Helicobacter pylori infection reduces the risk of Barrett's esophagus: A meta‐analysis and systematic review

Introduction

The prevalence of Helicobacter pylori infection (HPI) has been decreasing in developed countries, with an increasing prevalence of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) at the same time. The aim of our meta‐analysis was to quantify the risk of BE in the context of HPI.

Methods

A systematic search was conducted in 3 databases for studies on BE with data on prevalence of HPI from inception until December 2016. Odds ratios for BE in HPI were calculated by the random effects model with subgroup analyses for geographical location, presence of dysplasia in BE, and length of the BE segment.

Results

Seventy‐two studies were included in the meta‐analysis, including 84 717 BE cases and 390 749 controls. The overall analysis showed that HPI reduces the risk of BE; OR = 0.68 (95% CI: 0.58‐0.79, P < .001). Subgroup analyses revealed risk reduction in Asia OR = 0.53 (95% CI: 0.33‐0.84, P = .007), Australia OR = 0.56 (95% CI: 0.39‐0.80, P = .002), Europe OR = 0.77 (95% CI: 0.60‐0.98, P = .035), and North‐America OR = 0.59 (95% CI: 0.47‐0.74, P < .001). The risk was significantly reduced for dysplastic BE, OR = 0.37 (95% CI: 0.26‐0.51, P < .001) for non‐dysplastic BE, OR = 0.51 (95% CI: 0.35‐0.75, P = .001), and for long segment BE, OR = 0.25 (95% CI: 0.11‐0.59, P = .001) in case of HPI.

Conclusions

This extensive meta‐analysis provides additional evidence that HPI is associated with reduced risk of BE. Subgroup analyses confirmed that this risk reduction is independent of geographical location. HPI is associated with significantly lower risk of dysplastic, non‐dysplastic, and long segment BE.     

Isolation and characterisation of the Photosystem two reaction centre complex from a double mutant of Chlamydomonas reinhardtii

A rapid procedure has been developed for the isolation of the photosystem two reaction centre complex (PS II RC) from a double mutant of Chlamydomonas reinhardtii, F54-14, which lacks the Photosystem one complex and the chloroplast ATPase. Thylakoid membranes are solubilised with 1.5% (w/v) Triton X-100 and the PS II RC purified by anion-exchange chromatography using TSK DEAE-650(S) (Merck). The complex has a pigment stoichiometry of approximately six chlorophyll a: two pheophytin a: one cytochrome b-559: one to two -carotene. It photoaccumulates reduced pheophytin and oxidised P680 in the presence of sodium dithionite and silicomolybdate, respectively. Immunoblotting experiments have confirmed the presence of the D1 and D2 polypeptides in this complex. The -subunit of cytochrome b-559 was identified by N-terminal sequencing. Comparison of the complex with the PS II RC from pea using SDS-polyacrylamide gel electrophoresis showed that their polypeptide compositions were similar. However, the -subunit of cytochrome b-559 from C. reinhardtii has a lower apparent molecular weight than the pea counterpart whereas the -subunit is larger.Abbreviations DM n-dodecyl -d-maltoside - RC reaction centre - SiMo silicomolybdate, SiMo₁₂O₄₀ ^4– - TAP Tris-acetate-phosphate     

Rapid separation of bacteria from blood—review and outlook

The high morbidity and mortality rate of bloodstream infections involving antibiotic‐resistant bacteria necessitate a rapid identification of the infectious organism and its resistance profile. Traditional methods based on culturing the blood typically require at least 24 h, and genetic amplification by PCR in the presence of blood components has been problematic. The rapid separation of bacteria from blood would facilitate their genetic identification by PCR or other methods so that the proper antibiotic regimen can quickly be selected for the septic patient. Microfluidic systems that separate bacteria from whole blood have been developed, but these are designed to process only microliter quantities of whole blood or only highly diluted blood. However, symptoms of clinical blood infections can be manifest with bacterial burdens perhaps as low as 10 CFU/mL, and thus milliliter quantities of blood must be processed to collect enough bacteria for reliable genetic analysis. This review considers the advantages and shortcomings of various methods to separate bacteria from blood, with emphasis on techniques that can be done in less than 10 min on milliliter‐quantities of whole blood. These techniques include filtration, screening, centrifugation, sedimentation, hydrodynamic focusing, chemical capture on surfaces or beads, field‐flow fractionation, and dielectrophoresis. Techniques with the most promise include screening, sedimentation, and magnetic bead capture, as they allow large quantities of blood to be processed quickly. Some microfluidic techniques can be scaled up. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:823–839, 2016     

