Biomedical subjects

B Asman

Publications and source records attributed to B Asman.

At least 55 records · Page 3Linked to original sources

PubMed1999

Periodontitis increases chemiluminescence of the peripheral neutrophils independently of priming by the preparation method.

OBJECTIVE: The aim was to investigate whether increased Fcgamma-receptor (FcgammaR)-induced chemiluminescence (CL) from peripheral neutrophils in periodontitis could be due to increased sensitivity to non-specific priming by the cell preparation. DESIGN: Two methods of preparation were used: (1) cells purified by density centrifugation and lysis of erythrocytes; and (2) cells in a leukocyte suspension obtained by lysis of erythrocytes alone. METHODS: Neutrophils from 17 subjects with periodontitis and pair-matched healthy controls were studied by CL and flow cytometry (CD16, CD15 and CD11b). RESULTS: Higher CL was found in the purified neutrophils, indicating higher non-specific priming by the Percoll density centrifugation. Priming with TNFalpha and lipopolysaccharide abolished this difference. The net effect of specific priming was significantly lower in the purified neutrophils, indicating a depletion of the priming sensitivity by the density centrifugation. Both preparations reduced CD15 in relation to whole blood, while there was no difference between the two methods in any of the membrane markers. Thus, in both preparations, lysis alone changed the membranes to the same extent. Both methods gave nearly the same relative CL increase in the periodontitis patients as in the controls. CONCLUSION: There was no difference between the neutrophils from patients and controls in sensitivity to non-specific priming by the preparation method. The higher FcgammaR-induced CL in patients with periodontitis is not related to such a non-specific priming by density centrifugation.

Adult↗

PubMed1998

Hyper-reactive peripheral neutrophils in adult periodontitis: generation of chemiluminescence and intracellular hydrogen peroxide after in vitro priming and FcgammaR-stimulation.

We have earlier reported a higher Fcgamma-receptor (FcgammaR)-mediated generation of reactive oxygen species, measured as luminol-enhanced chemiluminescence (CL) from peripheral neutrophils in adult periodontitis patients. The aims of this study were to confirm our previous results and to elucidate the mechanism of this phenomenon by measuring CL in parallel with the intracellular production of hydrogen peroxide, after stimulation with opsonized bacteria. To determine whether the higher CL was associated with altered responsiveness to priming, the cells were preincubated with tumor necrosis factor alpha (TNFalpha) and lipopolysaccharide (LPS). While CL was significantly higher in subjects with periodontitis, there was no difference in hydrogen peroxide production between the patients and the controls, indicating that the hyperreactivity is related to the generation of other oxygen species than H2O2 and/or to processes in the outer cell membrane. The responsiveness to priming with LPS on CL was slightly but not significantly higher in the periodontitis group, suggesting that priming could be of value for distinguishing subjects with periodontitis. When assaying intracellular production of H2O2, TNFalpha and LPS had both a priming and an activating effect. There were no significant differences between the two groups. In conclusion, this study shows a higher FcgammaR-mediated CL of peripheral neutrophils from adult patients with periodontitis, thus confirming our earlier results. The hyperreactivity seems to be related to the outer cell membrane or to oxygen species other than H2O2.

Adult↗

PubMed1997

Peripheral neutrophils after allergic asthmatic reactions.

