Human migration

Helicobacter pylori strains from different geographic areas exhibit clear phylogeographical differentiation. The genotype of the virulence genes is useful as a tool to track human migration utilizing the high genetic diversity and frequent recombination between different H. pylori strains. Using combinations of the virulence genes, five major groups have been defined according to geographical associations. Multilocus sequence typing (MLST) analysis using seven housekeeping genes also are widely used markers for genomic diversity. It was revealed that seven modern population types of H. pylori which derived from six ancestral populations provide more detailed information on human migration than does the analysis of human genetics. Although approaches by MLST and virulence factors are effective, these methods focus on a small number of genes and may miss information conveyed by the rest of the genome. Genome-wide analyses using DNA microarray or whole-genome sequencing technology give a broad view on the genome of H. pylori. In particular, next-generation sequencers, which can read DNA sequences in less time and at lower costs than Sanger sequencing, enabled us to efficiently investigate not only the evolution of H. pylori, but also novel virulence factors and genomic changes related to drug resistance. © Springer Japan 2016

Role of vacuolating cytotoxin A in Helicobacter pylori infection and its impact on gastric pathogenesis

causes, via the influence of several virulence factors, persistent infection of the stomach, which leads to severe complications. Vacuolating cytotoxin A (VacA) is observed in almost all clinical strains of H. pylori; however, only some strains produce the toxigenic and pathogenic VacA, which is influenced by the gene sequence variations. VacA exerts its action by causing cell vacuolation and apoptosis. We performed a PubMed search to review the latest literatures published in English language. Areas covered Articles regarding H. pylori VacA and its genotypes, architecture, internalization, and role in gastric infection and pathogenicity are reviewed. We included the search for recently published literature until January 2020. Expert opinion H. pylori VacA plays a crucial role in severe gastric pathogenicity. In addition, VacA mediated in vivo bacterial survival leads to persistent infection and an enhanced bacterial evasion from the action of antibiotics and the innate host defense system, which leads to drug evasion. VacA as a co-stimulator for the CagA phosphorylation may exert a synergistic effect playing an important role in the CagA-mediated pathogenicity

Management of Helicobacter pylori

Meta-analysis has shown that successful Helicobacter pylori eradication therapy improved atrophic gastritis and intestinal metaplasia. Moreover, successful eradication therapy against atrophic gastritis has led to the suppression of the incidence of metachronous gastric cancer. Thus, the Japanese Society for Helicobacter Research concluded that all ‘H. pylori-infected persons’ should be considered for eradication therapy, irrespective of any background diseases. Successful eradication can prevent transmission of this bacterium, and recent publications show that curing H. pylori infection seems to reduce the risk of gastric cancer

Studies on the Mechanism of Bile Pigment Formation in Vivo. III. On the Transition of Biliverdin, and Bilirubin in the Bile of Rabbits.

1. In the bile of rabbits, the metabolisms of biliverdin and bilirubin are in a solucible state, and which have a ratio of 2: 1 in normal animals. 2. In the production of biliverdin, the liver, especially the parenchyma of the liver has a very important role, while that of the reticulo-endothelial system is rather minor. However, in the case of glucose administration, the reduction of bilirubin from biliverdin is performed in the reticulo-endothelial system, thus conferring an important part of this system. 3. The production of bilirubin is performed primarily extrahepatically, and the participation of the extrahepatical reticuloendothelial system is of a conservative nature, thus denying us any willingness to agree to the theory of bilirubin production in the reticulo-endothelial system. 4. On administration of hemolysed blood, bile pigments in bile demonstrate a remarkable increase, while as compared when injected into the auricle veins in cases of administration through the portal vein a decline in the functions of the liver reticulo-endothelial system is seen, causing a decrease in biliverdin amount. In the former modus of administration, an occasional stimulation of the liver reticulo- endothelial system is seen, causing reduction of biliverdin to bilirubin. 5. Concluding from these facts, biliverdin in rabbit bile occupies the role of an intermediate product in the production and metabolism of bilirubin.</p

