Human lung cancer harbors spatially organized stem-immunity hubs associated with response to immunotherapy.

The organization of immune cells in human tumors is not well understood. Immunogenic tumors harbor spatially localized multicellular 'immunity hubs' defined by expression of the T cell-attracting chemokines CXCL10/CXCL11 and abundant T cells. Here, we examined immunity hubs in human pre-immunotherapy lung cancer specimens and found an association with beneficial response to PD-1 blockade. Critically, we discovered the stem-immunity hub, a subtype of immunity hub strongly associated with favorable PD-1-blockade outcome. This hub is distinct from mature tertiary lymphoid structures and is enriched for stem-like TCF7+PD-1+CD8+ T cells, activated CCR7+LAMP3+ dendritic cells and CCL19+ fibroblasts as well as chemokines that organize these cells. Within the stem-immunity hub, we find preferential interactions between CXCL10+ macrophages and TCF7-CD8+ T cells as well as between mature regulatory dendritic cells and TCF7+CD4+ and regulatory T cells. These results provide a picture of the spatial organization of the human intratumoral immune response and its relevance to patient immunotherapy outcomes.

Circulating myeloid-derived MMP8 in stress susceptibility and depression.

Psychosocial stress has profound effects on the body, including the immune system and the brain1,2. Although a large number of pre-clinical and clinical studies have linked peripheral immune system alterations to stress-related disorders such as major depressive disorder (MDD)3, the underlying mechanisms are not well understood. Here we show that expression of a circulating myeloid cell-specific proteinase, matrix metalloproteinase 8 (MMP8), is increased in the serum of humans with MDD as well as in stress-susceptible mice following chronic social defeat stress (CSDS). In mice, we show that this increase leads to alterations in extracellular space and neurophysiological changes in the nucleus accumbens (NAc), as well as altered social behaviour. Using a combination of mass cytometry and single-cell RNA sequencing, we performed high-dimensional phenotyping of immune cells in circulation and in the brain and demonstrate that peripheral monocytes are strongly affected by stress. In stress-susceptible mice, both circulating monocytes and monocytes that traffic to the brain showed increased Mmp8 expression following chronic social defeat stress. We further demonstrate that circulating MMP8 directly infiltrates the NAc parenchyma and controls the ultrastructure of the extracellular space. Depleting MMP8 prevented stress-induced social avoidance behaviour and alterations in NAc neurophysiology and extracellular space. Collectively, these data establish a mechanism by which peripheral immune factors can affect central nervous system function and behaviour in the context of stress. Targeting specific peripheral immune cell-derived matrix metalloproteinases could constitute novel therapeutic targets for stress-related neuropsychiatric disorders.

Two distinct regulatory systems control pulcherrimin biosynthesis in Bacillus subtilis.

Regulation of transcription is a fundamental process that allows bacteria to respond to external stimuli with appropriate timing and magnitude of response. In the soil bacterium Bacillus subtilis, transcriptional regulation is at the core of developmental processes needed for cell survival. Gene expression in cells transitioning from exponential phase to stationary phase is under the control of a group of transcription factors called transition state regulators (TSRs). TSRs influence numerous developmental processes including the decision between biofilm formation and motility, genetic competence, and sporulation, but the extent to which TSRs influence bacterial physiology remains to be fully elucidated. Here, we demonstrate two TSRs, ScoC and AbrB, along with the MarR-family transcription factor PchR negatively regulate production of the iron chelator pulcherrimin in B. subtilis. Genetic analysis of the relationship between the three transcription factors indicate that all are necessary to limit pulcherrimin production during exponential phase and influence the rate and total amount of pulcherrimin produced. Similarly, expression of the pulcherrimin biosynthesis gene yvmC was found to be under control of ScoC, AbrB, and PchR and correlated with the amount of pulcherrimin produced by each background. Lastly, our in vitro data indicate a weak direct role for ScoC in controlling pulcherrimin production along with AbrB and PchR. The layered regulation by two distinct regulatory systems underscores the important role for pulcherrimin in B. subtilis physiology.

Reduction of embryonic E93 expression as a hypothetical driver of the evolution of insect metamorphosis.

