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Biomedical subjects

A Vecchi

Publications and source records attributed to A Vecchi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Reduced tumorigenicity and augmented leukocyte infiltration after monocyte chemotactic protein-3 (MCP-3) gene transfer: perivascular accumulation of dendritic cells in peritumoral tissue and neutrophil recruitment within the tumor.

Monocyte chemotactic protein-3 (MCP-3) is a C-C chemokine that interacts with the CCR1, CCR2, and CCR3 receptors and has a spectrum of action encompassing T cells, NK cells, eosinophils, and dendritic cells (DC), in addition to mononuclear phagocytes. This broad spectrum of action prompted the present study aimed at assessing the antitumor activity of MCP-3 in a gene transfer approach and at providing information as to the actual in vivo leukocyte recruiting capacity of MCP-3. P815 mastocytoma cells transfected with the gene coding MCP-3 (P815/MCP-3) grew in syngeneic hosts and underwent rejection. Rejection was associated with profound alterations of leukocyte infiltration and resistance to subsequent challenge with P815 cells. Tumor-associated macrophages, already present in copious numbers, T cells, eosinophils, and neutrophils, increased in tumor tissues after gene transfer. DC, identified as DEC205+, high MHC class II+, CD11c+ cells, did not increase substantially in the tumor mass. However, in peritumoral tissues, DC accumulated in perivascular areas. P815/MCP-3-transfected tumor cells grew normally in nude mice. Increased accumulation of macrophages and polymorphonuclear neutrophils was evident also in nude mice. mAb against CD4, CD8, and IFN-gamma, but not against IL-4, inhibited rejection of MCP-3-producing cells. An anti-polymorphonuclear mAb caused only a retardation of MCP-3-elicited tumor rejection. Thus, MCP-3 gene transfer elicits tumor rejection by activating type I T cell-dependent immunity. It is tempting to speculate that altered trafficking of APCs, which express receptors and respond to MCP-3, together with recruitment of activated T cells, underlies activation of specific immunity by MCP-3-transfected cells.

Animals↗
PubMed1998

Noncompetitive, chemokine-mediated inhibition of basic fibroblast growth factor-induced endothelial cell proliferation.

The proinflammatory and chemoattractant chemokine interleukin-8 (IL-8) inhibits cell proliferation induced by basic fibroblast growth factor (bFGF) in mouse endothelial cells isolated from subcutaneous sponge implant (sponge-induced mouse endothelial cells) and in bovine aortic endothelial GM 7373 cells. The mechanism of action of IL-8 was investigated in GM 7373 cells. IL-8 did not prevent the binding of bFGF to its tyrosine kinase FGF receptors (FGFRs) nor to cell surface heparan sulfate proteoglycans (HSPGs). A transient interaction of IL-8 with the cell before the addition of the growth factor was sufficient to prevent bFGF activity. The inhibitory activity of IL-8 was abolished by protein kinase C (PKC) inhibitors and was mimicked by the PKC activator 12-O-tetradecanoylphorbol-13-acetate. Accordingly, both IL-8 and 12-O-tetradecanoylphorbol-13-acetate caused a approximately 60% decrease of the binding capacity of GM 7373 cells due to the down-regulation of FGFRs. Several C-X-C and C-C chemokines exerted an inhibitory action on bFGF activity similar to IL-8. Soluble heparin, 6-O-desulfated heparin, N-desulfated heparin, and heparan sulfate but not 2-O-desulfated heparin, chondroitin-4-sulfate, hyaluronic acid, and K5 polysaccharide abrogated IL-8 inhibitory activity consistently with the presence of low affinity, high capacity HSPG-like chemokine-binding sites on GM 7373 cells. Finally, neovascularization induced by bFGF in murine subcutaneous sponge implants was reduced significantly by IL-8. In conclusion, IL-8 inhibits the mitogenic activity exerted by bFGF on cultured endothelial cells by a PKC-dependent, noncompetitive mechanism of action that causes FGFR down-regulation. This activity is shared by several chemokines and requires endothelial cell surface HSPGs. The endothelial cell line utilized in the present study may help to elucidate the complex interplay among chemokines, HSPGs, growth factors, and receptors in endothelial cells.

