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Biomedical subjects

S Frigerio

Publications and source records attributed to S Frigerio.

At least 19 recordsLinked to original sources
PubMed2006

Sporadic human renal tumors display frequent allelic imbalances and novel mutations of the HRPT2 gene.

Inactivation of the HRPT2 gene encoding parafibromin was recently linked to the familial hyperparathyroidism-jaw tumor syndrome. Patients with this syndrome carry an increased risk of parathyroid and renal tumors. To determine the relevance of HRPT2 for sporadic renal tumors, clear cell, papillary and chromophobe renal cell carcinomas as well as oncocytomas and Wilms tumors were analysed for HRPT2 gene alterations. Loss of heterozygosity (LOH) of HRPT2 was found in seven of 56 (12.5%) clear cell, three of 14 (21%) papillary, six of 10 (60%) chromophobe renal cell carcinomas, three of eight (38%) oncocytomas and four of 10 (40%) Wilms tumors. In addition, two novel HRPT2 point mutations, causing K34Q and R292K changes in parafibromin, were detected in one clear cell carcinoma and one Wilms tumor, respectively. These tumors displayed LOH of the remaining wild-type allele, but interestingly no von Hippel-Lindau (VHL) mutation. Functional analysis revealed that the K34Q mutant species of parafibromin is, unlike wild-type protein, defective in suppressing cyclin D1 expression in vivo. Taken together, these results suggest that renal cancer-associated mutations in parafibromin occur in the absence of VHL mutation, which in turn may contribute to constitutively elevated cyclin D1 expression and abnormal cell proliferation.

Aged↗
PubMed2006

Pravastatin in vivo reduces mononuclear cell migration through endothelial monolayers.

The objective was to evaluate pravastatin modulation on peripheral blood mononuclear cell (PBMC) migration across endothelial monolayers. Eleven hypercholesterolaemic patients were treated with pravastatin 20 mg/day. At baseline (T0), after 40 days (T40) and after 6 months (T 6 months) of treatment total serum cholesterol, low-density lipoprotein (LDL), high-density lipoprotein, triglycerides, C-reactive protein, as well as tumour necrosis factor-alpha (TNF-alpha) and metalloproteinases-9 plasma levels were evaluated. At the same time points the effect of pravastatin on migration of PBMCs through a monolayer of murine brain endothelial cells was studied both in basal conditions and after endothelial stimulation with recombinant mouse TNF-alpha 10 ng/ml for 24 h. Seven volunteers were used as healthy controls. Significant decreases in total cholesterol, LDL and triglycerides as well as inhibition of transmigration were observed. PBMCs transmigration in patients prior to pravastatin therapy was higher than in healthy controls. These results suggest that pravastatin could be of benefit in a spectrum of diseases characterised by extravasation of PBMCs into the central nervous system.

Aged↗
PubMed2006

[Assessment of translocations in routine diagnostics of a surgical pathology unit].

According to the current WHO classification of haematopoietic and lymphoid tissue, recurrent genetic aberrations constitute diagnostic markers for the histomorphological diagnosis of malignancies in these tissues. In lymphoma, translocations represent such genetic aberrations. Apart from their diagnostic impact, there is increasing evidence for their prognostic and predictive value. Despite the numerous translocations known in Non-Hodgkin's lymphoma (NHL), few are applied in routine diagnostics on a regular basis. To date, translocations have gained particular significance in B-cell NHLs, in contrast to T-cell NHLs where few are characterised. Refined tissue processing facilitates determination of translocations not only in fresh tissue, but increasingly also informalin fixed, paraffin embedded, and even decalcified biopsies. Hybridisation procedures (Southern blotting, FISH) and gene amplification methods (PCR, RT-PCR) are the primary molecular techniques employed to identify translocations. The article deals with the advantages and disadvantages of the currently used molecular techniques for the investigation of translocations in routine hematopathology diagnostics.

Apoptosis↗
PubMed2005

Activation of cerebral endothelium is required for mononuclear cell recruitment in a novel in vitro model of brain inflammation.

