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Biomedical subjects

A Amore

Publications and source records attributed to A Amore.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effects of a gluten-free diet in primary IgA nephropathy.

In an uncontrolled study a gluten-free diet was given to 29 patients affected by primary IgA nephropathy (IgAGN). All of them followed the diet for 6 months, 23 patients for 1 year and 9 for 2 to 4 years. Mean levels of IgA containing circulating immune complexes (IgAIC), detected by a specific conglutinin assay and by measuring IgA content in 2.5% polyethylene glycol precipitates, on an unrestricted diet, significantly decreased after 6 months of gluten-free diet (p less than 0.01) and remained reduced during the follow-up. A decrease in IgAIC levels was evident in 85.7% of the cases with basal positive data, with complete normalization in 64.3% of them. IgA to gluten antigens (ethanol- or saline-soluble gliadin, glutenin and the lectin fraction termed glyc-gli) as well as to heterologous bovine and egg albumins were found to be significantly increased on an unrestricted diet in the group of 14 IgAGN patients with basal positive IgAIC. The mean levels of IgA to most dietary antigens significantly decreased after 6 months to 1 year of a gluten-free diet. A decrease in IgA to ethanol-soluble gliadin was evident in 81.8% of the cases with basal positive data, with complete normalization in 63.6%. A subgroup of 27.5% of IgAGN patients showed positive IgAIC values associated with increased IgA values to a variety of dietary antigens. A gluten-free diet induced in 75% of the cases a parallel improvement in these abnormal immunological data. Mean proteinuria values were found to be significantly decreased after 6 months of the diet and a reduction was also observed in microscopic hematuria. However, mean blood creatinine levels showed a significant increase after the gluten-free diet. The data of this study indicate that a gluten-free diet can modify some immunological abnormalities in a group of IgAGN patients, reducing levels of IgAIC and IgA to dietary antigens. The clinical course does not seem to be favorably influenced, since a relentless progression towards renal failure was observed.

Adult↗
PubMed1989

Clearance of polymeric IgA aggregates in humans.

Clearance of aggregated human secretory immunoglobulin A (AHS-IgA) was studied in nine patients affected by primary IgA nephropathy (IgAGN) and six normal volunteers from the medical staff. Samples of whole blood, erythrocytes, and serum were taken from 3 to 120 minutes after injection of 0.5 mg of 131iodine-labeled AHS-IgA. No significant radioactivity was recorded on erythrocytes. The clearance curve of AHS-IgA from the circulation, calculated by measuring trichloroacetic acid precipitable radioactivity in serum, was found to be biexponential with an initial fast component significantly prolonged in patients (mean half-time, 19.4 minutes, range, 14 to 26 minutes) compared with controls (mean, 12.2 minutes, range, 7.6 to 16.8 minutes; P less than 0.01). These data indicate that clearance of aggregated polymeric IgA does not involve the erythrocyte transport system and seems to be defective in IgAGN patients.

Adult↗
PubMed1989

Functional changes of monocytes due to dialysis membranes.

The functional effects directly induced by dialysis membranes on peripheral monocytes were analyzed in a plasma-free model of simulated dialysis using Cuprophan, cuprammonium rayon, polyacrylonitrile, polymethylmetacrilate and polysulphone membranes. A severe reduction of monocyte phagocytosis of IgG-coated erythrocytes was found by using Cuprophan and cuproammonium rayon. The cytofluorimetric analysis of several cell surface receptors, involved in the immune phagocytosis and recognizable by five quoted monoclonal antibodies, did not reveal any significant change. The defective phagocytosis of the IgG-coated erythrocytes by monocytes, due to the exposure to cellulose-derived membranes, was paralleled by an impaired interiorization of heat-aggregated human immunoglobulins, as analyzed by electron microscopy. The cell membrane binding of aggregated immunoglobulins was found to be unaffected. The defect was associated to a remarkably depressed generation of reactive oxygen species after Zymosan stimulation. Therefore, the defective immune phagocytosis induced by exposure of monocytes to cellulosic membranes was not due to a receptor rearrangement or an impaired binding of ingestible particles, but to a reduced internalization capacity probably related to an energy source exhaustion (as shown by the lack of response to stimuli able to induce oxidizing species production). These features are similar to those described in monocytes from acute systemic lupus erythematosus patients.

Cell Survival↗
PubMed1989

Complement receptor (CR1) and IgG or IgA on erythrocytes and in circulating immune complexes in patients with glomerulonephritis.

This study reports the quantitative analysis of complement receptor (CR1) molecules on erythrocyte surface, the amount of immunoglobulin-containing material (IgG-IC and IgA1-IM) on the erythrocyte surface, and the concentrations of circulating immune complexes (IgG-CIC and IgA-CIC); also reported are the HLA phenotypes of 44 patients affected by various forms of glomerulonephritis (including 20 primary IgA nephropathy, 11 membranous glomerulonephritis, 9 lupus nephritis and 4 renal vasculitis). Erythrocyte CR1 molecules were found to be decreased (P less than 0.02) and erythrocyte IgG-IC were less than in controls (P less than 0.025) in lupus nephritis patients, whereas IgG-CIC were significantly greater (P less than 0.02). In patients affected by primary IgA nephropathy, mean erythrocyte CR1 concentrations were significantly decreased (P less than 0.02). Patients with impaired renal function had mean erythrocyte CR1 values significantly greater than those with normal renal function (P less than 0.002). Immunoglobulin-containing material on the erythrocyte surface was not significantly increased, whereas the serum concentrations of both IgA-CIC and IgG-CIC were significantly increased (P less than 0.02). In membranous nephropathy erythrocyte CR1 molecules were quantitatively similar to control data and no increase in CIC was observed. Conversely, erythrocyte IgG-IC were significantly increased (P less than 0.01). No significant relationship among erythrocyte CR1 molecules, erythrocyte surface-associated immunoglobulins, CIC, and HLA phenotype was observed in any patient group.