The response of peripheral neutrophils was studied in 16 patients with allergic asthma after challenge with birch/grass pollen allergen, in order to identify inflammatory markers associated with only the early asthmatic reaction and those associated with both early and late asthmatic reactions. The allergen challenge proceeded until the patients had an early asthmatic reaction with 100% increase in specific airway resistance. Bronchoconstriction after allergen challenge was monitored hourly over 9 h and finally after 18 h, by measurement of the forced expiratory volume in 1 s. Seven patients had a late reaction, defined as a decrease in forced expiratory volume in 1 s of more than 15%. Blood samples were taken before and 18 h after challenge. After allergen challenge (18 h) the blood concentration of neutrophils in patients with a late asthmatic reaction was 1.4 times higher than before challenge and there was a tendency for increased Fc gamma receptor-mediated chemiluminescence. Lewis X-antigen (CD 15), which is associated with endothelial adhesion and extravasation, significantly decreased at the same time. Neutrophils were incubated with the tetrapeptide arginine-glycine-aspartate-serine before and 18 h after allergen challenge. Both patient groups showed an increased Fc gamma receptor-mediated chemiluminescence and a decreased Fc gamma receptor membrane expression following allergen challenge, suggesting a preactivation. In conclusion, patients with a dual asthmatic reaction show a sustained primed inflammatory response and primed neutrophils compared with patients with only an early reaction when measured after the decline of clinical symptoms provoked by allergen challenge.

Adult↗

PubMed1997

Markers of inflammation in crevicular fluid from peri-implant mucosa surrounding single crystal sapphire implants.

The 19 patients included in this study had all been successfully treated for total or partial edentulism with single crystal sapphire implants as retention for overdentures or fixed bridges. As there is a need for more reliable non-invasive parameters for detecting changes surrounding endosseous implants, the aim of this study was to assess the content and the activity of neutrophils in crevicular fluid samples from 3 categories of sites: (1) crevices around implants from edentulous patients (2) crevices around implants in partially edentulous patients, and (3) crevices surrounding teeth. Fluid samples were taken with paper strips from 9 partially edentulous and 10 edentulous patients and the volume measured with a Periotron 6000. Elastase activity was measured as a marker of neutrophil activity and lactoferrin concentration as a marker of the number of neutrophils. Elastase activity per microliter and lactoferrin concentration was, despite similar clinical and radiographic signs, significantly higher in samples from crevices surrounding teeth and implants in the partially edentulous patients compared to samples from crevices around implants in the totally edentulous patients. There were no differences between teeth and implants in partially edentulous patients. The increased elastase activity and lactoferrin concentration indicates a higher neutrophil activity in patients with remaining teeth.

Adult↗

PubMed1997

Gingival crevicular neutrophils: membrane molecules do not distinguish between periodontitis and gingivitis.

We have earlier reported hyperreactive peripheral neutrophils in adult periodontitis, measured as respiratory burst after Fc gamma receptor-mediated activation in vitro, but we have not been able to relate this increased activity to aberrations in the expression of relevant membrane molecules. Various types of inflammatory conditions involving the gingiva should affect membranes differently. We therefore collected crevicular neutrophils from three types of inflammatory sites: (i) with and (ii) without tissue destruction in the same periodontitis patients and (iii) inflamed sites in controls with gingivitis alone and compared the expression of membrane molecules by flow cytometry. The % of positively stained cells and their mean intensities of fluorescence (IFL) were similar in the three types of sites for CD15, CD11a, CD11b and CD16. Peripheral neutrophils studied with the same markers were not activated. This was verified by similar plasma concentrations of lactoferrin and L-selectins in the periodontal and control groups. Compared to peripheral cells, the crevicular neutrophils showed a significantly lower percentage of stained cells, while the stained cells increased their IFL. In conclusion, hyperreactive peripheral neutrophils in periodontitis show the same expression of membrane molecules after migration through different types of inflammatory lesions as do normal neutrophils in gingivitis.

Adult↗

PubMed1997

Priming response to inflammatory mediators in hyperreactive peripheral neutrophils from adult periodontitis.