Animals↗
PubMed1998

Immunohistochemical localization of the murine transferrin receptor (TfR) on blood-tissue barriers using a novel anti-TfR monoclonal antibody.

A novel monoclonal antibody (mAb), 8D3 (IgG2a), that specifically recognizes the murine transferrin receptor (TfR) was produced by immunizing a Lewis rat with a polyoma middle T oncogene-transformed endothelioma cell line. The 8D3 mAb was obtained by immunohistochemical screening for exclusive staining of vessels forming a blood-brain barrier (BBB), but not of other vessels. The anti-TfR mAb 8D3 recognizes the TfR also in FACS analysis and in western blots and should prove to be useful for affinity purification of the TfR. Whereas 8D3 brightly stains BBB-forming vessels in the central nervous system of mice, it does not stain the fenestrated capillaries within the choroid plexus and the circumventricular organs. In testis, where the blood-tissue barrier is located at the level of the Sertoli cells, the 8D3 mAb specifically stains Sertoli cells but not endothelial cells. Finally, in vitro, 8D3 does not interfere with iron uptake of lymphocytes as it does not influence their proliferation. Taken together, 8D3 represents a versatile new tool to study the tissue distribution of the murine TfR and TfR-mediated transcytosis across tissue barriers in the mouse.

Animals↗
PubMed1998

Chemokines and chemokine receptors during activation and deactivation of monocytes and dendritic cells and in amplification of Th1 versus Th2 responses.

Chemokines are a superfamily of small cytokines which are generally chemotactic for leukocytes. The general features of chemokines and their receptors are reviewed. Recent evidence indicates that receptor expression dictates the spectrum of action of chemokines, as shown recently for Th1 and Th2 cells. Chemokines represent amplification loops of polarized Th1 and Th2 responses. Receptor expression is tightly regulated during differentiation, activation, and deactivation of mononuclear phagocytes and dendritic cells. Thus, regulation of receptor expression is crucial as a set point of the chemokine system.

Chemokines↗
PubMed1998

Therapeutic effect of interleukin 12 on mouse haemangiosarcomas is not associated with an increased anti-tumour cytotoxic T-lymphocyte activity.

In syngeneic mice, the H5V polyoma middle-T oncogene-transformed endothelioma cell line induces Kaposi's sarcoma-like cavernous haemangiomas that regress transiently, probably because of an anti-tumour immune response, but eventually grow progressively and kill the host. To evaluate the generation of tumour-specific cytotoxic T lymphocytes (CTLs), spleen cells of tumour-bearing mice were restimulated with irradiated H5V cells in mixed leucocyte-tumour cell cultures. Tumour-specific CTLs were demonstrable only when low numbers of H5V stimulator cells were used (<1 H5V cell per 50 splenocytes). We found that H5V cells secrete immunosuppressive mediators because CTL generation was blocked when H5V cells culture supernatants were added to allogeneic mixed leucocyte cultures. As numerous tumour-derived immunosuppressive mediators may interfere with interleukin 12 (IL-12) production, we tested whether IL-12 treatment of the tumour-bearing mice would augment their immune response and thus suppress tumour growth. Indeed, IL-12 inhibited tumour growth and prevented mortality, but did not increase anti-H5V CTL generation either in vitro or in vivo. Moreover, the anti-tumour activity in IL-12-treated mice was abrogated by anti-interferon (IFN)-gamma monoclonal antibody (MAb) co-administration. These results strongly suggest that the anti-tumour effect of IL-12 is principally mediated by IFN-gamma release that in turn blocks H5V cell proliferation and induces the release of factors that suppress angiogenesis.

Animals↗
PubMed1997

Benzydamine inhibits the release of tumor necrosis factor-alpha and monocyte chemotactic protein-1 by Candida albicans-stimulated human peripheral blood cells.

