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A Onetti Muda

Publications and source records attributed to A Onetti Muda.

At least 19 recordsLinked to original sources
PubMed2005

Alpha-SMA expression in hepatic stellate cells and quantitative analysis of hepatic fibrosis in cirrhosis and in recurrent chronic hepatitis after liver transplantation.

BACKGROUND: The alpha isotype of actin expressed by hepatic stellate cells reflects their activation to myofibroblast-like cell and has been directly related to experimental liver fibrogenesis, and indirectly to human fibrosis in chronic liver disease. AIMS: To evaluate the changes in distribution and percentage of alpha-smooth muscle actin-positive hepatic stellate cells and the correlation with the degree of the fibrosis in cirrhotic livers, as well as in patients with recurrent HCV chronic hepatitis after liver transplantation. METHODS: Human liver biopsies were divided in four groups: (1) normal livers obtained from cadaveric liver donors (n=35), (2) cirrhosis post-HBV hepatitis (n=11), (3) cirrhosis post-HCV hepatitis (n=10), and (4) post-transplant recurrent HCV chronic hepatitis (n=13). Samples were stained with anti-alpha-smooth muscle actin antibody by immunoperoxidase method and semi-quantitatively evaluated. Liver fibrosis was assessed from specimens stained with Masson's trichrome and quantified by computer image analysis. RESULTS: The percentage of alpha-smooth muscle actin-positive hepatic stellate cells was significantly higher in the HBV cirrhosis, HCV cirrhosis and post-transplant HCV recurrent hepatitis groups (36.1+/-15.2, 23.8+/-19.7 and 27.8+/-16.4%, respectively) compared to the liver donor group (2.9+/-4.0%). The alpha-smooth muscle actin-positive hepatic stellate cells to fibrous tissue ratio were significantly higher in the post-transplant recurrent HCV hepatitis group (2.36+/-1.12) compared to both the donor livers and the HCV cirrhosis groups (0.74+/-1.09 and 1.03+/-0.91, respectively). The alpha-smooth muscle actin-positive hepatic stellate cell percentage and fibrosis correlated positively in the post-transplant recurrent HCV hepatitis group and negatively in the HCV cirrhosis group. No difference in the immunohistochemical and morphometrical variables was found between the HCV cirrhosis and HBV cirrhosis groups. CONCLUSIONS: These results indirectly confirm that, in vivo, alpha-smooth muscle actin expression is a reliable marker of hepatic stellate cells activation which precedes fibrous tissue deposition even in the setting of recurrent HCV chronic hepatitis after liver transplantation, and it could be useful to identify the earliest stages of hepatic fibrosis and monitoring the efficacy of the therapy. In the presence of advanced cirrhosis other factors, rather than alpha-smooth muscle actin-positive hepatic stellate cells, may sustain fibrosis deposition.

Actins↗
PubMed2002

Co-occurrence of psoriatic arthritis with collagenous colitis: clinicopathologic findings of a case.

A 58-year-old man developed psoriatic arthritis and, after 6 months, persistent watery diarrhoea. Biopsies from the colorectal mucosa showed thickened subepithelial collagen consistent with collagenous colitis. There also was an inflammatory cell infiltration (mainly lymphocytes and monocytes) in the chorion. These findings and the parallel course of articular and bowel complaints suggest a clinicopathologic correlation between arthritis and colic involvement.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Collagen VII expression in glomerular sclerosis.