The early embryo of the cockroach Blattella germanica exhibits high E93 expression. In general, E93 triggers adult morphogenesis during postembryonic development. Here we show that E93 is also crucial in early embryogenesis in the cockroach, as a significant number of E93-depleted embryos are unable to develop the germ band under maternal RNAi treatment targeting E93. Moreover, transcriptomic analysis indicates that E93 depletion results in important gene expression changes in the early embryo, and many of the differentially expressed genes are involved in development. Then, using public databases, we gathered E93 expression data in embryo and preadult stages, finding that embryonic expression of E93 is high in hemimetabolan species (whose juveniles, or nymphs, are similar to the adult) and low in holometabolans (whose juveniles, or larvae, are different from the adult). E93 expression is also low in Thysanoptera and in Hemiptera Sternorrhyncha, hemimetabolans with postembryonic quiescent stages, as well as in Odonata, the nymph of which is very different from the adult. In ametabolans, such as the Zygentoma Thermobia domestica, E93 transcript levels are very high in the early embryo, whereas during postembryonic development they are medium and relatively constant. We propose the hypothesis that during evolution, a reduction of E93 expression in the embryo of hemimetabolans facilitated the larval development and the emergence of holometaboly. Independent decreases of E93 transcripts in the embryo of Odonata, Thysanoptera, and different groups of Hemiptera Sternorrhyncha would have allowed the development of modified juvenile stages adapted to specific ecophysiological conditions.

Critical reflection in team-based practice: A narrative review.

INTRODUCTION: Research on critical reflection (a process of recognising and challenging assumptions that frame health care practice) has demonstrated strong potential for making health care more collaborative and equitable, yet its enactment within team-based health care remains underexplored. We conducted a narrative review to advance understanding of how critical reflection develops, occurs in and impacts team-based practice and care. METHODS: We searched three databases (Medline, CINAHL and Scopus) for articles related to the concepts of critical reflection and/or critically reflective practice in the context of team-based health care and examined how teams engage with those theoretical concepts, to inform ideas for a new approach to support critically reflective practice. FINDINGS: The search identified 974 citations of which nine articles showed elements of critical reflection in team-based practice. However, since only one of the nine included articles explicitly used the term 'critical reflection' in their research, critical reflection as a theoretical concept was found to be largely missing from the current team-based health care literature. Instead, aspects of critical reflection were evident in terms of challenging power hierarchies and questioning practice assumptions through dialogue, with a goal of collaborative practice. This sharing of knowledge and skills allowed teams to push boundaries and innovate together in practice. The included articles also emphasised the importance of creating a purposeful environment for open dialogue and practice change to occur. CONCLUSION: To support equitable care through collaborative practices, we suggest dialogue as and for critical reflection should be explicitly developed and researched within team-based health care.

Integrating accompanying patients into clinical oncology teams: limiting and facilitating factors.

OBJECTIVES: Since 2018, four establishments in Quebec have been instrumental in implementing the PAROLE-Onco program, which introduced accompanying patients (APs) into healthcare teams to improve cancer patients' experience. APs are patient advisors who have acquired specific experiential knowledge related to living with cancer, using services, and interacting with healthcare professionals. They are therefore in a unique and reliable position to be able to provide emotional, informational, cognitive and navigational support to patients who are dealing with cancer. We aimed to explore APs' perspectives regarding the limiting and facilitating factors in terms of how they are integrated into the clinical oncology teams. METHODS: A qualitative study based on semi-structured interviews and focus groups was conducted with 20 APs at the beginning of their intervention (T1) and, two years later, during a second data collection (T2). Limiting and facilitating factors of APs' integration into clinical teams were analyzed in terms of governance, culture, resources and tools. RESULTS: The limited factors raised by APs to be integrated into clinical teams include the following: confusion about the specific roles played by APs, lifting the egos of certain professionals who feel they are already doing what APs typically do, lack of identification of patient needs, absence of APs in project governance organizational boundaries, and team members' availability. Various communication challenges were also raised, resulting in the program being inadequately promoted among patients. Also mentioned as limiting factors were the lack of time, space and compensation. Creating opportunities for team members to meet with APs, building trust and teaching team members how APs' activities complement theirs were enhancing factors. Other facilitators include APs being involved in decision-making committees, being leaders in promoting the PAROLE-Onco program to patients and clinical team members and creating opportunities to communicate with team members to help enhance their work and provide feedback to improve patient services. Awareness of APs' added value for the team and patients is also a key facilitator. Regarding tools, offering accompanying services by telephone allows both patients and APs to benefit from the flexibility they need. CONCLUSION: Over time, APs were able to identify optimal factors for successful implementation. Recommendations include APs and professionals working in co-construction on organization, leadership, resources and status factors. This could help catalyze a change in culture within health establishments and allow people dealing with cancer to benefit from the experiential knowledge of other patients within their clinical team.

