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Biomedical subjects

F P Schena

Publications and source records attributed to F P Schena.

At least 91 records · Page 5Linked to original sources
PubMed1994

Domenico Cotugno and his interest in proteinuria.

Cotugno (1736-1822) was the first to describe the presence of albumin in the urine of a patient with nephrotic syndrome, though he did not place much emphasis on this discovery, which is buried in his many other observations in anatomy, physiology, medical pathology and therapy. Cotugno was a well-known scholar of his time, though he came from a humble background and was largely self-taught. He gained a medical degree from the Salerno School of Medicine at the age of 20 years. He was a prolific researcher and writer, conscientious practitioner of medicine, and a collector of books and antiquities. Much of his library was lost after his death or burned by his wife for unknown reasons.

History, 18th Century↗
PubMed1994

Expression of platelet-derived growth factor receptors in normal and diseased human kidney. An immunohistochemistry and in situ hybridization study.

We studied the expression of PDGF-alpha and -beta receptors in 10 normal and 40 pathologic human kidneys (five minimal change disease, five membranous nephropathy, 25 IgA nephropathy, five lupus nephritis), by both immunohistochemistry and in situ hybridization techniques. In normal-appearing kidneys, both PDGF-alpha and -beta receptors were expressed at the glomerular and interstitial level, the latter receptor more intensely than the former. The distribution and degree of expression of both receptors in nonproliferative glomerulonephritides were comparable with those found in normal-appearing kidneys. PDGF-beta receptor gene and protein expression were upregulated in proliferative nephritides both at the glomerular and the interstitial level and strictly correlated with the grade of histologic lesions. Finally, PDGF beta receptor expression was observed at a low level in normal-appearing renal vessels, and strikingly increased in injured arteries. Diseased kidneys displayed only a slight increase of PDGF-alpha receptor expression, chiefly at the interstitial level. Noteworthy, a few cases of lupus nephritis showed a moderate increase of PDGF-alpha receptor also at the glomerular level. These data establish PDGF-beta receptor activation as a candidate for driving glomerular and interstitial proliferation and, probably, expansion of extracellular matrix in proliferative glomerulonephritis, while the role of PDGF-alpha receptor activation at the renal level remains to be elucidated.

Cells, Cultured↗
PubMed1994

In vitro immunoglobulin production in relatives of patients with IgA nephropathy.

We hypothesized that the altered immunoglobulin synthesis and/or lymphocyte function apparent in patients with IgA nephropathy might be, at least partially, genetically determined. To address this hypothesis, immunoglobulin production by peripheral blood mononuclear cells in 22 patients with IgA nephropathy and 44 of their first degree relatives was investigated. Spontaneous overproduction of IgA1 and IgM from patients' PBMC was found. After pokeweed mitogen stimulation, both patients and relatives produced significantly more IgA1 and IgM than normal subjects. However, relatives showed a higher index of stimulation by pokeweed mitogen compared to both normals and patients. No differences were revealed in IgA2 or IgG subclass production among the groups. We propose that patients with IgAN have defects in immunoregulation that likely depend upon the genetic substrate in the patients' relatives. Such defect may reside not with the balance between help for and suppression of a particular isotype, but rather with the overall balance of isotypes in response to a particular antigenic challenge.

Adult↗
PubMed1993

Abnormalities of the IgA immune system in members of unrelated pedigrees from patients with IgA nephropathy.

In the last few years many investigators have reported the recurrence of primary IgA nephropathy (IgAN) or the presence of persistent microhaematuria and/or proteinuria in family members of patients with IgAN. Our study was undertaken to investigate the relevance of abnormalities in the regulation of the IgA and IgM immune system in microhaematuric and asymptomatic family members of IgAN patients. Fifty-four out of 120 members of nine unrelated pedigrees were examined by urinalysis; polymeric IgA (pIgA), IgA rheumatoid factor (IgARF), IgA1-IgG immune complexes (IgA 1-IgG IC) and IgA 1-IgM IC, and other immunoglobulins were measured in serum samples. Moreover, we studied the production of immunoglobulins, pIgA and IgARF by peripheral blood mononuclear cells (PBMC) in basal conditions and after pokeweed mitogen (PWM) stimulation. Our data demonstrate that persistent microhaematuria was present in 24% of relatives. High serum levels of IgA, mainly pIgA and IgARF, IgA 1-IgG IC and IgA 1-IgM IC occurred in 66% of relatives. Abnormal spontaneous production of IgA by PBMC and after PWM stimulation was present in 64% of family members. Interestingly, high serum levels of IgM and abnormal production of this immunoglobulin by PBMC were observed in relatives. However, the immunological abnormalities did not correlate in any way with the presence of urinary abnormalities such as microhaematuria, which was most likely determined by an underlying glomerular alteration.

