Biomedical subjects

J Hed

Publications and source records attributed to J Hed.

At least 37 records · Page 2Linked to original sources

PubMed1994

Studies of neutrophil and monocyte oxidative responses in polycythaemia vera and related myeloproliferative disorders.

We have previously reported that polymorphonuclear granulocyte (PMN) chemiluminescence (CL) and superoxide anion production are abnormally low in patients with polycythaemia vera (PV) after simulation with n-formyl-methionyl-leucyl-phenylalanine (fMLP), but normal when elicited by phorbol myristate acetate (PMA). This study documents that both fMLP and PMA induced CL was normal in PMN from patients with chronic myelogenous leukaemia (CML) and essential thrombocythaemia (ET). Furthermore, we monitored intracellular hydrogen peroxide (H2O2) production in PMN and monocytes from patients with PV, CML and ET by flow cytometry. H2O2 production in resting and PMA-stimulated cells was normal in all diseases. So also was fMLP induced H2O2 generation in ET PMN and monocytes. In contrast, fMLP-induced H2O2 production was significantly lower both in PV PMN (1.8 +/- 0.7 mean fluorescence intensity units in PV compared to 8.4 +/- 3.4 in healthy controls; P < 0.02), and in PV monocytes (0.3 +/- 0.5 compared to 2.5 +/- 0.7 in controls; P < 0.02). A less pronounced reduction of fMLP stimulated H2O2 production was noted in CML PMN (3.8 +/- 3.1 compared to 8.4 +/- 3.4 in controls; P < 0.05), and monocytes (1.3 +/- 0.6 compared to 2.5 +/- 0.7 in controls; P < 0.05). The reduction of H2O2 generation in PV and CML PMN was not attributed to subpopulations of less responsive cells. However, one ET and one CML patient showed a subpopulation of less responsive PMN. Thus intracellular H2O2 (as well as extracellular release of superoxide ions) is reduced in fMLP-stimulated PV PMN and monocytes but normal after PMA stimulation, a phenomenon that is not consistently found in other myeloproliferative disorders.

Adult↗

PubMed1994

IgA antiendomysium antibodies have a high positive predictive value for celiac disease in asymptomatic patients.

Many attempts have been made to find screening tests for celiac disease to reduce the need for biopsy, or to achieve better selection criteria before intestinal biopsy. We have recently analyzed apparently healthy blood donors for antigliadin antibodies (AGA) to select subjects for further gastrointestinal investigation. A prevalence of gluten enteropathy of at least 1/256 was found in this population. The positive predictive value (+PV), however, was only 20%. In the present study we have analyzed IgA antiendomysium antibodies (IgA-EmA) to estimate the sensitivity and specificity of the test, and determine whether or not the +PV of the assay increases when screening for adult celiac disease in an asymptomatic population. We found that asymptomatic persons with celiac disease may have IgA-EmA. We found a 100% specificity of IgA-EmA in the tested population of blood donors, whereas the sensitivity was about the same as that of IgA-AGA. This result of a +PV of 100% indicates that a positive IgA-EmA could replace biopsy in diagnosing celiac disease. However, further extended studies are needed to determine whether this is applicable in other populations. To screen patients for celiac disease, we recommend the easy and cheap IgA-AGA assay as a preliminary test and the IgA-EmA to verify the diagnosis and avoid unnecessary biopsies.

Adult↗

PubMed1993

Quartz selectively down-regulates CR1 on activated human granulocytes.

We have investigated the interaction between quartz and granulocytes with respect to complement receptor expression. When N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated leukocytes were exposed to quartz at 37 degrees C, CR1 was down-regulated but CR3 was not affected. This was a direct effect on granulocytes because it occurred in a similar fashion when mixed leukocyte suspensions and isolated granulocyte populations were used as targets for quartz. The observed down-regulation by quartz was not affected by the microfilament-disrupting agent cytochalasin B and the total detectable pool of CR1 was reduced after quartz exposure. When protease inhibitors, such as aprotinin or phenylmethanesulfonyl fluoride, were present during quartz exposure, the down-regulation of CR1 was less pronounced, but this was not the case not when protease inhibitors such as EDTA-Na2 and pepstatin were present. Exposure to quartz was not accompanied by a pronounced release of beta-glucuronidase (marker for the primary granules) or vitamin B12 binding protein (marker for the secondary granules). In contrast to quartz, exposure to alumina did not affect the expression of CR1 and CR3. The spontaneous mobilization of CR1 at 37 degrees C was reduced when quartz was present but the CR3 mobilization was unaffected. Our results indicate that quartz induces a granule protease-dependent selective shedding of CR1 but not CR3 despite a low degree of degranulation.