Comparative study of sample preparation procedures to determine the main compounds in ayahuasca beverages by QuEChERS and high-performance liquid chromatography analysis.

INTRODUCTION: Ayahuasca is a psychoactive drink originally consumed by indigenous people of the Amazon. The lack of regulation of this drink leads to uncontrolled consumption, and it is often consumed in religious contexts. OBJECTIVE: The aim of this work is to compare three miniaturised extraction techniques for extracting the main ayahuasca compounds from beverages. METHODOLOGY: Three sample pretreatment techniques were evaluated (dispersive liquid-liquid microextraction [DLLME], microextraction by packed sorbent [MEPS] and QuEChERS [Quick, Easy, Cheap, Effective, Rugged and Safe]) for the simultaneous extraction of N,N-dimethyltryptamine (DMT), tetrahydroharmine (THH), harmine, harmaline, harmol and harmalol from ayahuasca beverage samples. Then, the most promising technique (QuEChERS) was chosen to pre-concentrate the analytes, subsequently detected by high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD). RESULTS: The procedure was optimised, with the final conditions being 500 µL of extractor solvent, 85 mg of primary secondary amine (PSA) and 4 s of vortexing. The analytical method was validated, showing to be linear between 0.16 and 10 µg/mL for ß-carbolines and between 0.016 and 1 µg/mL for DMT, with coefficients of determination (R2) between 0.9968 and 0.9993. The limit of detection (LOD) and lower limit of quantification (LLOQ) were 0.16 µg/mL for all compounds, except for DMT (0.016 µg/mL) and extraction efficiencies varied between 60.2% and 88.0%. CONCLUSION: The analytical methodology proved to be accurate and precise, with good linearity, LODs and LLOQs. This method has been fully validated and successfully applied to ayahuasca beverage samples.

Ureteral Stent Placement Prior to Definitive Stone Treatment Is Associated With Higher Postoperative Emergency Department Visits and Opioid Prescriptions for Youth Having Ureteroscopy or Shock Wave Lithotripsy.

PURPOSE: Little is known about the impact of ureteral stents on youth having stone surgery. We evaluated the association of ureteral stent placement before or concurrent with ureteroscopy and shock wave lithotripsy with emergency department visits and opioid prescriptions among pediatric patients. MATERIALS AND METHODS: We conducted a retrospective cohort study of individuals aged 0-24 years who underwent ureteroscopy or shock wave lithotripsy from 2009-2021 at 6 hospitals in PEDSnet, a research network that aggregates electronic health record data from children's health systems in the United States. The exposure, primary ureteral stent placement, was defined as a stent placed concurrent with or within 60 days before ureteroscopy or shock wave lithotripsy. Associations between primary stent placement and stone-related ED visits and opioid prescriptions within 120 days of the index procedure were evaluated with mixed-effects Poisson regression. RESULTS: Two-thousand ninety-three patients (60% female; median age 15 years, IQR 11-17) had 2,477 surgical episodes; 2,144 were ureteroscopy and 333 were shock wave lithotripsy. Primary stents were placed in 1,698 (79%) ureteroscopy episodes and 33 (10%) shock wave lithotripsy episodes. Ureteral stents were associated with a 33% higher rate of emergency department visits (IRR 1.33; 95% CI 1.02-1.73) and a 30% higher rate of opioid prescriptions (IRR 1.30; 95% CI 1.10-1.53). The magnitudes of both associations were greater for shock wave lithotripsy. Results were similar for age <18 and were lost when restricted to concurrent stent placement. CONCLUSIONS: Primary ureteral stent placement was associated with more frequent emergency department visits and opioid prescriptions, driven by pre-stenting. These results support elucidating situations where stents are not necessary for youth with nephrolithiasis.