Adolescent↗
PubMed1993

Study on the synthesis of complement components by human renal mesangial cells in culture. Assessment of the effect of cytokines.

Renal mesangial cell (MC) cultures are easily established and widely used. MC produce some complement (C) regulatory proteins. We studied whether MC synthesize C components (C3, C5, C8). MC cultures were established from normal portions of cortices of nephrectomies for renal cancer. After growing to near-confluence in RPMI/17% FBS and resting for 24 h in RPMI/0.5% FBS, MC were stimulated up to 72 h with IL-1 beta or IL-6 (10, 100, 1000 U/ml). Neither C5 nor C8 were detected by ELISA. While C3 was present in supernatant under basal conditions (15.5-107.6 ng/10(6) cells/24h) in different MC lines. IL-1 beta up-regulated the synthesis by 2.4-4.5 folds, whereas IL-6 did not show any effect. C3 synthetic rate was 1.76 ng/h/10(6) cells under IL-1 stimulation versus basal rate of 0.37 ng/h/10(6) cells. MC production of C3, especially induced by IL-1 may have pathogenetic relevance in glomerulonephritis.

Biotechnology↗
PubMed1993

C5b-9 generation and cytokine production in hemodialyzed patients.

The role of the complement system in the induction of cytokine release is controversial. Plasma terminal C complex C5b-9 along with Bb and C4d fragments were evaluated in 22 patients during routine acetate or bicarbonate hemodialysis using cuprophane membranes and hemodiafiltration (HDF) or acetate-free-biofiltration (AFB) using polyacrylonitrile (PAN) membranes. In a subgroup of six uremic patients we also evaluated the release of tumor necrosis factor (TNF alpha) and interleukin-6 (IL-6) from monocytes before and after six subsequent sessions with bicarbonate-cuprophane, HDF and AFB-PAN. At beginning of the dialysis increased plasma C5b-9 levels were found in patients treated by acetate or bicarbonate-cuprophane. Moreover, a rapid significant (P < 0.001) increase of C5b-9 levels occurred in both groups 15 minutes after the onset of the hemodialysis procedure with a plateau at 180 minutes. In contrast, only a slight increase in the plasma C5b-9 levels was observed in patients dialysed with HDF or AFB using PAN membranes. This increase was more pronounced with HDF at 0 minutes compared with controls. A positive linear correlation was found in all patients between C5b-9 generation and plasma Bb levels at different times in the dialysis session. The production of C4d fragment remained unchanged in all groups, indicating that C5b-9 complex generation is due to the prevalent alternative complement pathway activation. The pattern of cytokine production strictly resembled the complement system activation and C5b-9 generation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Primary IgA nephropathy: the relevance of experimental models in the understanding of human disease.

IgA nephropathy is the most common form of primary glomerulonephritis worldwide. About one quarter of patients progress to terminal renal failure 10 years after the apparent clinical onset. Therefore, the disease represents a social problem in terms of number of patients requiring maintenance hemodialysis. Despite the intense research effort devolved to clarify the pathogenesis of IgA nephropathy, the exact relationship linking the several factors involved is still unknown. In this review we analyze the experimental works reported since 1979, when the first animal model of IgA nephropathy was published by Rifai et al. We also discuss the interplay between experimental data and clinical observations to maximize the information gathered from the different animal models. Finally, we report the new insights into the role played by cytokines, growth factors and autacoids.

Animals↗
PubMed1992

Immunopathological aspects of immunoglobulin A nephropathy and other mesangial proliferative glomerulonephritides.

