Epidemiology of tuberculosis in immigrant patients hospitalised in Infectious Diseases Units in Italy: multicentric study

In order to retrospectively evaluate the prevalence of immigrant patients affected by active tuberculosis, we analysed the clinical data of 2255 immigrant patients hospitalised during 2002 in ordinary admission or in Day Hospital in 48 Clinics of Infectious Diseases. In all, 303 patients were affected by active tuberculosis (13.4% of the total immigrant hospitalised patients); 30 patients (9.9%) were also HIV-positive. There was a considerable male gender bias (62.5%); the mean age was 29.7 years; 144 patients were from Africa (47.5%), 72 (23.7%) from Asia, 47 (15.5%) from eastern Europe and 40 (13.2%) from South America. The clinical variants were: pulmonary (57.7%), lymph node (15.8%), meningitis (13.8%), intestinal (4.2%), bone (3.3%), pleurical (2.3%), peritoneal (2.3%) and renal (0.6%). We conclude that tuberculosis is a very frequent disease among immigrants, especially of African origin. The high percentage is due to several factors, such as no vaccine prophylaxis and poor, overcrowded living conditions. It is fundamental to focus on the need to provide better health support for all subjects by setting up screening plans to estimate the real incidence of this pathology and ensure medical treatment to prevent the spread of this infection among immigrants and the local host population.     

Role of endogenous IFN-gamma in macrophage programming induced by IL-12 and IL-18.

Besides the established role of interleukin-12 (IL-12) and IL-18 on interferon-gamma (IFN-gamma) production by natural killer (NK), T, and B cells, the effects of these cytokines on macrophages are largely unknown. Here, we investigated the role of IL-12/IL-18 on nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) production by CD11b(+) adherent peritoneal cells, focusing on the involvement of endogenously produced IFN-gamma. C57BL/6 cells released substantial amounts of NO when stimulated with IFN-gamma or lipopolysaccharide (LPS), but failed to respond to IL-12 or IL-18 or both. However, IL-12/IL-18 pretreatment was able to program these cells to release 6-8-fold more NO and TNF-alpha in response to LPS or Trypanosoma cruzi stimulation, with NO levels directly correlating with macrophage resistance to intracellular parasite growth. Analysis of IL-12/IL-18-primed cells from mice deficient in IFN-gamma, IFNGR, and IFN regulatory factor-1 (IRF-1) revealed that these molecules were essential for LPS-induced NO release, but TNF-alpha production was IFN-gamma independent. Conversely, the myeloid differentiation factor 88 (MyD88)-dependent pathway was indispensable for IL-12/IL-18-programmed LPS-induced TNF-alpha production, but not for NO release. Contaminant T and NK cells largely modulated the IL-12/IL-18 programming of LPS-induced NO response through IFN-gamma secretion. Nevertheless, a small population of IFN-gamma(+) cells with a macrophage phenotype was also identified, particularly in the peritoneum of chronically T. cruzi-infected mice, reinforcing the notion that macrophages can be an alternative source of IFN-gamma. Taken together, our data contribute to elucidate the molecular basis of the IL-12/IL-18 autocrine pathway of macrophage activation, showing that endogenous IFN-gamma plays an important role in programming the NO response, whereas the TNF-alpha response occurs through an IFN-gamma-independent pathway.     

Detection of minor and major satellite DNA in cytokinesis-blocked mouse splenocytes by a PRINS tandem labelling approach

A protocol for the simultaneous visualization of minor and majorsatellite DNA by primed in situ DNA synthesis PRINS was developedin cytokinesis–blocked murine splenocytes. After individuationof optimal experimental conditions, a micronucleus MN test wascarried out by treating splenocytes in vitro with the clastogenicagent mitomycin C and the aneugenic compound Colcemid. It wasfound that PRINS gives highly reproducible results, also comparablewith the literature on MN results obtained by fluorescent insitu hybridization FISH. Therefore the PRINS methodology maybe proposed as a fast alternative to FISH for the characterizationof induced MN. ¹To whom correspondence should be addressed     

Vaccine immune response and side effects with the use of acetaminophen with influenza vaccine.

