Effects of aspirin on the development of Helicobacter pylori-induced gastric inflammation and heterotopic proliferative glands in Mongolian gerbils

Background: Helicobacter pylori infection is a major cause of gastritis and gastric carcinoma. Aspirin has anti‐inflammatory and antineoplastic activity. The aim of the present study was to determine the effects of aspirin on H. pylori‐induced gastritis and the development of heterotopic proliferative glands. Methods: H. pylori strain SS1 was inoculated into the stomachs of Mongolian gerbils. Two weeks after inoculation, the animals were fed with the powder diets containing 0 p.p.m. (n = 10), 150 p.p.m. (n = 10), or 500 p.p.m. (n = 10) aspirin. Mongolian gerbils were killed after 36 weeks of infection. Uninfected Mongolian gerbils (n = 10) were used as controls. Histologic changes, epithelial cell proliferation and apoptosis, and prostaglandin E₂ (PGE₂) levels of gastric tissue were determined. Results: H. pylori infection induced gastric inflammation. Administration of aspirin did not change H. pylori‐induced gastritis, but alleviated H. pylori‐induced hyperplasia and the development of heterotopic proliferative glands. Administration of aspirin accelerated H. pylori‐associated apoptosis but decreased H. pylori‐associated cell proliferation. In addition, the increased gastric PGE₂ levels due to H. pylori infection were suppressed by treatment with aspirin, especially at the dose of 500 p.p.m. Conclusions: Aspirin alleviates H. pylori‐induced hyperplasia and the development of heterotopic proliferative glands. Moreover, aspirin increases H. pylori‐induced apoptosis. We demonstrated the antineoplastic activities of aspirin in H. pylori‐related gastric carcinogenesis.     

Role of RNA structure and susceptibility to RNase E in regulation of a cold shock mRNA, cspA mRNA

Degradation of the cspA mRNA in vivo is very rapid at temperatures greater than 30 degrees C and is moderately dependent on RNase E. Investigations in vitro show that degradosomes prepared from normal or cold-shocked cultures cleave the cspA mRNA preferentially at a single site in vitro between two stem-loops approximately 24 residues 3' to the termination codon and approximately 31 residues from the 3' end. The site of cleavage is independent of the temperature and largely independent of the phosphorylation status of the 5' end of cspA mRNA. A 5' stem-loop, potential occlusion of the initiation and termination codons, temperature-dependent translational efficiency, and the position of the RNase E cleavage site can explain the differential stability of the cspA mRNA.     

Structural chemistry and In vitro antitubercular activity of acetylpyridine benzoyl hydrazone and its copper complex against Mycobacterium smegmatis

Acetylpyridine benzoyl hydrazone (APBH) 1 and its copper complex [[(APBH)CuCl](2)].(EtOH) 2 were structurally characterized by elemental analysis, magnetic measurements, spectroscopy, electrochemistry and single crystal X-ray diffraction studies. The ligand assumes Z-isomeric form and planar geometry in solid state, coordinating through pyridyl nitrogen, azomethine nitrogen and the carbonyl oxygen of the benzoyl group. The copper complex is dimeric and has a distorted octahedral geometry in which the two copper atoms are bridged by two chloride atoms. Antimycobacterial screening of ligand and its copper compound against Mycobacterium smegmatis shows clear enhancement in the antitubercular activity upon copper complexation.     

Sampling strategy optimization to increase statistical power in landscape genomics: A simulation‐based approach

An increasing number of studies are using landscape genomics to investigate local adaptation in wild and domestic populations. Implementation of this approach requires the sampling phase to consider the complexity of environmental settings and the burden of logistical constraints. These important aspects are often underestimated in the literature dedicated to sampling strategies. In this study, we computed simulated genomic data sets to run against actual environmental data in order to trial landscape genomics experiments under distinct sampling strategies. These strategies differed by design approach (to enhance environmental and/or geographical representativeness at study sites), number of sampling locations and sample sizes. We then evaluated how these elements affected statistical performances (power and false discoveries) under two antithetical demographic scenarios. Our results highlight the importance of selecting an appropriate sample size, which should be modified based on the demographic characteristics of the studied population. For species with limited dispersal, sample sizes above 200 units are generally sufficient to detect most adaptive signals, while in random mating populations this threshold should be increased to 400 units. Furthermore, we describe a design approach that maximizes both environmental and geographical representativeness of sampling sites and show how it systematically outperforms random or regular sampling schemes. Finally, we show that although having more sampling locations (between 40 and 50 sites) increase statistical power and reduce false discovery rate, similar results can be achieved with a moderate number of sites (20 sites). Overall, this study provides valuable guidelines for optimizing sampling strategies for landscape genomics experiments.     