Immunoglobulin A nephropathy (IgAN) is an immune complex (IC) glomerulonephritis (GN) that represents one of the most common forms of primary glomerular disease. Proliferation of mesangial cells and the increase of mesangial matrix are histological hallmarks of mesangioproliferative GN. Increased serum levels of IgA, polymeric IgA, IgA rheumatoid factor, IgA-IC, and spontaneous or pokeweed mitogen-induced production of IgA by peripheral blood mononuclear cells are major humoral immune alterations reported in IgAN. Recently, we focused on the role of cytokines and growth factors in the mediation of glomerular injury. Platelet-derived growth factor, transforming growth factor beta, interleukin (IL)-1 and IL-6 are expressed by and act on mesangial cells. Increased expression of platelet-derived growth factor was found in both an active model of IgAN and in renal biopsies of patients with proliferative GN. A strict correlation between increased expression of B-chain mRNA and mesangial proliferation was found. Cytokines such as IL-1, interferon gamma, and IL-6, released by infiltrating mononuclear cells or produced locally by mesangial cells, affect the glomerular response to IgA-IC. In a passive murine experimental model of IgAN, IL-1 and interferon gamma increased mesangial hypercellularity, whereas IL-6 was highly pathogenic when associated to IL-1. In conclusion, classical immunological mechanisms in mesangial GN could interact with other pathways involving cytokines and growth factors in the progression of glomerular injury.

Animals↗
PubMed1992

Redistribution of natural killer (NK) cell frequency and NK cytotoxic activity in primary IgA nephropathy.

Recent findings have indicated an imbalance of immune responsiveness in primary IgA nephropathy (IgAN). Thus natural killer (NK) cell frequency and NK cytotoxicity were evaluated in fifteen IgAN patients. CD8+, CD11+, CD56+ and CD57+ lymphocyte percentages in IgAN individuals fell within normal values, while a significant decrease of CD16+ cells was observed in the same group of patients. In contrast, NK activity overlapped that seen in controls as assessed by an agarose-single cell cytotoxic assay. To further investigate the discrepancy between CD16+ cell level and NK cytotoxic activity in IgAN, the proportion of CD11+ CD57+, CD56+ CD16+ and CD57+ CD16+ lymphocytes was determined. In spite of the unaffected CD56+ CD16+ cell frequency, IgAN subjects exhibited a significant decrease of CD11+ CD57+ and CD57+ CD16+ lymphocyte percentages in comparison to controls. It is suggested that a redistribution of NK lymphocyte subsets occurs in IgAN. This may have an important role in the impairment of the immunoregulatory network.

Adult↗
PubMed1991

Urinary procoagulant and fibrinolytic activity in human glomerulonephritis. Relationship with renal function.

Fibrin deposition in kidney is a common event in some forms of human and experimental glomerulonephritis, and is thought to result from local activation of blood coagulation and/or impaired removal by the fibrinolytic system. We studied the urinary procoagulant and fibrinolytic activities in 46 patients with renal disease (26 with IgA nephritis, 13 with other forms of glomerulonephritis and 7 with non-inflammatory kidney disease) and in 15 matched healthy subjects, as possible indicators of the coagulation-fibrinolysis balance in kidney. Procoagulant activity was slightly but not significantly increased in patients with serum creatinine levels higher than 1.5 mg/dl (group II) as compared with patients with normal creatinine (group I) and controls. It was identified as tissue factor by biological criteria (dependence on factor VII). Fibrinolysis studies showed that both plasminogen activator activity and urokinase antigen were significantly lower in group II than in group I patients and controls (P less than 0.0005). Reduced fibrinolytic activity in patients' urine was due to decreased excretion of urokinase since no inhibitor was detected by both fibrin autography and functional assay. No differences were found between patients and controls in plasma fibrinolytic activity, plasminogen activator inhibitor, and procoagulant activity of blood monocytes. The urinary changes in severe renal disease may reflect an unbalance of the coagulation-fibrinolysis equilibrium in kidney and might be of pathogenetic and clinical relevance.

Adolescent↗