Benzydamine is a non-steroidal antiinflammatory drug, devoid of activity on arachidonic acid metabolism, which is extensively used as a topical drug in inflammatory conditions, particularly for the treatment of bacterial vaginosis and Candida albicans-sustained vaginitis. In the present study the effects of benzydamine on the production of several inflammatory cytokines were examined in cultures of Candida albicans-stimulated human mononuclear cells. Benzydamine (6.25-50 microM) inhibited Candida-induced tumor necrosis factor-alpha and, to a lesser extent, interleukin-1 beta production, whereas it did not affect interleukin-6 release. Benzydamine also blocked monocyte chemotactic protein-1 secretion, but it did not affect interleukin-8 production. Unlike benzydamine, ibuprofen and naproxen, two non-steroidal antiinflammatory drugs also used topically, were unable to suppress inflammatory lymphokine production from Candida-activated mononuclear cells. These data suggest that benzydamine may be effective in local Candida infections at least in part by suppressing inflammatory cytokine and monokine production in the vaginal mucosa and consequently decreasing their levels in vaginal secretions.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

A general strategy for isolation of endothelial cells from murine tissues. Characterization of two endothelial cell lines from the murine lung and subcutaneous sponge implants.

A rapid, reproducible method for the isolation of murine endothelial cells (ECs) has been developed. Murine ECs were highly enriched by collagenase digestion of mechanically minced lung and subcutaneous sponge implants followed by specific selection with rat anti-mouse CD31 (i.e., PECAM-1) monoclonal antibody-coated magnetic beads (Dynabeads). Pure EC populations were isolated from primary cultures by a second cycle of immunomagnetic selection. The cells from the lung were then cloned by a limiting-dilution method to exclude the possibility of nonendothelial cell contamination. Of the 300 cells plated, 29 clones (approximately 10%) were obtained. The clones were positive for CD31 as measured by flow cytometry, and one clone from the lungs (1G11) and the cells from sponge implants (designated as SIECs) were then subjected to subsequent culture in vitro for 40 and 30 passages (up to 5 months), respectively. Characterization was performed on cells between passage 3 and 10. Both cell types formed contact-inhibited monolayers on gelatin and capillary-like "tubes" on Matrigel. However, 1G11 cells exhibited a "cobblestone" morphology, whereas SIECs had a fibroblast-like appearance at confluence. By flow cytometry and enzyme-linked immunosorbent assay, these cells constitutively expressed CD31, VE-cadherin (cadherin-5), CD34, ICAM-1, VCAM-1, and P-selectin. After stimulation with 30 ng/mL of tumor necrosis factor-alpha, the cells became positive for E-selectin (at 4 hours poststimulation) and the expression of ICAM-1, VCAM-1, and P-selectin was upregulated (after 24 hours of stimulation). The presence of VE-cadherin in 1G11 cells and SIECs was confirmed by fluorescence microscopy and Northern blot analysis. The phenotype and morphology of both cell types were stable during 5 months of culture, and there was no evidence of overgrowth by contaminating cells. Taken together, the approach outlined herein may provide a general strategy for the isolation and culture of ECs from a variety of murine tissues. The general strategy outlined here is simple, effective, and flexible, allowing the inclusion of further positive or negative selection steps.

Animals↗
PubMed1997

Renal expression of monocyte chemoattractant protein-1 in lupus autoimmune mice.

Mononuclear cell infiltration in glomeruli and renal interstitium is a prominent feature of some types of glomerulonephritis, including lupus nephritis. The mechanism(s) underlying monocyte influx into the kidney is not fully understood. Recently, monocyte chemoattractant protein-1 (MCP-1) has been identified as a chemotactic factor involved in the recruitment of monocytes/macrophages in the glomeruli of rats with mesangioproliferative as well as anti-glomerular basement membrane glomerulonephritis. In the study presented here, renal MCP-1 mRNA expression in New Zealand Black x New Zealand White (NZB/W) F1 mice, a model of genetically determined immune complex disease that mimics systemic lupus in humans, was investigated. Northern blot analysis revealed a single 0.7 kb MCP-1 transcript of very low intensity in kidneys from 2-month-old NZB/W mice that had not yet developed proteinuria nor renal damage. Message levels, which increased markedly with the progression of nephritis and in association with mononuclear cell infiltration, were 10- and 15- fold higher in 8-10-month-old mice than in 2-month-old mice. By in situ hybridization, increased expression of MCP-1 mRNA was demonstrated in glomeruli and, even more striking, in tubular epithelial cells. Western blot analysis demonstrated increased expression of MCP-1 protein in kidneys of 10-month-old NZB/W mice, consistent with MCP-1 mRNA data. When NZB/W mice were treated with cyclophosphamide up to 12 months of age, expression of MCP-1 in the renal tissue remained low, the influx of inflammatory cells did not appear, and glomerular and tubular structures remained well preserved. These data suggest that elevated MCP-1 might act as a signal for inflammatory cells to infiltrate the kidney in lupus nephritis.