Glomerular sclerosis is the final stage of a variety of kidney diseases and matrix molecules not normally expressed in the extracellular matrix are synthesized and accumulate during the sclerotic process. Collagen type VII is the major component of the anchoring fibrils at the dermal-epidermal junction, but it is usually not present in normal glomeruli. The aim of this study was to investigate whether this type of fibrillary collagen, different from types I and III, is expressed in chronically diseased glomerular extracellular matrix. The presence and distribution of collagen VII have been examined in 50 renal biopsies by indirect immunofluorescence staining, standard electron microscopy, and immuno-electron microscopy. In selected cases, collagen VII mRNA expression was also measured by RT-PCR on isolated glomeruli. Cases included focal segmental glomerulosclerosis, minimal change disease, membranous glomerulonephritis, IgA nephropathy, SLE nephritis, diabetic glomerulosclerosis, ischaemic renal disease, extracapillary glomerulonephritis, and end-stage renal disease. Collagen VII protein and mRNA expression was absent or present in trace amounts in normal kidneys or in disorders with only a mild increase of mesangial matrix, without scarring of the tuft. Maximal expression was evident in the presence of adhesions between the glomerular tuft and Bowman's capsule or fibrous crescents. The results showed that collagen VII is actively synthesized and laid down in areas of glomerular and/or tubular scarring, irrespective of the underlying disease, confirming the de novo expression of fibrillary collagens in diseased renal extracellular matrix. The appearance of an anchoring collagen may be a response to support mechanical stress and it takes part in the process of cell proliferation and tissue repair.

Case-Control Studies↗
PubMed1998

Expression of TGF-beta receptors type I and II in human glomerulonephritis.

BACKGROUND: Transforming growth factor-beta (TGF-beta) is a multipotent cytokine involved in the turnover of the extracellular matrix. Signal transduction of TGF-beta is regulated via at least five different surface receptors; most of the effects, however, are mediated through the interaction of receptors type I and II (RI and RII). We investigated the glomerular expression of TGF-beta and its receptors RI and RII in human glomerulonephritis. METHODS: Indirect immunofluorescence using monoclonal and polyclonal antibodies against TGF-beta isoforms (1,2,3 and 2,3), TGF beta-RI and TGF beta-RII has been carried out on 30 consecutive renal biopsies (5 FSGS, 11 IgAN, 4 MCGN, 6 SLE, 2 RPGN) and on normal kidney tissue. RESULTS: Glomerular immunoreactivity for TGF-beta isoforms correlated with the severity of proliferative lesions: immunofluorescent signal was absent or trace-like in normal kidneys, FSGS, and IgAN with mild mesangial cellularity, and was highest in IgAN with severe mesangial proliferation, MPGN, RPGN, and SLE. Glomerular positivity for TGF-beta-RI and -RII was detectable in SLE and RPGN; a low signal was present also in MPGN. Other types of glomerulonephritis, including focal extracapillary proliferations, and glomeruli of normal kidneys were always negative. CONCLUSIONS: Our data show that TGF-beta expression is a good indicator of the severity of proliferative glomerular lesions in most, if not all cases and that RI-RII expression occurs at levels detectable with indirect immunofluorescence in limited number of glomerulonephritides, mostly associated with systemic diseases. A complex interaction between TGF-beta and its ligand may represent a critical factor conditioning the tissue response to immunological injury.

Fluorescent Antibody Technique, Indirect↗
PubMed1997

Transforming growth factor-beta enhances adhesion of melanoma cells to the endothelium in vitro.

Melanoma invasion requires migration through the vascular barrier. An early event in this process is the adhesion of metastatic cells to the endothelium. To elucidate the role of TGF-beta in the regulation of this process, human melanoma SK-MEL24 cells were labelled with [5'-(3)H]-thymidine and co-cultured with bovine pulmonary artery endothelial-cell monolayers. Radioactivity was assumed to be proportional to the number of SK-MEL24 cells bound to the endothelium. A low number of melanoma cells adhered to endothelial cells in a time-related manner. Pretreatment for 24 hr with 0.001 to 10 ng/ml TGF-beta1 or TGF-beta2 of both cell types enhanced melanoma-endothelium adhesion in a dose-dependent manner. Both melanoma and endothelial cells expressed RI- and RII-type TGF-beta receptors. The effect of TGF-beta was abolished by co-incubation with the proteoglycan decorin. Conditioned media from melanoma-endothelium co-cultures contained latent TGF-beta and failed to affect cell-cell adhesion. However, activation of TGF-beta by heating the medium or reducing the pH, increased melanoma-endothelium adhesion to an extent similar to that of the TGF-beta administered to the cultures. Zimography demonstrated that both cell types expressed urokinase-type plasminogen activator (uPA). Addition of plasminogen to the co-cultures, which was likely to be activated to plasmin by uPA, resulted in activation of TGF-beta and parallel stimulation of melanoma-endothelium adhesion. In conclusion, TGF-beta may enhance adhesion of melanoma cells to the endothelium, playing a relevant autocrine/paracrine role in the progression of invasive melanoma.

