1,721,039 research outputs found
Differences arising in human neutrophil activation passing from N-formyl to N-acetyl-oligopeptides
No full textN-formyl- and N-acetyl-peptides were synthesized and compared in order to understand which features can best elicit biological responses. The behavior of N-formyl-peptides confirms the previously found sequential obligations in the residues, while acetyl-derivatives do not seem suitable for an efficacious stimulation of human neutrophils
Synthesis and biological activity of D-glucopyranosyl peptide T derivatives
No full textThe solid phase procedure, based on the Fmoc (9-fluorenylmethyloxycarbonyl) chemistry, was used to prepare some peptide T analogues in which D-glucopyranosyl units are beta-O-glycosidically linked to Thr4 and/or Thr5 side chains. All glycopeptides showed significant human monocyte chemotaxis and high resistance to degradation by plasma or brain enzymes
Synthesis and biological activity of chelator-peptide T conjugates
No full textThe solid phase procedure was used to prepare two peptide T derivatives in which the 4-[(1,4,8,11-tetraazacyclotetradec-1-yl)methyl]benzoyl unit is linked to their N-terminus. In a human monocyte chemotaxis assay, both chelator-peptide conjugates showed a high binding property to the CD4 receptor, comparable to the parent H-D-Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-NH2 and its pentapeptide fragment T(4-8)-NH2. These encouraging results make the above cyclam-oligopeptides candidates for the development of the CD4 receptor imaging agents
Lymphocytes treated with natural alpha interferon produce a chemotactic factor for human neutrophils
No full textlymphocytes stimulated with alpha interferon released achemotactic factor for neutrophils. The process was not inhibited by cicloheximide, whereas mepacrine completely inhibited rellease of chemotacttic activity. Interferon did not stimulate lymphocytes to release a neutrophil chemotactic factor
ACTIVATION OF NEUTROPHIL CYTOTOXICITY BY SYNERGISTIC ACTION OF TPA AND TARGET IMMUNIZATION
No full textABSTRACTS OF THE SEVENTH MEETING OF THE ITALIAN ASSOCIATION FOR CELL BIOLOGY AND DIFEFRENTIATION, 16-19 OCTOBER, SPOLETO, ITAL
Does a relationship exist between neutrophil myeloperoxidase deficiency and the occurence of neoplasms ?
No full text36 unrelated individuals with neutrophil MPO deficiency, (10 totally MPO deficient) were found on screening a population of 148,000 subjects. A further 2 subjects with total and 22 with partial MPO deficiency were identified through family studies. The assessment of neutrophil function, i.e., peroxidase activity, superoxide anion generation, microbicidal activity towards fungi and bacteria, and locomotor behaviour, was carried out in 10 subjects with total and 4 with partial MPO deficiency. We found that the enzyme defect is associated with a marked impairment in the killing of both S. aureus and C. albicans, without affecting microbicidal activity against S. faecalis. There appears to be a high incidence of malignancy in patients with complete MPO deficiency, suggesting a relationship between a defective MPO system and neutrophil-mediated tumor cell cytotoxicity
Triggering of neutrophil cytotoxicity against an antibody-coated tumour target by TPA
No full textThe human erythroid myeloid leukaemia cell line K562 was used as target for human neutrophil cytotoxicity. Neutrophils demonstrated cytotoxicity against K562 only in the presence of a second stimulus, tetradecanoyl phorbol acetate (TPA), a result consistent with previous observations. We now demonstrate that antibody-coated K562 (using OKT9 and 345 monoclonal antibodies) are similarly only sensitive to neutrophils when TPA is added. The presence of both antibody and TPA in the cytotoxic assay resulted in significantly higher levels of cytotoxicity than in the absence of antibody; the result being consistent with a synergistic action between protein kinase C activation and Fc receptor perturbation in the neutrophil. The cytotoxicity against non-coated and antibody-coated targets was markedly inhibited, particularly against the former, by the protein kinase C inhibitor, 1-(5-isoquinoline-sulfonyl)-2-methyl piperazine (H-7). There were marked differences in the extracellular calcium dependency of the two types of cytotoxicity reactions. TPA-activated respiratory burst was unaffected by the presence of non-coated and OKT9-coated targets, whereas TPA-induced lysosomal enzyme release was significantly increased by non-coated targets and a further increase occurred in the presence of OKT9-coated K562
Does a relationship exist between neutrophil myeloperoxidase deficiency and the occurrence of neoplasms?
No full text36 unrelated individuals with neutrophil MPO deficiency, (10 totally MPO deficient) were found on screening a population of 148,000 subjects. A further 2 subjects with total and 22 with partial MPO deficiency were identified through family studies. The assessment of neutrophil function, i.e., peroxidase activity, superoxide anion generation, microbicidal activity towards fungi and bacteria, and locomotor behaviour, was carried out in 10 subjects with total and 4 with partial MPO deficiency. We found that the enzyme defect is associated with a marked impairment in the killing of both S. aureus and C. albicans, without affecting microbicidal activity against S. faecalis. There appears to be a high incidence of malignancy in patients with complete MPO deficiency, suggesting a relationship between a defective MPO system and neutrophil-mediated tumor cell cytotoxicity
Morphological, ultrastructural, cytochemical and functional analysis of neutrophils deficient in myeloperoxidase
No full textIMMUNE INTERFERON STIMULATES HUMAN NEUTROPHIL FUNCTION
No full textABSTRACTS OF 22ND MEETING OF THE EUROPEAN SOCIETY FOR CLINICAL INVESTIGATION,
GRAZ (AUSTRIA) APRIL 20th-23rd 198
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