a prednisolone course.

BACKGROUND: Both overtreating and undertreating asthma can be harmful, either because of side effects or development of uncontrolled asthma. As the eosinophil granulocyte is of importance in asthma, it is logical to study this cell in the search for a marker for the right level of treatment. OBJECTIVE: To study the changes in eosinophil activity and the correlation to clinical status in asthmatic patients who have deteriorated and during prednisolone treatment. METHODS: Nine patients were studied on two occasions: with exacerbation (visit 1) and during prednisolone treatment (visit 2). Clinical evaluation was performed as well as analysis of percentage of eosinophils, eosinophilic cationic protein (S-ECP) in serum and expression of intracellular ECP, measured by cell flow cytometry using a monoclonal antibody (EG2) against the activated form of ECP. RESULTS: Visit 1: four patients had eosinophils above normal, mean 6.5%, range 1.5 to 13.8. S-ECP was measured in seven patients of whom five had values above normal (16 micrograms/L), mean 29.5, range 1.5 to 13.8. Intracellular expression of ECP was above normal (mean 26.7 +/- 10.8) in seven out of nine (mean 48.1, range 28.8 to 69.6). Visit 2: all patients improved and all eosinophil parameters decreased. The eosinophil concentration fell to a mean of 3.0%, range 1.0 to 6.6, S-ECP to a mean of 10.5 micrograms/L, range 3.2 to 17 and intracellular expression of ECP to a mean of 33.4, range 19.4 to 40.9. CONCLUSIONS: Reduction in eosinophil activity followed improvement in clinical condition. Measuring intracellular expression of ECP may be of value in addition to eosinophil count and S-ECP in monitoring asthma.

Adult↗

Partial expression of GP Ib measured by flow cytometry in two patients with Bernard-Soulier syndrome.

Bernard-Soulier syndrome is a rare, congenital bleeding disorder caused by absent or defective GP Ib platelet membrane receptor for the von Willebrand factor (vWF). We studied two brothers with moderate bleeding symptoms. Bleeding time was prolonged and ristocetin-induced platelet aggregation was absent. Flow cytometric analysis showed that both boys had a subnormal expression of GP Ib. One antibody used (AN51) was bound only to 30% of the platelets and at a subnormal density. A second antibody (SZ2) also bound at a subnormal density but a normal fraction of the platelets were immunoreactive. Ristocetin stimulation of the patients' platelets in the presence of plasma resulted in a low binding of vWF, about 30% of healthy controls. On the other hand the expression of GP IIb/IIIa on the platelet membrane appeared to be supernormal even when the increased platelet size was taken into account as shown by the ratio between the density of GP IIIa and CD 9 structures. We conclude that these brothers have a variant of the Bernard-Soulier syndrome with a low expression of a GP Ib receptor.

Bernard-Soulier Syndrome↗

Differences in altered expression of L-selectin and Mac-1 in monocytes and neutrophils.

We have measured the altered expression of the adhesion-promoting glucoproteins L-selectin and Mac-1 on monocytes and neutrophils after incubation with different concentrations of the chemotactic factor FMLP. We found a time- and dose-related down-regulation of L-selectin on both monocytes and neutrophils, which was more pronounced on neutrophils as compared to monocytes at both low (10(-12) M) and high (10(-7) M) concentrations of the chemotactic factor FMLP. Presence of human albumin reduced the down-regulation of L-selectin on both monocytes and neutrophils but to a greater extent on monocytes. Mac-1 expression increased in a time and dose-dependent manner on both monocytes and neutrophils when they were incubated with both low (10(-12) M) and high (10(-7) M) concentrations of FMLP, but the expression was more pronounced on neutrophils. The up-regulation of Mac-1 was equally reduced by albumin on monocytes and neutrophils. Presence of EDTA in RPMI medium reduced the FMLP-induced down-regulation of L-selectin on both monocytes and neutrophils, indicating that the down-regulation of L-selectin is partly divalent cation dependent. Differences in the altered expression of L-selectin and Mac-1 in monocytes and neutrophils with sustained expression of L-selectin on monocytes can contribute to the sequential recruitment of these cells into an inflammatory site.

Adolescent↗

Sawdust-induced inflammatory changes in rat lung: effects on alveolar and interstitial cells in relation to time.

Exposure to sawdust and its contaminants, e.g., terpenes, may cause respiratory tract and lung parenchymal inflammation. To monitor these changes over time. Sprague-Dawley rats were exposed at one occasion to 2.5 mg sawdust or saline by intratracheal instillation. Flow cytometry analyses were done on bronchoalveolar lavage (BAL) cells. Lung tissue specimens were analyzed histologically and immunohistochemically. After one week, the number of BAL polymorphonuclear leukocytes was increased (P < 0.05, N = 8), followed at six weeks by increases of macrophages and lymphocytes (both P < 0.01, N = 8). Enhanced expressions of class II antigens and complement receptors on macrophages after one week were even more pronounced at six weeks, indicating cellular activation. The BAL findings, also including increased (P < 0.001, N = 8) concentrations of hyaluronan with progressing changes over time, confirmed the signs of inflammation, as did the histological analysis of the lung tissue specimens with an accumulation of polymorphonuclears, macrophages, and hyaluronan in the interstitium.

Animals↗

Altered expression of adhesion molecules (L-selectin and Mac-1) on granulocytes during storage.

BACKGROUND: The success of granulocyte transfusion therapy for neutropenic patients with sepsis is dependent on the number and quality of the granulocytes transfused. There is a progressive impairment in granulocyte function during storage. STUDY DESIGN AND METHODS: The effect of 1 to 2, 4, 24, and 48 hours' storage on receptor expression associated with granulocyte function has been analyzed. RESULTS: After 24 hours' storage, significant changes were found in the expression of receptors associated with adhesion to the endothelium: a decrease in L-selectin expression (p < 0.01) and an increase in Mac-1 expression (p < 0.01). Receptors (CR1 and FcRIII), associated with adhesion to target, were either increased (CR1) or unaltered (FcRIII). The capacity to produce a reactive oxygen metabolite (hydrogen peroxide) remained essentially unchanged after 48 hours' storage. The ability of N-formyl-methionyl-leucyl-phenyl alanine to mobilize Mac-1 and CR1 was reduced after 48 hours' storage. CONCLUSION: Since the regulation of adhesion molecules is important for the recruitment of granulocytes into an inflammatory site, the observed in vitro changes in L-selectin and Mac-1 expression during storage may be of importance for the quality of granulocyte concentrates.

Blood Preservation↗