Editorial: The Role of Mobile Genetic Elements in Bacterial Evolution and Their Adaptability

info:eu-repo/semantics/publishedVersio

<原著>肝右葉切除における短肝静脈, 右肝静脈処理のための前方アプローチ

A simple procedure of right hepatic lobectomy for bulky liver tumors is proposed. The procedure is named "Anterior approach", which is characterized by transection of hepatic parenchyma without mobilization and rotation of the right hepatic lobe. The transection directly reaches the ventral surface of the retrohepatic inferior vena cava first at the portion of caudate process. The hepatic parenchymal transection proceeds from ventral to dorsal and from caudal to cranial. Several dorsal short hepatic veins are severed on the ventral surface of the IVC and the right hepatic vein is finally severed from inside. This method enables the minimization of operative stress and is especially useful for cases with a huge tumor in the right hepatic lobe which invades the diaphragm or thoraco-abdominal wall.巨大肝腫瘍に対する合理的な肝右葉切除法としての前方アプローチを紹介する. 肝右葉切除の標準手技として, 右葉の授動と脱転がある. これは肝の右側から, 肝部下大静脈に注ぐ短肝静脈や右肝静脈の剥離と切離を行う方法であるが, 後区域や右葉全体を占める巨大肝腫瘍の場合には, それらの手技は困難なことが多く, また腫瘍の破裂をきたす恐れもあり危険を伴う. 前方アプローチは, 右葉の脱転を行わずに直接肝実質を切離して, 肝部下大静脈腹側面に到達し, 尾状葉突起から頭側に向かつて肝実質の離断を進める方法である. 肝部下大静脈腹側面に注ぐ短肝静脈を, 順次肝離断面側から剥離処理し, 最後に右肝静脈の離断も同様に行う. 横隔膜浸潤, 胸壁, 腹壁浸潤がある場合には, 肝切離が終了してから合併切除として最後に行う. また本法は, 脱転による残存肝の阻血, 門脈血液鬱滞を回避出来る利点があり, 肝ミトコンドリアの酸化還元状態を反映する動脈血中ケトン体比(AKBR)の術中低下も軽微であることが判明しており, 手術侵襲の点からみても有用である前方アプローチの良い適応は, 1)後区域, 又は右葉全体を占拠するような巨大肝腫瘍の場合, 2)腫蕩が右横隔膜, 胸壁, 腹壁に浸潤している場合, 3)右葉の腫瘍の下大静脈への浸潤が疑われ, 下大静脈合併切除の要否を判定する場合, 4)肝障害のために右葉切除を行うには機能的予備力の点で不安がある場合, などである

Role of Vonoprazan in Helicobacter pylori Eradication Therapy in Japan

Complete eradication of Helicobacter pylori is important for preventing the development of gastric cancer. The outcome of H. pylori eradication therapy is mainly dependent on bacterial susceptibility to antimicrobial agents and potent neutralization of intragastric pH across 24 h, especially when using acid-sensitive antimicrobial agents such as clarithromycin (CLR), amoxicillin and sitafloxacin. However, conventional regimens comprising twice-daily doses (bid) of proton pump inhibitors (PPIs) are generally insufficient for maintaining the required gastric acid secretion for 24 h for successful eradication in all H. pylori-positive patients. Further, the increasing prevalence of CLR-resistant strains with each year has led to a decrease in eradication rates of first-line PPI- and CLR-containing therapies in developed countries, including Japan. In 2015, the potassium-competitive acid blocker vonoprazan (VPZ) became clinically available in Japan. VPZ competitively inhibits H+/K+-ATPase activity more potently than PPIs (e.g., omeprazole, lansoprazole, rabeprazole, pantoprazole, and esomeprazole). Therefore, a VPZ-containing H. pylori eradication regimen is expected to increase the eradication rate compared with conventional regimens containing a standard dose of PPI. In fact, a recent meta-analysis that investigated the efficacy of first-line eradication therapy showed that a VPZ-containing regimen achieved a higher eradication rate than a PPI-containing regimen. While the Maastricht V/Florence Consensus Report recommends selecting a bismuth or non-bismuth quadruple therapy and concomitant therapy for patients living in areas with high prevalence of CLR resistance, a VPZ-containing regimen demonstrates effectiveness for patients infected with CLR-resistant strains and patients living in areas where the prevalence of CLR-resistant strains is &gt;15%. As a next step, studies are needed to determine the factors affecting the clinical outcome of VPZ-containing therapy and optimal VPZ-containing alternative regimens for tailored treatments. In this review, we summarize the advantages and disadvantages of VPZ in H. pylori eradication therapy