Aprotinin↗

PubMed1993

Differences in intracellular pool and receptor-dependent mobilization of the adhesion-promoting glycoprotein Mac-1 between eosinophils and neutrophils.

Recruitment of cells to an inflammatory site is a process that is selectively regulated. At an inflammatory site caused by bacterial infection, predominantly neutrophil accumulation is observed. This is in contrast to allergic inflammation, where predominantly eosinophil accumulation occurs. Mac-1 is an inducible adhesion molecule for both neutrophils and eosinophils. We examined the mobilization of this receptor on neutrophils and eosinophils after exposure to factors related to bacterial infections and allergic inflammation. We found more pronounced mobilization of Mac-1 on neutrophils than eosinophils after exposure to N-formylmethionyl-leucyl-phenylalanine, lipopolysaccharides, and activated sera (C5a). There was no significant difference in Mac-1 expression after exposure to aggregated immunoglobulin G. Incubation with interleukin-5 (IL-5) caused a significant increase of Mac-1 expression on eosinophils but not on neutrophils. Neutrophils seem to respond to a greater extent than eosinophils to factors related to bacterial infections, whereas eosinophils respond better to IL-5 associated with allergic inflammation. We measured the total pool of Mac-1 to evaluate whether these differences could depend on the size of the intracellular pool. Eosinophils had a larger total pool of Mac-1 than neutrophils. This finding increases the difference between eosinophils and neutrophils when relating the mobilized pool to the total pool. Stimulation with receptor-independent stimuli such as phorbol myristate acetate and ionomycin induced more pronounced mobilization of Mac-1 on eosinophils, but no differences were obtained if the mobilized pool was related to their total pool. These results indicate that the difference in responsiveness depends on different receptor-mediated signaling, since receptor-independent stimulation resulted in relatively similar mobilization of the intracellular pool of Mac-1.

Adolescent↗

PubMed1993

Terpenes enhance metabolic activity and alter expression of adhesion molecules (Mac-1 and L-selectin) on human granulocytes.

Granulocytes from healthy blood donors were exposed to terpenes dissolved in ethanol. Flow cytometry was used to measure the expression of the cell surface receptors Mac-1 L-selectin, and CR1, which were detected by monoclonal antibodies. The phagocytic activity was determined by using C3b-coated yeast particles as prey. The metabolic activity was measured by determining the intracellular hydrogen peroxide production using dichlorofluorescein diacetate. After terpene exposure the expression of Mac-1 and CR1 increased (P < 0.001 and P < 0.01, respectively) and the expression of L-selectin decreased (P < 0.001). There was also an increased metabolic activity (P < 0.001). The cell viability, the cell count, and the phagocytic activity remained unchanged. These findings suggest that terpene exposure triggers the granulocytes to a higher degree of activation in terms of an altered expression of the adhesion molecules and an increased metabolic activity.

Cell Adhesion↗

PubMed1993

Presence of serum modulates expression of complement receptor type 1 (CR1) on human granulocytes after quartz exposure.

We have investigated the interaction between granulocytes and quartz with respect to the expression of complement receptor type 1 (CR1) and the presence of normal human serum (NHS). Quartz down-regulates selectively CR1 on activated granulocytes. This down-regulation is abolished in the presence of both NHS and heat-inactivated NHS (NHS56) but not human albumin. When quartz was preincubated with NHS (quartz-NHS) before exposure to activated granulocytes, a down-regulating effect was observed in contrast to preincubation with NHS56, which did not induce a down-regulation. Preincubation with cytochalasin B reduced the down-regulation of quartz-NHS, indicating a cytoskeleton-dependent internalization of the receptor. The serine protease inhibitor PMSF partly reduced this down-regulation. Our results indicate that the presence of NHS in the alveolar space influences the interaction between quartz and recruited granulocytes with respect to CR1 expression. Since CR1 is an important opsonin receptor and soluble CR1 can modulate the inflammatory response, this may be of importance in the inflammation and fibrosing process induced by quartz in the alveolar space and lung interstitium.

Blood Physiological Phenomena↗

PubMed1993

Metabolic activity in human alveolar macrophages increases after cessation of smoking.

