Addition of phenylisocyanate to 3,5-diphenyl-1,2-dithiolium-4-olate gives a thioketone

The Type B mesoionic heterocycle, 3,5-diphenyl-1,2-dithiolium-4-olate, reacts with phenylisocyanate producing a thioketone derivative rather than a pseudo-semi-conjugated heterocyclic mesomeric betaine. The structure of the thioketone product was confirmed by an X-ray crystallographic investigation

Identification and Characterisation of an Iron-Responsive Candidate Probiotic

Background: Iron is an essential cofactor in almost all biological systems. The lactic acid bacteria (LAB), frequently employed as probiotics, are unusual in having little or no requirement for iron. Iron in the human body is sequestered by transferrins and lactoferrin, limiting bacterial growth. An increase in the availability of iron in the intestine by bleeding, surgery, or under stress leads to an increase in the growth and virulence of many pathogens. Under these high iron conditions, LAB are rapidly out-competed; for the levels of probiotic bacteria to be maintained under high iron conditions they must be able to respond by increasing growth rate to compete with the normal flora. Despite this, iron-responsive genera are poorly characterised as probiotics. Methodology/Principal Findings: Here, we show that a panel of probiotics are not able to respond to increased iron availability, and identify an isolate of Streptococcus thermophilus that can increase growth rate in response to increased iron availability. The isolate of S. thermophilus selected was able to reduce epithelial cell death as well as NF-kB signalling and IL-8 production triggered by pathogens. It was capable of crossing an epithelial cell barrier in conjunction with E. coli and downregulating Th1 and Th17 responses in primary human intestinal leukocytes. Conclusions/Significance: We propose that an inability to compete with potential pathogens under conditions of high iron availability such as stress and trauma may contribute to the lack of efficacy of many LAB-based probiotics in treatin

Population gene introgression and high genome plasticity for the zoonotic pathogen Streptococcus agalactiae

The influence that bacterial adaptation (or niche partitioning) within species has on gene spillover and transmission among bacteria populations occupying different niches is not well understood. Streptococcus agalactiae is an important bacterial pathogen that has a taxonomically diverse host range making it an excellent model system to study these processes. Here we analyze a global set of 901 genome sequences from nine diverse host species to advance our understanding of these processes. Bayesian clustering analysis delineated twelve major populations that closely aligned with niches. Comparative genomics revealed extensive gene gain/loss among populations and a large pan-genome of 9,527 genes, which remained open and was strongly partitioned among niches. As a result, the biochemical characteristics of eleven populations were highly distinctive (significantly enriched). Positive selection was detected and biochemical characteristics of the dispensable genes under selection were enriched in ten populations. Despite the strong gene partitioning, phylogenomics detected gene spillover. In particular, tetracycline resistance (which likely evolved in the human-associated population) from humans to bovine, canines, seals, and fish, demonstrating how a gene selected in one host can ultimately be transmitted into another, and biased transmission from humans to bovines was confirmed with a Bayesian migration analysis. Our findings show high bacterial genome plasticity acting in balance with selection pressure from distinct functional requirements of niches that is associated with an extensive and highly partitioned dispensable genome, likely facilitating continued and expansive adaptation

Recent advances in measuring the effects of diet on gastrointestinal physiology: Sniffing luminal gases and fecal volatile organic compounds.

Despite the huge pool of ideas on how diet can be manipulated to ameliorate or prevent illnesses, our understanding of how specific changes in diet influence the gastrointestinal tract is limited. This review aims to describe two innovative investigative techniques that are helping lift the veil of mystery about the workings of the gut. First, the gas-sensing capsule is a telemetric swallowable device that provides unique information on gastric physiology, small intestinal microbial activity, and fermentative patterns in the colon. Its ability to accurately measure regional and whole-gut transit times in ambulant humans has been confirmed. Luminal concentrations of hydrogen and carbon dioxide are measured by sampling through the gastrointestinal tract, and such application has enabled mapping of the relative amounts of fermentation of carbohydrates in proximal-versus-distal colon after manipulation of the types and amounts of dietary fiber. Second, changes in the smell of feces, via analysis of volatile organic compounds, occur in response to the diet, and by the presence and therapy of irritable bowel syndrome and inflammatory bowel disease. Such information is likely to aid our understanding of what dietary change can do to the colonic luminal microenvironment, and may value-add to diagnosis and therapeutic design. In conclusion, such methodologies enable a more complete physiological profile of the gastrointestinal tract to be created. Systematic description in various cohorts and effects of dietary interventions, particularly when co-ordinated with the analysis of microbiome, are needed

