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G Segoloni

Publications and source records attributed to G Segoloni.

At least 55 records · Page 3Linked to original sources
PubMed1982

In vitro alternative pathway activation of complement by the brush border of proximal tubules of normal rat kidney.

The purpose of this study was to investigate which structures of the nephron, if any, are capable of directly activating the complement (C) system. To this end, two sets of experiments were performed. First, activation of C was assessed on sections of frozen kidney tissue, using the indirect immunofluorescence technique for the demonstration of C fixation. Second, glomerular or tubular fractions of kidney were incubated with normal fresh serum, and subsequent C consumption was measured. The data obtained support the interpretation that the brush border of proximal tubules activates the alternative pathway of the C system. This phenomenon may have pathogenic significance in conditions of aselective proteinuria.

Anaphylatoxins↗
PubMed1981

Neutropenia induced by platelet-activating factor (PAF-acether) released from neutrophils: the inhibitory effect of prostacyclin (PGI2).

Soluble and phagocytic stimuli released PAF-acether from PMN leucocytes, as determined by chromatography and bioassay by platelet aggregation. The same material caused aggregation of human and rabbit PMN leucocytes in vitro which was inhibited by ETYA and PGI2. PGI2 also inhibited PAF-acether release by PMN leucocytes and, in vivo, PGI2 abolished not only PAF-acether-induced, but also immune complex or C5a-induced thrombocytopenia and neutropenia in rabbits. These data suggest that PAF-acether may be involved in activation of both platelets and PMN leucocytes in vivo.

Agranulocytosis↗
PubMed1981

Mediators of immune-complex-induced aggregation of polymorphonuclear neutrophils. II. Platelet-activating factor as the effector substance of immune-induced aggregation.

Platelet-activating factor (PAF) is released in vitro during human and rabbit polymorphonuclear neutrophil (PMN) aggregation induced by C5a anaphylatoxin, neutrophil cationic proteins (CP) and their carboxypeptidase-B-derived fragments, C5a des Arg and CP des Arg, as well as phagocytosis of opsonized baker's yeast particles and immune complexes (IC). Purified PAF itself is able to cause in vitro PMN aggregation. By using selective inhibitors, we show that PMN aggregation, induced either by PAF or by other soluble stimuli such as C5a, CP and their des Arg products, follows a similar metabolic pathway, which is both adenosine-diphosphate-(ADP)- and arachidonic acid (AA)- independent. The in vivo injection of purified PAF into rabbits leads both to formation of intravascular PMN aggregates and to development of acute neutropenia, which has the same features as those observed after challenge with IC, C5a and CP. In this respect, electron-microscopic studies of intravascular PMN aggregates in the pulmonary capillary network and glomeruli show identical ultrastructural patterns. Moreover, the intravascular release of PAF is demonstrated after the intravenous injection of IC and temporally correlated with the development of neutropenia. We suggest that PAF is probably the final, common, effector substance of IC-, C5a-, C5a-des-Arg-, CP-, CP-des-Arg-mediated PMN aggregation.

Adenosine Diphosphate↗
PubMed1980

Mediators of immune complex-induced aggregation of polymorphonuclear neutrophils. I. C5a anaphylatoxin, neutrophil cationic proteins and their cleavage fragments.

This study reports the results of in vitro investigations on the aggregation of polymorphonuclear neutrophils (PMN) induced by the C5a anaphylatoxin complement component as well as the cationic proteins (CP), which are released by challenging PMN with immune complexes (IC). The carboxy-peptidase-derived des-Arg fragments of CP and C5a; CPi and C5ai, inactive in terms of anaphylactic and chemotactic activity, nevertheless showed a more potent ability to aggregate PMN than CP and C5a. The process of PMN aggregation required metabolic energy and divalent cations, Ca++ and Mg++. The microtubular system and the subplasmalemmal microfilaments appeared to be of critical importance. Electron microscopic studies on aggregates of PMN obtained on stimulation with CP, C5a, CPi and C5ai showed parallel tracts of variable length of cell membranes at the points where cells were in contact with each other.

Anaphylatoxins↗
PubMed1978

[The quarantined dialysis room for Australia-antigen-positive patients. Theoretical, normative, structural, operational, organizational and management aspects].

The technical features of dialysis facilitate the transmission of hepatitis B virus and the outbreak of possibly serious epidemics among patients and hospital staffs. Statistical, epidemiological and clinical data have been collected on many occasions. They serve to emphasise the problem and the need for quarantined centres. The establishment of such a centre for HBsAg-positive patients is discussed in the light of personal experience in the design and setting up of quarantined rooms. The underlying technical and structural requirements are also examined. Reference is also made to two years' experience in the running of a room of this kind. Stress is laid on the importance of having a room for these patients, not only from the clinical standpoint (lessening of contagion), but also from teh social and exonomic standpoint (reduced costs and length of hospital stay, greater rehabilitation).

Cross Infection↗
PubMed1977

In vivo fixation of immune complexes on polymorphonuclear cells and release of neutrophil cationic proteins in systemic lupus erythematosus (SLE).

Neutrophils (PMN) appear to be involved in inflammatory phenomena as a result of direct interaction with immune complexes (IC). In SLE glomerulonephritis IC are fixed in vivo on the PMN surface through the receptors for FC fragments of complexed immunoglobulins and complement. Phagocytic properties are lost and immunological lysosomal release in vitro is markedly reduced by virtue of receptor occupation. The elimination of neutrophil cationic proteins (NCP) in urine is an expression of PMN lysosomal constituent release.

Antigen-Antibody Complex↗
PubMedDate not supplied

Circulating immune complexes in nephritis.

Serum samples from 115 patients with various kidney disease were studied by means of precipitation in 3.5% polyethylene-glycol (the PEG test) and by inhibition of agglutination of IgG-coated polystyrene particles induced by C1q, two tests developed for the detection of circulating immune complexes. Positive results were found in acute glomerulonephritis, particularly in its early stages, and also in chronic forms of glomerulonephritis: membranous, focal sclerosing, mesangiocapillary and focal glomerulonephritis. High levels of circulating immune complexes were found in lupus nephritis. In most cases the test results showed a good correlation with the clinical course of the diseases.

Antigen-Antibody Complex↗
PubMedDate not supplied

Leukocyte behaviour in chronic uraemic patients undergoing regular dialysis.

A review of the literature is followed by the presentation of data obtained during a study of white blood cell kinetics in patients undergoing regular dialysis treatment. It was found that contact between white blood cells and the dialyzer results in a very prompt 'neutropenia-neutrophilia' stage and the deposition of billions of white blood cells on the membranes at the end of each treatment. A comparison of intradialytic leukocyte behaviour and the mean baseline white blood cell values was made in a total of 49 patients subdivided in four groups: 1. patients using coil and parallel flow dialyzers; 2. patients using dialyzers of different surface area; 3. patients of different dialytic age; 4. patients employing monoused or re-usable filters. No differences were noted in groups 1 and 4. In contrast, employing large dialyzers and the increasing dialytic age led to a variety of white blood cell patterns. Contrary to the information in the literature on leukocyte adhesion, it was observed that the cell deposits on the membranes and on the bubble trap filters, while predominantly composed of neutrophils, also contained monocytes and lymphocytes in proportions similar to those of the normal differential blood count.

Adult↗