An exploratory cross-sectional study of the effects of ongoing relationships with accompanying patients on cancer care experience, self-efficacy, and psychological distress.

BACKGROUND: Centre hospitalier de l'Université de Montréal in Canada introduced accompanying patients (APs) into the breast cancer care trajectory. APs are patients who have been treated for breast cancer and have been integrated into the clinical team to expand the services offered to people affected by cancer. This study describes the profiles of the people who received the support and explores whether one-offs vs ongoing encounters with APs influence their experience of care, on self-efficacy in coping with cancer, and on their level of psychological distress. METHODS: An exploratory cross-sectional study was carried out among patients to compare patients who had one encounter with an AP (G1) with those who had had several encounters (G2). Five questionnaires were administered on socio-demographic characteristics, care pathway, evaluation of the support experience, self-efficacy in coping with cancer, and level of psychological distress. Logbooks, completed by the APs, determined the number of encounters. Linear regression models were used to evaluate the associations between the number of encounters, patient characteristics, care pathway, number of topics discussed, self-efficacy measures in coping with cancer, and level of psychological distress. RESULTS: Between April 2020 and December 2021, 60% of 535 patients who were offered support from an AP accepted. Of these, one hundred and twenty-four patients participated in the study. The study aimed to recruit a minimum of 70 patients with the expectation of obtaining at least 50 participants, assuming a response rate of 70%. There were no differences between G1 and G2 in terms of sociodemographic data and care pathways. Statistical differences were found between G1 and G2 for impacts on and the return to daily life (p = 0.000), the return to the work and impacts on professional life (p = 0.044), announcement of a diagnosis to family and friends (p = 0.033), and strategies for living with treatment under the best conditions (p = 0.000). Significant differences were found on the topics of cancer (p = 0.000), genetic testing (p = 0.023), therapeutic options (p = 0.000), fatigue following treatment (p = 0.005), pain and discomfort after treatment or surgery (p = 0.000), potential emotions and their management (p = 0.000) and the decision-making processes (p = 0.011). A significant relationship was found between the two groups for patients' ability to cope with cancer (p = 0.038), and their level of psychological distress at different stages of the care pathway (p = 0.024). CONCLUSIONS: This study shows differences between one-time and ongoing support for cancer patients. It highlights the potential for APs to help patients develop self-efficacy and cope with the challenges of cancer treatment.

Contrast-enhanced voiding urosonography (CEVUS) as a safe alternate means of assessing vesicoureteral reflux in pediatric kidney transplant patients.

BACKGROUND: Although voiding cystourethrogram (VCUG) is currently the gold standard in VUR evaluation, there is ionizing radiation exposure. Contrast-enhanced voiding urosonography (CEVUS) uses ultrasound contrast agents to visualize the urinary tract and has been reported to be safe and effective in VUR evaluation in children. CEVUS application has yet to be specifically described in VUR evaluation in the pediatric kidney transplant population. The purpose of this study was to report the use of CEVUS and VCUG in evaluating and managing VUR in pediatric renal transplant patients. METHODS: Retrospective review was conducted for pediatric kidney transplant patients (18 years and younger) who underwent VCUG or CEVUS to assess for transplant VUR from July 2019 through June 2021. Demographic information, reason for VUR evaluation, fluoroscopy time, and postimaging complications were evaluated. Costs of imaging modalities were also considered. RESULTS: Eight patients were evaluated for transplant VUR during the study period. Of the 3 patients who underwent VCUG, all 3 had VUR (median grade 3). Median fluoroscopy time was 18 s and dose-area product was 18.7 uGy*m2 . Of the 5 patients who underwent CEVUS, 4 had VUR (median grade 4). There were no complications for either modality. Based on clinical and radiographic findings, patients were recommended no intervention, behavioral modification, or ureteral reimplantation. The total cost of CEVUS was $800 less than that of VCUG. CONCLUSION: CEVUS can provide an alternate means of safely evaluating VUR in kidney transplant patients with similar outcomes, potentially lower costs, and no exposure to ionizing radiation.