Population-based strategies for Helicobacter pylori-associated disease management: Asian perspective

Asia has the largest population of any continent and the highest incidence of gastric cancer in the world, making it very important in the context of Helicobacter pylori infection. Several new guidelines in East Asian countries include expanded indications for H. pylori eradication. Importantly, the Japanese national health insurance system now covers expenses for all H. pylori-infected subjects up to second-line treatment. According to current guidelines, standard triple therapy containing a proton pump inhibitor (PPI) and two antibiotics, clarithromycin and amoxicillin/metronidazole, is still the preferred first-line regimen for treatment of H. pylori infection. However, in following years, the efficacy of legacy triple regimens has been seriously challenged, and they are becoming ineffective. Moreover, some regions in Asia show patterns of emerging antimicrobial resistance. Therefore, clarithromycin-containing triple therapy should be abandoned, as it is no longer effective unless local clarithromycin resistance is low or culture confirms susceptibility to clarithromycin. More effective clarithromycin-based regimens are now replacing standard triple therapies as empirical first-line treatments on the basis of the understanding of the local prevalence of H. pylori antimicrobial resistance. These include the bismuth and non-bismuth quadruple, sequential, and dual-concomitant (hybrid) regimens. © Springer Japan 2016

Current understanding and management of Helicobacter pylori infection: an updated appraisal [version 1; referees: 3 approved]

In addition to its role in gastric conditions, Helicobacter pylori has been found to contribute to the development of several non-gastric issues in recent years. Eradication therapy is the only effective management strategy to minimize the H. pylori-related gastric cancer and extra-gastric complications. For an effective “test and treat” strategy, diagnosis and therapy are both important. Because the infection is usually asymptomatic, patient selection is a critical issue for timely diagnosis and many clinical and demographic factors should be considered. Clarithromycin and metronidazole resistance rates also need to be considered while eradication therapy is offered. In this report, we discuss the issues which must be taken into account for the correct and timely diagnosis and for the antibiotic therapy-based management of H. pylori infection

Systematic review and meta-analysis: the relationship between the Helicobacter pylori dupA gene and clinical outcomes

<p>Abstract</p> <p>Background</p> <p>In 2005, the first disease-specific <it>Helicobacter pylori </it>virulence factor that induced duodenal ulcer and had a suppressive action on gastric cancer has been identified, and was named duodenal ulcer promoting gene (<it>dupA</it>). However, the importance of the <it>dupA </it>gene on clinical outcomes is conflicting in subsequent studies. The aim of this study was to estimate the magnitude of the risk for clinical outcomes associated with <it>dupA </it>gene.</p> <p>Methods</p> <p>A meta-analysis of case-control studies which provided raw data on the infection rates with the <it>dupA</it>-positive <it>H. pylori </it>detected by polymerase chain reaction was performed.</p> <p>Results</p> <p>Seventeen studies with a total of 2,466 patients were identified in the search. Infection with the <it>dupA</it>-positive <it>H. pylori </it>increased the risk for duodenal ulcer by 1.41-fold (95% confidence interval [CI], 1.12-1.76) overall. Subgroup analysis showed that the summary odds ratio (OR) was 1.57 (95% CI, 1.19-2.06) in Asian countries and 1.09 (95% CI, 0.73-1.62) in Western countries. There was no association between the presence of the <it>dupA </it>gene and gastric cancer and gastric ulcer. Publication bias did not exist.</p> <p>Conclusion</p> <p>Our meta-analysis confirmed the importance of the presence of the <it>dupA </it>gene for duodenal ulcer, especially in Asian countries.</p