Retrospective investigation of an influenza A/H1N1pdm outbreak in an Italian military ship cruising in the Mediterranean Sea, May-September 2009

Background

Clinical surveillance may have underestimated the real extent of the spread of the new strain of influenza A/H1N1, which surfaced in April 2009 originating the first influenza pandemic of the 21^st century. Here we report a serological investigation on an influenza A/H1N1pdm outbreak in an Italian military ship while cruising in the Mediterranean Sea (May 24-September 6, 2009).

Methods

The contemporary presence of HAI and CF antibodies was used to retrospectively estimate the extent of influenza A/H1N1pdm spread across the crew members (median age: 29 years).

Findings

During the cruise, 2 crew members fulfilled the surveillance case definition for influenza, but only one was laboratory confirmed by influenza A/H1N1pdm-specific RT-PCR; 52 reported acute respiratory illness (ARI) episodes, and 183 reported no ARI episodes. Overall, among the 211 crew member for whom a valid serological result was available, 39.3% tested seropositive for influenza A/H1N1pdm. The proportion of seropositives was significantly associated with more crowded living quarters and tended to be higher in those aged <40 and in those reporting ARI or suspected/confirmed influenza A/H1N1pdm compared to the asymptomatic individuals. No association was found with previous seasonal influenza vaccination.

Conclusions

These findings underline the risk for rapid spread of novel strains of influenza A in confined environment, such as military ships, where crowding, rigorous working environment, physiologic stress occur. The high proportion of asymptomatic infections in this ship-borne outbreak supports the concept that serological surveillance in such semi-closed communities is essential to appreciate the real extent of influenza A/H1N1pdm spread and can constitute, since the early stage of a pandemic, an useful model to predict the public health impact of pandemic influenza and to establish proportionate and effective countermeasures.     

Modulation of natural killer activity by thymosin alpha 1 and interferon

Summary A single injection of -interferon (-IFN) (30 000 units/mouse), a major biological modifier of natural killer (NK) cytolytic activity, strongly stimulated NK activity in normal mice, as expected, while the same treatment did not statistically alter the NK response in cyclophosphamide (CY)-suppressed animals.We investigated the possibility of thymosin ₁ cooperating with -IFN in boosting NK activity in CY-suppressed animals.The results show that treatment with thymosin ₁ (200 g/kg) for 4 days, followed by a single injection of -IFN 24 h before testing, strongly restored NK activity in CY-suppressed mice. Thymosin ₁ was, moreover, able to accelerate the recovery rate of NK activity in bone marrow reconstituted murine chimeras.Taken together the data support the concept that the synergic effect between thymosin ₁ and -IFN could be the result of effects on differentiation of the NK lineage at different levels.     

A novel functional role of iduronate-2-sulfatase in zebrafish early development

Sulfated glycosaminoglycan chains of extracellular matrix and cell membrane-tethered proteoglycans exert specific cellular functions by interacting with a broad spectrum of morphogens and growth factors.In humans, a congenital impaired catabolism of sulfated glycosaminoglycans is associated with severe metabolic disorders. Here, we report on the identification and characterization of a zebrafish iduronate sulfatase orthologue. By knocking down its function with antisense morpholino oligos, we demonstrate that iduronate sulfatase plays a critical role during early vertebrate development and its downregulation may be responsible for severe developmental defects, including a misshapen trunk and abnormal craniofacial cartilages. We show that the altered cartilage patterning is mediated by depauperation of sox10-expressing neural crest cell precursors. Through the application of a transactivation reporter assay, we also provide a molecular proof that increased TGFβ (Transforming Growth Factor β) signalling is tightly associated with downregulation of iduronate sulfatase function. Our results provide an insight into the early biological impairments underlying the Hunter syndrome and suggest the use of zebrafish as a novel tool to better understand lysosomal storage disorder pathogenesis.     

Probing the location of the substrate binding site of ascorbate oxidase near type 1 copper: an investigation through spectroscopic, inhibition and docking studies

The present investigation addresses the problem of the binding mode of phenolic inhibitors and the substrate ascorbate to the active site of ascorbate oxidase. The results from both types of compounds indicate that the binding site is located in a pocket near the type 1 copper center. This information is of general interest for blue multicopper oxidases. Docking calculations performed on the ascorbate oxidase-ascorbate complex show that binding of the substrate occurs in a pocket near type 1 Cu, and is stabilized by at least five hydrogen bonding interactions with protein residues, one of which involves the His512 Cu ligand. Similar docking studies show that the isomeric fluorophenols, which act as competitive inhibitors toward ascorbate, bind to the enzyme in a manner similar to ascorbate. The docking calculations are supported by 19F NMR relaxation measurements performed on fluorophenols in the presence of the enzyme, which show that the bound inhibitors undergo enhanced relaxation by the paramagnetic effect of a nearby Cu center. Unambiguous support to the location of the inhibitor close to type 1 Cu was obtained by comparative relaxation measurements of the fluorophenols in the presence of the ascorbate oxidase derivative where a Zn atom selectively replaces the paramagnetic type 2 Cu. The latter experiments show that contribution to relaxation of the bound inhibitors by the type 2 Cu site is negligible.     

