Interaction between renin-angiotensin system and cholinergic system in brain.

Intracerebroventricular (i.c.v.) injection of hemicholinium-3 (HC-3; 20 micrograms), which depletes acetylcholine stores in brain, reduced the increase in mean arterial pressure (MAP) and the drinking, but not the decrease in heart rate (HR), induced by intraventricular injection of angiotensin II (ANG II, 50 and 100 ng) in conscious rats. Intraventricular injection of atropine (up to 1 microgram) decreased only the pressor effect, while larger doses (up to 10 micrograms) decreased the bradycardia, too. Mecamylamine (100 micrograms i.c.v.) reduced the pressor response induced by angiotensin, without influencing the decrease in heart rate. A dose of 50 micrograms of mecamylamine had no effect. Neither atropine (10 micrograms i.c.v.) nor mecamylamine (50 micrograms i.c.v.) affected thirst induced by angiotensin. Intravenous (i.v.) atropine, but not atropine methylbromide, strongly reduced the drinking effect. The increase in arterial pressure and the decrease in heart rate induced by intraventricular injection of physostigmine, as well as the drinking behaviour after carbachol (250 ng, i.c.v.) or the increase in arterial pressure following intravenous injection of physostigmine (in methylatropine-pretreated rats), were not influenced by either saralasin (up to 10 micrograms/kg, i.c.v.) or captopril (up to 50 micrograms, i.c.v.). These results suggest that: (1) the increase in mean arterial pressure and drinking behaviour, induced by intraventricular injection of angiotensin II, are partially mediated via acetylcholine in brain, acting through muscarinic receptors; (2) decrease in heart rate induced by angiotensin II is not baroreceptor reflex-mediated; (3) the brain renin-angiotensin system does not participate in the cardiovascular and behavioural effect induced by cholinergic stimulation in the brain.

Secondary metabolites of Aspergillus exert immunobiological effects on human monocytes.

This project focused on the effects of aflatoxin B1 (AFB1), a food-contaminating mycotoxin produced by fungi, genus Aspergillus, on the release and genetic expression of some important cytokines, i.e., (interleukin-1 alpha (IL-1 alpha), IL-6, tumor necrosis factor-alpha (TNF alpha)) by human monocytes. Monocytes, preincubated for different time periods with concentrations of AFB1 ranging from 0.01 to 1.0 pg/mL, were then activated with bacterial lipopolysaccharide. Cytokine levels were measured by immunoassay and mRNA by cDNA amplification. Pretreatment of monocytes with AFB1 resulted in a decrease in IL-1, IL-6 and TNF alpha release already at a concentration of 0.05 pg/mL. The gene expression of the cytokines considered was drastically affected by treatment with AFB1. In fact, AFB1 completely blocked the transcription of IL-1 alpha, IL-6 and TNF alpha mRNAs, while it did not affect beta-actin mRNA at the concentrations used. It therefore appears that AFB1 exerts its effect on cytokine release through selective inhibition of specific mRNA, without affecting general protein synthesis.

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.

Correlation between Helicobacter pylori infection and IL-18 mRNA expression in human gastric biopsy specimens.

Our data indicate that H. pylori infection is associated with active interleukin-18 production in patients with chronic gastritis. Different cell types appear to be involved in this activity and may play a role in the development of immunopathologic damage.

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.

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.

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.

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.

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.

Serum levels of interleukin-18 and sICAM-1 in patients affected by breast cancer: preliminary considerations.

Interleukin-18 (IL-18), a cytokine that plays an important role in the T-cell-helper type 1 response, acts as an angiogenesis and tumor suppressor. Intercellular adhesion molecule-1 (ICAM-1) has a potential role in immunoregulation by mediating immune cell infiltration into the tissue. The aim of this study was to evaluate IL-18 and soluble (s) ICAM-1 serum levels in breast cancer (BCa) patients with liver (BCaM1 h) or bone (BCaM1 b) metastases compared to BCa patients without metastases (BCaM0) and healthy donors (HDs). Furthermore, since IL-18 enhances ICAM-1 expression, we investigated whether there was a direct correlation between sICAM-1 and IL-18 serum levels. Serum IL-18 and sICAM-1 levels were assayed by immunoenzymatic methods. The serum sICAM-1 levels in the three groups of cancer patients were significantly higher (p<0.05) than those of HDs. Serum IL-18 levels were significantly higher (p<0.05) in BCaM1h and BCaM1b patients compared to BCaM0 patients and HDs. sICAM-1 proved to be closely correlated with serum IL-18 levels in HDs, whereas a weaker correlation was found in BCaM1h, BCaM1b and BCaM0 patients. The defective correlation between sICAM-1 and IL-18 found in cancer patients may contribute to our understanding of the immunity upset occurring in cancer. Our data suggest that IL-18, irrespective of its biological activity, could represent a marker for metastatic breast cancer.

