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Biomedical subjects

A Arena

Publications and source records attributed to A Arena.

At least 19 recordsLinked to original sources
PubMed2006

Dialysis-related genotoxicity: sister chromatid exchanges and DNA lesions in T and B lymphocytes of uremic patients. Genomic damage in patients on hemodiafiltration.

BACKGROUND/AIMS: Patients with chronic renal failure show the presence of massive oxidative genome damage but the role played by dialysis is still a controversial issue. The aim of our study was to verify the genomic damage in B- and T-lymphocyte subpopulations of uremic patients after a single hemodiafiltration session. METHODS: We enrolled 30 patients on maintenance acetate-free biofiltration and 25 age-matched healthy volunteers and studied chromosomal alterations. RESULTS: Our data show that the basal levels of DNA damage, the number of sister chromatid exchanges and basal high-frequency cells levels are significantly higher in patients on hemodiafiltration than in controls and in T lymphocytes than in B cells. CONCLUSIONS: These findings suggest that hemodialytic treatment could represent a potential source of damage, maybe through the oxidative action of the extracorporeal circuit components, which might explain the well-known T-specific immunodeficiency correlated with uremia.

B-Lymphocytes↗
PubMed2006

Wide angle near-field optical probes by reverse tube etching.

We present a simple modification of the tube etching process for the fabrication of fiber probes for near-field optical microscopy. It increases the taper angle of the probe by a factor of two. The novelty is that the fiber is immersed in hydrofluoric acid and chemically etched in an upside-down geometry. The tip formation occurs inside the micrometer tube cavity formed by the polymeric jacket. By applying this approach, called reverse tube etching, to multimode fibers with 200/250 microm core/cladding diameter, we have fabricated tapered regions featuring high surface smoothness and average cone angles of approximately 30 degrees . A simple model based on the crucial role of the gravity in removing the etching products, explains the tip formation process.

Journal Article↗
PubMed2006

Solution-deposited microstructures based on aluminum-tris-hydroxyquinoline.

Iridescent organic films consisting of quasi-parallel wire-like microstructures are grown by castings from ethanol solutions containing mixtures of aluminium-tris-hydroxyquinoline and 1,10-phenanthroline. Spectrophotometric measurements carried out in the ultraviolet-visible range indicate that the microstructured films have angular-dependent optical behaviour, which is motivated by a refractive-index modulation over dimensions that are comparable to visible-light wavelengths. According to the results of investigations carried out by means of optical microscopy, atomic force microscopy (AFM), and scanning near-field optical microscopy (SNOM), the refractive-index modulation originates from a thickness modulation and a phase separation that occurs as the aluminium-tris-hydroxyquinoline and phenanthroline co-crystallize, with the former material being arranged to form a green luminescent pattern on the top of the latter one.

Journal Article↗
PubMed2005

Rheumatic symptoms in patients with human immunodeficiency virus are related to levels of tumor necrosis factor-alpha but not to viral load.

Infection with human immunodeficiency virus (HIV) can lead to osteoarticular involvement, usually in the late stages. The pathogenesis of these symptoms has usually been attributed to viral load or to dysregulated cytokine production. We evaluated the presence of rheumatic symptoms and levels of tumor necrosis factor (TNF)-alpha viral load and CD4 count in 46 patients with HIV from southern Italy. The prevalence of rheumatic symptoms was 23.9%; CD4 count and viral load presented no statistically significant differences between patients with rheumatic symptoms and patients without osteoarticular involvement, whereas TNF-alpha levels were increased in HIV patients with arthralgias compared with those in patients without arthralgias (p = 0.02). Evidence that TNF-alpha is increased in patients with osteoarticular or soft tissue involvement is a clear index of the pivotal role this cytokine plays in the pathogenesis of these manifestations.

Adult↗
PubMed2005

Intracorporeal Videoprobe (IVP).

The objective of the work in the EC project IVP is the development and evaluation of two prototypes of video systems:- a small wired videoprobe with a CMOS image sensorand- an autonomous video-capsule with a telemetric link for image data transfer to an external PC-based system.

Journal Article↗
PubMed2004

Design and synthesis of DNA-intercalating 9-fluoren-beta-O-glycosides as potential IFN-inducers, and antiviral and cytostatic agents.