Brain inflammation is a common event in the pathogenesis of several neurological diseases. It is unknown whether leukocyte/endothelium interactions are sufficient to promote homing of blood-borne cells into the brain compartment. The role of mononuclear cells and endothelium was analyzed in a new experimental model, the isolated guinea-pig brain maintained in vitro by arterial perfusion. This preparation allows one to investigate early steps of brain inflammation that are impracticable in vivo. We demonstrate by confocal microscopy analysis that in vitro co-perfusion of pro-inflammatory agents and pre-activated fluorescent mononuclear cells induced endothelial expression of selectins and intracellular adhesion molecule-1 in correspondence of arrested mononuclear cells, and correlates with a moderate increase in blood-brain barrier permeability. Separate perfusion of pro-inflammatory agents and mononuclear cells induced neither mononuclear cell adhesion nor adhesion molecule expression. We demonstrate that co-activation of mononuclear cells and cerebral endothelium is an essential requirement for cell arrest and adhesion in the early stages of experimental cerebral inflammation.

Animals↗
PubMed2005

Human microvascular endothelial cells from different fetal organs demonstrate organ-specific CAM expression.

In this work, we isolated and produced long-term cultures of human fetal endothelial cells (fECs) deriving from different organs of the same 12-week-old embryos. Highly pure endothelium cultures were obtained from specimens of brain, heart, lung, liver, aorta and kidney by using magnetic microspheres coated with CD31 or CD34 specific endothelial antibodies. The endothelial nature of these cells was confirmed by the presence of von Willebrand Factor (vWf), Flk-1/VEGFR2 and CD31. The fECs cultures showed organ-specific differences as regards to the morphological appearance, the growth rate and the expression of cellular adhesion molecules (CAMs) before or after stimulation by the inflammatory cytokines IL-1beta and TNF-alpha. For instance, TNF-alpha showed a specific effect on fetal heart ECs by stimulating E-selectin expression. Our findings indicate that fECs may represent an innovative tool to study differences among ECs of different vascular districts of the same individual, thus increasing the possibility to compare many pathological aspects of human adult and fetal microvasculature.

Antigens, Surface↗
PubMed2005

Visceral artery aneurysms.

Visceral artery aneurysms (VAA) frequently present as life-threatening emergencies. The purpose of this study was to review our experience with VAA treatment. Between 1988 and April 2002, 31 VAA were treated in 28 patients (14 males, 14 females) with average age of 55 +/- 15 years. The most common locations were the splenic artery (16) and the hepatic artery (7). Three patients underwent emergency surgery, 22 patients had elective open surgery, and 7 patients underwent endovascular treatment. In the surgical group the perioperative mortality rate was 3.6%. The perioperative morbidity rate was 7.1% (one case of respiratory distress manifested in the immediate postoperative period and one urgent case of bilious fistula). In the endovascular group none of the patients died; the perioperative morbidity rate was of 14.3% (one case of hepatic artery thrombosis after failure of gastroduodenal artery aneurysm embolization). Failure of the procedure was 42.9% (3 cases of aneurysm recanalization). In conclusion, we believe that an aggressive surgical approach is justified, even in the case of asymptomatic VAA, because of the low morbidity and mortality rates. Endovascular treatment should be reserved for selected cases.

Abdomen↗
PubMed2004

Immunotherapy with bovine aortic endothelial cells in subcutaneous and intracerebral glioma models in rats: effects on survival time, tumor growth, and tumor neovascularization.

High-grade gliomas are aggressive tumors of the central nervous system characterized by endothelial cell proliferation and a high degree of vascularity. Conventional antitumoral treatments (i.e., surgery, radiotherapy, and chemotherapy) do not achieve satisfactory results (median survival in glioblastoma 12-18 months). It has been suggested that immunotherapy with xenogenic endothelial cells could slow tumor growth rate in a number of tumors in a murine model, but the study did not include gliomas. In experiments performed in our laboratory, vaccination with proliferating bovine aortic endothelium increased survival time in Fischer rats inoculated intracerebrally with 9L. Immunotherapy was also able to reduce the growth of subcutaneously injected 9L gliosarcoma cells in Fischer rats and to decrease microvessel density within the tumors, in the absence of major organ toxicity. Immunoglobulins (Ig) in the sera from vaccinated rats stained bovine aortic endothelium as well as human umbilical vein endothelium in active proliferation. Moreover, immune sera from immunized rats stained microvessels of human malignant glioma specimens and vessels of intracerebrally implanted tumors. Two proteins of MW of 11 and 19 kDa were identified by Western blot as targets of Ig elicited by vaccination. A possible future development is to select peptides/proteins suitable for vaccination in humans, avoiding the biohazards connected with xenogenic whole-cell vaccination.

