57 research outputs found
A Role for the Vacuolating Cytotoxin, VacA, in Colonization and Helicobacter pylori-Induced Metaplasia in the Stomach
Carriage of Helicobacter pylori strains producing more active (s1/i1) forms of VacA is strongly associated with gas-tric adenocarcinoma. To our knowledge, we are the
first to determine effects of different polymorphic forms of VacA on inflammation and metaplasia in the mouse stomach. Bacteria producing the less active s2/i2 form of VacA colonized mice more efficiently than mutants null for VacA or producing more active forms of it, providing the
first evidence of a positive role for the minimally active s2/i2 toxin. Strains producing more active toxin forms induced more severe and extensive metaplasia and in flammation in the mouse stomach than strains producing weakly active (s2/i2) toxin. We also examined the association in humans, controlling for cag PAI status. In human gastric biopsy specimens, the vacA i1 allele was strongly associated with precancerous intestinal metaplasia, with almost complete absence of intestinal metaplasia in subjects infected with i2-type strains, even in a vacA s1, cagA+ background
Co-production of an educational package for the universal human papillomavirus (HPV) vaccination programme tailored for schools with low uptake:A participatory study protocol
AIM: To co-produce with young people an educational package about the human papillomavirus (HPV) vaccine that is tailored to increase vaccine uptake in schools and populations with lower uptake. INTRODUCTION: Persistent infection with HPV can result in cancers affecting men and especially women. From September 2019, the English-schools-based HPV vaccination programme was expanded to include young men (in addition to young women) aged 12-13 years. Some young people attending schools with lower uptake of the vaccine have unmet information needs. We hypothesise that mechanisms to address information needs and increase young people's autonomy in consent procedures will result in higher uptake. METHODS AND ANALYSIS: The Medical Research Council's framework for development and evaluation of complex interventions will inform intervention development. Recruitment of young people aged 12-15 years and key stakeholders (National Health Service commissioners, school staff, immunisation nurses and youth workers/practitioners) will be facilitated through existing links with healthcare organisations, schools and youth organisations in areas with lower uptake of the HPV vaccination programme. The proposed research will comprise three phases: (1) a rapid review of adolescent immunisation materials and preliminary qualitative interviews with young people and key stakeholders, (2) theory development and co-production of HPV vaccine communication materials through an iterative process with young people and (iii) testing delivery mechanisms and acceptability of the educational package in four schools with lower uptake. ETHICS AND DISSEMINATION: The University of Bristol's Faculty of Health Sciences and London School of Hygiene and Tropical Medicine's Research Ethics Committees provided approvals for the study. A dissemination event for young people and key stakeholders and webinar with the National Immunisation Network will be organised. The study findings will be published in peer-reviewed journals and presented at conferences. Recommendations for a future larger scale study will be made
Impact of a nurseâled enhanced monitoring, management and contact tracing intervention for chronic hepatitis B in England, 2015â2017
Around 200,000 people live with chronic hepatitis B in England. Despite national guidance on identification and management of cases and their close contacts, testing rates of close contacts is as low as 43% in high prevalence areas of London. Our study aimed to determine whether a nurseâled enhanced management and contact tracing of chronically infected individuals improved testing uptake, vaccination and onward referral of close contacts. The study was conducted across Greater Manchester and East of England regions between October 2015 and July 2017. All HBV chronically infected individuals registered with a GP and their close contacts were eligible for recruitment. The proportion of contacts who were tested, vaccinated and referred where appropriate were compared before and after the nurseâled intervention. Baseline and outcome information was collected using questionnaires. The intervention improved case referral rates by an additional 14% (from 86% (88/102 cases) to 99.7%; 648/650 cases). The proportion of contacts tested increased from 34% to 72%â94% with 18 new cases of HBV diagnosed. Amongst close contacts tested, vaccination rates of at least three doses increased from 77% (43/56) to 93% (452/491) during the study. Our study has shown that nurseâled enhanced management greatly improves identification, testing and vaccination of close contacts. The identification of new acute and chronic cases is likely to make the intervention cost effective and local health commissioners should consider providing a nurseâled service as part of hepatitis B care pathways
Tailoring immunisation programmes: Using behavioural insights to identify barriers and enablers to childhood immunisations in a Jewish community in London, UK.