Animals↗
PubMed1997

Detection of endothelial cells by MEC 13.3 monoclonal antibody in mice mammary tumors.

In order to clearly visualize blood vessels, the monoclonal antibody (mAb) MEC 13.3 was used for an immunohistochemical staining on frozen sections of different mice mammary tumors. MEC 13.3 mAb is specific for endothelial cells (ECs) of mouse blood vessels and recognizes a molecule related to the murine form of CD31/PECAM. This mAb with immunoenzymatic technique or immunofluorescent labelling, was found to be a useful tool to quantify tumor neovascularization. Specifically, membrane reinforcement could be observed in vessel ECs, indicating the expression of CD31/ PECAM in their surface. The staining of ECs from tumors and from normal tissues was also compared. In this work, the use of MEC13.3 mAb is reported to recognize mice mammary tumor ECs as a useful tool to identify neovascularization. It would also be helpful for research on the origin and function of vascular endothelium in murine tumor experimental models.

Adenocarcinoma↗
PubMed1997

[Comparison between the diagnostic accuracy in diagnosis of thyroid nodules with fine needle biopsy an intraoperative histological evaluation of frozen tissue].

BACKGROUND: The aim of this study was to compare the diagnostic accuracy of fine needle biopsy (FNB) and intraoperative frozen-section biopsy (FS) regarding the surgical management of thyroid nodules. METHODS: A total of 812 patients with solitary nodule or dominant nodule in a multinodular goiter were evaluated. The patients underwent preoperative FNB and intraoperative FS diagnosis. RESULTS: The definitive histological diagnosis (HD) was: i) 222 malignant lesions (118 papillary, 67 follicular, 16 anaplastic and 8 medullary cancers); ii) 590 benign lesions. FNB accuracy was 90.6%, sensitivity 96.8% and specificity 87.1%. FS accuracy was 97.4%, sensitivity 91.3% and specificity 100%. False negative (FN) were 10 for FNB and 21 for FS. False positive (FP) were 74 for FNB and 0 for FS. FS was less sensitive for the diagnosis of papillary cancer (more FN) and more specific for the diagnosis of follicular thyroid cancers (no FP). CONCLUSIONS: In conclusion, FS is useful in patients undergoing surgery for a thyroid nodule having a "suspicious" cytology. It adds no information in patients with an FNB diagnosis of malignancy and is of limited use in those in whom an FNB benign lesion is diagnosed.

Humans↗
PubMed1997

Characterization of MEC 14.7, a new monoclonal antibody recognizing mouse CD34: a useful reage for identifying and characterizing blood vessels and hematopoietic precursors.

Endothelial cell-specific molecules are potential targets for new therapeutic strategies in the control of inflammatory reactions, immune responses and neoangiogenesis. We describe the production and characterization of MEC 14.7, a monoclonal antibody directed to murine endothelial cells recognizing a glycosylated protein with an apparent molecular mass of about 100 kDa in cultured endothelioma cell lysate and about 80 kDa in lung lysate. MEC 14.7 antigen was selectively expressed by the endothelium in vivo, particularly in small vessels and neoformed capillaries and by developing vascular structures in embryonal bodies. Deglycosylation of the molecule with neuraminidase, O- and N-glycanase showed that the MEC 14.7 epitope is neuraminidase-sensitive. MEC 14.7 antigen was purified from lung lysates by chromatographic techniques, and sequenced internal peptides indicated it was identical with murine CD34. Thus the apparent molecular mass of CD34 is heterogeneous, depending on the glycosylation state in the different cell types. Immunomagnetic isolation and culture of MEC 14.7-positive bone marrow cells showed that this antibody recognizes hematopoietic progenitors (particularly myelomonocytic) and can be used in murine models of bone marrow reconstitution.

