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Biomedical subjects

E Losi

Publications and source records attributed to E Losi.

At least 19 recordsLinked to original sources
PubMed2004

Commonly used antibiotics induce expression of Hsp 27 and Hsp 60 and protect human lymphocytes from apoptosis.

Heat shock proteins (Hsps) are abundant molecular chaperones participating in the cytoprotection. The kinetics of synthesis of Hsps closely correlates with the kinetics of development of resistance to cell death. In this study, we analysed the probable involvement of Hsp 27 and Hsp 60 in the protection of cells undergoing apoptosis. Human lymphocytes cultured in the presence of ampicillin or ceftriaxone produced Hsp 60 and Hsp 27, estimated by immunoblotting in a time-dependent manner and the increased levels of Hsp 60 and Hsp 27 correlated with enhanced resistance of the lymphocytes to apoptosis, as determined by flow cytometry. Cultures treated with ampicillin or ceftriaxone also exhibited smaller numbers of apoptotic cells than untreated cultures when exposed to the apoptosis-inducing agent staurosporine (1 mM). In contrast, cloramphenicol induced the production of only small amounts of Hsp 60, and no resistance apoptosis. Further studies are needed to clarify the potential role of Hsp 27 and Hsp 60 in the resistance of human cells to apoptosis and the effects of antibiotics on this phenomenon.

Adjuvants, Immunologic↗
PubMed2002

Chlamydia pneumoniae infections prevent the programmed cell death on THP-1 cell line.

Chlamydia pneumoniae is an obligate intracellular bacterium which frequently causes airway infection in humans and has been implicated in chronic inflammatory disease and atherosclerosis. Here we show that infection with C. pneumoniae protects THP-1 cells against the apoptosis which spontaneously occurs in macrophages in the absence of an activation signal. Analysis by flow cytometry at different post-infection times revealed that 50+/-7% of THP-1 cells were apoptotic at 48 h after onset of the experiments, whereas C. pneumoniae-infected cultures (multiplicity of infection, MOI=30) displayed only 18+/-4% of cells in apoptosis. At MOI=20 and MOI=10 the cells susceptible to apoptosis at 48 h were 28+/-5% and 35+/-6% respectively. Moreover, the results show that heat-inactivated bacteria do not give significant protection against apoptosis, even at higher MOI (MOI=30), while UV-treated Chlamydia did provide a degree of protection against apoptosis. These data suggest that the anti-apoptotic effect of C. pneumoniae requires a heat-labile component released during infection, and that the effect is not lipopolysaccharide-dependent.

Apoptosis↗
PubMed2002

Human herpes virus-like particles in pityriasis rosea lesions: an electron microscopy study.

BACKGROUND: In a previous study we detected virions with electron microscopy features of human herpes viruses in the supernatant of cocultured mononuclear cells from patients with acute pityriasis rosea. Because of their morphology and of polymerase chain reaction studies, we ascribed them to human herpes virus 7. OBJECTIVE: To find such virions in the lesional skin of pityriasis rosea patients. METHODS: Skin specimens from lesions of 21 patients with acute pityriasis rosea were examined by elecron microscopy. RESULTS: In 15 (71%) patients, human herpes virus particles in various stages of morphogenesis were detected. Mature enveloped virions appeared as typical human herpes virus virions, measuring about 160-200 nm in diameter and containing an electrodense cylindrical core, a capsid, an envelope with typical spikes and a very distinct tegument layer between the capsid and the envelope. They were very similar to those we reported in the supernatant of co-cultured circulating mononuclear cells from patients with pityriasis rosea. CONCLUSION: Our results confirm our previous findings and provides further evidence of a viral etiology for pityriasis rosea.

Herpesvirus 7, Human↗
PubMed2002

p53 and anti-p53 antibodies as possible markers of a switch towards a neoplastic phenotype in patients infected by Helicobacter pylori.