Novel 9-fluoren-beta-O-glycosides, designed as DNA-intercalating agents in structural correlation with antiviral tilorone and anticancer anthracyclines, have been prepared with yields in beta-anomers ranging between 25 and 63%. They have been screened for antiproliferative, immunostimulating and antiviral properties against HSV-1 and HSV-2 viruses. Compounds displaying significant antiviral activity against HSV-2 are acetylated 1 and deprotected 6 9-fluorenyl-O-d-arabinopyranoses, whereas 9-fluorenyl-O-d-glucopyranose 3 is the most effective on HSV-1 replication, followed by 1 and 6. The conformational properties of these compounds have been evaluated by molecular modelling techniques.

Antineoplastic Agents↗
PubMed2003

Treatment of PBMC with killed Helicobacter pylori subverts the environment of inflammatory cytokines.

It is well known that inflammation induced by Helicobacter pylori is characterized by the local production of cytokines and chemokines. In the present study, we analyse the kinetics of MCP-1, IL-12 and IL-4 induction during the interaction of peripheral blood mononuclear cells with killed and/or live H. pylori. Our results demonstrate that live H. pylori does not induce IL-4 release whereas it stimulates MCP-1 and IL-12 production. In addition, the neutralization of IL-12 with monoclonal antibodies determines a lower MCP-1 release. These data demonstrate that MCP-1 production is in part supported by IL-12 induced by live H. pylori. On the contrary, killed H. pylori stimulates the IL-4 but not MCP-1 and IL-12 production. The combined treatment with killed and live H. pylori upregulates the IL-4 production and at the same time downregulates IL-12 and MCP-1 production.

Chemokine CCL2↗
PubMed2003

Differential induction of TNFalpha and IL-18 in human peripheral blood mononuclear cells infected with Leishmania major or Leishmania donovani.

Several cytokines are involved in the host response to Leishmania. However, the role played by cytokines during infection with different species of Leishmania is not univocal. In this work, the production of tumor necrosis factor alpha (TNFalpha) and interleukin 18 (IL-18) during interaction of human phagocytes with Leishmania major or L. donovani was comparatively investigated. Peripheral blood mononuclear cells (PBMC) and monocytes from healthy donors were used. The release of TNFalpha and IL-18 during infection of cells with different species of Leishmania "in vitro" was evaluated. L. donovani induced in both PBMC and monocytes significantly more TNFalpha and IL-18 with respect to L. major. The amounts of TNFalpha released by PBMC were always significantly higher than those released by monocytes of the same donors.

Animals↗
PubMed2002

Different modulation by live or killed Helicobacter pylori on cytokine production from peripheral blood mononuclear cells.

The mechanisms by which H. pylori colonizes and persists within the gastric mucosa are poorly understood. The induction and maintenance of gastric inflammation appear to depend on the complex interaction between a number of cytokines and chemokines. The gastric immune response observed "in vivo", during H. pylori infection, is characterized by a polarization of Th1 cell type that seems to be responsible for gastric pathology. The purpose of this study was to test the direct effect of H. pylori (live or gentamicin-killed) on human PBMC in order to evaluate the "in vitro" Th1-Th2 balance by monitoring IL-18, IFNgamma and IL-10 production. This study demonstrates for the first time that "in vitro" pretreatment with gentamicin-killed H. pylori of PBMC, followed by infection with live bacteria, downregulates the production of inflammatory cytokines such as IL-18 and IFNgamma Our results provide a possible strategy to restore the immunological disorders determined by H. pylori infection.

Anti-Bacterial Agents↗
PubMed2002

Modulatory effect of HHV-6 on MCP-1 production by human monocytes.

Chemokines represent a large family of proinflammatory proteins that orchestrate leukocyte trafficking to sites of viral infection. Human Herpes virus type 6 (HHV-6) is a typical immunosuppressive agent, as suggested by its tropism. In this study the production of monocyte chemoattractant protein-1 (MCP-1) and interleukin-10 (IL-10) by human peripheral blood monocytes was evaluated during HHV-6 infection. Our results demonstrate that HHV-6 infection triggers monocytes to release MCP-1 and IL-10. The addition of exogenous recombinant MCP-1 upregulates the release of extracellular virus, whereas does not influence the percentage of viral-antigen positive cells. Furthermore, the addition of monoclonal antibodies anti-IL-10 down-regulates MCP-1 release induced by HHV-6. These findings indicate that IL-10 and MCP-1 production was closely related and that the marked amounts of MCP-1 were supported not only by virus but also by virus-induced IL-10.