The dynamic nature of patient engagement within a Canadian patient-oriented kidney health research network: Perspectives of researchers and patient partners.

INTRODUCTION: Canadians Seeking Solutions and Innovations to Overcome Chronic Kidney Disease (Can-SOLVE CKD) is a pan-Canadian health research network that engages patients as partners across 18 unique projects and core infrastructure. In this qualitative study, we explored how research teams integrated patient partners into network research activities to inform our patient engagement approach. METHODS: To capture a breadth of perspectives, this qualitative descriptive study purposively sampled researchers and patient partners across 18 network research teams. We conducted 4 focus groups (2 patients and 2 researchers; n = 26) and 28 individual telephone interviews (n = 12 patient partners; n = 16 researchers). Transcripts were coded in duplicate, and themes were developed through an inductive, thematic analysis approach. RESULTS: We included 24 patient partners and 24 researchers from 17 of the 18 projects and all core committees within the network. Overarching concepts relate participants' initial impressions and uncertainty about patient engagement to an evolving appreciation of its value, impact and sustainability. We identified four themes with subthemes that characterized the dynamic nature of patient engagement and how participants integrated patients across network initiatives: (1) Reinforcing a shared purpose (learning together, collective commitment, evolving attitudes); (2) Fostering a culture of responsive and innovative research (accessible supports, strengthened process and product); (3) Aligning priorities, goals and needs (amenability to patient involvement, mutually productive relationships, harmonizing expectations); (4) Building a path to sustainability (value creation, capacity building, sustaining knowledge use). CONCLUSIONS: Our findings demonstrate the dynamic and adaptive processes related to patient engagement within a national, patient-oriented kidney health research network. Optimization of support structures and capacity are key factors to promote sustainability of engagement processes within and beyond the network. PATIENT OR PUBLIC CONTRIBUTION: This project was conceived in collaboration with a Can-SOLVE CKD patient partner (N. F.), with lived experience of kidney failure. He also co-designed the study's protocol, led focus groups and researcher interviews, and contributed to data analysis. L. G. has lived experience as a caregiver for a person with CKD and facilitated patient partner focus groups. The patient partners, both of whom are listed authors, provided important insights that shaped our interpretation and presentation of study findings.

Accompanying patients in clinical oncology teams: Reported activities and perceived effects.

INTRODUCTION: Since 2018, four establishments in Quebec, Canada, have decided to implement the PAROLE-Onco programme, which introduced accompanying patients (APs) in healthcare teams to improve the experience of cancer patients. APs are patient advisors who have had a cancer treatment experience and who conduct consultations to complement the service offered by providing emotional, informational and educational support to patients undergoing treatments (e.g., radiotherapy, chemotherapy, surgery), mostly for breast cancer. We aimed to explore the evolution of APs' perspectives regarding their activities within the clinical oncology teams as well as the perceived effects of their intervention with patients, the clinical team and themselves. METHODS: A qualitative study based on semistructured interviews and focus groups was conducted with APs at the beginning of their intervention (T1) and 2 years afterwards (T2). The themes discussed were APs' activities and the perceived effects of their interventions on themselves, on the patients and on the clinical team. RESULTS: In total, 20 APs were interviewed. In T2, APs' activities shifted from listening and sharing experiences to empowering patients by helping them become partners in their care and felt generally more integrated into the clinical team. APs help patients feel understood and supported, alleviate stress and become partners in the care they receive. They also alleviate the clinical team's workload by offering a complementary service through emotional support, which, according to them, helps patients feel calmer and more prepared for their appointments with healthcare professionals. They communicate additional information about their patients' health journey, which makes the appointment more efficient for healthcare professionals. When APs accompany patients, they feel as if they can make a difference in patients' lives. Their activities are perceived by some as an opportunity to give back but also as a way of giving meaning to their own experience, in turn serving as a learning experience. CONCLUSION: By mobilizing their experiential knowledge, APs provide emotional, informational, cognitive and navigational support, which allows patients to be more empowered in their care and which complements professionals' scientific knowledge, thereby helping to refine their sensitivity to the patients' experiences. PATIENT OR PUBLIC CONTRIBUTION: Two patient-researchers have contributed to the study design, the conduct of the study, the data analysis and interpretation, as well as in the preparation and writing of this manuscript.