Animals↗
PubMed2003

Effects of thalidomide on parameters involved in angiogenesis: an in vitro study.

In an attempt to elucidate the mechanism(s) of action of thalidomide, a reportedly antiangiogenic molecule recently tested in the treatment of relapsing malignant gliomas, we performed an in vitro study on the following parameters: (a) effect of thalidomide on proliferation of endothelial cells; (b) effect of thalidomide on expression of alpha(v)beta3 integrin on the surface of endothelial cells; (c) effect of thalidomide on the release by endothelial cells of MMP-2, IL-8 and TNF-alpha. The results show that thalidomide inhibits endotelial cell proliferation induced by bFGF and VEGF, more so if the cells are grown on vitronectin; moreover, treatment with thalidomide reduces the release of MMP-2 and IL-8 by endothelial cells, suggesting a further pathway for the antiangiogenic activity of drug. On the other hand, thalidomide does not modify expression of alpha(v)beta3 on endothelial cells.

Angiogenesis Inhibitors↗
PubMed2002

Response of rainbow trout (Oncorhynchus mykiss) D-11 cell line to 3-methylcholanthrene (3MC) exposure.

The rainbow trout cytochrome P4501A gene subfamily consists of two members, CYP1A1 and CYP1A3, which are induced by polycyclic aromatic hydrocarbons (PAHs). In this study, we investigated the induction of cytochrome P4501A3 in the rainbow trout (Onchorhynchus mykiss) D-11 cell line after 3-methylcholanthrene (3MC) exposure by generating chimeric constructs in which a 2.3 kb fragment or portion of the 5'-flanking region of the trout cytochrome CYP1A3 gene was fused to the firefly luciferase (Luc) gene. The constructs were then transiently transfected into the trout D-11 cells and their transcriptional activity measured by luciferase assay after treatment with different 3MC concentrations. Maximal induction following exposure to 2 microM 3MC was 2.2-fold after 72 h. Deletion of the region specifying the 5' untranslated region (5'UTR) of the mRNA encoding the CYP1A3 gene increased unstimulated luciferase activity but also led to a loss of response to 3MC treatment. This finding suggests that the region specifying the 5'UTR contains a negative element that is also involved in the transcriptional response to 3MC.

Animals↗
PubMed2002

Vascular prosthetic graft infection: epidemiology, bacteriology, pathogenesis and treatment.

UNLABELLED: Vascular prosthetic graft infection remains a major surgical challenge. Prevention of risk factors and antibiotic therapy can reduced but not eradicate it. Management of infected vascular grafts depends on several factors, including the location of the infected prosthesis, the extent of infection, and the underlying micro-organism. Classic treatment consists of extra-anatomic bypass grafting. The disappointing results due to the high mortality and amputation rate have kindled interest in alternative approaches, such as in situ reconstruction with antibiotic-bonded prostheses, autogenous veins or arterial allografts. PURPOSE: We focused on the treatment of aortic graft infection by means of both fresh and cryopreserved arterial allograft. Here, the experience of the Italian Collaborative Vascular Homograft Group is reported. METHODS: Between March 1994 and December 2000 seventy-nine patients with aortic graft infection were treated. The results of 68 patients are analysed. Eleven patients were treated with fresh, and 57 with cryopreserved homograft. Emergency surgical procedures were performed in 12 patients (17%). Aortoenteric fistula was diagnosed in 22 patients. The mean interval between the first procedure and the insertion of a homograft for patients with infected aortic graft was 3 years (range 1-15). The mean duration of follow-up was 30 months (range 1-68). Clinical and duplex scanning evaluation were routinely performed. Computer tomography (CT), magnetic resonance (MR), or arteriography were performed on the basis of duplex scanning results. RESULTS: The analysis was performed on 68 cases for which there were sufficient reliable data. Eleven deaths occurred during the early postoperative period (30 days), a mortality rate of 16%. There were also seventeen late deaths, a mortality rate of 25%. Eleven patients had graft occlusion; six cases were successfully treated with thrombectomy. In three cases leg amputation was necessary. The results of fresh and cryopreserved homografts were compared. No significant differences of early postoperative mortality, late mortality, homograft-related mortality, graft failure were observed. The presence of aortoenteric fistula is a negative predicting factor of perioperative early mortality, which causes a rapid decline in the survival curve. Thirty-six months after the surgery the actuarial survival of the patients was 57% and the actuarial patency of the allograft was 41%. CONCLUSION: No significant difference in terms of clinical outcome was observed when using fresh, rather than cryopreserved homografts. The only factor that significantly influenced the survival rate appeared to be the aorto-enteric fistula.