Adult↗
PubMed1989

Phenotypic and functional analysis of circulating phagocytic cells in IgA nephropathy patients.

We analysed the possible mechanisms responsible for the functional abnormalities reported on phagocyte cell function in IgA nephropathy patients. The oxidative metabolism by the superoxide anion ferricytochrome C reduction test on monocytes and the chemiluminescence response on neutrophils was examined in 32 patients. Moreover the expression of cell membrane structures involved in immune response and phagocytosis (i.e. Fc receptors and HLA class II antigens) was evaluated cytofluorimetrically using specific monoclonal antibodies. Our own results did not show striking differences in oxidative potential and phenotype of patients' phagocyte cells as compared with healthy controls. However a HLA class II-associated structure was found to be quantitatively more expressed in patients' monocytes than in normal controls (P less than 0.005). These findings suggest that the defective phagocyte system function reported in IgA nephropathy patients is not simply due to a loss of cell surface receptors, nor to abnormalities in intracellular metabolic pathways implying oxygen consumption. The increase in expression of some HLA class II structures, often associated with the presence of circulating IgA immune complexes, probably reflects a protracted immunological stimulation.

Adolescent↗
PubMed1989

Gluten-induced experimental IgA glomerulopathy.

The effect of alimentary gluten and of its lectin-like fraction gliadin in inducing IgA mesangial deposits in BALB/c mice was investigated. In the pilot study G1 (4 mice), G2 (4 mice) and G3 (6 mice) received ovalbumin, human gamma-globulins, and crude gluten, respectively. The antigens, 1 mg/ml, were given in drinking water for 14 weeks. G4 (20 mice) were fed with standard mouse fodder. Gluten, as well as other alimentary antigens, induced IgA mesangial deposits with intense IgA staining in each animal, however a positive IgA staining was also observed in 10 of 20 adult controls. Antigliadin IgA antibodies were detected in renal tissue eluates from gluten-immunized mice but were found in eluates from control animals too. IgA deposits and antigliadin IgA in renal tissue were also observed in 3 of 7 adult mice (G7) fed for 30 weeks with standard fodder, then for 1 month with a protein-free diet supplemented with 20% amino acids. Conversely, there were no IgA mesangial deposits or IgA anti-gliadin antibodies in renal eluates of 1- or 2-week-old mice (G5 and G6). For the definitive protocol, 4-week-old BALB/c mice were selected and fed with basal glutenfree diet. G8 (14 mice) did not receive any alimentary immunogen in the drinking water, whereas G9 (15 mice) and G10 (15 mice) received ovalbumin and gliadin, respectively. G11 (15 mice) had standard gluten-containing diet. IgA deposits semiquantified by immunofluorescence scores were found to be significantly greater in G9 and G10 than in G8 (Student' t-test p1 less than 0.003, Mann-Whitney test p2 less than 0.001 and p1 less than 0.01, p2 less than 0.007, respectively), and in G11 than in G8 (p1 and p2 less than 0.05). The presence of positive IgA staining (greater than or equal to 2/6 scores) was significantly less frequent in G8 in comparison to G9 (chi-square test p3 less than 0.002), G10 (p3 less than 0.02) and G11 (p3 less than 0.04). Total serum IgA were significantly higher in orally immunized G9 and G10 than in G8 control mice (p1 less than 0.005, p2 less than 0.002). Anti-gliadin IgA in circulation as well as in renal deposit eluates were significantly increased in gluten-eating mice (G10 and G11) as compared with the gluten-free control group G8. These observations indicate that gliadin does induce IgA immune deposits in BALB/c mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Single kidney function: effect of acute protein and water loading on microalbuminuria.

The hyperfiltration induced by an acute response to an oral protein and water load was investigated to ascertain whether it can modify the urinary albumin excretion (UAE) in the microalbuminuric range by further increasing the glomerular filter permeability. To this end, six patients with a single kidney selected as having microalbuminuria on a regular diet without the clinical or laboratory data of overt renal disease and eight healthy subjects received a short-term protein and water load (150 g of meat-derived protein and 1 liter of water). In patients with one kidney, mean basal UAE values were significantly higher than in control subjects (p less than 0.006), whereas endogenous creatinine clearance values were only slightly lower (p greater than 0.05). One hour after the protein and water load, an abrupt increase in microalbuminuria levels was found in patients with one kidney and mean UAE values were significantly higher than in control subjects (p less than 0.002), whereas mean creatinine clearance values were significantly lower in patients than in control subjects (p less than 0.01). High UAE (p less than 0.002) and low creatinine clearance (p less than 0.002) values were maintained over the following four hours in patients with one kidney. These data suggest that in the single kidney with reduced renal functional reserve, an oral protein and water load magnifies the pre-existing loss of glomerular permselective properties due to chronic hyperfiltration as manifested by a further increase in microalbuminuria.

Adult↗
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

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

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

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↗