Vibrio cholerae adapts to sessile and motile lifestyles by cyclic di-GMP regulation of cell shape.

The cell morphology of rod-shaped bacteria is determined by the rigid net of peptidoglycan forming the cell wall. Alterations to the rod shape, such as the curved rod, occur through manipulating the process of cell wall synthesis. The human pathogen Vibrio cholerae typically exists as a curved rod, but straight rods have been observed under certain conditions. While this appears to be a regulated process, the regulatory pathways controlling cell shape transitions in V. cholerae and the benefits of switching between rod and curved shape have not been determined. We demonstrate that cell shape in V. cholerae is regulated by the bacterial second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) by posttranscriptionally repressing expression of crvA, a gene encoding an intermediate filament-like protein necessary for curvature formation in V. cholerae. This regulation is mediated by the transcriptional cascade that also induces production of biofilm matrix components, indicating that cell shape is coregulated with V. cholerae's induction of sessility. During microcolony formation, wild-type V. cholerae cells tended to exist as straight rods, while genetically engineering cells to maintain high curvature reduced microcolony formation and biofilm density. Conversely, straight V. cholerae mutants have reduced swimming speed when using flagellar motility in liquid. Our results demonstrate regulation of cell shape in bacteria is a mechanism to increase fitness in planktonic and biofilm lifestyles.

One gene, multiple ecological strategies: A biofilm regulator is a capacitor for sustainable diversity.

Many bacteria cycle between sessile and motile forms in which they must sense and respond to internal and external signals to coordinate appropriate physiology. Maintaining fitness requires genetic networks that have been honed in variable environments to integrate these signals. The identity of the major regulators and how their control mechanisms evolved remain largely unknown in most organisms. During four different evolution experiments with the opportunist betaproteobacterium Burkholderia cenocepacia in a biofilm model, mutations were most frequently selected in the conserved gene rpfR RpfR uniquely integrates two major signaling systems-quorum sensing and the motile-sessile switch mediated by cyclic-di-GMP-by two domains that sense, respond to, and control the synthesis of the autoinducer cis-2-dodecenoic acid (BDSF). The BDSF response in turn regulates the activity of diguanylate cyclase and phosphodiesterase domains acting on cyclic-di-GMP. Parallel adaptive substitutions evolved in each of these domains to produce unique life history strategies by regulating cyclic-di-GMP levels, global transcriptional responses, biofilm production, and polysaccharide composition. These phenotypes translated into distinct ecology and biofilm structures that enabled mutants to coexist and produce more biomass than expected from their constituents grown alone. This study shows that when bacterial populations are selected in environments challenging the limits of their plasticity, the evolved mutations not only alter genes at the nexus of signaling networks but also reveal the scope of their regulatory functions.

A positive perspective on DNA methylation: regulatory functions of DNA methylation outside of host defense in Gram-positive bacteria.

The presence of post-replicative DNA methylation is pervasive among both prokaryotic and eukaryotic organisms. In bacteria, the study of DNA methylation has largely been in the context of restriction-modification systems, where DNA methylation serves to safeguard the chromosome against restriction endonuclease cleavage intended for invading DNA. There has been a growing recognition that the methyltransferase component of restriction-modification systems can also regulate gene expression, with important contributions to virulence factor gene expression in bacterial pathogens. Outside of restriction-modification systems, DNA methylation from orphan methyltransferases, which lack cognate restriction endonucleases, has been shown to regulate important processes, including DNA replication, DNA mismatch repair, and the regulation of gene expression. The majority of research and review articles have been focused on DNA methylation in the context of Gram-negative bacteria, with emphasis toward Escherichia coli, Caulobacter crescentus, and related Proteobacteria. Here we summarize the epigenetic functions of DNA methylation outside of host defense in Gram-positive bacteria, with a focus on the regulatory effects of both phase variable methyltransferases and DNA methyltransferases from traditional restriction-modification systems.

Structural basis of DSF recognition by its receptor RpfR and its regulatory interaction with the DSF synthase RpfF.

