Is Antrum or Corpus the Best Site for Culture of Helicobacter pylori?

Background Isolating Helicobacter pylori on culture media and performing antibiotic susceptibility testing is potentially the most useful tool for guiding antibiotic therapy, especially when antimicrobial resistance is suspected. The aim of this study was to determine whether the yield of H. pylori culture was related to the site from which the gastric specimen was obtained either before or after therapy.
Methods. Gastric mucosal biopsies from the antrum and the corpus of the stomach were cultured. H. pylori status was determined by histological assessment using the Genta stain.
Results. Fifty-two patients with documented H. pylori infection were studied: Twenty-three were tested before antibiotic therapy and 29 after therapy had failed. In 47 patients (90%), both antral and corpus culture specimens were positive. In 5 patients (10%), only one site was positive, with three false-negative antral and two false negative corpus cultures. The overall sensitivity of culture in detecting H. pylori infection was 95% (95% confidence interval = 89–98%) and was not significantly different for the antrum or corpus, either before or after therapy.
Conclusion. Culture of gastric biopsies from either the antrum or the corpus has an excellent diagnostic yield even in patients who failed antimicrobial therapy.     

Is Helicobacter pylori the cause of dyspepsia?

OBJECTIVE--To determine the association between infection with Helicobacter pylori and dyspepsia. DESIGN--Cross sectional study of dyspeptic subjects and age and sex matched controls identified by a questionnaire survey of all inhabitants aged 20-69. (Endoscopy, histological examination, and microbiological examinations of biopsies from the gastric mucosa were performed blind.) SETTING--Population based survey in Sørreisa, Norway. SUBJECTS--All 782 dyspeptic subjects (excluding those with a previous history of peptic ulcer, gall stones or kidney stones, and coronary heart disease) and controls were offered an endoscopy, of whom 309 dyspeptic subjects and 310 controls attended. MAIN OUTCOME MEASURES--Prevalences of endoscopic and histological diagnoses and of cultures positive for H pylori. RESULTS--A high prevalence of positive cultures, increasing with age, was found in both dyspeptic subjects (48%) and non-dyspeptic controls (36%) (p = 0.004). Positive cultures in both dyspeptic subjects and controls were strongly associated with histological gastritis (70%, 95% confidence interval 65.5 to 85.3; 60%, 52.7 to 67.7, respectively) and peptic ulcer (92%, 61.5 to 99.8; 64.1, 9.4 to 99.2, respectively). Only 3% of subjects with a histologically non-inflamed gastric mucosa had this infection (dyspeptic subjects 2%, 0.2 to 7.0; controls 4%; 1.2 to 8.8). CONCLUSIONS--The relation between dyspeptic symptoms and H pylori is dubious; H pylori seems to have a pathogenetic role in gastritis and may be a contributing factor but not a cause of peptic ulcer.     

The use of fetal bovine serum: ethical or scientific problem?

Fetal bovine serum (FBS) is a common component of animal cell culture media. It is harvested from bovine fetuses taken from pregnant cows during slaughter. FBS is commonly harvested by means of a cardiac puncture without any form of anaesthesia. Fetuses are probably exposed to pain and/or discomfort, so the current practice of fetal blood harvesting is inhumane. Apart from moral concerns, several scientific and technical problems exist with regard to the use of FBS in cell culture. Efforts should be made to reduce the use of FBS or, preferably, to replace it with synthetic alternatives.     

Structural Basis for the Inhibition of Helicobacter pylori α-Carbonic Anhydrase by Sulfonamides

Periplasmic α-carbonic anhydrase of Helicobacter pylori (HpαCA), an oncogenic bacterium in the human stomach, is essential for its acclimation to low pH. It catalyses the conversion of carbon dioxide to bicarbonate using Zn(II) as the cofactor. In H. pylori, Neisseria spp., Brucella suis and Streptococcus pneumoniae this enzyme is the target for sulfonamide antibacterial agents. We present structural analysis correlated with inhibition data, on the complexes of HpαCA with two pharmacological inhibitors of human carbonic anhydrases, acetazolamide and methazolamide. This analysis reveals that two sulfonamide oxygen atoms of the inhibitors are positioned proximal to the putative location of the oxygens of the CO₂ substrate in the Michaelis complex, whilst the zinc-coordinating sulfonamide nitrogen occupies the position of the catalytic water molecule. The structures are consistent with acetazolamide acting as site-directed, nanomolar inhibitors of the enzyme by mimicking its reaction transition state. Additionally, inhibitor binding provides insights into the channel for substrate entry and product exit. This analysis has implications for the structure-based design of inhibitors of bacterial carbonic anhydrases.     