Antigens, Viral↗
PubMed2001

Role of interleukin-18 in peripheral blood mononuclear cells infected with human herpes virus type 6.

OBJECTIVE: Interleukin 18 (IL-18) production represents a critical step in the polarization of the Th1 immune response. Human herpes virus type 6 (HHV-6) possesses a peculiar tropism for immunocompetent cells. To understand the relationships among immunocompetent cells, HHV-6 and cytokines, the role of IL-18 during infection of peripheral blood mononuclear cells (PBMC) with HHV-6 was evaluated. METHODS: PBMC were obtained from healthy HHV-6-seronegative donors, after centrifugation of heparinized venous blood over a Ficoll-Hypaque gradient. Supernatants from PBMC were analyzed for the presence of cytokines. To study the effects of exogenous recombinant human (rh) IL-18 on HHV-6 replication, the number of cells expressing viral antigens and the amount of extracellular virus were analysed. RESULTS: No basal production of IL-18 was found in supernatants of unstimulated PBMC. Appreciable amounts of the cytokine were produced by lipopolysaccharide (LPS)-stimulated PBMC. HHV-6 infection of LPS-treated PBMC downregulated IL-18 production. It was found that the addition of rhIL-18 to HHV-6-infected PBMC downregulated the percentage of antigen-positive cells and the release of extracellular virus. CONCLUSION: Impairment of IL-18 release, which is involved in the induction of antiviral cytokines, such as interferon-gamma, could represent a strategy of the virus to evade the immune response of the host.

Cells, Cultured↗
PubMed2000

In vitro effect of lithium chloride on interleukin-15 production by monocytes from IL-breast cancer patients.

Lithium salt compounds are used to limit the degree and duration of neutropenia in patients receiving chemotherapy for cancer. Interleukin-15 (IL-15) is a cytokine which possesses promoting activities on hematopoiesis and is also involved in antitumor response, activating NK, CTL and LAK cells. In this study we analyzed IL-15 production by monocyte cultures treated with lithium chloride (LiCl). Monocytes were obtained from patients affected by non-metastatic and metastatic breast cancer. LiCl treatment induced IL-15 production by monocytes mainly from non-metastatic patients. Combined lipopolysaccharide/LiCl treatment of monocyte cultures up-regulated IL-15 release compared to those treated with LPS alone (p<0.0001). The modulation of LiCl-induced IL-15 could counteract the immunosuppression state of cancer patients, which should be taken into account when developing new immunotherapeutic strategies.

Aged↗
PubMed2000

Evaluation of interleukin-18 production by in vitro differentiated monocytes from breast cancer patients.

Interleukin-18 (IL-18) is a multifunctional cytokine which may play an important role in cancer. In previous studies it has been reported that mononuclear cells from breast cancer patients were defective in cytokine production. In this report we examined in vitro IL-18 release by monocytes (Mo) and differentiated monocytes (Mphi) for 6 or 12 days from healthy donors (HD) and nonmetastatic breast cancer (BCa) patients prior to chemo-, hormonal or radiotherapy. Our results show no production of this cytokine by Mo and Mphi for 6 days in all the experimental conditions. HD Mphi cultured for 12 days were responsive to lipopolysaccharides only after 24 h of treatment, while significantly (p<0.05) lower amounts of IL-18 were produced by BCa Mphi cultures in the same experimental conditions. Since BCa Mphi are defective in IL-18 production, and this cytokine elicits in vivo protective antitumor effects, we hypothesize a future possibility for the use of IL-18 in cancer therapy.

Aged↗
PubMed2000

Role of IL-15 on monocytic resistance to human herpesvirus 6 infection.