The diffusible signal factors (DSFs) are a family of quorum-sensing autoinducers (AIs) produced and detected by numerous gram-negative bacteria. The DSF family AIs are fatty acids, differing in their acyl chain length, branching, and substitution but having in common a cis-2 double bond that is required for their activity. In both human and plant pathogens, DSFs regulate diverse phenotypes, including virulence factor expression, antibiotic resistance, and biofilm dispersal. Despite their widespread relevance to both human health and agriculture, the molecular basis of DSF recognition by their cellular receptors remained a mystery. Here, we report the first structure-function studies of the DSF receptor regulation of pathogenicity factor R (RpfR). We present the X-ray crystal structure of the RpfR DSF-binding domain in complex with the Burkholderia DSF (BDSF), which to our knowledge is the first structure of a DSF receptor in complex with its AI. To begin to understand the mechanistic role of the BDSF-RpfR contacts observed in the biologically important complex, we have also determined the X-ray crystal structure of the RpfR DSF-binding domain in complex with the inactive, saturated isomer of BDSF, dodecanoic acid (C12:0). In addition to these ligand-receptor complex structures, we report the discovery of a previously overlooked RpfR domain and show that it binds to and negatively regulates the DSF synthase regulation of pathogenicity factor F (RpfF). We have named this RpfR region the RpfF interaction (FI) domain, and we have determined its X-ray crystal structure alone and in complex with RpfF. These X-ray crystal structures, together with extensive complementary in vivo and in vitro functional studies, reveal the molecular basis of DSF recognition and the importance of the cis-2 double bond to DSF function. Finally, we show that throughout cellular growth, the production of BDSF by RpfF is post-translationally controlled by the RpfR N-terminal FI domain, affecting the cellular concentration of the bacterial second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Thus, in addition to describing the molecular basis for the binding and specificity of a DSF for its receptor, we describe a receptor-synthase interaction regulating bacterial quorum-sensing signaling and second messenger signal transduction.

Does mitomycin-C concentration have any influence on XEN45 gel stent outcomes in a real-world setting?

BACKGROUND: To compare the effectiveness and safety of XEN45 implanted with mitomycin-C (MMC) 0.01% versus (vs) XEN45 implanted with MMC 0.02%. METHODS: Retrospective and single-center study conducted on consecutive patients with open-angle glaucoma or ocular hypertension who underwent XEN45-implant, either alone or in combination with cataract surgery. The primary end-point was the mean change in intraocular pressure (IOP) from baseline to the last follow-up visit. RESULTS: Fifty-five patients (63 eyes) were included. Thirty-seven (58.7%) eyes underwent surgery with MMC 0.01% and 26 (41.3%) ones with MMC 0.02%. In the overall study sample, the mean (standard error) IOP was significantly lowered from 17.6 (0.7) mm Hg at baseline to 12.6 (0.3) mm Hg at month 12. The IOP was significantly lowered from 17.3 (15.4 to 19.2) mm Hg and 17.9 (16.1 to 17.8) mm Hg at baseline to 12.3 (11.3 to 13.3) mm Hg and 13.1 (12.3 to 13.9) mm Hg at month 12 in the MMC 0.01% and MMC 0.02% groups, respectively; p < 0.0001 each. The mean number of ocular-hypotensive medications significantly decreased from 2.1 (1.9 to 2.3) at baseline to 0.2 (0.04 to 0.3) at month 12, p < 0.0001, with no significant differences between MMC 0.01% and MMC 0.02% groups, p = 0.5181. At month 12, 50 (80.6%) eyes had functioning blebs. Regarding safety, 18 (28.6%) eyes have experience adverse events. CONCLUSION: XEN45, either alone or in combination with cataract surgery, showed a good effectiveness and safety profile. MMC dose had no influence on the IOP lowering, which may support the use of the lowest dose.

The Student-Generated Reasoning Tool (SGRT): Linking medical knowledge and clinical reasoning in preclinical education.

