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Biomedical subjects

F P Schena

Publications and source records attributed to F P Schena.

At least 145 records · Page 8Linked to original sources
PubMed1982

Behaviour of immune complexes and the complement system in normal pregnancy and pre-eclampsia.

A quantitative study of the circulating immune complexes (IC) was carried out on women during normal pregnancy (286) and the post-partum period (20) and women with pre-eclampsia (30). Furthermore, the behaviour of the complement (C) system was followed. Results showed that IC were low in the first trimester of normal pregnancy (25.3%) and decreased in the following trimesters, whereas they were always present in pre-eclampsia. A very significant difference (p less than 0.0001) was seen when we compared the incidence of IC in normal pregnancy at the third trimester and the pre-eclamptic patients. The follow-up study of the IC, carried out on 4 pre-eclamptic women, showed an increase in the IC levels associated with the exacerbation of the pre-eclamptic picture and a decrease after delivery. The study of complement in normal pregnancy showed a decrease in C1-INH, C1s and C1q, whereas C3, C5, C9 and the properdin factor B increased during the following weeks of gestation; CH50 did not vary excepting during the 1st trimester. In the puerperium all values increased. There was no significant difference between the serum levels of the C components in the 3rd trimester of normal pregnancy and pre-eclampsia. High levels of C3d were observed in normal pregnancy at the 3rd trimester and in pre-eclampsia. The study of this split product of C3 showed that there is activation of the C system, but, since the synthesis of the C components is increased, activation could be masked. Alloantibodies and circulating IC could be the factors responsible for this activation in normal pregnancy and in pre-eclampsia, respectively.

Adult↗
PubMed1982

Biological significance of the C3 nephritic factor in membranoproliferative glomerulonephritis.

Serum levels of the C3 nephritic factor (C3NeF), an IgG autoantibody directed against the C3bBb convertase of the alternative complement pathway, and of eight complement components (C1q, C4, C3, C3d, C5, C9, fB and properdin) were measured in 109 serum samples from 27 patients with idiopathic membranoproliferative glomerulonephritis (MPGN) (type I, 20 cases, and type II, 7 cases) and 14 patients with secondary MPGN. Correlations between the concentrations of C3NeF, serum complement levels and progression of the renal damage were studied during the course of the disease in 14 patients with C3NeF activity. The results showed that (1) C3NeF activity was more frequent in patients with type II MPGN than in patients with type I disease; nevertheless there was a high incidence of this splitting activity in patients with secondary MPGN, (2) high levels of the complement components were present in patients with MPGN, (3) low levels of C3 occurred frequently in type II disease and in secondary MPGN, (4) there was no correlation between C3, fB and C3NeF levels, (5) the presence of C3NeF was associated with a more rapid deterioration of renal function. Longitudinal studies showed that serum levels of C3NeF were not satisfactory for monitoring the clinical course of the illness and, in this respect, are similar to the levels of other autoantibodies in patients with autoimmune disease. As MPGN is a clinical syndrome with various pathogeneses, we suggest that the autoantibody, C3NeF, should be considered only as a marker of some forms of MPGN.

Autoantibodies↗
PubMed1981

Activation of the alternative complement pathway by unidentified substances in human glomerulonephritis.

Activation of the alternative complement pathway (AP) has been investigated in 79 serial serum samples obtained from 28 patients which had different types of glomerulonephritis. Serum factors activating the AP of the complement system have been detected in 12 patients with various forms of glomerulonephritis. Immune complexes (IC), levels of complement components of the classical and the alternative pathways and cobra venom factor activity were measured. Serum specimens were subcategorized as 2 study populations: (i) patients with serum factors activating AP and (ii) patients with both serum activators and IC. Although CoVF-AH50, properdin factor B and C3 concentrations were comparably depressed in these two groups, the levels of Clq and C4 were very low only in patients with circulating IC. These data were highly suggestive of AP activation due to serum factor. In contrast the patients also showing circulating IC had activation of both pathways. The presence of these factors suggests that renal damage can be determined by other immunological stimuli.

Antigen-Antibody Complex↗
PubMed1981

Variability of antibody-specific induction and regulation of plaque-forming cells in cultures of normal human peripheral blood lymphocytes.

PFC have been detected in normal human PBL cultures, immunized with sheep red blood cells (SRBC) and supplemented with Concanavalin-A (Con-A) on day 0 (suppressive effect), and on day 2 (helper effect). Five PBL cultures responded punctually on established days, while four cultures failed to reproduce an enhancing effect when Con-A was added on day 2. In one case only no suppression was observed following addition of Con-A on day 0. Furthermore, it should be taken into consideration the dose of Con-A employed that can give suppressive, enhancing and no effects irrespective of the day of its addition in culture. On the basis of these considerations, it has been concluded that such a method is not suitable for clinical purposes, for instance in patients with immunological disorders, since the individual response to Con-A is extremely variable.

Antibody Specificity↗
PubMed1980

[Significance of immunocomplexes and complement in renal transplantation. Preliminary data].