: Due to regular vaccine preventable disease outbreaks and sub-optimal immunisation uptake in the London borough of Hackney, home to the largest Charedi Orthodox Jewish community in Europe, it was decided, in consultation with the community, to implement the WHO Tailoring Immunization Programmes approach (TIP). : The WHO Tailoring Immunization Programmes (TIP) approach was used. TIP provides a framework based on behavioural insights methodology to identify populations susceptible to vaccine preventable diseases, diagnose supply and demand side barriers and enablers to vaccination and recommend evidence-informed responses to improve vaccination coverage. : The results of the formative research and behavioural analysis challenged the assumption that a cultural or religious anti-vaccination sentiment existed within the community. Critical issues related to access to and convenience of immunisation services. Service providers in the area have challenges due to having to deliver immunisation services to the large numbers of children without additional resource. Where mothers were choosing to delay or refuse vaccinations their reasons were broadly similar to the wider population. The behavioural analysis identified potential categorisation of subgroups within the community enabling a more tailored approach to addressing concerns and meeting parents' needs. : The TIP approach was an effective way of investigating factors linked to sub-optimal immunisation within the Charedi community. The use of behavioural insights enabled the categorisation of subgroups so that more targeted interventions could be developed. The comprehensive stakeholder engagement which is a key pillar of the TIP approach ensured a deeper understanding of the barriers and enablers to vaccination as well as increasing the level of ownership in the community. TIP should be considered as a useful approach to identify main facilitators and barriers to vaccination in communities with suboptimal immunisation uptake.<br/
The active form of Helicobacter pylori vacuolating cytotoxin induces decay-accelerating factor CD55 in association with intestinal metaplasia in the human gastric mucosa
High-level expression of decay-accelerating factor, CD55, has previously been found in human gastric cancer (GC) and intestinal metaplasia (IM) tissues. Therapeutic effects of CD55 inhibition in cancer have been reported. However, the role of Helicobacter pylori infection and virulence factors in the induction of CD55 and its association with histological changes of the human gastric mucosa remain incompletely understood. We hypothesised that CD55 would be increased during infection with more virulent strains of H. pylori, and with more marked gastric mucosal pathology. RT-qPCR and immunohistochemical analyses of gastric biopsy samples from 42 H. pylori-infected and 42 uninfected patients revealed that CD55 mRNA and protein were significantly higher in the gastric antrum of H. pylori-infected patients, and this was associated with the presence of IM, but not atrophy, or inflammation. Increased gastric CD55 and IM were both linked with colonisation by vacA i1-type strains independently of cagA status, and in vitro studies using isogenic mutants of vacA confirmed the ability of VacA to induce CD55 and sCD55 in gastric epithelial cell lines. siRNA experiments to investigate the function of H. pylori-induced CD55 showed that CD55 knockdown in gastric epithelial cells partially reduced IL-8 secretion in response to H. pylori, but this was not due to modulation of bacterial adhesion or cytotoxicity. Finally, plasma samples taken from the same patients were analysed for the soluble form of CD55 (sCD55) by ELISA. sCD55 levels were not influenced by IM and did not correlate with gastric CD55 mRNA levels. These results suggest a new link between active vacA i1-type H. pylori, IM, and CD55, and identify CD55 as a molecule of potential interest in the management of IM as well as GC treatment. Š 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland
Helicobacter pylori vacA transcription is genetically-determined and stratifies the level of human gastric inflammation and atrophy
Aims Helicobacter pylori infection is the major cause of peptic ulceration and gastric cancer, and an important virulence determinant is its vacuolating cytotoxin, vacA. Previously, we have described allelic variation in vacA which determines toxin activity and disease risk. We now aimed to quantify vacA mRNA expression in the human stomach, define its genetic determinants and assess how well itpredicted gastric pathology. Methods Gastric biopsies were donated by 39 H. pylori-infected patients attending for endoscopy at Queenâs Medical Centre, Nottingham, UK. Total RNA was extracted, and vacA mRNA quantified by reverse transcriptase quantitative polymerase chain reaction. Separate biopsies were histologically scored for inflammation and atrophy using the updated Sydney system. H. pylori strains were isolated from further biopsies, and the nucleotide sequence upstream of vacA determined. Results vacA mRNA levels in human stomachs varied by two orders of magnitude independently of vacA allelic type. Among vacA i1-type (toxic) strains, increased vacA expression was strongly associated with higher grade gastric inflammation (
COVID-19 outbreaks following full reopening of primary and secondary schools in England: Cross-sectional national surveillance, November 2020.
