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Biomedical subjects

U Mrowietz

Publications and source records attributed to U Mrowietz.

87 records · Page 5Linked to original sources

Recombinant human tumour necrosis factor beta (lymphotoxin) lacks chemotactic activity for human peripheral blood neutrophils, monocytes, and T cells.

Human recombinant tumour necrosis factor beta (rhuTNF beta)/lymphotoxin was tested for human neutrophil granulocyte (PMN), monocytes (MO), and T-cell chemotactic activity by means of a modified Boyden chamber system. Over a wide range of concentrations (10(-7)-10(-14)M)rhuTNF beta showed no chemotactic activity for PMN, MO, or T cells. In contrast, strong chemotactic migration was elicited in PMN and MO with the tripeptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) and in T cells when complement split product C5a and leukotriene B4 (LTB4) were used as chemotaxins. The results of this study indicate that rhuTNF beta/lymphotoxin is not a chemotaxin for human PMN, MO, or T lymphocytes in vitro.

Chemotactic Factors↗

Identification of two endogenous neutrophil-activating peptides in psoriatic skin and inflammatory cells: C5ades arg and NAP.

Migration of polymorphonuclear leukocytes (PMN) into the upper layers of involved epidermis represents a characteristic feature of psoriasis. By analysis of psoriatic scale material we were able to identify two potent proinflammatory peptides, which are present in the upper epidermis from psoriatic lesions. Both factors (C5ades arg and NAP) show strong chemotactic activity for human neutrophils in vitro as well as in vivo. Whereas C5ades arg is a known mediator activated by either alternative or classical activation of the complement cascade, NAP represents a newly detected peptide with a molecular weight of 8,000 daltons which is produced by a variety of cells participating in the psoriatic tissue reaction.

Cell Movement↗

Recombinant human tumor necrosis factor alpha lacks chemotactic activity for human peripheral blood neutrophils and monocytes.

Preparations of recombinant human tumor necrosis factor alpha (rhuTNF alpha) free of aminoterminal methionine were tested for human neutrophil granulocyte (PMN) and monocyte (MO) chemotactic activity using the Boyden chamber system. Over a wide range of concentrations (10(-7)-10(-15) M) rhuTNF alpha of two different sources failed to elicit chemotactic responses in PMN or MO, whereas strong PMN and MO chemotactic activity could be detected using the tripeptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). In addition, rhuTNF alpha containing 62% aminoterminal methionine failed to induce PMN and MO chemotaxis. It is concluded that rhuTNF alpha may not be a chemotaxin for human PMN and MO in vitro.

Chemotaxis, Leukocyte↗

Purification and partial biologic characterization of a human lymphocyte-derived peptide with potent neutrophil-stimulating activity.

A novel neutrophil-activating peptide is detected in supernatants from mitogen-stimulated human T lymphocyte preparations. This chemotaxin was purified to apparent homogeneity by sequential Gel G-75 permeation chromatography, wide pore reversed phase (RP-8) HPLC, size exclusion HPLC, and reversed phase (RP-18) HPLC. Additional characterization of this lymphocyte-derived neutrophil-activating peptide (LYNAP) resulted in a single peak upon reversed phase HPLC and size exclusion HPLC. SDS-PAGE under nonreducing conditions revealed a single line at 10 kDa. LYNAP stimulated neutrophil chemotaxis (ED50 of 3 +/- 3 ng/ml), chemokinesis (ED50 of 2 +/- 2 ng/ml), and caused degranulation of cytochalasin B pretreated human neutrophils (ED50 of 20 ng/ml). In purified human monocytes, chemotactic responses to LYNAP at doses up to 100 ng/ml were absent, indicating nonidentity with a lymphocyte-derived monocyte chemotactic factor previously described by other workers. LYNAP shows biochemical and biologic similarities to a recently detected monocyte-derived neutrophil-activating peptide (MONAP). Moreover, desensitization experiments revealed cross-deactivation between LYNAP and MONAP, not, however, between these two chemotactic peptides and other well characterized polymorphonuclear leukocyte chemotaxins, e.g., C5a, FMLP, leukotriene B4, or platelet-activating factor. This finding points toward structure identity or homology of both chemotaxins, MONAP and LYNAP.

