Transcriptomic characterization of human lateral septum neurons reveals conserved and divergent marker genes across species.

The lateral septum (LS) is a midline, subcortical structure, which regulates social behaviors that are frequently impaired in neurodevelopmental disorders including schizophrenia and autism spectrum disorder. Mouse studies have identified neuronal populations within the LS that express a variety of molecular markers, including vasopressin receptor, oxytocin receptor, and corticotropin releasing hormone receptor, that control specific facets of social behavior. Despite its critical role in the regulation of social behavior and notable gene expression patterns, comprehensive molecular profiling of the human LS has not been performed. Here, we conducted single nucleus RNA-sequencing (snRNA-seq) to generate the first transcriptomic profiles of the human LS using postmortem human brain tissue samples from 3 neurotypical donors. Our analysis identified 4 transcriptionally distinct neuronal cell types within the human LS that are enriched for TRPC4 , the gene encoding Trp-related protein 4. Differential expression analysis revealed a distinct LS neuronal cell type that is enriched for OPRM1 , the gene encoding the µ-opioid receptor. Leveraging recently collected mouse LS snRNA-seq datasets, we also conducted a cross-species analysis. Our results demonstrate that TRPC4 enrichment in the LS is highly conserved between human and mouse, while FREM2 , which encodes FRAS1 related extracellular matrix protein 2, is enriched only in the human LS. Together, these results highlight transcriptional heterogeneity of the human LS, and identify robust marker genes for the human LS.

Guideline for the management of Clostridioides difficile infection in pediatric patients with cancer and hematopoietic cell transplantation recipients: 2024 update.

Our objective was to update a clinical practice guideline for the prevention and treatment of Clostridioides difficile infection (CDI) in pediatric patients with cancer and hematopoietic cell transplantation recipients. We reconvened an international multi-disciplinary panel. A systematic review of randomized controlled trials (RCTs) for the prevention or treatment of CDI in any population was updated and identified 31 new RCTs. Strong recommendations were made to use either oral metronidazole or oral vancomycin for non-severe CDI treatment, and to use either oral vancomycin or oral fidaxomicin for severe CDI. A strong recommendation that fecal microbiota transplantation should not be routinely used to treat CDI was also made. The panel made two new good practice statements to follow infection control practices including isolation in patients experiencing CDI, and to minimize systemic antibacterial administration where feasible, especially in patients who have experienced CDI.

Underlying reasons for primary care visits where chlamydia testing was performed in the United States, 2019-2022.

BACKGROUND: In the United States (US), most chlamydia cases are reported from non-STD clinics, and there is limited information focusing on the reasons for chlamydia testing in private settings. These analyses describe clinical visits to primary care providers where chlamydia testing was performed to help discern between screening and diagnostic testing for chlamydia. METHODS: Using the largest primary care clinical registry in the US, the PRIME registry, chlamydia tests were identified using Current Procedural Terminology (CPT) procedure codes and categorized as either diagnostic testing for sexually transmitted infection (STI) related symptoms, screening for chlamydia, or "other", based on ICD-10 Evaluation and Management codes selected for visits. RESULTS: Of 120,013 clinical visits with chlamydia testing between January 1, 2019 and December 31, 2022, 70.4% were women; 20.6% were with STI-related symptoms, 59.9% were for screening, and 19.5% for "other" reasons. Of those 120,013 clinical visits with chlamydia testing, the logit model showed that patients were significantly more likely to have STI-related symptoms if they were female than male, non-Hispanic black than non-Hispanic white, aged 15-24 years than aged ≥45 years, and resided in the South than in the Northeast. CONCLUSION: It is important to know what proportion of chlamydial infections are identified through screening programs and to have this information stratified by demographics. The inclusion of lab results could further facilitate a better understanding of the impact of chlamydia screening programs on the identification and treatment of chlamydia in private office settings in the United States.

Primary Care Physicians' Satisfaction With Interoperable Health Information Technology.