OBJECTIVES: To study the response to in vitro priming of peripheral neutrophils from patients with periodontitis compared to healthy controls. Peripheral neutrophils from these patients had shown increased production of oxygen radicals after activation with opsonized bacteria and a difference in priming response could suggest an explanation for this hyperreactivity. MATERIALS AND METHODS: Peripheral neutrophils from a group of patients with periodontitis and from age- and sex-matched controls were preincubated with tumor necrosis factor alpha, lipopolysaccharide (LPS), formyl-methionyl-leucyl-phenylalanine and the tetra peptide arginyl-glycyl-aspartate-serine. After preincubation, the cells were activated with gammaglobulin opsonized-bacteria, i.e., a Fc gamma R-stimulation. The priming effect was assessed as the production of oxygen radicals and as the degranulation or primary granules. RESULTS: Showed that the patients had a slightly lower responsiveness to priming than had the controls. This difference in priming response was most pronounced when measured as degranulation of primary granules after preincubation with LPS and 20 min of activation. CONCLUSIONS: This study shows no difference in response to priming, with optimal concentrations of inflammatory mediators, between peripheral neutrophils from patients with adult periodontitis and healthy controls.

Adult↗

PubMed1996

Priming of neutrophils with tumor necrosis factor-alpha measured as Fc gamma receptor-mediated respiratory burst correlates with increased complement receptor 3 membrane density.

Hyperactive or primed neutrophils which damage tissue via cytokines and membrane receptors may be implicated in the pathogenesis of inflammatory conditions. The purpose of this study was to elucidate the priming mechanism in neutrophils by assessing changes in membrane receptors and the Fc gamma R-mediated respiratory burst, measured as chemiluminescence. Purified neutrophilic granulocytes from healthy volunteers were preincubated with recombinant human tumor necrosis factor-alpha. This had a priming effect, increasing both the Fc gamma receptor-mediated luminol-enhanced chemiluminescence and the membrane expression of the C3bi receptor (CRB) (r = 0.843). The membrane densities of Fc gamma RII, Fc gamma RIII, and CR1 were unaffected by tumor necrosis factor-alpha. The mechanism of increased chemiluminescence may involve redistribution of the Fc gamma receptors and cooperation with upregulated CR3, facilitating crosslinking of the receptors. The experiments were performed in a buffer without divalent cations, since these increased the background activity and abolished the priming effect of tumor necrosis factor-alpha. In conclusion, a simultaneous increase in the Fc gamma R-mediated respiratory burst and CR3 density after priming with tumor necrosis factor-alpha indicates a cooperation between Fc gamma R and CR3.

Acetylglucosamine↗

PubMed1996

Increased release of free oxygen radicals from peripheral neutrophils in adult periodontitis after Fc delta-receptor stimulation.

The release of free oxygen radicals and degranulation was studied in neutrophils from 14 patients with adult periodontitis and 14 age- and sex-matched healthy controls. The neutrophils were activated by Fc gamma-receptor stimulation, using Staphylococcus aureus opsonized with gamma globulin. Release of oxygen radicals was measured as luminol-enhanced chemiluminescence. Degranulation was assessed as release of elastase, measured with a specific substrate and as release of lactoferrin measured with ELISA. The neutrophils from the patients showed a significantly higher chemiluminescence and a slightly higher release of elastase, whereas the release of lactoferrin was the same in both groups. In contrast, the ratio between the 2 degranulation products, elastase and lactoferrin, was significantly higher in the group with periodontitis. A flow cytometric analysis of the membrane expression of the adhesion molecules CD 11a, CD 11b, CD 15, CD 16, CD 35 and Mel 14 showed no differences in the median immunofluorescence between the 2 groups. This study showed a more than 2-fold higher release of free oxygen radicals from Fc-gamma-receptor stimulated neutrophils compared with healthy controls, which indicates a specific neutrophil-associated host response in adult periodontitis.

Adult↗

PubMed1995

Lower protein concentration in GCF from patients with periodontitis: an indicator of host-specific inflammatory reaction.

To study the local inflammatory reaction associated with gingivitis and periodontitis, the protein concentrations were measured in gingival crevicular fluid (GCF) from 3 types of site: (i) inflamed sites in patients with gingivitis alone; (ii) inflamed sites with or (iii) without tissue destruction in patients with periodontitis. The GCF was sampled with paper strips and the protein concentration was measured with the Bradford protein assay. Higher protein concentrations in GCF were found at inflamed sites in patients with gingivitis alone than at clinically similar sites without tissue destruction in patients with periodontitis. In contrast, the sites with various degrees of disease in the same periodontitis patient showed the same protein concentrations. These discrepancies indicate that the local inflammatory reaction in the gingiva is host- and not site-specific, i.e., the tissue destruction in periodontitis reflects a specific host response.