Anti-Bacterial Agents↗
PubMed2001

CDKN2A and CDK4 mutation analysis in Italian melanoma-prone families: functional characterization of a novel CDKN2A germ line mutation.

Physical interaction between CDKN2A/p16 and CDK4 proteins regulates the cell cycle progression through the G1 phase and dysfunction of these proteins by gene mutation is implicated in genetic predisposition to melanoma. We analysed 15 Italian melanoma families for germ line mutations in the coding region of the CDKN2A gene and exon 2 of the CDK4 gene. One novel disease-associated mutation (P48T), 3 known pathological mutations (R24P, G101W and N71S) and 2 common polymorphisms (A148T and Nt500 G>C) were identified in the CDKN2A gene. In a family harbouring the R24P mutation, an intronic variant (IVS1, +37 G>C) of uncertain significance was detected in a non-carrier melanoma case. The overall incidence of CDKN2A mutations was 33.3%, but this percentage was higher in families with 3 or more melanoma cases (50%) than in those with only 2 affected relatives (25%). Noteworthy, functional analysis established that the novel mutated protein, while being impaired in cell growth and inhibition assays, retains some in vitro binding to CDK4/6. No variant in the p16-binding region of CDK4 was identified in our families. Our results, obtained in a heterogeneous group of families, support the view that inactivating mutations of CDKN2A contribute to melanoma susceptibility more than activating mutations of CDK4 and that other genetic factors must be responsible for melanoma clustering in a high proportion of families. In addition, they indicate the need for a combination of functional assays to determine the pathogenetic nature of new CDKN2A mutations.

Adult↗
PubMed2001

Modulation of experimental allergic encephalomyelitis in Lewis rats by administration of a peptide of Fas ligand.

The effects of modulation of apoptosis in experimental allergic encephalomyelitis (EAE) in Lewis rats have been investigated using a peptide of the Fas-Ligand protein (FasL-p). The peptide was administered both subcutaneously and intra-cerebro-ventricularly (i.c.v.) after EAE induction. Rats treated subcutaneously with FasL-p showed a worse clinical score as compared to saline treated animals, while i.c.v. treatment with FasL-p did not modify significantly the severity of EAE. Apoptotic lymphomonocytes (identified by TUNEL) infiltrating the brain and the spinal cord were decreased in rats treated i.c.v. with FasL-p. The data suggest that the Fas/Fas-ligand pathway may be modulated by treatments with peptides of Fas-Ligand and that it may be at work within the central nervous system in EAE.

Animals↗
PubMed2000

Modulation of fas-ligand (Fas-L) on human microglial cells: an in vitro study.

The expression of Fas-Ligand (Fas-L) on microglia could be relevant in multiple sclerosis immunopathology. The present study was performed to evaluate in vitro the expression of Fas-L in human microglial cells both unstimulated and after stimulation with IFN-gamma, beta-IFN-1b and beta-IFN-1b+IFN-gamma. Cells were stimulated for 6,12, 24 and 48 h. Surface Fas-L was evaluated by flow cytometry, total Fas-L by Western blot, whereas mRNA for Fas-L was measured by RT-PCR. We also evaluated the capacity of microglial cells to induce, in vitro, apoptosis on Fas-positive T leukemia Jurkat cells. Our results showed a constitutive expression of Fas-L on microglia. IFN-gamma downregulated the expression of the molecule, while beta-IFN-1b and beta-IFN-1b+IFN- gamma did not. The amount of surface Fas-L was related to the ability of microglial cells to induce apoptosis in Fas-positive target cells, which was partly inhibited by blockade of the Fas-Fas-L pathway.

Cells, Cultured↗
PubMed2000

Extensible expanded polytetrafluoroethylene vascular grafts for aortoiliac and aortofemoral reconstruction.