Alveolar macrophages (AMs) were recruited by bronchoalveolar lavage (BAL) from human smokers before and one, three, and six months after smoking cessation. The metabolic activity of the AM was quantified as luminol-enhanced chemiluminescence (CL) both at rest and after in vitro stimulation with phorbol myristate acetate (PMA). The resting CL values did not differ before and after smoking cessation. The activity after PMA stimulation was unaltered at one and three months. However, the maximal metabolic response, as well as the rate, were significantly (P < 0.02 and P < 0.01, respectively) higher at six months, compared to prior smoking cessation. In addition, the time to reach the maximal peak was reduced after six smoke-free months, indicating a more rapid cell activation. The cell concentration in the BAL-fluid decreased (P < 0.001) as soon as after one smoke-free month and remained low at the following lavages. The lower metabolic response one and three months after smoking cessation, and the increased response six months after, together with a rapid normalization of the cell concentration in the BAL fluid, may be explained by the persistence of tobacco-smoke particles in the alveolar space, which could influence cell activity.

Bronchoalveolar Lavage Fluid↗

PubMed1993

Seasonal variation and sex differences of circulating macrophages, immunoglobulins and lymphocytes in healthy school children.

Subpopulations of T and B lymphocytes and levels of serum immunoglobulins G, A, M, E and subclasses G1, G2 and G3 were studied in 45 healthy school children aged 8-16 years during four seasons of the year. There were significant increases in CD4+ T helper cells, total T lymphocytes and CD4+/CD8+ (helper/cytotoxic) T-cell ratio during the spring season. While the levels of CD8+ T cells and total B lymphocytes remained statistically unchanged during all four seasons, the levels of natural (HNK-1) killer cells and macrophages increased significantly during the autumn and summer seasons respectively. The levels of immunoglobulins G, A, M and E remained statistically unchanged during all four seasons. Girls had higher levels of CD4+ T cells and a higher CD4+/CD8+ T-cell ratio than boys. Girls also had slightly higher levels of immunoglobulin G and M. These observations suggest that seasonal variations of some immunological parameters occur in healthy children. This may be an adaptive response to variable climatic and other environmental factors. These natural variations due to seasonal changes should be taken into account when immunological tests are used in clinical investigations.

Adolescent↗

PubMed1993

Counts of activated blood eosinophils for monitoring asthma.

The FOG method is a new cell membrane permeabilization technique which makes it possible to identify the eosinophils in unseparated peripheral blood and allows analyses of both surface and intracellular antigens by flow cytometry. This technique has been adapted to analyse eosinophil activity in peripheral blood from asthmatic patients by measuring the expression of the EG2-epitope on intracellular ECP.

Antibodies, Monoclonal↗

PubMed1993

Adenoid tissue lymphocyte subpopulations--evaluation of a quantitative analysis with flow cytometry.

Secretory otitis media (SOM) is a common childhood disease without a completely clarified etiology. A chronic inflammatory condition in the nasopharynx, presumably caused by an increased bacterial load, is one factor of probable etiological importance. In the present study a flow cytometric method for analysis of adenoid lymphoid cell populations was developed to facilitate quantitative comparisons between children with SOM and children without ear disease. Adenoids removed from 18 children due to adenoid hyperplasia and obstructive symptoms were studied. Results of the flow cytometric analysis correlated well with the findings from immunohistological studies of five of the adenoids. PCA-1 and CD25 were found to be good markers of increased cellular activity after non-specific stimulation in cell culture. It is concluded that the flow cytometric method is suitable for further quantitative analysis of adenoid tissue.

Adenoidectomy↗

PubMed1993

Diversity in regulation of adhesion molecules (Mac-1 and L-selectin) in monocytes and neutrophils from neonates and adults.

The surface expression and regulation of the adhesion promoting glycoproteins Mac-1 and L-selectin was measured on monocytes and neutrophils from neonates and adults. A significant decrease in Mac-1 up regulation on both monocytes and neutrophils was found in neonates after both high (10(-7)M) and low (10(-9)M) concentrations of the chemotactic factor N-formyl-methionyl-phenylalanine (FMLP). A significant difference was obtained after incubation for five minutes, which was further enhanced after incubation for 15 minutes. Factors related to bacterial infections, lipopolysaccharides, activated sera (C5a), and aggregated IgG induced an impaired Mac-1 up regulation on both monocytes and neutrophils from neonates compared with adults. The expression of L-selectin was significantly lower on neutrophils from neonates and was less down regulated upon stimulation with a low concentration (10(-12)M) of FMLP. On monocytes from neonates, the expression and down regulation of L-selectin did not differ from monocytes from adults. Mode of delivery did not influence the regulation of Mac-1 and L-selectin in neonates. Diversity in expression and regulation of Mac-1 and L-selectin on monocytes and neutrophils may contribute to the increased susceptibility to infections observed in neonates.

