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Biomedical subjects

G Segoloni

Publications and source records attributed to G Segoloni.

At least 37 records · Page 2Linked to original sources

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

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

[Epstein-Barr virus infection and immunoglobulin abnormalities in renal transplant recipients].

The relationship between immunoglobulin abnormalities and EBV infection has been investigated in 65 renal transplant patients. Immunoglobulins abnormalities were demonstrated in 44 (68%) patients, 8 of them (18%, 12% of all patients) had a monoclonal component. Up to now no lymphoproliferative disorder has been observed in these patients. All patients were EBV seropositive at the beginning of the study and in 22 of them (33%) a reactivation of EBV infection could be demonstrated. No relation has been observed between immunoglobulin abnormalities, EBV reactivation, age or sex. By contrast, a significant relation was found between EBV reactivation and immunosuppressive treatment: patients under triple therapy with Azathioprine, Cyclosporine A and Prednisone had less EBV reactivation compared to those under Cyclosporine A treatment.

Adolescent

[Role of tumor necrosis factor in hemodiafiltration].

The Authors review the mechanisms involved in the production of cytokines during substitutive extracorporeal treatment with particular reference to microbial contamination and possibility of backfiltration of bacterial constituents more likely to occur with high permeability membranes. Recent and on-going studies from our laboratory support the contention that patients treated with high permeability membranes may be chronically stimulated. Use of "ultrapure" solution indeed brings about a marked reduction in predialytic plasma levels of tumor necrosis factor (TNF) in regard to what observed when standard solutions are adopted.

Acrylic Resins

[Magnetic resonance in renal transplants].

The authors report their experience in the study of renal transplant recipients by MR, in order to determine its clinical potentials. The main purpose of this work is to focus on MR patterns in relation to clinical findings of rejected or normally functioning kidney. Twenty-four patients were examined with a 0.5 T superconductive magnet, body coil, spin-echo pulse sequence (SE) and inversion-recovery (IR). MRI patterns could be seen in normally functioning kidneys and transplant rejections, while variable MRI findings were observed in transplants with acute tubular necrosis (ATN). In the normally functioning transplanted kidney there is a clear corticomedullary differentiation (CMD), and the extent of vascular penetration into the renal parenchyma is clearly seen. In transplant rejection, CMD is either diminished or absent, and there is no vascular penetration into the parenchyma; to differentiate acute from chronic rejections, the increase/decrease in renal size and the change in renal shape (spherical shape in acute transplant rejection) respectively must be observed. MRI proves thus to be useful in the study of renal transplants, even in case of questionable clinical findings, and in patients in whom renal biopsy is contraindicated.

Adolescent

Evidence for the involvement of the IgE-basophil-mastocyte system in human acute post-streptococcal glomerulonephritis.

Several findings reveal the involvement of the IgE-basophil-mastocyte-platelet-activating-factor (PAF) system in human acute post-streptococcal glomerulonephritis. In the acute phases of the disease there is a transient, marked reduction in the circulating metachromatically staining basophils, indicating an in vivo basophil degranulation. The blood reservoirs of PAF are depleted. The number of metachromatic mastocytes in renal biopsy samples was very low and morphological aspects of degranulation were present. In vitro, we demonstrated basophil degranulation and PAF release in presence of exogenous streptococcal Ags after recovery. These findings suggest that the IgE-basophil-mastocyte-PAF system may play a role in human pathology, as has been shown in immune complex (Ic) deposition in acute serum sickness in rabbits.

Acute Disease

Immunological mechanisms of human platelet involvement.

Several immunological mechanisms of platelet involvement in inflammation are described. Basophils degranulate and release a platelet-activating factor (PAF) when challenged with anaphylotoxins, cationic proteins (CP) from polymorphonuclear cells (PMN) as well as with specific antigens from atopic patients. PAF is a newly-discovered mediator of anaphylaxis present in rabbit and human basophils. This factor is a small phospholipid, probably a lyso-1-phosphatidylcholine with a significant aggregating activity on rabbit and human platelets. PAF is released, together with a small amount of arachidonic acid, from basophils in the presence of anaphylotoxins, CP and specific antigens from atopic patients. The already well-known direct interaction between immune complexes (Ics) and human platelets is compared here with the mechanism of PAF-induced aggregation. It is shown that the latter process of aggregation differs from the former. Human platelet aggregation starts more rapidly in the presence of PAF than of Ics. PAF-induced aggregation is ADP-independent as it is not affected by ADP inhibitors. On the contrary, Ic-dependent aggregation is brought about by endogenous ADP release and therefore inhibited by ADP inhibitors. The interaction between Ics and platelets leads to the release of CP. The latter produce a cascade reaction involving basophils which degranulate and release PAF. A self-maintaining mechanism of tissue injury is thus triggered.

Adenosine Diphosphate