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Biomedical subjects

R Coppo

Publications and source records attributed to R Coppo.

At least 91 records · Page 5Linked to original sources
PubMed1988

Microalbuminuria in single kidney patients: relationship with protein intake.

Experimental models have shown that the reduction in renal mass induces an increase in glomerular filtration rate of the remnant nephrons, leading to proteinuria and glomerular sclerosis. Since the presence of microalbuminuria - increased urinary albumin excretion (UAE) undetectable by routine assays - can be an early sign of this phenomenon, UAE in the normo- and microalbuminuric range was measured in 24 single kidney patients with negative Albustix. Nephrectomy had been performed in 22 cases 1 to 28 years before, mostly because of renal lithiasis. Patients were selected as being normotensive, normoglycemic and free of recurrent urinary infections or stones. On regular diet (mean protein intake 1.2 g/kg/day), UAE mean values were significantly higher in single kidney patients than in 20 controls both in supine position during overnight rest (clinostatism) (37.71 +/- 56.32 vs 2.56 +/- 2.27 micrograms/min, p less than 0.001) and in erect position during moderate physical effort (orthostatism) (67.31 +/- 86.12 vs 4.59 +/- 5.73 micrograms/min, p less than 0.004). Microalbuminuria was observed in 18/24 single kidney patients in clinostatism and 15/24 in orthostatism. A subgroup of 14 patients was also studied on different protein dietetic regimens. After one month on a 0.6 g/kg/day protein containing diet, UAE mean levels significantly decreased in comparison to those found on regular diet (clinostatism: 26.15 +/- 35.93 vs 49.24 +/- 70.29 micrograms/min, p less than 0.02; orthostatism: 31.73 +/- 46.97 vs 68.92 +/- 83.53 micrograms/min, p less than 0.001). One month after a 1.6 g/kg/day protein diet UAE mean values significantly increased (clinostatism 83.99 +/- 88.04 micrograms/min, p less than 0.001; orthostatism: 117.19 +/- 116.12 micrograms/min, p less than 0.001). Our data indicate that microalbuminuria, detectable in the majority of patients with a single kidney, can be modulated by different protein intakes.

Adult↗
PubMed1987

Failure to relate mononuclear phagocyte system function to HLA-A, B, C, DR, DQ antigens in membranous nephropathy.

Nineteen patients with idiopathic membranous nephropathy were typed for HLA pattern and analyzed for the Fc receptor function of splenic macrophages by detecting in vivo the clearance of IgG-sensitized 51Cr-labelled autologous erythrocytes. Seven out of 19 patients were found to have a macrophage dysfunction. This defect was not related to any HLA-A, B, C, DR, DQ antigen tested nor to the levels of IgG-containing immune complexes, as detected by a Clq solid phase test, nor to the magnitude of proteinuria. Since HLA-B8 and HLA-DR3 antigens were significantly more frequent in patients than in the control group, the factors that may impair the macrophage system in individuals predisposed to this nephropathy are discussed.

Adult↗
PubMed1987

Fc-receptor function of the mononuclear phagocyte system in glomerulonephritis secondary to some multisystem diseases.

The Fc-receptor function of the mononuclear phagocyte system was examined in 30 patients affected by multisystem diseases with glomerular involvement by measuring the immune clearance of IgG-sensitized autologous red blood cells in vivo and the immune phagocytosis of monocytes in vitro. Patients studied in the phase of clinically active renal disease showed a significantly reduced Fc-receptor function by both in vivo (p less than 0.001) and in vitro (p = 0.003) assays, as compared to those studied during an inactive phase. Though the nature of the defect remains uncertain, it appears to be related to the active phase of the renal disease as also confirmed by the analysis of individual cases studied longitudinally.

Adolescent↗
PubMed1987

Quantitative and functional analysis of IgG Fc receptor molecules in polymorphonuclear leukocytes and monocyte macrophages in patients with essential mixed cryoglobulinaemia.

In order to gain insight into the role of IgG Fc receptors in essential mixed cryoglobulinaemia (EMC), we analyzed quantitatively the expression of such molecules on polymorphonuclear leukocytes (PMN) and assessed them, functionally, on PMN, tissue macrophages and circulating monocytes in 6 HLA-B8-, DR3-negative patients with EMC and glomerulonephritis. The Fc receptors expressed on PMN surface, as estimated by using AB 8.28 monoclonal antibody to PMN Fc receptor and 125I-labelled rabbit F(ab')2 fragments to mouse IgG as detecting system, were found to be quantitatively normal in EMC patients, whereas PMN Fc- receptor-mediated phagocytosis was reduced. Moreover, the patients were found to have prolonged macrophage clearance of IgG-sensitized autologous erythrocytes and reduced kinetics of ingestion of IgG-coated material by circulating monocytes. This impairment of Fc receptor function may play a remarkable role in the tissue localization of immune material in this disease.