The purpose of this study was to determine whether acetaminophen impairs the immune response to influenza vaccine. Influenza vaccine is an under-utilized preventive measure, partly because of the unfounded perception that fever and myalgias frequently follow vaccination. While acetaminophen may decrease these infrequent side effects, it may also alter the immune response to vaccination. We compare the effect of acetaminophen with placebo on the humoral immune response to the 1991-1992 commercially available influenza vaccine. We studied 60 healthy, elderly subjects from a geriatric clinic and 20 infirm, elderly subjects from a nursing home. The subjects were randomly assigned to receive placebo or acetaminophen (1,000 mg every 6 h) for 2 days. Acetaminophen did not depress or enhance the immune development of serum hemagglutination inhibition antibody to the three vaccine antigens. The systemic side effects of fever and myalgia were uncommon in both groups. The healthy elderly subjects mounted a significantly better immune response to the influenza virus A/Taiwan/1/86 (H1N1) vaccine strain than did the infirm elderly subjects (geometric mean titer, 115 versus 51; P = 0.003). The functional activity score obtained by using the chronic healthy evaluation component of the Acute Physiology and Chronic Health Evaluation system could be used to distinguish the healthy from the infirm elderly (scores of 1.27 versus 3.75, P < 0.001). Acetaminophen neither depressed nor enhanced the serum antibody response to the vaccine in the healthy and infirm elderly subjects studied.     

Long-term growth of human T cell lines and clones on anti-CD3 antibody-treated tissue culture plates

Long-term growth of antigen-specific human T cells requires, in addition to IL-2, periodic exposure to antigen and accessory cells. In certain cases, accessory cells are not available or their presence in culture is undesired. We have developed a method of growing and sustaining human T cell lines and clones in long-term tissue culture in the absence of specific antigen or accessory cells. The requirement for antigen and/or accessory cells could be replaced by a monoclonal antibody to the CD3 determinant of human T cells (OKT3) bound to the surface of plastic tissue culture wells. Autoreactive, alloreactive, and antigen-reactive T cell lines and clones were maintained in culture for 8-12 weeks without antigen or accessory cells. The antigen specificity of these T cells was maintained.     

Bacterial Clearance and Cytokine Profiles in a Murine Model of Postsurgical Nosocomial Pneumonia

The development of a nosocomial pneumonia is facilitated by alterations in host innate pulmonary antibacterial defenses following surgical trauma, which can result in decreased pulmonary bacterial clearance and increased morbidity and mortality. In a murine model of postoperative nosocomial infection, surgical stress (laparotomy) decreased Escherichia coli clearance from the lungs of animals that underwent surgery. Consistent with previous studies, (i) pulmonary levels of tumor necrosis factor alpha at 6 h and of interleukin-1β (IL-1β), IL-6, and gamma interferon (IFN-γ) at 24 h post-bacterial infection (PBI) were decreased in animals that underwent laparotomy 24 h prior to E. coli infection (LAP/E. coli) compared to animals that received E. coli only; (ii) KC and macrophage inhibitory protein 2 were elevated at 6 h PBI in LAP/E. coli animals compared to E. coli-only animals; however, at 24 h PBI, levels were higher in the E. coli-only group; (iii) at 24 h PBI, monocyte chemoattractant protein 1 was lower in the LAP/E. coli group compared to the E. coli-only group; (iv) IL-10 levels were unaffected at all time points evaluated; and (v) the total number of neutrophils present in the lungs of LAP/E. coli animals at 6 h PBI was decreased in comparison to that in E. coli-only animals, resulting in decreased bacterial clearance and increased mortality in LAP/E. coli animals by 24 h PBI. Similar changes in cytokine profiles, pulmonary bacterial clearance, and mortality were consistent with reported findings in patients following surgical trauma. This model, therefore, provides a clinically relevant system in which the molecular and cellular mechanisms that lead to the development of nosocomial pneumonia can be further explored.     