Adolescent↗

PubMed1993

Short-term in vivo exposure to cigarette-smoke increases the fluorescence in rat alveolar macrophages.

Alveolar macrophages (AMs) from human smokers exhibit a strong intracellular fluorescence. In order to study the mechanisms behind the fluorescence, we wanted to determine whether it could be induced by short term exposure to smoke. We therefore exposed rats for either one or five days to cigarette smoke. AMs were recovered by bronchoalveolar lavage (BAL), and their fluorescence was quantified by flow cytofluorometry. AMs from rats exposed to two cigarettes, on a single occasion, showed an increased fluorescence compared to controls. The fluorescence was further enhanced by exposing rats to two cigarettes, for five consecutive days. Larger and more granular/complex AMs were more fluorescent than smaller and less granular/complex cells. Smoke-exposed rats (five consecutive days) lavaged immediately after the exposure, had less cells in their BAL fluid than control animals. However, when rats were lavaged three smoke-free days after the exposure, the cell recovery increased, probably due to less airway obstruction. In conclusion, we found that a short-term in vivo exposure to cigarette smoke results in an increased AM fluorescence. The findings can be one explanation for the strong fluorescence seen in AMs from human smokers, possibly due to endocytosis of fluorescent material.

Animals↗

PubMed1992

Lability in complement receptor mobilization of granulocytes in patients with bronchial hyperreactivity.

The recruitment of activated granulocytes to bronchial mucosa seems to be involved in the prolonged inflammatory response observed in asthma and probably associated with bronchial hyperresponsiveness. We studied the patients with bronchial hyperresponsiveness with respect to the expression of complement receptor type 1 (CR1), its variability and readiness to become mobilized on peripheral granulocytes from patients with bronchial hyperresponsiveness. CR1 expression and its hourly variation was significantly (P less than 0.02, P less than 0.01 respectively) higher in the patient group compared with the control group. In addition the ability to mobilize CR1 spontaneously at +37 degrees C correlated to the variation of CR1 expression that occurred during a 4 hr period. These findings indicate that granulocytes from patients with bronchial hyperresponsiveness have a higher degree of variation in CR1 expression that correlates to their ability to mobilize CR1 and may reflect a more pronounced lability.

Adolescent↗

PubMed1992

Autoantibodies to leucocyte antigens in hydralazine-associated nephritis.

Clinical and laboratory findings and drug history were studied in 17 patients with suspected hydralazine-associated nephritis, five of whom only had renal disease, while twelve also had extrarenal manifestations. Renal biopsies revealed extracapillary proliferative or focal segmental proliferative glomerulonephritis in 10 patients, and tubulo-interstitial nephritis in five patients. Antinuclear antibody (ANA) was found in 16 patients, but none of the 14 patients tested had antibodies to DNA. Tests for antibodies to myeloperoxidase (anti-MPO) and antibodies to neutrophil cytoplasm antigen (ANCA) were performed by ELISA. Twelve of the 14 patients tested had anti-MPO; five of these 14 patients had ANCA, while one had borderline levels. These findings suggest that hydralazine facilitates the induction of a systemic disease with multiple autoantibody production.

Antibodies, Antinuclear↗

PubMed1992

Increased expression of adhesion proteins (MAC-1) and altered metabolic response in human leukocytes exposed to surfactant in vitro.

In this study the modulatory effects of a well-defined surfactant preparation on blood leukocytes were investigated. The expression of the cell surface receptor MAC-1 was analyzed by flow cytofluorometry, and the metabolic response was measured by a chemiluminescence technique. An increase (p less than 0.05) in the MAC-1 receptor expression was observed in the granulocytes but not in the monocytes. There was a decrease in the metabolic response of the leukocytes after stimulation with phorbol myristate acetate (PMA) and a delay (p less than 0.01 for both) in the peak activity. Formyl-methionyl-leucyl-phenylalanine (fMLP) caused an increased peak (p less than 0.01). Thus, the surfactant preparation had a modulatory effect on blood leukocytes with regard to the expression of the cell surface receptor MAC-1 and the metabolic response.

Adolescent↗

PubMed1992

Mobilization of an intracellular glycoprotein (Mac-1) on monocytes and granulocytes during hemodialysis.