Adult↗
PubMed1986

Mediterranean diet and primary IgA nephropathy.

Since IgA nephropathy can be experimentally induced by alimentary antigens, mechanisms of oral immunization might be supposed also in human primary IgA nephropathy (PIgAGN). IgA immune complexes (IgAIC) are thought to play a major role in PIgAGN, hence this parameter was monitored in six PIgAGN patients subjected to diets excluding gluten, meat or eggs respectively and selected as having persistent urinary activity and high IgAIC levels. On gluten-free diet IgAIC significantly decreased over 3 different periods of 10 days (Student's t-test p 1 less than 0.03, Rank-Signed test p 2 less than 0.02), 1 month (p 1 less than 0.007, p 2 less than 0.02) and 6 months (p 1 less than 0.05, p 2 less than 0.02). IgAIC significantly increased again on a gluten containing diet over 1 month (p 1 less than 0.008, p 2 less than 0.04) and 3 months (p 1 less than 0.02, p 2 less than 0.04). After 6 months on a gluten-free diet, all patients had normal IgAIC values and decreased IgA2 subclass-IgAIC, in agreement with the hypothesis of withdrawal of an antigen challenging the mucosal immune system. These data indicate a relationship between a gluten-containing diet and high levels of IgAIC in PIgAGN patients, suggesting that dietetic factors might play a role in the different geographical distribution of this nephropathy.

Adult↗
PubMed1985

Presence and origin of IgA1- and IgA2-containing circulating immune complexes in chronic alcoholic liver diseases with and without glomerulonephritis.

Levels of IgA-containing circulating immune complexes (IgAIC) and their content of IgA1 and IgA2 subclasses were determined in chronic alcoholics with various degrees of liver damage and with or without associated glomerulonephritis. In patients with chronic alcoholic liver diseases, significantly increased IgAIC mean values were found independent of the presence of renal involvement, while in chronic alcoholics without biochemical evidence of liver damage IgAIC levels were normal. Both IgA subclasses were evidenced in IgAIC with an IgA pattern similar to that found in secretions, in agreement with the impaired liver clearance of IgAIC derived from intestinal mucosa. Nevertheless, no significant correlation between IgAIC and markers of hepatocytolysis or of cholestasis was found. One cannot therefore rule out the hypothesis of increased IgA synthesis in alcoholic liver disease due to abnormal alimentary antigen challenge and pathologic lymphocytic responsiveness. Finally, high IgAIC levels were found not only in patients with IgA glomerular deposits, but also in patients without clinical evidence of renal involvement.

Adult↗
PubMed1985

In vitro study of Fc-receptor function in autoimmune diseases.

A simple test for studying in vitro Fc-receptor function of mononuclear phagocytes is described. Immune phagocytosis is analyzed as a dynamic phenomenon by using nearly pure suspensions of monocytes incubated for diverse times with autologous erythrocytes sensitized with highly purified IgG. In a series of normal volunteers and patients with vasculitis a strict correlation has been found between this in vitro assay and the measure of splenic clearance of IgG-coated red blood cells (RBC), the classical approach for studying in vivo macrophage Fc-receptor function by using sodium chromate 51Cr as tag. The use of this in vitro assay appears to be valuable mainly in cases requiring repeated measurements of Fc-receptor function for monitoring the course of disease or the effects of therapy.

Autoimmune Diseases↗
PubMed1985

Immunological monitoring of plasma exchange in primary IgA nephropathy.

Plasma exchange (PE) has recently been proposed for primary immunoglobulin (Ig)-A nephropathy (PIgAGN) with progressive course. To develop suitable guidelines for PE in these cases, the authors evaluated the clinical usefulness of some immunological parameters in five patients with PIgAGN treated with PE combined with immunosuppressive drugs and small doses of corticosteroids. These parameters included the levels of IgA-containing immune complexes (IgAIC) by a specific conglutinin assay, the function of the mononuclear phagocyte system (MPS) by the in vivo clearance of IgG-sensitized erythrocytes, and complement activation as determined by C3d measurement. HLA types were also determined. Three patients had an acute nephritic syndrome with a rapidly progressive course, one of them showing sclerotic histologic changes. The two other cases had a relentless progression toward renal failure. In the patient with sclerotic PIgAGN, the MPS function was normal and the IgAIC and C3d levels were low throughout the treatment. In the other four cases, the high IgAIC and C3d levels and the MPS dysfunction found before treatment markedly improved after several PEs. The immunological parameters remained normal during the post-PE follow-up in two cases with acute nephritic syndrome and rapidly progressive course, but worsened again in two cases with a relentless course, particularly in one who possessed the B8/DR3 HLA type. Immunological monitoring including IgAIC, C3d, and MPS function is proposed, in addition to histological and clinical evaluation, as a guideline for PE in PIgAGN with evolving course.