Interleukin-15 (IL-15) is a cytokine that possesses a variety of biological functions, including stimulation and maintenance of cellular immune responses. Recently, it has been demonstrated that Human Herpes virus type 6 (HHV-6) enhances NK activity of human PBMC by inducing IL-15. HHV-6 is a typical immunosuppressive agent, as suggested by its tropism for both CD4+ and CD8+ T cells, B cells, monocytes/macrophages, megakaryocytes and NK cells. Moreover, several studies have indicated that mononuclear phagocyte resistance to virus infection is influenced by the cellular differentiation state. This paper describes the effect of pretreatment "in vitro" with IL-15 on the resistance of human monocytes (HM) to HHV-6 infection. Our results demonstrate that undifferentiated HM were highly resistant to HHV-6 infection, whereas HM pretreated with human recombinant IL-15 showed an increased permissiveness for HHV-6 infection. This permissiveness was characterised by higher release of extracellular virus as well as an increased percentage of antigen positive cells. Moreover, we evaluated IL-15 production after the addition of HHV-6 to monocytes precultured in different experimental conditions. Our data indicate that HHV-6-induced IL-15 production by human monocytes is not affected by the condition of "in vitro" precultivation/differentiation. Furthermore, the neutralization of IL-15 induced by HHV-6 in differentiated monocytes did not affect viral replication. These findings suggest that IL-15 acts only on the mechanisms of cellular differentiation, rendering HM more susceptible to HHV-6 infection, without interfering with virus replication.

Cell Differentiation↗
PubMed1999

Interleukin-12 and interleukin-10 production by mononuclear phagocytic cells from breast cancer patients.

Interleukin-10 (IL-10) and Interleukin 12 (IL-12) generation may be regulated by a complex monocyte and macrophage-derived cytokine network and an impairment of the immune system can be observed in neoplastic disease. In this study, we examined the production of these cytokines by phagocytic cells, obtained from breast cancer (BCa)-bearing patients. Our results suggest that an increased IL-10 formation may represent an important regulatory pathway of IL-12 production by BCa mononuclear cells. In this report, we show that mononuclear cells of patients affected by breast cancer have a defective IL-12 production capability while generating higher amounts of IL-10.

Aged↗
PubMed1999

Granulocyte-macrophage colony stimulating factor modulates the production of TNF alpha by differentiated U937 cells infected with Leishmania major.

In this work, the production of tumor necrosis factor alpha (TNF alpha) during interaction of human phagocytes with the intracellular parasite Leishmania major was further investigated. The human monocytic cell line U937, differentiated with a combination of 1 alpha, 25 dihydroxyvitamin D3 (VD) and retinoic acid (RA), or with granulocyte macrophage colony stimulating factor (GM-CSF) was used. Differentiated U937 cells were infected with Leishmania major promastigotes, and TNF alpha was assayed in cell culture supernatants. It was found that the cytokine was produced only by U937 cells differentiated with VD/RA and further incubated with GM-CSF and LPS or interferon gamma (IFN gamma). L. major induced TNF alpha production only in the presence of GM-CSF. No direct relationship was found, however, between production of TNF alpha and resistance of differentiated U937 cells to infection with L. major.

Adjuvants, Immunologic↗
PubMed1999

Altered cytokine production after human herpes virus type 6 infection.

Several strategies allow viruses to elude the surveillance of the immune system and to establish persistent infection in the host. One of such mechanisms is the immunosuppression caused by the direct infection and functional impairment of immune cells. Human Herpes virus type 6 (HHV-6) is a typical immunosuppressive agent, as suggested by its tropism for both CD4+ and CD8+ T cells, B cells, monocytes/macrophages, megakaryocytes and NK cells. In this study the production of IL-10 and IL-12 by peripheral blood mononuclear cells (PBMC) was evaluated during HHV-6 infection "in vitro". Our results demonstrate that HHV-6 up-regulates IL-10 production by PBMC. Furthermore, our data suggest that rhIFN gamma addition counteracts the effect of HHV-6 in promoting IL-10 release. To gain more insight into the role of IFN gamma, anti-IFN gamma monoclonal antibodies were added to PBMC stimulated with LPS. Neutralization of endogenous IFN gamma upregulated IL-10 release. Furthermore, HHV-6 infection inhibited IFN gamma release induced by LPS in PBMC. No basal production of IL-12 was found in PBMC. Moreover, HHV-6 infection did not induce IL-12 release by PBMC. On the contrary, IL-12 was detected in the supernatants of PBMC treated with LPS with or without rhIFN gamma. In these experimental conditions the further addition of HHV-6 markedly impaired IL-12 production. Moreover, the neutralization of IL-10 resulted in a significant up-regulation of IL-12. Finally our data suggest that the immunodysregulation induced by HHV-6 could be accounted for by a shift from a Th-1 to a Th-2 type cytokine profile.

Cells, Cultured↗