Hepatitis A vaccination and its immunological and epidemiological long-term effects - a review of the evidence

Hepatitis A virus (HAV) infections continue to represent a significant disease burden causing approximately 200 million infections, 30 million symptomatic illnesses and 30,000 deaths each year. Effective and safe hepatitis A vaccinfes have been available since the early 1990s. Initially developed for individual prophylaxis, HAV vaccines are now increasingly used to control hepatitis A in endemic areas. The human enteral HAV is eradicable in principle, however, HAV eradication is currently not being pursued. Inactivated HAV vaccines are safe and, after two doses, elicit seroprotection in healthy children, adolescents, and young adults for an estimated 30-40 years, if not lifelong, with no need for a later second booster. The long-term effects of the single-dose live-attenuated HAV vaccines are less well documented but available data suggest they are safe and provide long-lasting immunity and protection. A universal mass vaccination strategy (UMV) based on two doses of inactivated vaccine is commonly implemented in endemic countries and eliminates clinical hepatitis A disease in toddlers within a few years. Consequently, older age groups also benefit due to the herd protection effects. Single-dose UMV programs have shown promising outcomes but need to be monitored for many more years in order to document an effective immune memory persistence. In non-endemic countries, prevention efforts need to focus on 'new' risk groups, such as men having sex with men, prisoners, the homeless, and families visiting friends and relatives in endemic countries. This narrative review presents the current evidence regarding the immunological and epidemiological long-term effects of the hepatitis A vaccination and finally discusses emerging issues and areas for research

QSAR analysis of salicylamide isosteres with the use of quantum chemical molecular descriptors

Quantitative relationships between the molecular structure and the biological activity of 49 isosteric salicylamide derivatives as potential antituberculotics with a new mechanism of action against three Mycobacterial strains were investigated. The molecular structures were represented by quantum chemical B3LYP/6-31G* based molecular descriptors. A resulting set of 220 molecular descriptors, including especially electronic properties, was statistically analyzed using multiple linear regression, resulting in acceptable and robust QSAR models. The best QSAR model was found for Mycobacterium tuberculosis (r(2) = 0.92; q(2) = 0.89), and somewhat less good QSAR models were found for Mycobacterium avium (r(2) = 0.84; q(2) = 0.78) and Mycobacterium kansasii (r(2) = 0.80; q(2) = 0.56). All QSAR models were cross-validated using the leave-10-out procedure

Seasonal patterns in the fish and crustacean community of a turbid temperate estuary (Zeeschelde Estuary, Belgium)

Fish and crustaceans were sampled for 1 year in the upper reaches of a temperate estuary characterized by high turbidity and a tidal range of up to 5 m. Samples were taken in the cooling-water circuit of the Doel Nuclear Power station (Zeeschelde, Belgium). Between July 1994 and June 1995, 55 fish species, two shrimp species and four crab species were recorded. The fish community was composed of 36 marine species, 16 freshwater species and three diadromous species. Shrimps, Gobiidae and Clupeidae dominated the samples both in numbers and biomass. An exceptionally clear seasonal succession was observed in the species composition. It is argued that young fish and crustaceans use the highly turbid Zeeschelde Estuary as a refuge from predators

The Westerschelde estuary: two food webs and a nutrient rich desert

Hummel et al. (1988) hypothesised the concomitant existence of two separate food chains in the Westerschelde: a photo-autotrophic coastal food chain in the marine part and a heterotrophic chain in the brackish part. The present study intends to re-examine the hypothesis on the basis of recently published data. Biomass gradients of the important functional units along an estuarine transect were observed to differ from those reported by Hummel et al. (1988) in some important aspects. The biomodal primary production gradient reported by Spaendonck et al. (in press) does not resemble the phytoplankton biomass curve, gradually increasing from the sea to Antwerp proposed by Hummel et al. (1988). Estimates of mesozooplankton biomass were found to be about an order of magnitude lower than reported by Hummel et al. (1988) and to display a completely different and more complex spatial pattern. However, the new gradient found is more in line with the hypothesis of two food chains than the gradient reported by Hummel et al. (1988). In the macrobenthos the biomass peak in the brackish part reported by Hummel et al. (1988) could not be confirmed. This finding does not falsify the original hypothesis as the function of this detritus dependent macrobenthic fauna is largely taken over by the hyperbenthic mysids, a group of previously unknown importance in the system. The existence of two food chains is also supported by the gradients observed in fish and epibenthic invertebrates, functional units not addressed by Hummel et al. (1988). In the zone between the two different food chains the dominant animal groups of the pelagic system have only a low biomass, this is the nutrient rich desert of the title. The zone upstream of the Dutch-Belgian border supports no hyperbenthos, no epibenthos and no mesozooplankton because of the low dissolved oxygen concentrations (less than 40% saturation), but there is a prominent peak in the microzooplankton. Clearly, in the brackish part, the richness of most functional units can only be explained on the basis of an input of organic matter from outside, consumed through a heterotrophic food chain. A second, smaller peak is observed close to the mouth of the estuary and is dependent on the primary production in the marine part of the estuary. Even for individual species this clear bimodal pattern can be observed. This disqualifies simplistic physiological models of estuarine succession as a basis for the findings. In the oxygenated part of the system there is no good general correlation between macrobenthic biomass (mostly suspension-feeders) and primary production. Macrobenthic biomass is highly variable in this zone, probably as a result of local differences in current velocity maxima. The new data confirm the view of Hummel et al. (1988) but it is concluded that these authors must have formulated their hypothesis intuitively and could not have done so from the data available at the time

Protein processing characterized by a gel-free proteomics approach

We describe a method for the specific isolation of representative N-terminal peptides of proteins and their proteolytic fragments. Their isolation is based on a gel-free, peptidecentric proteomics approach using the principle of diagonal chromatography. We will indicate that the introduction of an altered chemical property to internal peptides holding a free α-N-terminus results in altered column retention of these peptides, thereby enabling the isolation and further characterization by mass spectrometry of N-terminal peptides. Besides pointing to changes in protein expression levels when performing such proteome surveys in a differential modus, protease specificity and substrate repertoires can be allocated since both are specified by neo-N-termini generated after a protease cleavage event. As such, our gel-free proteomics technology is widely applicable and amenable for a variety of proteome-driven protease degradomics research

Occurrence, distribution and diversity of Listeria monocytogenes contamination on beef and pig carcasses after slaughter

In this study we investigated the prevalence and location of Listeria monocytogenes and hygiene indicator bacteria on beef and pig carcasses. Carcasses were sampled after slaughter and before cooling at eight and nine sites on the carcass, respectively. For each sample, detection and enumeration of Listeria was performed, as well as the enumeration of Total Aerobic Counts (TAC) and Enterobacteriaceae. The L. monocytogenes isolates were also typed to determine pulsotypes and clonal complexes (CC). L. monocytogenes was detected on 46% [95% CI: 35-56%] of beef and 22% [95% CI: 11-32%] of pig carcasses. Contamination levels at the different carcass sites differed considerably between beef and pigs. Genetic typing of strains suggests that carcass contamination originates from both incoming animals with transmission during slaughter practices as well as persistent (CC9) contamination from the slaughterhouse environment. These findings can be used to understand the complexity of introduction and persistence of this pathogen in slaughter facilities. Accurate correlation of L. monocytogenes presence proved unfeasible with any of the tested hygiene indicator bacteria

PF4V1 (Platelet Factor 4 Variant 1)

Review on PF4V1 (Platelet Factor 4 Variant 1), with data on DNA, on the protein encoded, and where the gene is implicated