The authors have measured circulating immune complexes (ic) and some components (C1q, C4, C3 and properdin factor B) in 87 serum samples obtained during the follow-up of five renal transplantation. Results showed high serum levels of ic with normal renal function of the graft especially in one patient, and an increase of the values in some rejection crises. The behaviour of the complement system was variable for the different components, while frequently low properdin factor B serum levels were noticed in some renal transplantations during the normal function of the graft and during the rejection crisis. In conclusion, the Authors report that a) high levels of ic can be seen also in grafts with normal function and their presence may be correlated with viral infections; b) an increase of ic during the rejection crisis is due to humoral immune response; c) the reduction of C3 and C1q associated to an increase of ic has been frequently seen, and finally; d) the low levels of properdin factor B show a probable intervention of the alternative complement pathway in the rejection crisis.

Antigen-Antibody Complex↗
PubMed1980

A kinetic test for the assay of the C1 esterase-inhibitor.

The most satisfactory diagnostic procedure for hereditary angioneurotic oedema is the demonstration of low serum levels of C1 esterase-inhibitor. A modified method for the assay of this protein is described. It is based on the kinetic measurement of the C1 esterase-inhibitor when it inhibits the hydrolysis of N-acetyl-L-tyrosine-ethyl ester by C1 esterase. The relative C1 esterase-inhibitor concentration is based on the initial hydrolytic velocity, which can be evaluated from the pH change in a short time and within a small range. High reproducibility, cheap instrumentation and short time of analysis are some of the favorable aspects of this method in comparison with the 'end point titrimetric' method. Furthermore, this paper describes the mechanism of inhibition of C1 esterase by C1 esterase-inhibitor. The results are indicative of a non-competitive mechanism. The value of the Michaelis-Menten constant, Km, is 0.017 +/- 0.001 mol/l at 37 degrees C, in the optimum pH range 7.2-7.4. An estimate of KI in arbitrary units is also given.

Angioedema↗
PubMed1980

The behaviour of beta-2-microglobulin in acute and chronic leukaemias.

Two hundred-one patients (97 leukaemias, 18 lymphoproliferative disorders, 86 solid tumors) were studied for B2M by radioimmune technique. Serum levels were high in all cases, excepting for ALL which presented normal values in 81% of the patients. The follow-up of the microprotein was carried out in 17 patients with acute leukaemias. The data obtained seem to suggest that subjects with high serum levels of B2M at the beginning of the disease do not respond favourably to chemotherapy.

Acute Disease↗
PubMed1979

[Action of complement in normal pregnancy and gestosis].

Behaviour of the complement system was studied in normal pregnancy, puerperium and in pre-eclampsia. CH50 showed no variations during normal pregnancy, excepting for first trimester, whereas it increased in puerperium. CVFAH50 increased steadily during all trimesters. C1q, C1s and C1-INH progressively decreased, while C3, C5, C9 and C3PA augmented. All values were clearly raised in puerperium. The decreased values of the early classical pathway components could be attributed to "blocking factors" (antibodies or immune-complexes) which could interfere with cellular immunity at fetoplacental level. The other components probably increase because there is a hormone-stimulated raised synthesis and a high turnover. The data obtained from pre-eclampsia did not reveal significant variations as compared to normal third trimester pregnancy, excepting for CVFAH50 which was reduced. This, however, does not exclude the possibility that there is an immunological pathogenesis of the pre-eclampsia, since activation of the C system is not always detectable in circulation.

Adult↗
PubMed1979

Immunological and bacteriological studies in chronic pyelonephritis associated with kidney stones.

Histological and immunofluorescent techniques, urine, stone and renal fragment culture, demonstration of bacteria with fluorescent specific antisera in the renal tissue and determination of circulating antiGBM and antiTBM antibodies in the serum, were studied on the renal biopsies of 46 patients with chronic pyelonephritis (CPN) associated to kidney stones. Results show that the bacteria are often present in renal tissue of CPN with negative urine culture. The presence of C3 and C4 in some cases, and C3 and C3PA in others, at the tubular level associated with bacteria, suggest that the activation of the C system may be through the classic way, i.e., through the bacteriological immune complexes, or the alternate pathway, i.e., through the bacteria or their products. In conclusion, the evolution of the CPN may be related to the activation of the C system and the coagulation mechanism, as shown by frequent fibrinogen deposits.

Adolescent↗
PubMed1978

[Antibacterial activity of fosfomycin in chronic kidney infections].

Authors have carried out a retrospective study in vitro on the bacteria isolated from renal parenchyma and stones in patients with CPN associated to kidney stones. Results show a different inhibitory action of the some antibiotics to Proteus, E. coli and P. aeruginosa. Fosfomycin inhibits the growth of bacteria in a wide range of concentration (50-1000 microgram/ml). A prospective study in vivo shows an excellent therapeutic action of fosfomycin in recurrent urinary infections, and a very good one in CPN and in some forms associated to kidney stones.

Adult↗
PubMed1975

[Tubular proteinuria (electrophoretic studies and properties of the microglobulins)].

The electrophoretic study of tubular proteinuria, carried out on the acrylamide-agarose electrophoresis, shows various patterns of tubular proteinuria characterized by low molecular weight proteins: alpha2-microglobulin, beta2-microglobulin and post gamma. The immunoprotidologic study of the microglobulins is difficult since they have a similar molecular weight. The zonal acrylamide-agarose electrophoresis allows the isolation of beta2m and post gamma. Recent studies suggest a number of hypothesis on the function of the microglobulins.

Albuminuria↗