We studied the upregulation of the intracellular glycoprotein Mac-1 (CD11b/CD18, CR3) on monocytes and granulocytes during 36 bicarbonate hemodialyses in 12 patients who were randomly treated with Cuprophan (Cu), Hemophan (He) or Polysulfone (PS; low-flux) membranes. The degree of mobilization of this adhesion protein was related to changes in granulocyte and monocyte count, generation of C3a and production of interleukin-1 beta in plasma. Mac-1 expression on granulocytes was significantly higher after 5 and 15 min of Cu hemodialysis as compared to He or PS dialyses (p < 0.001) and correlated to changes in granulocyte count at 15 min (r = 0.62 and r = 0.76, p < 0.001). No differences in early Mac-1 mobilization on circulating monocytes was observed despite a decrease in cell count. Mac-1 expression on monocytes and granulocytes in the venous blood line at 180 min of treatment was significantly higher during Cu dialysis as compared to He and PS dialyses (p < 0.02 and p < 0.001, respectively). Early generation of C3a was higher in patients on Cu dialysis than in He or PS dialysis (p < 0.001) and correlated both to granulocytopenia (r = 0.45, p < 0.01) and to the subsequent increase in Mac-1 expression on granulocytes (r = 0.63, p < 0.001). An early increase in Mac-1 expression on monocytes was accompanied by an increase in plasma interleukin-1 beta later during dialysis (p < 0.05). Studies of Mac-1 expression during hemodialysis increased the sensitivity of biocompatibility measurements and correlated better than complement generation to changes in granulocyte count as it mediates adhesion to endothelial cells.

Adult↗

PubMed1992

Dialysis granulocytopenia is preceded by an increased surface expression of the adhesion-promoting glucoprotein Mac-1.

We studied the expression of Mac-1 on granulocytes (flow cytometry) from 9 patients (27 examinations) during hemodialysis with cuprophane membranes (CuM). Samples were drawn before dialysis and from the arterial and venous lines at 5, 15 and 180 min. Granulocytopenia was most pronounced after 15 min of treatment. Mac-1 expression on granulocytes increased during dialysis, and a pronounced enhancement occurred across the dialyzer. Mac-1 expression on granulocytes increased 116% across the dialyzer at 5 min, and the degree of Mac-1 mobilization at 5 min correlated with the degree of subsequent granulocytopenia at 15 min. In in vitro experiments, granulocytes from healthy blood donors were incubated with plasma drawn from the arterial and venous lines at 5 min. Plasma drawn from the venous line at 5 min had a greater ability to mobilize Mac-1 than plasma from the arterial line (p less than 0.002). This difference correlated with the degree of granulocytopenia at 15 min (r = 0.76, p = 0.01). Pieces of a washed CuM were incubated in normal human serum (NHS) preparations for different times. Inactivation of the alternative pathway of complement activation (NHS-50 degrees) did not alter the generation of Mac-1-mobilizating capacity compared to NHS. In contrast, inactivation of the classical pathway (NHS-EGTA) decreased the early but not the late generation of Mac-1-mobilizating capacity. Our results indicate that the early mobilization and not the absolute expression of Mac-1 correlates with granulocytopenia, and that sera in vitro attain Mac-1-mobilizating capacity more rapidly when the classical pathway of complement activation is intact.

Aged↗

PubMed1992

Smoking cessation rapidly reduces cell recovery in bronchoalveolar lavage fluid, while alveolar macrophage fluorescence remains high.

Bronchoalveolar lavage (BAL) was performed in smokers (22.6 +/- 7.8 pack-years) before (n = 18) and 1 (n = 14), 3 (n = 13), 6 (n = 11), 9 (n = 9), and 15 (n = 8) months after smoking cessation. The recovery of the BAL fluid increased after smoking cessation (p less than 0.05). The total number of cells and the cell concentration were significantly lower already at one month (p less than 0.05 and p less than 0.01, respectively), and this decline was more pronounced at the following lavages. By using flow cytofluorometry, alveolar macrophage (AM) fluorescence was quantified, since it is known that AMs lavaged from smokers have an increased fluorescence, due to interaction with fluorescent substances in the inhaled smoke. Not until six months after smoking cessation was a significant (p less than 0.05) decrease in AMs fluorescence noted. At 15 months, the fluorescence was still increased, with great individual variations, compared with AMs from nonsmokers. The decline in fluorescence of AMs after smoking cessation was negatively correlated to the previous cigarette consumption. The absence of new, low fluorescent cells in the BAL fluid, despite a slow, but significant decrease in the fluorescence intensity of the whole cell population, suggests that the fluorescent material is redistributed from older AMs to newly recruited cells. These substances can thus remain in the alveolar space for a longer time than the estimated life span of the AMs.

Adult↗