Adolescent↗
PubMed1985

Plasmapheresis in a patient with rapidly progressive idiopathic IgA nephropathy: removal of IgA-containing circulating immune complexes and clinical recovery.

Primary IgA nephropathy is generally considered a benign disease, but progression to renal failure is not uncommon and a rapidly progressive course is observed in some cases, especially when extensive epithelial crescents are present. Circulating IgA-containing immune complexes (IgAIC) seem to play the most important pathogenetical role, hence the authors adopted plasmapheretic treatment in association with immunosuppressive drugs for 1 patient affected by primary IgA nephritis, with florid crescents and progressive renal failure. IgAIC decreased significantly after each plasma exchange and finally returned to normal values; over the same period urinary protein loss and heavy microscopic hematuria gradually disappeared and renal function was completely recovered.

Antigen-Antibody Complex↗
PubMed1985

Circulating Fc-receptor blocking factors in IgA nephropathies.

Twenty-one patients with primary IgA nephropathy, 7 patients with Henoch-Schönlein nephritis and 4 patients with IgA nephropathy associated to alcoholic liver cirrhosis were tested for Fc-receptor phagocyte function by measuring the clearance of radiolabelled IgG-sensitized erythrocytes in vivo and the immune phagocytosis by monocytes in vitro. Meanwhile IgG-, IgA-, IgA1-, IgA2-, containing immune complexes, the complement components C3, C4, C3d and the HLA-A, B, DR phenotype were determined. The patients with major urinary abnormalities were well discriminated from those with only minimal hematuria by a defective macrophage function (p less than 0.01) and high levels of IgA immune complexes (p less than 0.02). Since non HLA-A, B, C, DR phenotype was prevalent in patients who had defective Fc-receptor function, whereas a significant correlation was found between Fc-receptor impairment and levels of IgA immune complexes, it appears likely that circulating blocking factors, possibly related to IgA containing immune materials, may impair macrophage function in IgA nephropathies.

Adolescent↗
PubMed1985

Macrophage function in primary and secondary glomerulonephritis.

The function of the mononuclear phagocyte system was assessed in vivo in 85 patients with primary and secondary glomerulonephritis, by measuring the clearance of IgG - sensitised 51Cr-labelled autologous erythrocytes. Eleven per cent of patients in clinical remission were found to have a delayed clearance, whereas impaired macrophage function was present in 62.5 per cent of the patients with major urinary abnormalities. Blockade of mononuclear phagocyte system, induced at least in part by unidentified factors, might have a role in development and perpetuation of glomerular injury.

Adult↗
PubMed1985

Plasma exchange in progressive primary IgA nephropathy.

Five patients with progressive primary IgA nephropathy (PIgAGN) were treated by plasma-exchange (PE) combined with immunosuppressive drugs. Circulating IgA-containing immune complexes (IgAIC), detected by a specific conglutinin solid phase assay, were monitored. Two patients with acute nephritic syndrome and rapidly progressing course, crescent formations and high levels of IgAIC had substantial lasting clinical improvement after several PE, with a fall in IgAIC levels. Another rapidly progressive case with marked sclerotic changes and a longer history of nephritic syndrome, but with normal levels of IgAIC, did not show any clinical improvement after PE. Two patients with a PIgAGN diagnosed several years before and presenting slowly evolutive course had no substantial clinical benefit from PE treatment. IgAIC levels, very high before PE temporarily decreased, but returned to the previous values after the end of the treatment. We conclude that PE combined with immunosuppressive treatment may be of clinical benefit for cases with acute nephritic syndrome of recent onset who still have high levels of IgAIC, even when important crescent formations are present.

Adolescent↗
PubMed1984

Comparison of pathologic and normal sera by immune complex determination: five disease groups within 190 samples are discriminated by computer-selected combinations of 13 methods. Report of the Italian committee for the study of immune complexes (WIC).

Pathological (190) and normal (33) sera were tested for their content of circulating immune complexes (CIC) by a battery of 13 assays performed in 11 laboratories. Statistical processing was done both by pooling all pathological samples and by extracting those falling into well-defined disease groups, i.e., rheumatoid arthritis, diabetes, lupus, melanoma, and glomerulonephritis. Highly significant correlations between methods--taken two at a time--for each disease differed in proportion (ranging from 6 to 30%) and in the pattern displayed on a checkerboard. Disease-linked patterns were also found when a function maximizing discrimination between pathological and normal samples was derived by combining the information from all methods. Here the order and the weight attributed by the computer to the methods differed for each of the disease groups. Taken together these results are interpreted as an indication that all assays may not determine the same classes of CIC, and thus vary in sensitivity depending on the prevailing properties of the complexes present in the serum, which in turn may depend on the etiology, pathogenesis, and stage of the disease.

Antigen-Antibody Complex↗