Importance: Enabling widespread interoperability-the ability of health information technology systems to exchange information and to use that information without special effort-is a primary focus of public policy on health information technology. More information on clinicians' experience using that technology can serve as one measure of the impact of that policy. Objective: To assess primary care physician perspectives on the state of interoperability. Design, Setting, and Participants: A cross-sectional survey of family medicine physicians in the US was conducted from December 12, 2021, to October 12, 2022. A sample of family medicine physicians who completed the Continuous Certification Questionnaire (CCQ), a required part of the American Board of Family Medicine certification process, which has a 100% response rate, were invited to participate. Main Outcomes and Measures: Eighteen items on the CCQ assessed experience accessing and using various information from outside organizations, including medications, immunizations, and allergies. Results: A total of 2088 physicians (1053 women [50%]; age reported categorically as either ≥50 years or <50 years) completed the CCQ interoperability questions in 2022. Of these respondents, 35% practiced in hospital or health system-owned practices, while 27% practiced in independently owned practices. Eleven percent were very satisfied with their ability to electronically access all 10 types of information from outside organizations included on the questionnaire, and a mean of 70% were at least somewhat satisfied. A total of 23% of family medicine physicians reported information from outside organizations was very easy to use, and an additional 65% reported that information was somewhat easy to use. Only 8% reported that information from different electronic health record (EHR) developers' products was very easy to use compared with 38% who reported information from the same EHR developer's product was very easy to use. Conclusions and Relevance: This survey study of family medicine physicians found modest and uneven improvement in physicians' experience with interoperability. These findings suggest that substantial heterogeneity in satisfaction by information type, source of information, EHR, practice type, ownership, and patient population necessitates diverse policy and strategies to improve interoperability.

The effectiveness and safety of proton beam radiation therapy in children and young adults with Central Nervous System (CNS) tumours: a systematic review.

BACKGROUND: Central nervous system (CNS) tumours account for around 25% of childhood neoplasms. With multi-modal therapy, 5-year survival is at around 75% in the UK. Conventional photon radiotherapy has made significant contributions to survival, but can be associated with long-term side effects. Proton beam radiotherapy (PBT) reduces the volume of irradiated tissue outside the tumour target volume which may potentially reduce toxicity. Our aim was to assess the effectiveness and safety of PBT and make recommendations for future research for this evolving treatment. METHODS: A systematic review assessing the effects of PBT for treating CNS tumours in children/young adults was undertaken using methods recommended by Cochrane and reported using PRISMA guidelines. Any study design was included where clinical and toxicity outcomes were reported. Searches were to May 2021, with a narrative synthesis employed. RESULTS: Thirty-one case series studies involving 1731 patients from 10 PBT centres were included. Eleven studies involved children with medulloblastoma / primitive neuroectodermal tumours (n = 712), five ependymoma (n = 398), four atypical teratoid/rhabdoid tumour (n = 72), six craniopharyngioma (n = 272), three low-grade gliomas (n = 233), one germ cell tumours (n = 22) and one pineoblastoma (n = 22). Clinical outcomes were the most frequently reported with overall survival values ranging from 100 to 28% depending on the tumour type. Endocrine outcomes were the most frequently reported toxicity outcomes with quality of life the least reported. CONCLUSIONS: This review highlights areas of uncertainty in this research area. A well-defined, well-funded research agenda is needed to best maximise the potential of PBT. SYSTEMATIC REVIEW REGISTRATION: PROSPERO-CRD42016036802.

Prevalence and Predictors of Burnout Among Resident Family Physicians.