Activin Receptors, Type I↗
PubMed1997

[Ehlers-Danlos syndrome type I. Ultrastructural study].

Ehlers-Danlos syndrome comprises a very heterogeneous group of collagen diseases characterised in clinical terms by fragility and cutaneous hyperextensability, ligamentous hyperlaxity, ecchymosis, scarring, visceral and neurological manifestations. Having been described in detail by Ehlers in 1899 and Danlos in 1908, it was subsequently classified into various clinical types. At present at least 11 forms are recognised on the basis of their clinical characteristics, methods of transmission and biochemical defect; the first four types of the syndrome account for approximately 95% of cases. Almost all forms are transmitted with a dominant autosomic character. Specific genetic mutations have been ascertained whereas the biochemical defect has been identified in numerous types. Ehlers-Danlos type 1 syndrome is the most frequent and most severe form. The biochemical anomaly underlying the altered deposition of collagen fibre is still unknown and this is responsible for the "storiform" appearance of collagen fibre on ultrastructural examination. The authors have described a typical case of "Ehlers-Danlos type 1 syndrome" in which the diagnosis was confirmed by comparing clinical data and the results of ultrastructural tests which revealed the characteristic "pattern" of collagen fibres.

Adolescent↗
PubMed1995

Role of endothelial cells in the development of glomerular lesions of mesangiocapillary glomerulonephritis.

The histological and ultrastructural changes of mesangiocapillary glomerulonephritis (MCGN) are not unique to this entity: splitting of basement membrane (BM) is seen in a number of conditions with an altered coagulation pattern. The distribution of endothelial cells in the glomerular capillaries in five cases of MCGN was studied by light and electron microscopy and immunocytochemistry; endothelial cells were stained with peroxidase or FITC-conjugated antibodies against Factor VIII-related antigen or CD34 antigen and observed with conventional light/immunofluorescence microscopy and confocal laser scanning microscopy for three-dimensional reconstruction. Electron microscopy was performed with colloidal gold labelling. Endothelial cells were shown to be present within the duplicated basement membranes of capillaries and continuity was demonstrated with endothelial cells lining the capillary lumina. These results suggest that endothelial cells as well as mesangial cells can participate in the formation of the characteristic double contour of capillary walls in MCGN, especially in the early stages. There are some similarities to the changes seen in larger arteries as a consequence of thrombotic disease.

Adult↗
PubMed1992

Freeze-drying of bone tissue: immunocytochemistry and enzyme histochemistry on paraffin embedded and low-temperature resin embedded specimens.

A simple protocol of tissue preparation was sought, which would enable marker enzymes of bone cells and extracellular matrix antigens to be localized in the same tissue section with high optical resolution. For this purpose, snap-frozen samples of rat fetal skeletal tissues were dried in a FDU 010 freeze-drying unit (Balzers) for 8-12 h at -50 to -40 degrees C and 0.02 bar. Freeze-dried tissues were either vacuum-infiltrated at 45 degrees C and embedded undemineralized in Paraplast, or vacuum-infiltrated overnight at 4 degrees C and embedded undemineralized in glycol methacrylate. These procedures enabled enzyme cytochemistry for alkaline phosphatase and tartrate-resistant acid phosphatase, and immunocytochemical staining for collagen types I, III, and laminin to be performed on the same sections. No pretreatment of the sections was necessary to reveal collagen antigenicity. This study reveals the possibility of complementing immunocytochemical studies of extracellular matrix with enzyme cytochemistry and, above all, with the excellent tissue preservation and high resolution afforded by plastic embedding.

Animals↗
PubMed1992

Infantile condylomata of the oral cavity.

A child had condylomata acuminata localized to the oral cavity. Main points of interest were this exclusive localization, the extremely high number of papillary lesions, not reported in the literature until now, and the excellent response to interferon and local applications of podophyllin. Histologic, ultrastructural, and in situ molecular hybridization techniques were performed to make a correct diagnosis. Transmission of the etiologic agent and therapeutic approaches are discussed.

Cheek↗