Inhibition of microglial inflammatory responses by norepinephrine: effects on nitric oxide and interleukin-1β production

Background

Under pathological conditions, microglia produce proinflammatory mediators which contribute to neurologic damage, and whose levels can be modulated by endogenous factors including neurotransmitters such as norepinephrine (NE). We investigated the ability of NE to suppress microglial activation, in particular its effects on induction and activity of the inducible form of nitric oxide synthase (NOS2) and the possible role that IL-1β plays in that response.

Methods

Rat cortical microglia were stimulated with bacterial lipopolysaccharide (LPS) to induce NOS2 expression (assessed by nitrite and nitrate accumulation, NO production, and NOS2 mRNA levels) and IL-1β release (assessed by ELISA). Effects of NE were examined by co-incubating cells with different concentrations of NE, adrenergic receptor agonists and antagonists, cAMP analogs, and protein kinase (PK) A and adenylate cyclase (AC) inhibitors. Effects on the NFκB:IκB pathway were examined by using selective a NFκB inhibitor and measuring IκBα protein levels by western blots. A role for IL-1β in NOS2 induction was tested by examining effects of caspase-1 inhibitors and using caspase-1 deficient cells.

Results

LPS caused a time-dependent increase in NOS2 mRNA levels and NO production; which was blocked by a selective NFκB inhibitor. NE dose-dependently reduced NOS2 expression and NO generation, via activation of β2-adrenergic receptors (β2-ARs), and reduced loss of inhibitory IkBα protein. NE effects were replicated by dibutyryl-cyclic AMP. However, co-incubation with either PKA or AC inhibitors did not reverse suppressive effects of NE, but instead reduced nitrite production. A role for IL-1β was suggested since NE potently blocked microglial IL-1β production. However, incubation with a caspase-1 inhibitor, which reduced IL-1β levels, had no effect on NO production; incubation with IL-receptor antagonist had biphasic effects on nitrite production; and NE inhibited nitrite production in caspase-1 deficient microglia.

Conclusions

NE reduces microglial NOS2 expression and IL-1β production, however IL-1β does not play a critical role in NOS2 induction nor in mediating NE suppressive effects. Changes in magnitude or kinetics of cAMP may modulate NOS2 induction as well as suppression by NE. These results suggest that dysregulation of the central cathecolaminergic system may contribute to detrimental inflammatory responses and brain damage in neurological disease or trauma.     

The stability of methacrylate biomaterials when enzyme challenged: kinetic and systematic evaluations

This study addressed whether methacrylate monomers and polymers used in dentistry might degrade from enzymolysis by acetylcholinesterase (ACHE), cholesterol esterase (CHE), porcine liver esterase (PRLE), and a pancreatic lipase (PNL). Short (hour) and long-term (day) exposures were performed. Product ratios were used to determine surface hydrolysis of the polymeric materials. Enzyme kinetics were studied for the monomers when challenged by ACHE, CHE, and PRLE. In the case of PRLE, the V(max) for the dimethacrylate substrates varied slightly, but amounted to as much as 10% of that of p-nitrophenylacetate. The K(m) for triethylene glycol dimethacrylate (TEGDMA) was 197 microM for ACHE and 1107 microM for CHE. The V(max) was 2.7 nmol/min for ACHE and 3.5 nmol/min for CHE. TEGDMA was converted by CHE at 2% the rate of cholesteryl oleate. Long-term incubations of monomers with CHE and ACHE produced degrees of hydrolysis that evidenced structure dependency in the ability of the enzymes to effect hydrolysis. Particularly resistant were aromativ derivatives and those with branching in methacrylate linkages. Overall, the study confirms the ability of physiologically important esterases to catalyze the hydrolysis of biomaterial methacrylates.