Evaluation of a four-drug, three-antibiotic, nonbismuth-containing "concomitant" therapy as first-line Helicobacter pylori eradication regimen in Greece

Background: The eradication rates of Helicobacter pylori (H. pylori) with standard treatments are decreasing worldwide as in Greece. Studies with new antibiotic combinations are needed to find better methods of eradication. Therefore, the aim of this study was to evaluate efficacy and tolerability of a 10‐day, four‐drug, three‐antibiotic, nonbismuth–containing concomitant regimen. Materials and Methods: This is a prospective, open‐label, multicenter study that included 131 patients infected with H. pylori. All patients were diagnosed with peptic ulcer disease or nonulcer dyspepsia by endoscopy. H. pylori infection was established by at least two positive tests among rapid urease test, gastric histology, and ¹³C‐urea breath test. For 10 days, all patients received esomeprazole 40 mg, amoxycillin 1000 mg, clarithromycin 500 mg, and metronidazole 500 mg, all b.d. eradication was assessed with ¹³C urea breath test 8 weeks after the start of treatment. Intention‐to‐treat and per‐protocol eradication rates were determined. Results: One hundred and twenty‐seven of the 131 patients completed the study. At intention‐to‐treat analysis, the eradication rate was 91.6% (95% confidence interval (CI), 85.5–95.7%). For the per‐protocol analysis, the eradication rate was 94.5% (95% CI, 89–97.8%). Adverse events were noted in 42 of 131 (32.1%); drug compliance was excellent with 96.9% of the patients taking more than 90% of the prescribed medication. Conclusion: A 10‐day concomitant regimen appears to be an effective, safe, and well‐tolerated treatment option for first‐line H. pylori eradication in Greece.     

Comparison of the Bacterial Composition and Structure in Symptomatic and Asymptomatic Endodontic Infections Associated with Root-Filled Teeth Using Pyrosequencing

Residual microorganisms and/or re-infections are a major cause for root canal therapy failure. Understanding of the bacterial content could improve treatment protocols. Fifty samples from 25 symptomatic and 25 asymptomatic previously root-filled teeth were collected from Sudanese patients with periradicular lesions. Amplified 16S rRNA gene (V1-V2) variable regions were subjected to pyrosequencing (FLX 454) to determine the bacterial profile. Obtained quality-controlled sequences from forty samples were classified into 741 operational taxonomic units (OTUs) at 3% dissimilarity, 525 at 5% dissimilarity and 297 at 10% dissimilarity, approximately corresponding to species-, genus- and class levels. The most abundant phyla were: Firmicutes (29.9%), Proteobacteria (26.1%), Actinobacteria (22.72%), Bacteroidetes (13.31%) and Fusobacteria (4.55%). Symptomatic patients had more Firmicutes and Fusobacteria than asymptomatic patients, while asymptomatic patients showed more Proteobacteria and Actinobacteria. Interaction of disease status and age was observed by two-way ANOSIM. Canonical correspondence analysis for age, tooth restoration and disease status showed a correlation of disease status with the composition and prevalence of different members of the microbial community. The pyrosequencing analysis revealed a distinctly higher diversity of the microbiota compared to earlier reports. The comparison of symptomatic and asymptomatic patients showed a clear association of the composition of the bacterial community with the presence and absence of symptoms in conjunction with the patients’ age.     

Microscope-Based Imaging Platform for Large-Scale Analysis of Oral Biofilms

A microscopic method for noninvasively monitoring oral biofilms at the macroscale was developed to describe the spatial distribution of biofilms of different bacterial composition on bovine enamel surfaces (BES). For this purpose, oral biofilm was grown in situ on BES that were fixed at approximal sites of individual upper jaw acrylic devices worn by a volunteer for 3 or 5 days. Eubacteria, Streptococcus spp., and Fusobacterium nucleatum were stained using specific fluorescence in situ hybridization (FISH) probes. The resulting fluorescence signals were subsequently tested by confocal laser scanning microscopy (CLSM) and monitored by an automated wide-field microscope-based imaging platform (Scan∧R). Automated image processing and data analysis were conducted by microscope-associated software and followed by statistical evaluation of the results. The full segmentation of biofilm images revealed a random distribution of bacteria across the entire area of the enamel surfaces examined. Significant differences in the composition of the microflora were recorded across individual as well as between different enamel surfaces varying from sparsely colonized (47.26%) after 3 days to almost full surface coverage (84.45%) after 5 days. The enamel plates that were positioned at the back or in the middle of the oral cavity were found to be more suitable for the examination of biofilms up to 3 days old. In conclusion, automated microscopy combined with the use of FISH can enable the efficient visualization and meaningful quantification of bacterial composition over the entire sample surface. Due to the possibility of automation, Scan∧R overcomes the technical limitations of conventional CLSM.     