The intestinal mast cell response to Trichinella spiralis infection in mast cell-deficient w/wv mice

The intestinal mast cell response and lymphoblast activity, as measured by the incorporation of 3H-thymidine into mesenteric lymph node cells (MLN) of WBB6F1-w/wv(w/wv) mice, their normal congenic littermates (+/+) and C57BL/6J mice, were compared after infection with Trichinella spiralis. Marked and similar blast cell activity and an increase in number of cells were observed in the MLN of infected w/wv and C57BL/6J mice 7 and 15 days P.I. In contrast to C57BL/6J mice, primary T. spiralis intestinal infections were prolonged in w/wv mice and more muscle larvae were recovered from w/wv mice 29 days post-infection. In C57BL/6J mice mucosal mast cell (MMC) numbers increased on day 7 P.I. whereas in w/wv mice these cells did not increase significantly until day 15 post-infection, reaching a peak on day 22. In w/wv mice, the response to secondary infection as determined by an accelerated expulsion of adult worms did not occur until day 11 postchallenge whereas in +/+ and C57BL/6J mice worm expulsion was nearly complete at that time. In both primary and secondary infections, the MMC numbers in w/wv mice were significantly lower than in C57BL/6J or +/+ mice. The results suggest that prolongation of T. spiralis infection in w/wv mice is associated with delayed appearance of mast cells in the intestinal mucosa which may reflect slow generation of the intestinal inflammatory response.     

Studies on the interaction between nanodiamond and human hemoglobin by surface tension measurement and spectroscopy methods

In this study, a novel method to probe molecular interactions and binding of human hemoglobin (Hb) with nanodiamond (ND) was introduced based on the surface tension measurement. This method complements conventional techniques, which are basically done by zeta potential and dynamic light scattering (DLS) measurements, near and far circular dichroism (CD) spectroscopy, intrinsic and extrinsic fluorescence spectroscopy. Addition of ND to Hb solution increased the surface tension value of Hb–ND complex relative to those of Hb and ND molecules. The zeta potential values reveled that Hb and ND provide identical charge distribution at pH 7.5. DLS measurements demonstrated that Hb, ND, and ND–Hb complex have hydrodynamic radiuses of 98.37 ± 4.57, 122.07 ± 7.88 nm and 62.27 ± 3.70 at pH of 7.5 respectively. Far and near UV-CD results indicated the loss of α-helix structure and conformational changes of Hb, respectively. Intrinsic fluorescence data demonstrated that the fluorescence quenching of Hb by ND was the result of the static quenching. The hydrophobic interaction plays a pivotal role in the interaction of ND with Hb. Fluorescence intensity changes over time revealed conformational change of Hb continues after the mixing of the components (Hb–ND) till 15 min, which is indicative of the denaturation of the Hb relative to the protein control. Extrinsic fluorescence data showed a considerable enhancement of the ANS fluorescence intensity of Hb–ND system relative to the Hb till 60 nM of ND, likely persuaded by greater exposure of nonpolar residues of Hb hydrophobic pocket. The remarkable decrease in T_m value of Hb in Hb–ND complex exhibits interaction of Hb with ND conducts to conformational changes of Hb. This study offers consequential discrimination into the interaction of ND with proteins, which may be of significance for further appeal of these nanoparticles in biotechnology prosecution.     