INTRODUCTION: The simultaneous integration of knowledge acquisition and development of clinical reasoning in preclinical medical education remains a challenge. To help address this challenge, the authors developed and implemented the Student-Generated Reasoning Tool (SGRT)-a tool asking students to propose and justify pathophysiological hypotheses, generate findings, and critically appraise information. METHODS: In 2019, students in a first-year preclinical course (n = 171; SGRT group) were assigned to one of 20 teams. Students used the SGRT individually, then in teams, and faculty provided feedback. The control group (n = 168) consisted of students from 2018 who did not use SGRT. Outcomes included academic performance, effectiveness of collaborative environments using the SGRT, and student feedback. RESULTS: Students were five times more likely to get questions correct if they were in the SGRT group versus control group. Accuracy of pathophysiological hypotheses was significantly lower for individuals than teams. Qualitative analysis indicated students benefited from generating their own data, justifying their reasoning, and working individually as well as in teams. CONCLUSIONS: This study introduces the SGRT as a potentially engaging, case-based, and collaborative learning method that may help preclinical medical students become aware of their knowledge gaps and integrate their knowledge in basic and clinical sciences in the context of clinical reasoning.

Endolymphatic hydrops in the unaffected ear of patients with unilateral Ménière's disease.

PURPOSE: Current studies show that frequency tuning modification is a good marker for the detection of endolymphatic hydrops (EH) employing magnetic resonance imaging (MRI) in patients with Ménière's disease (MD). The purpose of the present study is to analyze the auditory and vestibular function with audiometric and vestibular-evoked myogenic potentials (VEMP) responses, respectively, in both the affected and unaffected ears of patients with unilateral MD using MRI as diagnostic support for the degree of EH. METHODS: We retrospectively reviewed the medical records of 76 consecutive patients with unilateral definite MD (age 55 (28-75); 39 women, 37 men). MRI was used through intravenous gadolinium administration, audiometry, and VEMPs. Functional tests were performed up to a week after the MRI. All were followed up one year after imaging utilizing clinical, auditory, and vestibular testing to rule out bilateral involvement. RESULTS: In the unaffected ear, the mean pure-tone average is normal even in cases with hydrops and, for a similar severity of hydrops is significantly lower than in the affected ear. Significant differences for the amplitude of the response at 0.5 kHz, at 1 kHz between the affected and unaffected ears were found to be lower in the affected ears. The relative amplitude ratio (1 Kz-0.5 kHz) was significantly lower in the affected ear and in the case of the oVEMP response depends on the degree of EH. The response in the unaffected ear was not modified by the presence or the degree of hydrops. CONCLUSION: In the unaffected ear, hydrops is not associated with hearing deterioration. For a similar degree of hydrops, hearing loss is significantly greater in the affected ear. The endolymphatic hydrops in the vestibule induces a frequency bias in the VEMP response only in the affected ear and not in the unaffected ear. Because of these findings we consider that hydrops does not represent an active disorder in the unaffected ear.

Stability of Cocaine, Opiates, and Metabolites in Dried Saliva Spots.

Drug abuse still represents a global problem, and it is associated with an increased risk of diseases, injuries, and deaths. Cocaine (COC) and opiates are the most abused drugs and account for a significant number of fatalities. Therefore, it is important to develop methods capable of effectively identifying and quantifying these substances. The present study aims to evaluate the long-term stability of COC, ecgonine methylester (EME), benzoylecgonine (BEG), cocaethylene (COET), norcocaine (NCOC), morphine (MOR), codeine (COD) and 6-monoacetylmorphine (6-MAM) in oral fluid samples. The analytes of interest were isolated from the matrix (50 µL) using the dried saliva spots (DSS) sampling approach and were subsequently analyzed by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The parameters that could influence the stability of the target compounds were studied, and these were storage temperature, light, use of preservatives (and respective concentrations), and time. The effects of each parameter were evaluated using the design of experiments (DOE) approach. The stability of the target analytes was improved when the DSS were stored at room temperature, in the presence of light and using 1% sodium fluoride. The best conditions were then adopted for the DSS storage and long-term stability was assessed. COD was only stable for 1 day, EME was stable for 3 days, COC, COET, NCOC and 6-MAM were stable for 7 days, MOR for 14 days and BEG remained stable throughout the study (136 days). This is the first study that evaluates the stability of these compounds in oral fluid samples after application in DSS cards, and optimizes the conditions in order to improve their stability.