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.

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.

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.

In vitro interleukin-8 production by monocytes treated with lithium chloride from breast cancer patients.

AIMS AND BACKGROUND: Since interleukin-8 (IL-8) has a suppressive effect on hematopoiesis, lithium induces leukocytosis and granulocytosis and mononuclear cells are defective in patients affected by neoplastic disease, we analyzed IL-8 production by monocytes obtained from patients with nonmetastatic breast cancer (BCaM0) and metastatic breast cancer (BCaM1) and the effect of lithium chloride (LiCl) on these cells. Lithium salt compounds are used to limit the degree and duration of neutropenia in patients receiving chemotherapy for cancer and acute leukemia. Lithium influences the hematopoietic system, which is known to be regulated by numerous cytokines including IL-8. METHODS: We selected three groups of subjects (15 per group): patients affected by BCaM0, BCaM1 and healthy donors (HD) matched for sex and age. IL-8 release was assessed in supernatants of lipopolysaccharide (LPS) and/or LiCl-treated monocyte cultures. RESULTS: Monocytes from BCaM1 released higher IL-8 levels than monocytes from BCaM0 (P <0.0001); the IL-8 levels of both groups were significantly higher (P <0.0001) than those of HD. In vitro LiCl treatment reduced IL-8 production by monocytes obtained from all subjects compared to the same cells when untreated or LPS treated. The suppressive effect of LiCl on IL-8 production by monocytes from breast cancer patients was particularly marked in monocytes from BCaM0 with respect to those from BCaM1. LPS treatment increased the IL-8 production more in BCaM1 monocytes than in BCaM0 monocytes. Moreover, combined LPS/LiCl treatment of monocytes significantly (p <0.0001) downregulated the release of IL-8 compared to treatment with LPS alone. CONCLUSIONS: Our data demonstrate that monocytes from BCaM0 release larger amounts of IL-8 than monocytes from BCaM0 and from HD. Lithium was able to downregulate IL-8 production by monocytes from different subgroups. Further studies are needed to clarify if the improvement of the hematopoietic system in vivo observed following lithium therapy could reside, at least in part, in the ability of lithium to downregulate this chemokine.

An electron microscopical investigation of small round viruses in non-bacterial gastroenteritis.

Small round viruses implied in non-bacterial gastroenteritis were observed by electron microscope in stool specimens collected from 1993 to 1996. The specimens relative to 1981 were re-examined. The identified viruses are astroviruses (n = 6), caliciviruses (n = 7), Norwalk-like viruses (n = 34) and Parvoviruses (n = 6). Immunoelectron microscopy (IEM) and solid-phase immunoelectron microscopy (SPIEM) were used in order to verify serological differences existing among Norwalk-like viruses from different outbreaks. The results obtained suggest a possible circulation, in Liguria, of two serotypes of antigenically different viruses in the period considered.

Cardiovascular responses of conscious DOCA-salt hypertensive rats to acute intracerebroventricular and intravenous administration of captopril.

The effect on blood pressure and heart rate, following administration of the same intracerebroventricular (ivt) and intravenous (iv) doses of captopril, was compared in freely moving DOCA-salt hypertensive rats, with chronically implanted ivt, iv and intraarterial cannulae. Ivt captopril (500 micrograms) in DOCA-salt rats showed an initial pressor response followed by a long lasting hypotensive effect. The ivt effect was greater than that following iv administration. No effect was observed in normotensive controls either ivt or iv. ASA or naloxone pretreatments significantly lowered the captopril hypotensive effect, thus suggesting an involvement of prostaglandin and opioid systems in blood pressure elevation in "non renin dependent" hypertension.