Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 51

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  eosinophil
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
3
Content available remote

Eosinophil - epithelial cell interaction augments cysteinyl leukotrienes synthesis

88%
Eosinophils accumulation in the airways and sustained eosinophil-derived cysteinyl leukotrienes production represent key elements of the inflammatory response seen in asthma.However,it is not known whether activated epithelial cells influence cysteinyl leukotrienes production by eosinophils from healthy valunteers.The aim of the present study was therefore to analyse the effects of interactions between non-atopic eosinophils and epithelial cells on cysteinyl leukotrienes production in vitro .We measured cysteinyl leukotrienes released by phorbol 12-myristate 13-acetate (PMA)–activated human eosinophils or epithelial cells (human bronchial epithelial cell line -BEAS-2B)cultured alone or together.While activated BEAS-2B cells barely formed leukotrienes (1.39 pg/ml ± 0.2))(n=32),activated eosinophils produced considerable amount of them (62.25 pg/ml ± 10.29))(n=32).Interestingly,when activated eosinophils and epithelial cells were co-incubated,production of cysteinyl leukotrienes increased substantially (571.1 pg/ml ± 80.9))(n=32).Thus,eosinophil-epithelial cell interactions,when occur,are associated with increased biosythesis of cysteinyl leukotrienes.
Eosinophils were elicited from non-lactating mammary glands of non-pregnant ewes by infusion of Trichostrongylus colubriformis infective third stage larvae or Ascaris suum embryonated eggs with polymyxin В sulphate. The cell preparations obtained were mixed with T. colubriformis exsheathed third stage larvae with or without sheep serum and incubated. Larval migration or paralysis was influenced by those cell preparation that contained > 19% eosinophils. This inhibitory activity was demonstrated to be associated with eosinophils by using cell preparations that were predominantly eosinophils or Percoll density gradient fractions that consisted totally or largely of eosinophils. Serum from sheep infected with T. colubriformis significantly augmented the effect of the cells. Soluble extracts from eosinophils and their granules also inhibited the activity of the larvae. The activity of the granule extract was associated with the void volume fraction of this extract from a Sephadex G-50 column.
Blood was collected from grazing lambs from lines of Romney sheep selected on the basis of low (resistant line) or high (susceptible line) faecal nematode egg count. Leucocytes were prepared by osmotic lysis of erythrocytes and then subjected to centrifugation on discontinuous Percoll density gradients. Lambs from the resistant line had significantly more hypodense eosinophils than did lambs in the susceptible line.
The host-parasite relationship of the post-infection tissue resident and migratory stages of Uncinaria stenocephala are areas, which have received very little attention to-date. In the present experiments cellular and serum antibody responses were evaluated in mice infected percutaneously with infective larvae of the nematode. Significant eosinophil infiltration was observed in the skin at the site of infection. The number of these cells increased significantly (p<0.01) and dramatically at the site of the first infection (abdomen) within 24 h of exposure to the second dose of larvae which was administered at a different site (back). A clear IgE response of mice to somatic and surface antigens of L3 was observed. There was no further increase in IgE to the somatic antigen preparations following challenge, but a significantly higher concentration of IgE reactivity to surface antigens was detected 14 days after challenge. A short-lived, IgM, IgG and IgA response to the somatic antigens was also detected.
Eosinophils have long been considered to play solely crucial role in the pathogenesis of aspirin-induced asthma, however increasing evidence suggest that the bronchial epithelium is also involved in the initiation and maintenance of allergic inflammation. Epithelial cells and eosinophils retained within airways interact reciprocally to mount and sustain inflammatory response. Recently, we have shown that eosinophil-epithelial cell interactions are capable of amplifying the production of cysteinyl leukotrienes (Cys-LTs). The aim of this study was to investigate if there is any influence of aspirin (ASA) on Cys-LTs and prostaglandin E2 (PGE2) production in the model of co-cultured human epithelial cells (line BEAS-2B) and human eosinophils. Synthesis of Cys-LTs in eosinophils was increased after incubation with ASA. At the same time the production of PGE2 was decreased by aspirin (n=32). BEAS-2B cells barely formed Cys-LTs; addition of ASA increased this production, while production of PGE2 was inhibited by aspirin (n=32). Synthesis of Cys-LTs by eosinophils co-incubated with BEAS-2B was nearly 7-fold higher than that of activated eosinophils alone (1631.5 pg/ml ± 154 vs. 258 pg/ml ± 31; p<0.05; n=32). Surprisingly, in the eosinophil-epithelial cell co-culture, aspirin inhibited both augmentation of Cys-LTs synthesis (from 1631.5 pg/ml ± 154 to 1458 pg/ml ± 137; p<0.05; n=32) and the production of PGE2 (from 2640 pg/ml ± 231 to 319 pg/ml ± 27; p<0.05; n=32). In summary, we have demonstrated that interactions between non-atopic eosinophils and epithelial cells result in augmentation of Cys-LTs production, and this augmentation could be inhibited by aspirin.
Platelet-leukocyte interactions represent an important determinant of the inflammatory response. Although mechanisms of platelet-neutrophil adhesion were studied extensively, little is known on the mechanisms of platelet-eosinophil interactions. The aim of the present study was to analyze the involvement of adhesion molecules and lipid mediators in platelet-eosinophil adhesion as compared to platelet-neutrophil adhesion. For that purpose human platelets, eosinophils and neutrophils were isolated and platelet-eosinophil and platelet-neutrophil adhesion induced by thrombin (30 mU/ml), LPS (0.01 µg/ml) and fMLP (1 µM) was quantified using the "rosettes" assay. The involvement of adhesion molecules such as selectin P, glycoprotein IIb/IIIa (GPIIb/IIIa) and lipid mediators such as of thromboxane A2 (TXA2), platelet activating factor (PAF) and cysteinyl leukotrienes (cysLTs) were studied using monoclonal antibodies and pharmacological inhibitors, respectively. Thrombin (30 mU/ml), LPS (0.01 µg/ml) and fMLP (1 µM) each of them induced platelet-eosinophil adhesion that was even more pronounced as compared with platelet-neutrophil adhesion induced by the same stimulus. Anti-CD62P antibody (1 µg/ml) and anti-GP IIb/IIIa antibody (abciximab - 3 µg/ml) strongly inhibited platelet-eosinophil as well as platelet-neutrophil adhesion. Aspirin inhibited platelet-eosinophil adhesion, while MK 886 - a FLAP inhibitor (10 µM), or WEB 2170 - a PAF receptor antagonist (100 µM) were less active. On the other hand aspirin, MK 886 and WEB 2170 all three of them inhibited platelet-neutrophil adhesion. In summary, platelets adhered avidly to eosinophils both after activation of platelets by thrombin, eosinophils by fMLP or simultaneous activation of platelets and eosinophils by LPS. Similarly to platelet-neutrophil interaction adhesion of platelets to eosinophils involved not only adhesion molecules (selectin P, GPIIb/IIIa), but also lipid mediators such as TXA2. The involvement of PAF and cysteinyl leukotrienes in platelet-eosinophil adhesion was less pronounced as compared to platelet-neutrophil adhesion.
Effect of ketosis on the number and activity of leukocytes was investigated in 8 cows. The high level of ketone bodies in the blood was associated with a significant decrease in the total white blood cell count, neutrophils, and eosinophils, and insignificant decrease in lymphocytes. The number of monocytes was not changed. At the stage of ketosis, the neutrophil ability to NBT reduction was significantly lower, while the phagocytic index was slightly higher compared with the values during the time when the disease was not found.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.