The use of β-galactosidase as a tracer in immunocytochemistry

Summary A new immunocytochemical method using -galactosidase as a tracer is described. The positive staining appears blue on an unstained background. The present method has the high sensitivity and specificity of the immunoperoxidase method and appears to be a practical alternative. The substrate has no carcinogenic activity. Staining is permanent and the sections can be dehydrated and mounted in synthetic media. Enzyme and substrate solutions are stable for several months.     

What is the blood concentration of extracellular vesicles? Implications for the use of extracellular vesicles as blood-borne biomarkers of cancer

Circulating biomarkers have a great potential in diagnosing cancer diseases at early stages, where curative treatment is a realistic possibility. In the recent years, using extracellular vesicles (EVs) derived from blood as biomarkers has gained widespread popularity, mainly because they are thought to be easy to isolate and carry a vast variety of biological cargos that can be analyzed for biomarker purposes. However, our current knowledge on the plasma EV concentration in normophysiological states is sparse. Here, we provide the very first mean estimate of the plasma EV concentration based on values obtained from a thorough literature review. The different estimates obtained from the literature are correlated to the isolation techniques used to obtain them, illustrating how some methodologies may over- or underestimate the plasma EV concentration. We also show that the estimated plasma EV concentration (approximately 10¹⁰ EVs per mL) defines EVs as a minority population compared to other colloidal particles of the systemic circulation, namely the lipoproteins, which are known contaminants in EV isolates and carry biomarker molecules themselves. Lastly, we introduce the possibility of regarding EVs and lipoproteins as a continuum of lipid-containing particles to which biomarker molecules can be associated. Using such a holistic approach, increased strength of plasma-derived cancer biomarkers may soon be revealed.     

The use of self-pollinated progenies as ’in-groups’ for the genetic characterization of cocoa germplasm

Theobroma cacao ) genotypes. Six primers were sufficient to distinguish all but three pairs of the 62 accessions examined. A UPGMA dendrogram was used to provide a measure of the genetic variability between genotypes. The scale was supplied by the inclusion of Theobroma grandiflora as an ’out group’ and also by the use of two contrasting progenies as ’in groups’. The ’in groups’ were obtained from the self-pollination of one plant (SPEC 54.1) known to be highly homozygous and also of a second, highly heterozygous, clone (P 19B). These reference points allowed several documentation errors to be resolved and provided a basis for identifying unwanted or low-priority material. Implications of the work for the routine maintenance of large germplasm collections are briefly discussed. Received: 20 January 1999 / Accepted: 25 May 1999     

Can we use the Shiga-bacteriophage as indicator for a faecal pollution of water?

Summary and conclusions In an important percentage of stools of healthy persons Shiga bacteriophage occurs.The Shiga bacteriophage occurs during some lapse of time in water which has been polluted by human faeces. The Shiga bacteriophage could be ascertained in water by means of the enrichment method ofNyberg.The Shiga bacteriophage method for indicating the pollution of strongly polluted water is as sensitive or sometimes less so than the methods ofEijkman and ofClemesha.For the examination of water in several stages of purification in water works the Shiga bacteriophage method is as sensitive or even more so than the other methods.The Shiga bacteriophage does not act strongly in the self-purification of polluted water.The Shiga bacteriophage may be used as indicator for a faecal pollution of water and this method may be applied along with the other bacteriological methods in water control. It may be advantageous to study more closely its limits and its benefits in the practice of water control     

Experiences with the use of a starter culture in the fermentation of maize for ‘kenkey’ production in Ghana

Controlled fermentation of maize was carried out using six strains of Lactobacillus fermentum and one strain of yeast, Saccharomyces cerevisiae, isolated from traditionally fermented maize dough as starter cultures for inoculum enrichement. The fermentations were monitored by pH, acidity, microbiological analysis and taste panel evaluation of two products, kenkey and koko, prepared from the fermented doughs. The strains of L. fermentum used as starter culture dominated the microflora during fermentation and in most inoculated doughs the required pH was attained by 24 h instead of 48 h of dough fermentation. Higher contents of lactic acid bacteria and yeasts were observed in inoculated doughs at the initial stages of fermentation but the spontaneously fermented doughs attained similar lactic acid bacteria and yeasts counts by 24 h of dough fermentation. The organoleptic quality of kenkey and koko prepared from doughs fermented with starter culture for 48 h was not significantly different from the traditional products. Kenkey prepared from doughs fermented for 24 h with starter culture were found to be unacceptable by the taste panel although similarly produced koko was acceptable.The authors are with the Food Research Institute, Council for Scientific and Industrial Research, P.O Box M 20. Accra, Ghana.     