Upper gastrointestinal diseases in patients for endoscopy in South-Western Uganda

Background: There is a paucity of published data regarding upper gastrointestinal diseases in Ugandans with upper gastrointestinal symptoms referred for endoscopy. Objectives: To study the presenting complaints, pathology and Helicobacter pylori prevalence among patients with upper gastrointestinal symptoms in South-Western Uganda. Methods: Patients presenting with upper gastrointestinal symptoms underwent upper endoscopy and a urease test for Helicobacter Pylori, all suspicious lesions were biopsied for histopathology review as appropriate. Results: The most common presenting complaints were epigastric pain (51.6%), dysphagia (13.6%) and odynophagia (7.1%). The most common endoscopy finding was gastritis (40.2%), followed by normal examination (15.2%), oesophageal cancer (13.6%), gastric ulcer (7.6%) and gastric cancer (7.1%). Patients older than 40 years (n=110) had significant findings including gastritis (50.9%), oesophageal cancer (22.7%) and gastric cancer (11.8%). However in younger patients, with the age range of 18-40 years (n=74), most examinations were normal (92.9%). Of the 176 patients able to undergo Helicobacter pylori testing 75.6% were positive. Helicobacter pylori infection was associated with statistically significant increase in gastritis, oesophageal cancer, gastric ulcer, gastric cancer, and duodenal ulcers (p-values< 0.05). Conclusion: Gastritis, ulcerative disease, and upper gastrointestinal malignancies are common in South-Western Ugandans and are associated with a high prevalence of Helicobacter pylori

Nanoscale Si fishbone structures for manipulating heat transport using phononic resonators for thermoelectric applications

Thermoelectric materials have the potential to convert waste heat into electricity, but their thermoelectric efficiency must be improved before they are effective and economically viable. One promising route to improving thermoelectric efficiency in thin-film thermoelectric materials is to reduce the material’s thermal conductivity through nanopatterning the surface. In this work nanoscale phononic resonators are introduced to the surface, and their potential to reduce thermal conductivity is explored via coupled experimental and theoretical techniques. Atomistic modelling is used to predict the dependence of the thermal conductivity on different design parameters and used to guide the design and fabrication of silicon fishbone nanostructures. The nanostructure design incorporates a variation on design parameters such as barb length, width and spacing along the shaft length to enable correlation with changes in thermal conductivity. The thermal characteristics of the nanostructures are investigated experimentally using the spatial resolution of scanning thermal microscopy to correlate changes in thermal conductivity with the changes in the structure parameters. The method developed uses a microheater to establish a temperature gradient along the structure which will be affected by any local variations in thermal conductivity. The impact on the thermal gradient and consequently on the tip temperature is modelled using finite element computer simulations. Experimental changes as small as 7.5% are shown to be detectable in this way. Despite the experimental technique being shown to be able to detect thermal changes far smaller than those predicted by the modelling, no modifications of the thermal conductivity are detected. It is concluded that in order to realise the effects of phononic resonators to reduce thermal conductivity, that much smaller structures with a greater ratio of resonator to shaft will be needed