Amino Acid Sequence↗
PubMed1996

Anti-tumor activity of cytokines against opportunistic vascular tumors in mice.

Polyoma middle T (PmT)-transformed endothelial cells may represent a unique murine model for human opportunistic vascular tumors. The present study was designed to evaluate the anti-tumor potential of a panel of 13 cytokines against murine PmT-transformed endothelial cells. Interferon gamma (IFNgamma) and transforming growth factor beta 1 (TGFbeta1) substantially decreased in a dose-dependent manner the proliferation of a panel of 6 PmT-transformed cell lines. IFNalpha and tumor necrosis factor alpha(TNFalpha) had marginal anti-proliferative activity, whereas other molecules (interleukins-1, -2, -4, -6 and -13, IFNbeta, leukemia inhibitory factor, oncostatin M, granulocyte-macrophage colony-stimulating factor) caused no growth inhibition. IFNgamma and TGFbeta1 were therefore selected for further analysis of their mechanism of action and in vivo relevance. IFNgamma and TGFbeta1 reduced the activity of phosphatidylinositol-3-kinase and the production of phosphatidylinositol 3,4-biphosphate, without modifying the tyrosine kinase(s) activity associated with PmT. IFNgamma and TGFbeta1 were also tested for their ability to modify the in vivo growth of the PmT-transformed endothelial cells H5V in syngeneic C57B1/6 mice. Treatment with IFNnu and TGFbeta1 significantly delayed tumor growth and increased survival time. In contrast, treatment with IFNalpha and TNFalpha failed to prolong survival. In nude mice, IFNgamma and TGFbeta1 had a transient effect on tumor growth but no effect on survival, suggesting a contribution of T cells to the in vivo anti-tumor activity of these cytokines.

Animals↗
PubMed1996

Inhibition of inflammatory cytokine production and protection against endotoxin toxicity by benzydamine.

The present study was designed to assess the effect of N,N-dimethyl-3-[(1-benzyl-1H-indazol-3-yl)ossi]-1-propana mine (benzydamine) on in vivo and in vitro production of inflammatory cytokines. Benzydamine inhibited tumour necrosis factor-alpha (TNF-alpha) production in vitro by human lipopolysaccharide-stimulated monocytes with an ED50 of approximately 25 microM (12 donors). Under the same conditions, benzydamine had modest or no effect on production of interleukin (IL-1), IL-6 and IL-8. Inhibition of TNF-alpha production was not restricted to LPS in that similar results were obtained using inactivated streptococci. Inhibition of TNF production was associated with a modest (about 30% at 50 microM, 7 donors) reduction of mRNA. A similar inhibition of TNF-alpha production was also detected with mouse peritoneal macrophages. With mouse cells benzydamine also substantially inhibited IL-1 production in vitro. In vivo treatment with benzydamine (40 mg/kg s.c.) protected mice against LPS lethality. Protection against septic shock was observed when benzydamine was administered before or concomitantly with LPS. Protection against LPS toxicity was associated with a marked reduction of serum levels of TNF-alpha and IL-1 beta, whereas IL-6 was unaffected. Inhibition of inflammatory cytokine production may play a role in the anti-inflammatory activity of benzydamine and provide suggestions for novel therapeutic applications.

Animals↗
PubMed1996

In vivo biological response following low-dose interleukin-2 in complete remission B-cell non-Hodgkin's lymphoma patients. Italian Lymphoma Study Group (GISL).

The aim of the present study is to verify whether recombinant interleukin-2 (rIL-2) at low doses is well tolerated in aggressive lymphoma in complete remission (CR), and if there may be a biological justification for its use as a remission-maintenance therapy able to reduce the percentage of relapses. We treated 6 patients with B-cell non-Hodgkin's lymphoma (B-NHL) in CR following PM-Cytabom with rIL-2 3 IMU s.c. x 5 d per wk, every other wk for 8 wk. Our results show that this treatment provokes statistically significant changes in the absolute number of lymphocytes, eosinophils, CD25+ and CD122+ cells and soluble IL-2 receptors; these doses, however, are not sufficient to modify CD3+, CD16+ and CD56+ cell values or natural killer and lymphokine activated killer cell activity. Thus these findings do not appear to constitute a biological rationale for the use of rIL-2 at this dose and schedule as a remission-maintenance therapy in B-cell NHL. Nevertheless, the results are a valid basis for further study of the use of the same rIL-2 doses for a longer period of time in combination with other cytokines, in the hope that the biological effects can be augmented without increasing the toxic side effects.