The operative experience and medium-term outcome achieved with longitudinally extensible ('stretch') expanded polytetrafluoroethylene (ePTFE) bifurcated grafts in patients undergoing aortoiliac or aortofemoral reconstruction for occlusive disease at our institution was reviewed. Between 1991 and 1998, 242 patients received a bifurcated stretch graft. Forty-one patients (17%) required an aortic endarterectomy, and 63 (26%) underwent femoral artery endarterectomy. 228 patients were followed for a mean of 32 months. One patient (0.4%) died perioperatively. The perioperative morbidity included cardiac (3.7%), respiratory (2.5%), and renal (3.3%) complications. Three patients required early reoperation for bleeding. Four (1.7%) grafts thrombosed within 24h of surgery; eight additional grafts (3.3%) thrombosed 5-8 months later. There were three postoperative aortic graft infections, one inguinal infection, three inguinal pseudoaneurysms, and one aortic pseudoaneurysm. Ultrasonography during follow-up showed no periprosthetic fluid collections or graft dilatations. The bifurcated ePTFE stretch graft is suitable for aortoiliac and aortofemoral reconstruction, and its physical characteristics may help to reduce graft-related complications.

Aged↗
PubMed2000

Nitric oxide production and Fas surface expression mediate two independent pathways of cytokine-induced murine beta-cell damage.

Activated T-cells and macrophages infiltrate pancreatic islets early in the pathogenesis of type 1 diabetes. Their secretion of different pro-inflammatory cytokines such as interleukin (IL)-1beta, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha affects beta-cell function. Here we report that a combination of these cytokines inhibits insulin release, stimulates inducible nitric oxide synthase (iNOS), and upregulates the surface expression of Fas in NIT-1 beta-cells and intact mouse islets. Using iNOS-deficient and Fas-deficient islets, respectively, we investigated the relative contribution of NO and Fas upregulation in cytokine-induced beta-cell damage. Interestingly, inhibition of insulin release did not occur in the absence of NO production. However, de novo expression of Fas-specific mRNA and Fas cell surface expression were detected and thus appear to be NO-independent. The lack of NO production partially protected islets from cytokine-induced apoptosis but had no effect on cell death induced by cell surface cross-linking of Fas with soluble Fas ligand (FasL). The absence of FasL on alpha-cells and the degree of apoptosis observed in Fas-deficient islets exclude the possibility of cytokine-induced fratricide. In conclusion, pro-inflammatory cytokines exert a cytotoxic effect on beta-cells via an NO-dependent pathway and, in parallel, render beta-cells susceptible to Fas:FasL-mediated, NO-independent cell death triggered by activated T-cells.

Animals↗
PubMed1999

Circulating intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and plasma thrombomodulin levels in glioblastoma patients.

Cellular adhesion molecules have been implicated in tumor progression and metastasis. Serum samples from 22 patients with glioblastoma (GBM), before surgery, and 19 sex and age matched healthy controls were analyzed for circulating levels of ICAM-1 and VCAM-1. At the same time also soluble plasma thrombomodulin, a marker of endothelial cell damage and activation, was detected. Soluble ICAM-1 and VCAM-1 levels were comparable in glioblastoma patients and healthy controls, while plasma thrombomodulin (TM) was significantly increased in cancer patients. There was no correlation between thrombomodulin levels and the presence of an intratumoral hemorrhage detected by CT scan, while entity of post-contrast enhacemement at CT correlated with higher TM levels. Further study with serial sampling of GBM patients and correlation with enhancement at CT will allow to ascertain the value of serum TM as a marker of disease recurrence or angiogenesis in those tumors.

Female↗
PubMed1999

Tumor necrosis factor microsatellite polymorphisms in Italian glioblastoma patients.

Tumor necrosis factor (TNF) genes map on the short arm of chromosome 6 and have been described to contain several polymorphic regions, the most informative of which are TNFa (13 alleles) and TNFb (8 alleles) microsatellites. We analyze TNFa and TNFb microsatellite polymorphisms in 58 Italian patients with glioblastoma (GBL) and 95 unrelated healthy controls. At the TNFb locus, we detected a statistically significant decrease in the TNFb4 allele in GBL patients compared with the controls (P = 0.002; Pcorr = 0.015). Among the patients, 8 were homozygous TNFb4 (+/+), 23 were TNFb4 heterozygous (+/-), and 27 were negative for TNFb4 (-/-). In a comparison with the controls, we detected a statistically significant difference (P = 0.017). In fact, although no difference was detected in +/-, statistically significant differences were detected both for an increase in -/- and for a decrease in +/+ in the patient groups (P = 0.006 and P = 0.047, respectively). These data suggest that TNFb4-negative individuals might preferentially develop a Th2-type immune response that could lead to a reduction in antitumor activity.

Adolescent↗