The role of iron in the pathogenesis of endometriosis: a systematic review

Abstract STUDY QUESTION What is the role of iron in the pathophysiology of endometriosis? SUMMARY ANSWER Iron excess is demonstrated wherever endometriotic tissues are found and is associated with oxidative stress, an inflammatory microenvironment and cell damage; the iron-mediated oxidative stress is independently linked to subfertility, symptom severity and malignant transformation. WHAT IS KNOWN ALREADY Iron is found in excess in endometriotic tissues, and multiple mechanisms have been studied and posited to explain this. It is clear that iron excess plays a vital role in promoting oxidative stress and cell damage. The evidence base is large, but no comprehensive reviews exist to summarise our understanding and highlight the overarching themes to further our understanding and suggest future directions of study for the field. STUDY DESIGN, SIZE, DURATION This systematic review with a thematic analysis retrieved studies from the PubMed, Embase, Web of Science and Cochrane Library databases and searches were conducted from inception through to August 2022. Human and animal studies published in the English language were included and identified using a combination of exploded MeSH terms (‘Iron’ and ‘Endometriosis’) and free-text search terms (‘Iron’, ‘Ferric’, ‘Ferrous’, ‘Endometriosis’, ‘Endometrioma’). PARTICIPANTS/MATERIALS, SETTING, METHODS This review was reported in accordance with the PRISMA guidelines. All studies reporting original data concerning the role of iron or iron complexes in the pathophysiology of endometriosis were included. Studies which did not report original data or provided a review of the field were excluded. Bias analysis was completed for each included study by using the Newcastle-Ottawa scoring system. MAIN RESULTS AND THE ROLE OF CHANCE There were 776 records identified and these were screened down to 53 studies which met the eligibility criteria, including 6 animal and 47 human studies, with 3,556 individual participants. Iron excess is demonstrated in various tissues and fluids, including ovarian endometriomas, ovarian follicles, ectopic endometriotic lesions and peritoneal fluid. Markers of oxidative stress are strongly associated with high iron levels, and aberrant expression of iron-transport proteins has been demonstrated. Abnormal resistance to ferroptosis is likely. Iron-mediated oxidative stress is responsible for a pro-inflammatory micro-environment and is linked to subfertility, symptom severity and, possibly, malignant transformation. LIMITATIONS, REASONS FOR CAUTION A minority of the included studies were of objectively low quality with a high-risk of bias and may lead to misleading conclusions. Additionally, multiple studies failed to appropriately characterise the included patients by known confounding variables such as menstrual cycle phase, which may introduce bias to the findings. WIDER IMPLICATIONS OF THE FINDINGS Current literature depicts a central role of aberrant iron mechanics and subsequent oxidative stress in endometriosis. It is likely that iron excess is at least partly responsible for the persistence and proliferation of ectopic endometriotic lesions. As such, iron mechanics represent an attractive target for novel therapeutics, including iron chelators or effectors of the iron-oxidative stress pathway. There are significant gaps in our current understanding, and this review highlights and recommends several topics for further research. These include the role of iron chelation, resistance to ferroptosis, the relationship between iron excess and localised hypoxia, systemic iron pathophysiology in endometriosis, and the role of oxidative stress in malignant transformation. STUDY FUNDING/COMPETING INTEREST(S) J.W and S.P are supported by clinical fellowships at Liverpool University Hospital NHS Foundation trust. No additional funding was requested or required for the completion of this work. C.J.H. is supported by a Wellbeing of Women project grant (RG2137). D.K.H. is supported by a Wellbeing of Women project grant (RG2137) and MRC clinical research training fellowship (MR/V007238/1). The authors have no conflicts of interest to declare. REGISTRATION NUMBER A protocol was prospectively registered with the PROSPERO database in August 2021 (CRD42021272818) </jats:sec

Patient preferences for non-invasive diagnostic biospecimens among women with chronic pelvic pain: A cross-sectional survey

Background Chronic pelvic pain (CPP) frequently prompts visits to gynaecology services, commonly resulting in invasive laparoscopic examinations. Various non-invasive sampling methods are the subject of research, but patient preferences remain largely unexplored. This study aims to delineate the acceptability of different non-invasive biosamples and explore the reasoning behind preferences. Methods A questionnaire was developed to investigate acceptability and preferences regarding the provision and testing of five different biological samples: urine, blood, saliva, vaginal tampons, and faeces. Premenopausal women with CPP and suspected or confirmed endometriosis were recruited between October 2022 and January 2023. Participants were classified into three groups based on laparoscopic findings: superficial or ovarian endometriosis, deep bowel-involving endometriosis, and no endometriosis. Responses were statistically compared between groups. Results Eighty-seven participants completed the survey. Urine testing was the preferred biosample with 86 (98.8%) respondents ranking it as their first, second or third most preferred sample type. Blood and saliva samples ranked second and third, respectively with 82 (94.3%) and 61 (70.1%) respondents ranking this test third or higher. Tampon (28, (32.2%)) and faeces (4 (4.6%)) tests were ranked lowest and were described as "uncomfortable" or "embarrassing" by 48 (55.1%) and 68 (78.1%) respondents, respectively. There were minimal differences in responses between those with and without endometriosis. Conclusion Among this cohort, urine testing provided the most acceptable non-invasive sample type, followed by blood and saliva tests. However, respondents indicated that any non-invasive test would be largely acceptable to determine the need for more invasive diagnostic tests

Challenges in estimation, uncertainty quantification and elicitation for pandemic modelling

The estimation of parameters and model structure for informing infectious disease response has become a focal point of the recent pandemic. However, it has also highlighted a plethora of challenges remaining in the fast and robust extraction of information using data and models to help inform policy. In this paper, we identify and discuss four broad challenges in the estimation paradigm relating to infectious disease modelling, namely the Uncertainty Quantification framework, data challenges in estimation, model-based inference and prediction, and expert judgement. We also postulate priorities in estimation methodology to facilitate preparation for future pandemics