RNA interference-mediated inhibition of Semliki Forest virus replication in mammalian cells

RNA interference (RNAi) has recently shown promise as a mode of inhibition of slowly replicating viruses causing chronic diseases such as hepatitis C. To investigate whether RNAi is also feasible for rapidly growing RNA viruses such as alphaviruses, we tested the ability of expressed short hairpin RNAs (shRNAs) to inhibit the Semliki Forest virus (SFV), a rapidly replicating positive-strand RNA virus. Plasmids expressing shRNAs targeting SFV target sequences under the control of a human U6 promoter were introduced into BHK-21 cells. The targets included sequences encoding nonstructural (nsP1, 2, and 4) and structural (capsid) proteins as well as nonviral sequences serving as control targets. Twenty-four to 48 hours following transfection with shRNA plasmids, the cells were infected with replication-competent or replication-deficient recombinant SFV expressing green fluorescent protein (GFP) at a multiplicity of infection (MOI) of approximately 5. Viral replication was monitored by fluorescence microscopy and flow cytometry. Specific and marked reduction of viral replication was observed with shRNAs targeting nsP1 and nsP4. The degree of inhibition of the replication-deficient SFV was >or=70% over a 5-day period, a level similar to the transfection efficiency, suggesting complete inhibition of nonreplicating virus in the transfected cell population. However, only nsP1 shRNA was inhibitory against replication-competent SFV (approximately 30%-50% reduction), and this effect was transient. No inhibition was observed with control shRNAs. In contrast to the recent success of RNAi approaches for slowly growing viruses, these results illustrate the challenge of inhibiting very rapidly replicating RNA viruses by RNAi. However, the addition of RNAi approaches to other antiviral modalities might improve the response to acute infections.     

Evaluation of antifungal activity of carbonate and bicarbonate salts alone or in combination with biocontrol agents in control of citrus green mold

The aim of this research was to determine if the attacks of green mold on orange could be reduced by edible salts alone or in combination with biocontrol agent. For this purpose toxicity to Pantoea digitatum and practical use of sodium carbonate (SC), sodium bicarbonate (SBC) and potassium carbonate, and potassium bicarbonate alone or in combination with antagonistic bacteria (Pseudomonas fluorescens isolate PN, Bacillus subtilis isolate VHN, Pantoea agglomerans isolate CA) to control green mold were determined. All were fungistatic. SC and SBC were equal and superior to the other salts for control of green mold on oranges inoculated 6h before treatment and were chosen for subsequent trails under cold storage conditions. The biocontrol agents were found completely tolerant to 3% sodium bicarbonate and sodium carbonate at room temperature; although their culturability was reduced by > 1000-fold after 60 min in 1% other salt solutions. Satisfactory results were also obtained with the combined treatment for control of green mold. A significant increase in biocontrol activity of all isolate was observed when combined with sodium carbonate and sodium bicarbonate. The treatments comprising CA combined with SB was as effective as fungicide treatment. Thus, use of sodium bicarbonate treatment at 3% followed by the antagonist P. agglomerans CA could be an alternative to chemical fungicides for control of green mold on oranges.     

Enhanced regeneration of haploid plantlets from microspores of <Emphasis Type="Italic">Brassica napus</Emphasis> L. using bleomycin,PCIB, and phytohormones

The effects of three periods of incubation (10, 20 and 30 min) at different levels of bleomycin (0, 0.1, 0.2, 0.3, 0.4 and 0.5 μg ml⁻¹), as well as three periods of exposure (12, 24 and 48 h) to different levels of the anti-auxin p-chlorophenoxyisobutyric acid (PCIB), including 1, 2, 3, 4 and 5 mg l⁻¹, on microspore embryogenesis of rapeseed cv. ‘Amica’ were investigated. Microspore embryogenesis was significantly enhanced following 20 min treatment with 0.2 μg ml⁻¹ bleomycin compared with untreated cultures. Highest embryo yield (163 embryos Petri dish⁻¹) was observed with 24 h treatment of 4 mg l⁻¹ PCIB. The highest percentage of secondary embryogenesis was observed on B₅ medium containing 0.15 mg l⁻¹ of gibberellic acid (GA₃) and 0.2 mg l⁻¹ 6-benzyladenine (BA) in 4–6 mm microspore-derived embryos (MDEs). Most callus formed on B₅ medium containing 0.15 mg l⁻¹ GA₃, 0.1 mg l⁻¹ BA and 0.1 mg l⁻¹ indole-3-acetic acid (IAA) when 4–6 mm embryos were used. Regeneration was highest on B₅ medium containing 0.05 mg l⁻¹ GA₃ or 0.1 mg l⁻¹ BA and 0.2 mg l⁻¹ IAA with 2–4 mm embryos. Microspore embryogenesis and plant regeneration could be improved by both bleomycin and PCIB when the appropriate MDE length and phytohormone level were selected.