The use of β-propiolactone for the sterilization of heat-labile materials

A short literature survey on chemical sterilization with -propiolactone is given. The auto-inactivatio 1 of this compound in aqueous solution appears to be one of its main advantages.Time-kill studies have been carried out with bacterial cells and spores, and with fungal spores. The compatibility of BPL with textiles and plastics was also studied to some extent. It is concluded that heat-sensitive materials can be sterilized with a 1.0% aqueous solution of BPL within one hour at room temperature. The compatibility of BPL with the materials studied does not appear to offer serious problems.     

A Variable Gene in a Conserved Region of the Helicobacter pylori Genome: Isotopic Gene Replacement or Rapid Evolution?

The present study concerns the identification of a novel coding sequence in a region of the Helicobacter pylori genome, located between JHP1069/HP1141 and JHP1071/HP1143 according to the numbering of the J99 and 26695 reference strains, respectively, and spanning three different coding DNA sequences (CDSs). The CDSs located at the centre of this locus were highly polymorphic, as determined by the analysis of 24 European isolates, 3 Asian, and 3 African isolates. Phylogenetic and molecular evolutionary analyses showed that the CDSs were not restricted to the geographical origin of the strains. Despite a very high variability observed in the deduced protein sequences, significant similarity was observed, always with the same protein families, i.e. ATPase and bacteriophage receptor/invasion proteins. Although this variability could be explained by isotopic gene replacement via horizontal transfer of a gene with the same function but coming from a variety of sources, it seems more likely that the very high sequence variation observed at this locus is the result of a strong selection pressure exerted on the corresponding gene product. The CDSs identified in the present study could be used as strain specific markers.     

Phosphatidylethanolamine of Helicobacter pylori functions as a steroid-binding lipid in the assimilation of free cholesterol and 3β-hydroxl steroids into the bacterial cell membrane

One of the unique features of Helicobacter pylori is its ability to assimilate free-cholesterol (FC) into its membranes. Via FC assimilation, H. pylori strengthens the membrane lipid barrier and/or evades the host immune system. No previous studies, however, have investigated the FC uptake mechanisms of the H. pylori cell. Phosphatidylethanolamine (PE) is the most prevalent lipid component of bacteria, including H. pylori, but the function of PE remains unclear. We were therefore interested in H. pylori PE (HpPE) and investigated the interaction of its PE with cholesterols. The PE isolated from H. pylori underwent a unique molecular interaction with FC, cholesterol ester (CE), and 2,6-di-O-methyl-β-cyclodextrin (dMβCD), a sterol solubilizer. HpPE interacted not only with the FC molecule, but also with the FC-dMβCD inclusion complex. In contrast, Escherichia coli PE (EcPE), prepared as a reference PE, seemed to bind only FC, and only via a hydrophobic interaction, without binding dMβCD. HpPE was clearly more potent than EcPE in binding FC. Intriguingly, HpPE had a negligible affinity for CE, while EcPE had a high affinity for CE, comparable to its affinity for FC. Further, HpPE interacted with 3β-OH steroids, pregnenolone and dehydroepiandrosterone, in the absence of dMβCD. Gas chromatogram-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) analyses revealed that the fatty acid compositions of HpPE were quite distinct from those of EcPE, and the C(14:0) fatty acid in the HpPE molecule was found to be significant in binding FC selectively. These results indicate that PE is a key candidate of nonesterified steroid-binding lipids in H. pylori.     

The quest for a vaccine against Helicobacter pylori: how to move from mouse to man?

Several lines of evidence from experimental animal models of infection have clearly demonstrated the feasibility of a prophylactic and therapeutic vaccine against Helicobacter pylori. However, comparatively few clinical studies have been carried out to evaluate whether the positive results obtained in animals can be reproduced in humans. The preliminary results obtained with single component, mucosally delivered vaccines have shown very limited results thus far. Very good immunogenicity and safety profiles are now being obtained with parenterally delivered, aluminium hydroxide-adjuvanted multicomponent candidate vaccines. For sure, better vaccine formulations, better antigen preparation(s), better adjuvants, and better delivery systems have to be designed and tested for safety and immunogenicity. These studies are also needed for deciphering those aspects of the effector immune responses that correlate with protection against H. pylori infection and disease.     

Is there seasonal periodicity in the prevalence of Helicobacter pylori?