Adult↗

PubMed1995

Granulocyte elastase in gingival crevicular fluid: improved monitoring of the site-specific response to treatment in patients with destructive periodontitis.

In 13 patients with severe destructive periodontitis, the response to periodontal therapy was estimated by granulocyte elastase level in gingival crevicular fluid (GCF). 62 sites were classified according to changes of probing depths (PD) and quantitative bone height (BH%) before and after 5-year regular maintenance treatment: (i) 17 consistently healthy sites with no changes of PD and BH%; (ii) 6 initially healthy sites with deterioration in PD and BH%; (iii) 14 diseased sites with improvement in PD and BH%; (iv) 25 diseased sites with no improvement in PD and BH%. GCF was collected by an intracrevicular washing system. The released elastase in the supernatants (EA-S) and the cell-bound elastase in the pellets (EA-P) were determined with a low molecular weight substrate specific for granulocyte elastase. The ratio of EA-S and EA-P (S/P-ratio) was used as a relative measure of elastase released by the granulocytes present. The sites classified as diseased with no improvement or initially healthy but deteriorating, had significantly higher EA-S, EA-P and S/P-ratios than the consistently healthy sites or diseased but improving sites (p < 0.01). Both EA-S and S/P-ratio showed strongly positive correlations with the current levels of gingival inflammation and periodontal destruction (p < 0.001). The present study suggests that increased elastase level is associated with disease progression, and may be used to monitor the response to longitudinal maintenance therapy.

Adult↗

PubMed1995

Increased collagen degradation by experimentally-induced granulation tissue inoculated with bacteria.

Periodontitis is characterized by asymptomatic periodic collagen degradation, which is accompanied by the formation of granulation tissue induced by bacteria. The lesions sometimes contain micro-organisms and/or micro-abscesses that are of unknown significance. The aim of this study was to determine whether bacteria in a sterile granulation tissue could enhance its collagenolytic capacity. The formation of granulation tissue was induced by implanting a cellulose sponge in the subcutaneous tissue in the back of the rat. Bacteria were injected every other day into the sponge from day 8 to day 18. The cell-dependent degradation of a homologous 3H-collagen powder enveloped in the sponge was measured by the radioactivity of the urine excreted 8-18 days after the implantation. The injections increased the excretion of radioactivity by about 40% compared with the controls (n = 8, p < or = 0.005), but caused no clinical signs of acute infection or inflammation. On day 18, 2 days after the last injection of bacteria, no bacteria or increased cell infiltration were observed in the granulation tissue. The appearance of the latter could not be distinguished from that of the control tissues injected with buffer alone. It seems reasonable to assume that the increased collagen degradation results from enhanced activity of phagocytes, which may also be related to an increased release of tissue-destructive proteases and free oxygen radicals into the extracellular space. In conclusion, brief recurrent episodes of bacteria in granulation tissue can increase its collagen degrading-capacity. The latter may be due to augmented cell activity in the tissue. This response seems to have some features comparable to the pathogenesis of episodic periodontitis, e.g., by mimicking the collagen degradation.

Aggregatibacter actinomycetemcomitans↗

PubMed1995

Variations in crevicular fluid elastase levels in periodontitis patients on long-term maintenance.