Helicobacter pylori is a definite carcinogen whose mechanism of action is still unknown. The aim of this work was (1) to determine the presence of p53 protein and related antibodies in patients affected by various gastric pathologies and chronically infected with H. pylori, and (2) to try to discover a test to be used as a marker of a possible switch towards a neoplastic phenotype.

Antibodies↗
PubMed2002

Cytokine induction in murine bladder tissue by type 1 fimbriated Escherichia coli.

The local cytokine response to uropathogenic phenotype Escherichia coli KBC211 infection exhibits characteristics of both TH1 and TH2 profiles. Interleukin (IL)-6, MIP-2, IL-12, IL-18, and tumor necrosis factor-alpha (TNF-alpha) are expressed, but IL-4, IL-5, and IL-10 are also present at low levels. This is clearly a complex response that should be explored more fully. The relative contributions of the bladder epithelium and other cells of the bladder wall should also be determined. Epithelial cytokine responses may be considerable, and because these cells are the first to encounter the pathogen, they will be of great importance in the immune response to pathogenic E. coli.

Animals↗
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↗
PubMed1997

In vitro activities of new quinolones against Helicobacter pylori.

Compounds belonging to a new class of quinolones in which the fundamental C-6 fluorine atom was replaced were evaluated for in vitro antibacterial activity against 32 Helicobacter pylori strains. Since these substitutions resulted in higher inhibitory activities, these new desfluoroquinolones may be useful in eradicating H. pylori infections.

4-Quinolones↗
PubMed1997

Human herpesvirus 7 in patients with pityriasis rosea. Electron microscopy investigations and polymerase chain reaction in mononuclear cells, plasma and skin.

BACKGROUND: Clinical evidence suggests a viral etiology for pityriasis rosea (PR). OBJECTIVE: To evaluate human herpesvirus (HHV)-6 and HHV-7 as candidates for the etiology of PR. METHODS: Blood and skin tissue from 12 patients with acute PR, and 12 patients with other dermatoses were studied, as well as blood samples from 25 healthy persons. Serum interferon (IFN)-alpha and IFN-gamma were analyzed by ELISA. Analysis of morphological changes in cocultured peripheral blood mononuclear cells (PBMC) and electron microscopy (EM) to identify viral particles were performed. Polymerase chain reaction (PCR) with specific primers for HHV-6 and HHV-7 DNA sequences was performed on the plasma and PBMC of patients and healthy controls and on the skin of patients with PR and other skin diseases. RESULTS: PR plasma contained detectable IFN-alpha and IFN-gamma, whereas plasma from controls did not. PBMC from PR patients showed ballooning cells and syncytia after 7 days in culture whereas PBMC from controls and recovered PR patients did not. This cytopathic effect was also documented in a PR patient who relapsed and in Sup-T1 cell cultures inoculated with the cell-free supernatant from centrifuged cultured PBMC; in this supernatant, herpesvirus, virions were detected by EM, PCR identified HHV-7 DNA in PBMC, plasma and skin from all patients with active PR and in the PBMC only of 5 patients tested 10-14 months later. Weaker signals of HHV-7 DNA were detected in PBMC of 11 controls, but not in their plasma. Skin was negative for HHV-7 in all control specimens. CONCLUSIONS: Although the detection of HHV-7 DNA in PBMC and tissues does not prove directly a causal role, HHV-7 DNA in cell-free plasma corresponds to active replication which supports a causal relationship. We propose that PR is a clinical presentation of HHV-7 reactivation.

Cells, Cultured↗
PubMed1997

In vitro effects of lithium chloride on TNF alpha and IL-6 production by monocytes from breast cancer patients.