Evaluation in rabbits of different anti-SHIV vaccine strategies based on DNA/fowlpox priming and virus-like particle boosting

Two different prime-boost immunization protocols were tested in rabbits and their immune response was evaluated and compared with the final aim of defining a vaccine strategy that might be able to protect non-human primates from infection with the pathogenic simian/human immunodeficiency virus, SHIV(89.6P). The two regimens were based on three priming immunizations with either an expression plasmid plus a fowlpox (FP) recombinant vector or with two FP recombinant vectors, each one expressing either the SIV(mac239) gag/pol or the HIV-1env(89.6P) genes. In both protocols, priming immunizations were followed by two boosts with SHIV-mimicking virus-like particles (VLP). A complete SHIV-specific response was observed in all animals. Interestingly, the DNA vaccine was three to 10 times more efficient than the FP recombinant in inducing an anti-gag humoral response. Real-time PCR confirmed the memory effect on T-cell subsets secreting interleukin-4 and interferon-gamma, as a consequence of stimulation of both arms of the immune system. Although both protocols were almost equally effective in eliciting homologous neutralizing antibodies and highlighted the efficacy of VLP administration for boosting, protocol A seemed to be more effective in promoting a balanced T-cell memory immune response and appears more promising for vaccine purposes.     

Determination of the oxido-redox status of plasma albumin in hemodialysis patients

The oxido-redox status of plasma albumin in patients treated with hemodialysis was characterized with LC-ESI-MS/MS and was compared with models of oxidative stress. Oxidised albumin was characterized by sulfonation (SO3-) of the SH at Cys 34, unfolding and acidification of the molecule. Albumin in hemodialysis patients presented, instead, only intermediate oxidation products such as sulfenic (SO2), sulfonic (SO)and methionine sulfoxide (C5H9NO2S) involving Cys 165-269 and Met 329-548 but did not present SO3- at Cys 34. Absence of charge and structural alterations compared to the oxidised templates was also confirmed with electrophoretic titration and calorimetry. In conclusion, the oxido-redox status of plasma albumin in hemodialysis patients lacks the hallmarks of the advanced oxidation products. LC-ESI-MS/MS was crucial to characterize albumin in conditions of oxidation stress; surrogate techniques can mirror conformational changes induced by oxidation.     

Nuclear metabolism. II. Further studies on epoxide hydrolase activity

Apparent K_m- and V_max-values of nuclear styrene 7,8-oxide hydrolase were determined at different protein concentrations. In the protein concentrations range used no significant differences in the apparent K_m-values were observed. The influence of the incubation with different modifiers (i.e. SKF-525A, metyrapone, 1,2-epoxy-3,3,3 trichloropropane, cyclohexene oxide) at two different concentrations on this enzyme activity was also determined. Cyclohexene oxide and 1,2-epoxy-3,3,3-trichloropropane, two well known inhibitors of the microsomal epoxide hydrolase(s) caused a marked inhibition, metyrapone had a strong activating effect whereas SKF-525A had no effect. In vivo pretreatment with phenobarbital significantly induced the nuclear epoxide hydrolase whereas β-naphthoflavone caused a lower degree of induction. This pattern is quantitatively different but qualitatively very similar to the microsomal one. Moreover a toxifying to detoxifying enzymatic activity balance is attempted for the metabolization of the alkenic double bond of styrene, taking into account the ratio between the styrene monooxygenase (toxifying enzyme) and the styrene 7,8-oxide hydrolase (detoxifying enzyme) after the above mentioned pretreatments, both in the microsomal and nuclear fractions.     

Mast cells, angiogenesis, and tumour growth

Accumulation of mast cells (MCs) in tumours was described by Ehrlich in his doctoral thesis. Since this early account, ample evidence has been provided highlighting participation of MCs to the inflammatory reaction that occurs in many clinical and experimental tumour settings. MCs are bone marrow-derived tissue-homing leukocytes that are endowed with a panoply of releasable mediators and surface receptors. These cells actively take part to innate and acquired immune reactions as well as to a series of fundamental functions such as angiogenesis, tissue repair, and tissue remodelling. The involvement of MCs in tumour development is debated. Although some evidence suggests that MCs can promote tumourigenesis and tumour progression, there are some clinical sets as well as experimental tumour models in which MCs seem to have functions that favour the host. One of the major issues linking MCs to cancer is the ability of these cells to release potent pro-angiogenic factors. This review will focus on the most recent acquisitions about this intriguing field of research. This article is part of a Special Issue entitled: Mast cells in inflammation.