Background: The full reopening of schools in September 2020 was associated with an increase in COVID-19 cases and outbreaks in educational settings across England. Methods: Primary and secondary schools reporting an outbreak (âĽ2 laboratory-confirmed cases within 14 days) to Public Health England (PHE) between 31 August and 18 October 2020 were contacted in November 2020 to complete an online questionnaire. Interpretation: There were 969 school outbreaks reported to PHE, comprising 2% (n = 450) of primary schools and 10% (n = 519) of secondary schools in England. Of the 369 geographically-representative schools contacted, 179 completed the questionnaire (100 primary schools, 79 secondary schools) and 2,314 cases were reported. Outbreaks were larger and across more year groups in secondary schools than in primary schools. Teaching staff were more likely to be the index case in primary (48/100, 48%) than secondary (25/79, 32%) school outbreaks (P = 0.027). When an outbreak occurred, attack rates were higher in staff (881/17,362; 5.07; 95%CI, 4.75-5.41) than students, especially primary school teaching staff (378/3852; 9.81%; 95%CI, 8.90-10.82%) compared to secondary school teaching staff (284/7146; 3.97%; 95%CI, 3.79-5.69%). Secondary school students (1105/91,919; 1.20%; 95%CI, 1.13-1.28%) had higher attack rates than primary school students (328/39,027; 0.84%; 95%CI, 0.75-0.94%). Conclusions: A higher proportion of secondary schools than primary schools reported a COVID-19 outbreak and experienced larger outbreaks across multiple school year groups. The higher attack rate among teaching staff during an outbreak, especially in primary schools, suggests that additional protective measures may be needed. Funding: PHE
TOIB Study. Are topical or oral ibuprofen equally effective for the treatment of chronic knee pain presenting in primary care: a randomised controlled trial with patient preference study. [ISRCTN79353052]
BACKGROUND: Many older people have chronic knee pain. Both topical and oral non- steroidal anti-inflammatory drugs (NSAIDs) are commonly used to treat this. Oral NSAIDS are effective, at least in the short term, but can have severe adverse effects. Topical NSAIDs also appear to be effective, at least in the short term. One might expect topical NSAIDs both to be less effective and to have fewer adverse effects than oral NSAIDs. If topical NSAIDs have fewer adverse effects this may outweigh both the reduction in effectiveness and the higher cost of topical compared to oral treatment. Patient preferences may influence the comparative effectiveness of drugs delivered via different routes. METHODS: TOIB is a randomised trial comparing topical and oral ibuprofen, with a parallel patient preference study. We are recruiting people aged 50 or over with chronic knee pain, from 27 MRC General Practice Research Framework practices across the UK. We are seeking to recruit 283 participants to the RCT and 379 to the PPS. Participants will be followed up for up to two years (with the majority reaching one year). Outcomes will be assessed by postal questionnaire, nurse examination, laboratory tests and medical record searches at one and two years or the end of the study. DISCUSSION: This study will provide new evidence on the overall costs and benefits of treating chronic knee pain with either oral or topical ibuprofen. The use of a patient preference design is unusual, but will allow us to explore how preference influences response to a medication. In addition, it will provide more information on adverse events. This study will provide evidence to inform primary care practitioners, and possibly influence practice
The Characterization of Helicobacter pylori DNA Associated with Ancient Human Remains Recovered from a Canadian Glacier
Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of nearly half of the world's population. Genotypic characterization of H. pylori strains involves the analysis of virulence-associated genes, such as vacA, which has multiple alleles. Previous phylogenetic analyses have revealed a connection between modern H. pylori strains and the movement of ancient human populations. In this study, H. pylori DNA was amplified from the stomach tissue of the Kwäday Dän Ts'Ïnchi individual. This ancient individual was recovered from the Samuel Glacier in Tatshenshini-Alsek Park, British Columbia, Canada on the traditional territory of the Champagne and Aishihik First Nations and radiocarbon dated to a timeframe of approximately AD 1670 to 1850. This is the first ancient H. pylori strain to be characterized with vacA sequence data. The Tatshenshini H. pylori strain has a potential hybrid vacA m2a/m1d middle (m) region allele and a vacA s2 signal (s) region allele. A vacA s2 allele is more commonly identified with Western strains, and this suggests that European strains were present in northwestern Canada during the ancient individual's time. Phylogenetic analysis indicated that the vacA m1d region of the ancient strain clusters with previously published novel Native American strains that are closely related to Asian strains. This indicates a past connection between the Kwäday Dän Ts'Ïnchi individual and the ancestors who arrived in the New World thousands of years ago
Relationship between tobacco, cagA and vacA i1 virulence factors and bacterial load in patients infected by Helicobacter pylori
Background and Aim
Several biological and epidemiological studies support a relationship between smoking and Helicobacter pylori (H. pylori) to increase the risk of pathology. However, there have been few studies on the potential synergistic association between specific cagA and vacA virulence factors and smoking in patients infected by Helicobacter pylori. We studied the relationship between smoking and cagA, vacA i1 virulence factors and bacterial load in H. pylori infected patients.
Methods
Biopsies of the gastric corpus and antrum from 155 consecutive patients in whom there was clinical suspicion of infection by H. pylori were processed. In 106 patients H. pylori infection was detected. Molecular methods were used to quantify the number of microorganisms and presence of cagA and vacA i1 genes. A standardized questionnaire was used to obtain patientsâ clinical data and lifestyle variables, including tobacco and alcohol consumption. Adjusted Odds Ratios (ORadjusted) were estimated by unconditional logistic regression.
Results
cagA was significantly associated with active-smoking at endoscope: ORadjusted 4.52. Evidence of association was found for vacA i1 (ORadjusted 3.15). Bacterial load was higher in active-smokers, although these differences did not yield statistical significance (median of 262.2 versus 79.4 copies of H. pylori per cell).
Conclusions
The association between smoking and a higher risk of being infected by a virulent bacterial population and with higher bacterial load, support a complex interaction between H. pylori infection and environmental factors
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