It is well known that lithium chloride (LiCl) is able to trigger human monocytes to release tumor necrosis factor alpha (TNF alpha). In this study we have evaluated the in vitro effect of LiCl on TNF alpha and interleukin-6 (IL-6) release by monocytes from patients affected by non-metastatic (BCa/M0) and metastatic breast cancer (BCa/M1), preincubated with autologous serum (sPt). Our data demonstrate that monocytes from cancer patients (BCa) treated with LiCl released lower amounts of TNF alpha compared to those from healthy donors (HD). Preincubation in autologous serum (sPt) impaired TNF alpha production by monocytes from BCa with LiCl. On the contrary, our data indicate that IL-6 production by monocytes treated was not impaired. Moreover, the results obtained from the same cells, preincubated in sPt and treated with LiCl, indicate that serum factors may synergize with LiCl treatment in releasing IL-6.

Aged↗
PubMed1996

Immunobiological activities of mould products: functional impairment of human monocytes exposed to aflatoxin B1.

In order to elucidate the effects upon the human immune system of aflatoxin B1 produced by the food-contaminating mould Aspergillus flavus, phagocytosis, microbicidal activity, superoxide production and intrinsic antiviral activity were studied in monocytes exposed to aflatoxin B1 for different times at concentrations ranging from 0.1 to 1 pg/ml. Phagocytosis and microbicidal activity were significantly impaired (p < 0.05) by aflatoxin B1 at doses as low as 0.1 pg/ml. However, pretreatment of monocytes with aflatoxin B1 did not modify intrinsic antiviral activity or superoxide production. These results confirmed data obtained from animals fed with mycotoxin-contaminated foods. The potential danger to human health of exposure to mycotoxins demonstrates the necessity for careful microbiological control of food.

Aflatoxin B1↗
PubMed1996

Role of gamma interferon in a neonatal mouse model of group B streptococcal disease.

The aim of this study was to assess the role of gamma interferon (IFN-gamma) in a neonatal mouse model of group B streptococcal (GBS) sepsis. IFN-gamma was produced by spleen cells at 24, 48, and 72 h after GBS challenge. Treatment with anti-IFN-gamma at 6 h before challenge totally abrogated the IFN-gamma response but did not affect survival. Subcutaneous administration of recombinant IFN-gamma (2,500 IU per pup) at 18 h after challenge resulted in increased survival time and reduced blood colony counts at 48 and 72 h. In vitro preincubation of neonatal whole blood with IFN-gamma before the addition of GBS resulted in significant restriction of bacterial growth. These data indicate that administration of recombinant IFN-gamma can partially restore impaired host defenses against GBS in neonatal mice. This cytokine may be useful for the treatment of neonatal infections.

Animals↗
PubMed1996

Lymphocyte number and stress parameter modifications in untreated breast cancer patients with depressive mood and previous life stress.

Depressive mood disorders and severe, chronic stressful life events (DSM-III-R criteria) were more frequently diagnosed in 106 breast cancer patients with respect to 37 patients with benign breast diseases (control group) (p < 0.001), during a stressful period such as hospital admission, diagnosis uncertainty, and when awaiting surgery. The study was performed 5 +/- 3 days before histological diagnosis had been done. Controls showed reduced 24-h diuresis and low catecholamine excretion (norepinephrine, NE; and epinephrine, E) that positively correlated with 24-h diuresis (p < 0.001) and CD3+ lymphocytes (p = 0.056), as during a normal stress response. In contrast, breast cancer patients showed increased 24-h diuresis (with respect to controls p < 0.001) and catecholamine values (p < 0.05). Patients' 24-h diuresis correlated positively with NE (p = 0.02) and 17-ketosteroids (p = 0.004); blood cortisol correlated positively with CD3+ (p = 0.01), CD4+ (p = 0.02), CD8+ (p < 0.01), CD16+ (p = 0.01) lymphocytes and negatively with E (p < 0.03); catecholamines correlated negatively with CD8+ (p = 0.006). These preliminary data are discussed in relation to upregulation of the adrenergic system and the different mechanisms of immune system regulation involved in breast cancer patients, compared with those in subjects with benign breast disease. The differences in these mechanisms may be a result of an imbalance of the bi-directional regulatory circuit of the psycho-neuro-endocrine-immune system, caused by previous life stress or the presence of the tumor mass.

Breast Neoplasms↗