Granulocyte elastase was determined in the gingival crevicular fluid (GCF) of 18 periodontitis patients. They initially had similar severity of disease but had responded differently to 5-yr maintenance, 13 responders and 5 non-responders. A total of 102 sites were investigated and categorized as: i) consistently healthy, ii) healthy after treatment, iii) gingivitis, and iv) periodontitis, according to clinical criteria. GCF elastase activity was determined with a granulocyte-specific substrate. The sites from non-responders had consistently higher elastase levels than the corresponding category of sites from responders, despite similar gingival inflammation and periodontal destruction, with the exception of consistently healthy sites. Within the non-responders, the periodontitis sites had higher elastase levels than the gingivitis sites commensurate with probing depth, while no difference existed between gingivitis sites and sites healthy after treatment, despite a difference in probing depth. In contrast, in the responders similar elastase levels were found at the periodontitis sites and gingivitis sites despite difference in probing depth, while both diseased sites had higher elastase levels than the sites healthy after treatment, commensurate with probing depth. This study suggests that increased granulocyte-specific elastase levels in GCF may serve as a diagnostic marker for refractory periodontitis patients.

Adult↗

PubMed1994

Altered relation between granulocyte elastase and alpha-2-macroglobulin in gingival crevicular fluid from sites with periodontal destruction.

Granulocyte elastase activity and alpha-2-macroglobulin (alpha-2-MG) were studied in the gingival crevicular fluid (GCF) from 3 categories of sites in 6 patients with gingivitis and 6 patients with periodontitis. 6 inflamed sites in each gingivitis patient were sampled on paper strips and 12 sites, 6 with and 6 without attachment loss and periodontal pockets, were selected in each periodontitis patient. To avoid the influence of increase GCF volume from deep pockets, the elastase activity and the alpha-2-MG were calculated per microliters of GCF. The proteolytic activity of elastase was measured with a low molecular weight substrate and the antiprotease, alpha-2-MG, with ELISA. The measured activity could be ascribed to elastase that had been released into the gingival tissues and into the GCF prior to sampling. In the periodontitis patients, the sites with tissue destruction had a significantly higher elastase activity per site and per microliters GCF and a significantly lower alpha-2-MG per microliters than the 2 other categories of sites without tissue destruction. The destructive inflammation seems to be associated with increased release of elastase, either from more numerous or from more active granulocytes and with an increased proteolytic consumption of the inhibitor accompanied by the fast elimination of the protease-inhibitor-complex. In conclusion, the study shows a strong relationship between elastase activity and tissue destruction, a finding that supports the pathogenic theory of an involvement of granulocytes and their proteolytic enzymes in the mechanism of periodontal destruction.

Adult↗

PubMed1994

Reduction of collagen degradation in experimental granulation tissue by vitamin E and selenium.

The importance of antioxidants in inflammatory tissues has been studied in vivo. Degradation of homologous 3H-collagen powder by experimental granulation tissue induced by cellulose sponges in the rat was monitored as the radioactivity excreted in urine. By administering pharmacological doses of both vitamin E and selenium subcutaneously and by injection into sponges implanted subcutaneously, this breakdown of collagen was reduced. Injections in the sponges also arrested the maturation of the granulation tissue. Vitamin E and selenium are potential inhibitors of the free oxygen radicals from phagocytic inflammatory cells. It is therefore suggested that these radicals may play a rôle in the collagen destruction by granulation tissues, as in periodontitis.

Animals↗

PubMed1994

Elastase and lactoferrin in gingival crevicular fluid: possible indicators of a granulocyte-associated specific host response.

Periodontitis affects a limited number of susceptible humans. The aim of this study was to determine whether there is a difference in the inflammatory reaction between patients with gingivitis and those with periodontitis. For this purpose the levels of elastase and lactoferrin were measured in gingival crevicular fluid (GCF) from three types of sites: i) inflamed sites in patients with gingivitis alone, inflamed sites both ii) with and iii) without tissue destruction in patients with periodontitis. Elastase activity, measured with a chromogenic substrate was significantly higher in the two types of sites in periodontitis patients. Lactoferrin levels, measured with ELISA were the same in the three types of sites. In vitro activation of granulocytes from healthy volunteers with Fc-receptor stimulation showed that the entire release of lactoferrin occurred immediately. In contrast, elastase release was time-dependent and continued throughout the experiment. Thus, the degranulation of the specific (lactoferrin) and azurophil granule (elastase) are under separate control and the two parameters can be combined in a ratio in order to characterize the granulocytes of a given patient. Assuming an immediate release of lactoferrin from the activated granulocytes in vivo, similar amounts of lactoferrin in the three types of sites can be regarded as reflecting similar numbers of granulocytes in the three types of sites. Consequently, a higher elastase activity in GCF from patients with periodontitis indicates a higher rate of release from the cells per se and a granulocyte-associated specific host response.