BACKGROUND AND OBJECTIVES: Resident burnout may affect career choices and empathy. We examined predictors of burnout among family medicine residents. METHODS: We used data from the 2019-2021 American Board of Family Medicine Initial Certification Questionnaire, which is required of graduating residents. Burnout was a binary variable defined as reporting callousness or emotional exhaustion once a week or more. We evaluated associations using bivariate and multilevel multivariable regression analyses. RESULTS: Among 11,570 residents, 36.4% (n=4,211) reported burnout. This prevalence did not significantly vary from 2019 to 2021 and was not significantly attributable to the residency program (ICC=0.07). Residents identifying as female reported higher rates of burnout (39.0% vs 33.4%, AOR=1.29 [95% CI 1.19-1.40]). Residents reporting Asian race (30.5%, AOR=0.78 [95% CI 0.70-0.86]) and Black race (32.3%, AOR=0.71 [95% CI 0.60-0.86]) reported lower odds of burnout than residents reporting White race (39.2%). We observed lower rates among international medical graduates (26.7% vs 40.3%, AOR=0.54 [95% CI 0.48-0.60]), those planning to provide outpatient continuity care (36.0% vs 38.7%, AOR=0.77 [95% CI 0.68-0.86]), and those at smaller programs (31.7% for <6 residents per class vs 36.3% for 6-10 per class vs 40.2% for >10 per class). Educational debt greater than $250,000 was associated with higher odds of burnout than no debt (AOR=1.29 [95% CI 1.15-1.45]). CONCLUSIONS: More than one-third of recent family medicine residents reported burnout. Odds of burnout varied significantly with resident and program characteristics.

TrkB-dependent regulation of molecular signaling across septal cell types.

The lateral septum (LS), a GABAergic structure located in the basal forebrain, is implicated in social behavior, learning, and memory. We previously demonstrated that expression of tropomyosin kinase receptor B (TrkB) in LS neurons is required for social novelty recognition. To better understand molecular mechanisms by which TrkB signaling controls behavior, we locally knocked down TrkB in LS and used bulk RNA-sequencing to identify changes in gene expression downstream of TrkB. TrkB knockdown induces upregulation of genes associated with inflammation and immune responses, and downregulation of genes associated with synaptic signaling and plasticity. Next, we generated one of the first atlases of molecular profiles for LS cell types using single nucleus RNA-sequencing (snRNA-seq). We identified markers for the septum broadly, and the LS specifically, as well as for all neuronal cell types. We then investigated whether the differentially expressed genes (DEGs) induced by TrkB knockdown map to specific LS cell types. Enrichment testing identified that downregulated DEGs are broadly expressed across neuronal clusters. Enrichment analyses of these DEGs demonstrated that downregulated genes are uniquely expressed in the LS, and associated with either synaptic plasticity or neurodevelopmental disorders. Upregulated genes are enriched in LS microglia, associated with immune response and inflammation, and linked to both neurodegenerative disease and neuropsychiatric disorders. In addition, many of these genes are implicated in regulating social behaviors. In summary, the findings implicate TrkB signaling in the LS as a critical regulator of gene networks associated with psychiatric disorders that display social deficits, including schizophrenia and autism, and with neurodegenerative diseases, including Alzheimer's.

Mechanistic implications of the ternary complex structural models for the photoenzyme protochlorophyllide oxidoreductase.

The photoenzyme protochlorophyllide oxidoreductase (POR) is an important enzyme for understanding biological H-transfer mechanisms. It uses light to catalyse the reduction of protochlorophyllide to chlorophyllide, a key step in chlorophyll biosynthesis. Although a wealth of spectroscopic data have provided crucial mechanistic insight, a structural rationale for POR photocatalysis has proved challenging and remains hotly debated. Recent structural models of the ternary enzyme-substrate complex, derived from crystal and electron microscopy data, show differences in the orientation of the protochlorophyllide substrate and the architecture of the POR active site, with significant implications for the catalytic mechanism. Here, we use a combination of computational and experimental approaches to investigate the compatibility of each structural model with the hypothesised reaction mechanisms and propose an alternative structural model for the cyanobacterial POR ternary complex. We show that a strictly conserved tyrosine, previously proposed to act as the proton donor in POR photocatalysis, is unlikely to be involved in this step of the reaction but is crucial for Pchlide binding. Instead, an active site cysteine is important for both hydride and proton transfer reactions in POR and is proposed to act as the proton donor, either directly or through a water-mediated network. Moreover, a conserved glutamine is important for Pchlide binding and ensuring efficient photochemistry by tuning its electronic properties, likely by interacting with the central Mg atom of the substrate. This optimal 'binding pose' for the POR ternary enzyme-substrate complex illustrates how light energy can be harnessed to facilitate enzyme catalysis by this unique enzyme.