The objective of the present study was to evaluate seasonal periodicity in the prevalence of Helicobacter pylori. A prospective study was performed on 1076 consecutive patients who were investigated in our hospital over a 3-year span because of epigastric complaints. Our findings indicate a significant accumulation of positive Helicobacter pylori tests in October. Gastric acidity, gender, and age did not influence Helicobacter pylori infection significantly. There was no significant correlation between potential seasonal influence on the diagnosis of ulcer disease and the seasonal fluctuation of Helicobacter pylori infection. The seasonality was confirmed by cosinor analysis for the absolute frequencies of H. pylori infections and also for the number of cases positive for H. pylori per number of presenting patients per month. A seasonal concept of a sensitivity threshold for positive Helicobacter pylori testing is introduced, taking into account such factors as immune system, nutrition, and medication status.     

The first 5 years of Helicobacter pylori research—With an emphasis on the United Kingdom

In the 1970s, 1% of the UK population consulted with dyspepsia; fiberoptic gastroscopy allowed biopsy specimens under direct vision enabling systematic histopathology. Steer et al described clusters of flagellated bacteria closely apposed to the gastric epithelium associated with chronic active gastritis. The first UK series of Helicobacter pylori following Marshall's 1983 visit to Worcester confirmed the association of H. pylori with gastritis. UK researchers completed much early helicobacter research as there were many UK campylobacteriologists. Steer and Newell proved the Campylobacter-like organisms grown on culture were the same as those seen in the gastric mucosa using antiserum raised by inoculating rabbits with H. pylori from cultures. Wyatt, Rathbone, and others showed a strong correlation between the number of organisms, type and severity of acute gastritis, immunological response, and bacterial adhesion similar to enteropathogenic E coli. Seroprevalence studies indicated H. pylori increased with age. Histopathologists also showed peptic duodenitis was in effect “gastritis in the duodenum” caused by H. pylori, unifying its role in the pathogenesis of both gastritis and duodenal ulceration. These bacteria were initially called Campylobacter pyloridis and then C. pylori. However, electron microscopy suggested that the bacteria were not campylobacters, and this was supported by differences in fatty acid and polyacrylamide electrophoresis profiles. In-vitro tests indicated that H. pylori was susceptible to penicillins, erythromycin, and quinolones, but not trimethoprim or cefsulodin allowing development of selective media for culture. Monotherapy with erythromycin ethylsuccinate was ineffective, and patients treated with bismuth subsalicylate initially responded with clearance of H. pylori and the associated gastritis, but then many relapsed. Thus, pharmacokinetic and treatment studies were important to direct suitable dual and triple treatments. Work optimized serology, and the rapid biopsy urease and urea breath tests. The link between H.pylori and gastric cancer was established in large seroprevalence studies, and H. pylori test and treat for dyspepsia became routine.     

Different Expression of Helicobacter pylori Gastritis in Children: Evidence for a Specific Pediatric Disease?

Background Infection with Helicobacter pylori causes active chronic gastritis. Once the infection is acquired, gastritis will persist for almost the rest of one's life. To date, very few data are available on H. pylori gastritis in relation to age. Therefore, we attempted to inestigate whether H. pylori gastritis in children exhibits features different from H. pylori gastritis in adults of two different age groups. Materials and Methods. Fifty consecutive children with a median age of 11 years (range, 3–18 years) were compared with two groups of 50 adult patients, one group with a median age of 43 (range, 19–56 years) and another group with a median age of 70 years (range, 59–86 years). All patients had H. pylori gastritis unrelated to active peptic ulcer disease. Two biopsy specimens were taken from the antrum and two from the corpus, and the following gastritis parameters were evaluated: degree and activity of gastritis, H. pylori colonization, replacement of foveolar epithelium by regenerative epithelium, mucous depletion, presence of atrophic gastritis with intestinal metaplasia, and presence of lymphoid follicles. Results. Degree and activity of gastritis, extent of H. pylori colonization, degree of replacement by regenerative epithelium, extent of mucous depletion, degree of atrophic gastritis with intestinal metaplasia, and the presence of lymphoid follicles in the antrum, as well as the presence of lymphoid follicles in the corpus differed significantly (chi-square test: p < .05). All these differences—except the once frequent occurrence of atrophic gastritis with intestinal metaplasia in adults—were attributable to a higher expression of these gastritis parameters in children. Conclusions. We conclude that H. pylori gastritis, particularly in the antrum, is more severely expressed in childhood. One reason for this might be a child-specific immune response to an infection with H. pylori. Alternatively, infection may represent a pediatric disease characterized by a nonatrophic, highly expressed form of gastritis, which changes its appearance once the host becomes adapted over time.