Chemical Phenomena↗

Identification of different charged species of a human monocyte derived neutrophil activating peptide (MONAP).

Lipopolysaccharide-stimulated human monocytes secrete a 10 kD peptide (MONAP) of high neutrophil, not however monocyte or eosinophil stimulating activity. By reversed phase HPLC MONAP could be distinguished from Interleukin 1. Analytic isoelecto-focusing of pure MONAP (single line upon sodiumdodecylsulfate polyacrylamide gel electrophoresis, single peak after RP-18-HPLC), obtained by size exclusion HPLC followed by two different reversed phase HPLC steps revealed charge heterogeneity giving major components with isoelectric points at 4.7, 4.9, 6.4 and 6.9, all of which exhibited chemotactic activity.

Chromatography, High Pressure Liquid↗

Structure determination of a human lymphocyte derived neutrophil activating peptide (LYNAP).

Phytohemagglutinin or Concanavalin A-stimulated human T-lymphocytes produce a factor (LYNAP) with potent chemotactic and enzyme degranulating activity in peripheral human neutrophils. Sequence analysis of LYNAP established an apparently novel 72 residue polypeptide structure. Examination of protein data bases showed that LYNAP had about 30% sequence homology with recently characterised connective tissue activating proteins produced by platelets. Furthermore, it was subsequently found that the amino acid sequence is largely the same as that predicted from a cDNA clone derived from mRNA elevated in peripheral human leukocytes stimulated by mitogens.

Amino Acid Sequence↗

Atopic dermatitis: influence of bacterial infections on human monocyte and neutrophil granulocyte functional activities.

In 15 patients with atopic dermatitis (AD) and without concomitant viral or bacterial infections, chemotaxis, superoxide-anion (O2-) generation, and beta-glucuronidase release of purified monocytes (MO) and neutrophils (PMN) were determined. Defined receptor-dependent stimulators (i.e., N-formyl-methionyl-leucyl-phenylalanine, C5a, and leukotriene B4, as well as native and opsonized zymosan particles) were used for phagocyte stimulation. PMN functional activities in response to the stimuli tested were found to be normal in patients with AD and without infections. MO from these patients revealed a slight enhancement of O2- production after stimulation with opsonized zymosan and a small increase of N-formyl-methionyl-leucyl-phenylalanine-induced chemotaxis. Other MO functions tested were within the normal range. However, investigations of MO and PMN functions during the course of concomitant bacterial infections of three patients with AD demonstrated striking alterations of cellular responsiveness. These changes ranged from enhanced to decreased phagocyte functions, depending on the activity of the infectious disorder. Chemotaxis of PMN and MO was depressed around the third day after onset of the infectious disease. In the beginning of infection, there was a decreased O2- generation and beta-glucuronidase release in PMNs. In MOs, both parameters were enhanced. The results of these investigations provide evidence that functional abnormalities of phagocytes observed in patients with AD are sequelae of concomitant skin infections and not signs of an intrinsic defect present in MOs and PMNs.

Adolescent↗

Modulation of human monocyte functions during acute bacterial infection.

The in vitro functions of highly purified blood monocytes were studied in 11 patients suffering from acute bacterial infections (e.g. erysipelas, appendicitis, abscesses). Chemotaxis, superoxide-anion generation, and beta-glucuronidase release of the patients' monocytes in response to the receptor-dependent stimuli formyl-methionyl-leucyl-phenylalanine (FMLP), complement split product C5a, leukotriene B4 (LTB4), and opsonized zymosan particles were measured. All the patients were examined in a follow-up study during the course of illness. A group of 33 healthy volunteers served as control. The patients revealed a transient decrease in monocyte chemotactic migration in response to all stimuli between days 3 and 5 after onset of clinical symptoms. Superoxide-anion generation from patients' monocytes was found to be enhanced 3 days after impaired chemotaxis. Stimulated release of lysosomal beta-glucuronidase showed a decrease in the first days of the disease. However, spontaneous beta-glucuronidase release was enhanced between days 3 and 7 in the patients' monocytes. Serial measurements of monocyte responsiveness. These results indicate a distinct modulation of monocyte functions during the course of an acute bacterial infection. Changes in monocyte maturity and/or activation under inflammatory conditions may be responsible for these alterations in monocyte function.