Self-help materials for the prevention of smoking relapse: study protocol for a randomised controlled trial

ABSTRACT: BACKGROUND: Most people who stop smoking successfully for a few weeks will return to smoking again in the medium term. There are few effective interventions to prevent this relapse and none used routinely in clinical practice. A previous exploratory meta-analysis suggested that self-help booklets may be effective but requires confirmation. This trial aims to evaluate the effectiveness and cost-effectiveness of a set of self-help educational materials to prevent smoking relapse in the NHS Stop Smoking Service. METHODS: This is an open, randomised controlled trial. The target population is carbon monoxide (CO) verified quitters at 4 weeks in the NHS stop smoking clinic (total sample size N=1,400). The experimental intervention tested is a set of 8 revised Forever Free booklets, including an introduction booklet and more extensive information on all important issues for relapse prevention. The control intervention is a leaflet that has no evidence to suggest it is effective but is currently given to some patients using NHS stop smoking services. Two follow-up telephone interviews will be conducted at 3 and 12 months after quit date. The primary outcome will be prolonged abstinence from months 4-12 with no more than 5 lapses, confirmed by carbon monoxide test at 12 month assessment. The secondary outcomes will be 7-day self-report point prevalence abstinence at 3 months and 7-day biochemically confirmed point prevalence abstinence at 12 months. To assess cost-effectiveness, costs will be estimated from a health service perspective and the EQ-5D will be used to estimate the QALY (Quality Adjusted Life Year) gain associated with each intervention. The comparison of smoking abstinence rates (and any other binary outcomes) between the two trial arms will be carried out using odds ratio as the outcome statistic and other related statistical tests. Exploratory subgroup analyses, including logistic regression analyses with interaction terms, will be conducted to investigate possible effect modifying variables. DISCUSSION: The possible effect of self-help educational materials for the prevention of smoking relapse has important public health implications. Trial Registration: Current Controlled Trials ISRCTN36980856.     

SpecNet: A Spatial Network Algorithm that Generates a Wide Range of Specific Structures

Network measures are used to predict the behavior of different systems. To be able to investigate how various structures behave and interact we need a wide range of theoretical networks to explore. Both spatial and non-spatial methods exist for generating networks but they are limited in the ability of producing wide range of network structures. We extend an earlier version of a spatial spectral network algorithm to generate a large variety of networks across almost all the theoretical spectra of the following network measures: average clustering coefficient, degree assortativity, fragmentation index, and mean degree. We compare this extended spatial spectral network-generating algorithm with a non-spatial algorithm regarding their ability to create networks with different structures and network measures. The spatial spectral network-generating algorithm can generate networks over a much broader scale than the non-spatial and other known network algorithms. To exemplify the ability to regenerate real networks, we regenerate networks with structures similar to two real Swedish swine transport networks. Results show that the spatial algorithm is an appropriate model with correlation coefficients at 0.99. This novel algorithm can even create negative assortativity and managed to achieve assortativity values that spans over almost the entire theoretical range.     

Does the size of small objects influence chemical reactivity in living systems?

Previous theoretical works showed that chemical reactions in micro- and nano-droplets, bubbles and solid particles were strongly affected by their confinement. In particular, the smallness of the systems leads to high internal pressure compared to the external pressure, which then significantly modifies the values of chemical equilibrium and kinetic constants. In addition, surface tension or surface stress, reactional dilatation and surface charge play also a major role on the chemical reactivity. As living systems are also made of very complex dispersed subsystems, i.e. organelles, it seemed obvious to illustrate our theory by some biological actual examples encountered in pulmonary alveolae, in vacuolae and in medical applications, such as dissolution of gallstones.