Cytokines↗
PubMed1996

[Cytological diagnosis of thyroid nodules. Comparison of results obtained with guided echography with those from of a "blind" biopsy].

The goal of the study was to verify if echographic fine needle biopsy (US-FNB) improved the diagnostic accuracy of thyroid nodules with respect to a "blind" technique (B-FNB). The study group involved 6,693 patients who underwent aspiration biopsies (989 males and 5,704 females; mean age 46.3 +/- 13.7; range 5-88 years). Total biopsies were 7,952 as some patients underwent two or more biopsies in different nodules. 7,324 nodules with B-FNB and 628 nodules with US-FNB were studied; in this latter cases 136 nodules were not palpable. The diagnosis of malignancy was higher in US- FNB than B-FNB. However, non-diagnostic samples were more prevalent in US-FNB with respect to B-FNB. A histological diagnosis was available in 27 patients with US-FNB and 379 with B-FNB. In US-FNB, accuracy was 81.8%, sensitivity 86.6% and specificity 77.7%. In B-FNB, accuracy was 80.6%, sensitivity 85.1% and specificity 78.1%. These data show that US-FNB diagnostic accuracy was not better than B-FNB. The higher incidence of malignancy found in US-FNB was not dependent on better accuracy, sensitivity or specificity of the US-FNB technique with respect to the B-FNB examination. It is possible that the higher number of malignancies in patients studied with US-FNB was due to the fact that the US-FNB technique aspirated smaller nodules and particular areas of echographic suspicion, thus increasing the possibility of finding a malignancy. Based on our data, we feel that US-FNB results in a greater number of diagnostically inadequate samples. This may depend in part on the smaller size of the biopsied nodules (which are relatively more vascular than larger nodules) and in part on the greater difficulty in carrying-out this technique which directed towards particular echographic areas of suspicion resulting in greater biopsy blood contamination. The authors feel that US-FNB should be carried-out in all cases of non-palpable nodes found incidentally so as to rule out malignancy.

Adolescent↗
PubMed1996

[Evaluation of the role of repeat needle biopsy in the diagnosis and follow-up of thyroid nodules].

The goal of the present study was to determine in what percentage of cases was an initial benign cytological diagnosis modified to malignant or suspicion of malignancy by a second aspiration biopsy. The study group consisted of 708 patients, 98 males and 610 females, mean age 46.3 +/- 13.7; FNB was always repeated on the same nodule. The first FNB (cytology I), classified the nodule as: non-diagnostic (group I, 205 cases) or diagnostic (group II, 503 cases); these latter were classified as benign (471) or suspect (32). In 82 cases of group I the second examination after six months (cytology II) was still unable to arrive at a diagnosis; in the remaining 123 cases, it was able to classify 120 as benign and 3 as suspect (the latter being followed up by diagnostic surgery). In group II, cytology II modified the initial diagnosis from benign to suspect (8 cases) or non-diagnostic (7 cases). On the other hand, 29 cases had a change of their initial diagnosis from suspect to benign. The remaining cases of group II repeated a thyroid FNB after one year (cytology III) with a result of benign (486) or non-diagnostic (6). In the 14 cases followed up by diagnostic surgery, due to a second biopsy diagnosis of suspicion, histology showed the presence of Follicular Adenoma in 12 cases and Hashimoto's Thyroiditis in the remaining 2. Based on follow-up surgery, the suspicious lesions seen on the second biopsy turned out to be all non-malignant. However, it is important to underline the greater number of cases where the second examination gave a benign diagnosis when the first examination was judged suspicious. One can conclude that it may be useful to repeat FNB: 1) when the first exam resulted in an inadequate sample, as a second biopsy allows one to classify the nodule 60% of the time; 2) in all cases where there is an initial benign diagnosis, when non-surgical follow-up (clinical and/or echographic) is suspicious.

Adenoma↗