Temporally specific gene expression and chromatin remodeling programs regulate a conserved Pdyn enhancer.

Neuronal and behavioral adaptations to novel stimuli are regulated by temporally dynamic waves of transcriptional activity, which shape neuronal function and guide enduring plasticity. Neuronal activation promotes expression of an immediate early gene (IEG) program comprised primarily of activity-dependent transcription factors, which are thought to regulate a second set of late response genes (LRGs). However, while the mechanisms governing IEG activation have been well studied, the molecular interplay between IEGs and LRGs remain poorly characterized. Here, we used transcriptomic and chromatin accessibility profiling to define activity-driven responses in rat striatal neurons. As expected, neuronal depolarization generated robust changes in gene expression, with early changes (1 hr) enriched for inducible transcription factors and later changes (4 hr) enriched for neuropeptides, synaptic proteins, and ion channels. Remarkably, while depolarization did not induce chromatin remodeling after 1 hr, we found broad increases in chromatin accessibility at thousands of sites in the genome at 4 hr after neuronal stimulation. These putative regulatory elements were found almost exclusively at non-coding regions of the genome, and harbored consensus motifs for numerous activity-dependent transcription factors such as AP-1. Furthermore, blocking protein synthesis prevented activity-dependent chromatin remodeling, suggesting that IEG proteins are required for this process. Targeted analysis of LRG loci identified a putative enhancer upstream of Pdyn (prodynorphin), a gene encoding an opioid neuropeptide implicated in motivated behavior and neuropsychiatric disease states. CRISPR-based functional assays demonstrated that this enhancer is both necessary and sufficient for Pdyn transcription. This regulatory element is also conserved at the human PDYN locus, where its activation is sufficient to drive PDYN transcription in human cells. These results suggest that IEGs participate in chromatin remodeling at enhancers and identify a conserved enhancer that may act as a therapeutic target for brain disorders involving dysregulation of Pdyn.

Chst9 Marks a Spatially and Transcriptionally Unique Population of Oprm1 -Expressing Neurons in the Nucleus Accumbens.

Opioids produce addictive, analgesic, and euphoric effects via actions at mu opioid receptors (µORs). The µOR is encoded by the Oprm1 gene and is expressed in multiple brain regions that regulate reward and motivation, such as the nucleus accumbens (NAc). Oprm1 expression in NAc medium spiny neurons (MSNs) mediates opioid place preference, seeking, and consumption. However, recent single nucleus RNA sequencing (snRNA-seq) studies in rodent, primate, and human NAc have revealed that multiple subpopulations of NAc neurons express Oprm1 mRNA, making it unclear which populations mediate diverse behaviors resulting from µOR activation. Using published snRNA-seq datasets from the rat NAc, we identified a novel population of MSNs that express the highest levels of Oprm1 of any NAc cell type. Here, we show that this population is selectively marked by expression of Chst9 , a gene encoding a carbohydrate sulfotransferase. To validate this observation and characterize spatial localization of this population in the rat NAc, we performed multiplexed RNAscope fluorescence in situ hybridization studies to detect expression of Oprm1 and Chst9 mRNA along with well-validated markers of MSNs. Notably, Chst9 + neurons exhibited more abundant expression of Oprm1 as compared to other cell types, and formed discrete cellular clusters along the medial and ventral borders of the NAc shell subregion. Moreover, CHST9 mRNA was also found to mark specific MSN populations in published human and primate snRNA-seq studies, indicating that this unique population may be conserved across species. Together, these results identify a spatially and transcriptionally distinct NAc neuron population characterized by the expression of Chst9 . The abundant expression of Oprm1 in this population and the conservation of these cells across species suggests that they may play a key functional role in opioid response and identify this subpopulation as a target for further investigation.