Cancer associated mutations in Sec61γ alter the permeability of the ER translocase

Translocation of secretory and integral membrane proteins across or into the ER membrane occurs via the Sec61 complex, a heterotrimeric protein complex possessing two essential sub-units, Sec61p/Sec61α and Sss1p/Sec61γ and the non-essential Sbh1p/Sec61β subunit. In addition to forming a protein conducting channel, the Sec61 complex maintains the ER permeability barrier, preventing flow of molecules and ions. Loss of Sec61 integrity is detrimental and implicated in the progression of disease. The Sss1p/Sec61γ C-terminus is juxtaposed to the key gating module of Sec61p/Sec61α and is important for gating the translocon. Inspection of the cancer genome database identifies six mutations in highly conserved amino acids of Sec61γ/Sss1p. We identify that five out of the six mutations identified affect gating of the ER translocon, albeit with varying strength. Together, we find that mutations in Sec61γ that arise in malignant cells result in altered translocon gating dynamics, this offers the potential for the translocon to represent a target in co-therapy for cancer treatment.     

Lactose uptake rate by kefir yeast using C-labelled lactose to explain kinetic aspects in its fermentation

Τhe present work shows the relation between kefir fermentation ability and carbohydrate uptake rate. This was examined in a model system containing kefir co-culture and lactose in order to study fermentation induced by yeasts and bacteria at the same time. Lactose uptake rate was recorded by using ¹⁴C-labelled lactose. The effect of lactose, cell concentration and pH on lactose fermentation was examined. Results have shown increase of lactose uptake rate at lower cell concentrations and specifically the maximum values of lactose uptake rate were obtained at 30 °C, 5.5 pH value and initial lactose and cell concentration 10% w/v and 16 g/L, respectively. Likewise, lighten that the increase of the fermentation rate by immobilized cells can be attributed also, in addition to other factors, to lower cell concentration on the surface of the support or of the promoter. Besides, it is shown that the effect of pH value on the biochemical reactions, carried out by intracellular enzymes can be attributed, except to the effect of pH on enzyme ability, in addition to the effect of pH on carbohydrate uptake rate.     

Comprehensive Analysis of Secondary Dental Root Canal Infections: A Combination of Culture and Culture-Independent Approaches Reveals New Insights

Persistence of microorganisms or reinfections are the main reasons for failure of root canal therapy. Very few studies to date have included culture-independent methods to assess the microbiota, including non-cultivable microorganisms. The aim of this study was to combine culture methods with culture-independent cloning methods to analyze the microbial flora of root-filled teeth with periradicular lesions. Twenty-one samples from previously root-filled teeth were collected from patients with periradicular lesions. Microorganisms were cultivated, isolated and biochemically identified. In addition, ribosomal DNA of bacteria, fungi and archaea derived from the same samples was amplified and the PCR products were used to construct clone libraries. DNA of selected clones was sequenced and microbial species were identified, comparing the sequences with public databases. Microorganisms were found in 12 samples with culture-dependent and -independent methods combined. The number of bacterial species ranged from 1 to 12 in one sample. The majority of the 26 taxa belonged to the phylum Firmicutes (14 taxa), followed by Actinobacteria, Proteobacteria and Bacteroidetes. One sample was positive for fungi, and archaea could not be detected. The results obtained with both methods differed. The cloning technique detected several as-yet-uncultivated taxa. Using a combination of both methods 13 taxa were detected that had not been found in root-filled teeth so far. Enterococcus faecalis was only detected in two samples using culture methods. Combining the culture-dependent and –independent approaches revealed new candidate endodontic pathogens and a high diversity of the microbial flora in root-filled teeth with periradicular lesions. Both methods yielded differing results, emphasizing the benefit of combined methods for the detection of the actual microbial diversity in apical periodontitis.     

Metal Phytoremediation by the Halophyte Limoniastrum monopetalum (L.) Boiss: Two Contrasting Ecotypes

The phytoremediation potential of the halophyte Limoniastrum monopetalum for the removal of Cd and Pb from polluted sites is assessed in this work. Two pot experiments were conducted; the first with wild L. monopetalum grown on soil polluted with Cd and Pb irrigated at different salinities, and the second with commonly cultivated ornamental L. monopetalum grown on soil polluted with Cd irrigated also at different salinities. The data revealed that wild L. monopetalum is a Cd and Pb tolerant plant able to accumulate at least 100 ppm of cadmium in its shoots without showing any significant decrease in terms of biomass production, chlorophyll content or water content suggesting that it could be an accumulator of Cd. Pb above-ground accumulation was kept at low levels with the majority of Pb localized in the roots. On the other hand, contrasting results were obtained for ornamental L. monopetalum which although it was found to be also Cd tolerant, Cd accumulation in its tissues was kept at significantly lower levels especially compared to that of the wild ecotype. In addition for ornamental L. monopetalum salinity did not have a positive effect on Cd accumulation and translocation as observed in the wild type and in other halophytes. Analysis of the salt excretion crystals on the leaf surface confirmed that wild and cultivated ornamental L. monopetalum excrete cadmium and lead through their salt glands as a possible metal detoxification mechanism, although the amount excreted by the ornamental L. monopetalum is significantly less.