Acute Disease↗

Purification and partial biochemical characterization of a human monocyte-derived, neutrophil-activating peptide that lacks interleukin 1 activity.

A novel monocyte-derived neutrophil-activating peptide (MONAP) produced by lipopolysaccharide- and phorbol myristate acetate-stimulated human peripheral blood monocytes was purified by sequential ion exchange-high performance liquid chromatography (HPLC), size exclusion HPLC, and reversed phase HPLC. Biologic activities of the purified cytokine were monitored by either an enzyme release assay or a chemotaxis assay, using peripheral human neutrophils. Purified MONAP was found to be homogeneous, giving a single peak on size-exclusion HPLC, reversed-phase HPLC, as well as a single 10-kDa band on silver-stained polyacrylamide gels. Purified MONAP stimulate human neutrophil chemotaxis at an estimated molarity of 5 x 10(-11) M. Half-maximal enzyme release of cytochalasin B pretreated neutrophils occurred at 2 to 3 x 10(-10) M, whereas superoxide anion production elicited by various concentrations of MONAP was found to be low. Isolated human peripheral monocytes, as well as human eosinophils, showed no chemotactic response to MONAP, indicating neutrophil specificity. MONAP activity was separated from thymocyte-stimulating activity by reversed-phase HPLC, indicating nonidentity with interleukin (IL)-1. This was further supported by heat resistance of MONAP, which is in contrast to the heat sensitivity of IL-1. In addition, IL-1 obtained as a by-product during isolation of MONAP did not stimulate human neutrophil chemotaxis.

Animals↗

C5a-specific modulation of phagocyte functions in patients with localized bacterial infections.

Chemotaxis, enzyme release and superoxide-anion (O2-) generation of purified peripheral blood neutrophils (PMN) and monocytes were studied in a total of 87 patients suffering from localized bacterial infections. Shortly after disease onset, single or several PMN functions became non-responsive to the complement split product C5a. Functional activities elicited by the synthetic peptide f-met-leu-phe or leukotriene B4 remained unaltered. C5a-specific impairment lasted one to several days and returned to normal with the subsidence of the disease. C5a elicited release of beta-glucuronidase as well as generation of superoxide-anions was seen more often to be impaired as compared to chemotactic migration. In contrast to PMN, monocytes from the same patients failed to show paralleling C5a-specific functional alterations. There was no correlation between impairment of PMN functions and plasma levels of the complement split-products C3a and C4a as determined by RIA. It is concluded that in acute infectious disease a graded C5a-specific modulation of PMN functions may be present. This phenomenon is transient and not paralleled by functional alterations of monocytes or changes in plasma complement levels.

Bacterial Infections↗

Monocyte chemotaxis: a method for routine in vitro investigation using lactic dehydrogenase as a marker enzyme.

Using the cytoplasmic enzyme lactic dehydrogenase (LDH) as a marker, a method for routine measurements of highly purified monocyte chemotaxis is described. Standardization of this assay was carried out in order to achieve objective and reproducible results. The LDH-method showed a good correlation with both the 51Cr-chemotactic assay and the leading-front technique. The sensitivity of the LDH-method could be compared with the 51Cr-assay and was significantly higher compared to the leading-front technique. Being objective, inexpensive and requiring only a photometer as equipment, the LDH-method was proved to be suitable for routine investigations of monocyte chemotaxis as a part of monocyte functional activity in laboratories engaged in leukocyte research.

Cell Separation↗

Macrolide immunosuppressants.

Macrolide immunosuppressants are a new class of compounds sharing a macrolide-like structure and potent immunosuppressive activity in vitro and in vivo. Tacrolimus, the best known substance of this group, is registered in many countries for the prevention of transplant rejection. Numerous new substances of this group are in the pipelines of the pharmaceutical industries. Macrolide immunosuppressants are also effective in dermatological disorders. Due to their chemical structure these compounds can be used for topical treatment. Clinical studies have already shown highly effective topical therapy of atopic dermatitis with tacrolimus and the ascomycin derivative SDZ ASM 981, another macrolide immunosuppressant. In this article the pharmacological aspects of macrolide immunosuppressants, their supposed mechanisms of action, pre-clinical and clinical experience are reviewed.

Cyclosporine↗