Adult↗

PubMed1993

Improved maintenance of plaque control by electrical toothbrushing in periodontitis patients with low compliance.

Patients showing low compliance with oral hygiene were selected from a population of patients referred for specialist treatment of periodontitis. The patients selected did not show an acceptable plaque control in spite of a prolonged training period. Plaque around 40% of the tooth surfaces, documented over a period of 4 to 40 months of frequent information and instructions, was found in 10 patients around the age of 40 years with a marked overrepresentation of men. Substitution of the ordinary toothbrush with an electrical toothbrush using the same working principles, resulted in a decreased plaque score of approximately 10% maintained over a considerable time period (12-36 months). A common complaint among the patients was that the oral hygiene procedures were time-consuming and cumbersome. They considered the electrical toothbrush as simple and time saving. Even if these possibilities were not investigated, merely the patients' positive attitude may have made the efforts of tooth cleaning including the proximal cleaning more tolerable, thus improving the compliance. Contributing to the improved compliance might also have been the electrical toothbrush per se. The cleaning technique allows the patient to concentrate on aiming the bristles at the gingival sulcus, while the brush makes the movements. In conclusion, it should be worthwhile recommending an electrical toothbrush with simple working technique to low compliant periodontitis patients restricting the recalls to twice a year.

Adult↗

PubMed1993

Luminol enhanced Fc-receptor dependent chemiluminescence from peripheral PMN cells. A methodological study.

Maximal luminol enhanced chemiluminescence (CL) of PMN cells after Fc-gamma-receptor stimulation is a way to study the cell activity in connection with phagocytic function. Optimal conditions for such a method were elaborated for practical clinical use. After blood sampling and gentle mixing the blood sample was allowed to stand at +20 degrees C for not more than 1 h. The PMN cells prepared at +20 degrees C were washed at +4 degrees C with a phosphate buffer containing human serum albumin. A gentle lysis of the red blood cells with NH4Cl solution reduced the number of red cells sufficiently not to interfere with the CL. Important factors for the precision of the method were reproducible amounts of bacteria and a reproducible mixing of the particles during the CL analysis. The method had a variation (CV) of 10-15% in healthy individuals.

Adult↗

PubMed1992

Expression of Fc-gamma-RIII and fibronectin in peripheral polymorphonuclear neutrophils with increased response to Fc stimulation in patients with juvenile periodontitis.

The nature of increased luminol-enhanced chemiluminescence (CL) in peripheral polymorphonuclear neutrophils (PMN) in juvenile periodontitis is of pathophysiological interest and may serve as a model for tissue damage caused by granulocytes. Activation of PMNs by opsonized Staphylococcus aureus was compared with that of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis, regarded as being more specific for juvenile periodontitis. The CL was higher in the PMNs from the patients, independently of bacteria and mode of opsonization (autologous serum or gamma-globulin). Fc-gamma-RIII assessed on the washed fragments from peripheral PMNs was significantly (p < or = 0.005) lower in the patients with juvenile periodontitis than in their pair-matched healthy controls, while the content of fibronectin was higher (p < or = 0.032). However, when Fc-gamma-RIII and fibronectin were studied in fresh PMNs by flow cytometry no difference could be found between the two groups. The increased generation of CL of peripheral PMNs found in patients with juvenile periodontitis seems to be independent of humoral factors and of bacterial species and may be related to the properties of the PMN cell membranes.

Adult↗