Heterogeneity of mature oligodendrocytes in the central nervous system.

Mature oligodendrocytes form myelin sheaths that are crucial for the insulation of axons and efficient signal transmission in the central nervous system. Recent evidence has challenged the classical view of the functionally static mature oligodendrocyte and revealed a gamut of dynamic functions such as the ability to modulate neuronal circuitry and provide metabolic support to axons. Despite the recognition of potential heterogeneity in mature oligodendrocyte function, a comprehensive summary of mature oligodendrocyte diversity is lacking. We delve into early 20 th -century studies by Robertson and Río-Hortega that laid the foundation for the modern identification of regional and morphological heterogeneity in mature oligodendrocytes. Indeed, recent morphologic and functional studies call into question the long-assumed homogeneity of mature oligodendrocyte function through the identification of distinct subtypes with varying myelination preferences. Furthermore, modern molecular investigations, employing techniques such as single cell/nucleus RNA sequencing, consistently unveil at least six mature oligodendrocyte subpopulations in the human central nervous system that are highly transcriptomically diverse and vary with central nervous system region. Age and disease related mature oligodendrocyte variation denotes the impact of pathological conditions such as multiple sclerosis, Alzheimer's disease, and psychiatric disorders. Nevertheless, caution is warranted when subclassifying mature oligodendrocytes because of the simplification needed to make conclusions about cell identity from temporally confined investigations. Future studies leveraging advanced techniques like spatial transcriptomics and single-cell proteomics promise a more nuanced understanding of mature oligodendrocyte heterogeneity. Such research avenues that precisely evaluate mature oligodendrocyte heterogeneity with care to understand the mitigating influence of species, sex, central nervous system region, age, and disease, hold promise for the development of therapeutic interventions targeting varied central nervous system pathology.

Six-month outcomes after traumatic brain injury in the Augmented versus Routine Approach to Giving Energy multicentre, double-blind, randomised controlled Trial (TARGET).

BACKGROUND: Critically ill patients with a traumatic brain injury (TBI) may require prolonged intensive care unit (ICU) admission and hence receive greater exposure to hospital enteral nutrition. It is unknown if augmented energy delivery with enteral nutrition during ICU admission impacts quality of life in survivors or gastrointestinal tolerance during nutrition delivery in the ICU. OBJECTIVES: The objective of this study was to compare health-related quality of life, using the EuroQol five-dimensions five-level visual analogue scale at 6 months, in survivors who presented with a TBI and received augmented energy (1.5 kcal/ml) to those who received routine energy (1.0 kcal/ml). Secondary objectives were to explore differences in total energy and protein delivery, gastrointestinal tolerance, and mortality between groups. METHODS: Secondary analysis of participants admitted with a TBI in the Augmented versus Routine Approach to Giving Energy Trial (TARGET) randomised controlled trial. Data are represented as n (%) or median (interquartile range). RESULTS: Of the 3957 patients in TARGET, 231 (5.8%) were admitted after a TBI (augmented = 124; routine = 107). Patients within TARGET who were admitted with a TBI were relatively young (42 [27, 61] years) and received TARGET enteral nutrition for an extended period (9 [5, 15] days). At 6 months, EuroQol five-dimensions five-level quality-of-life scores were available for 166 TBI survivors (72% of TBI cohort randomised, augmented = 97, routine = 69). There was no evidence of a difference in quality of life (augmented = 70 [52, 90]; routine = 70 [55, 85]; median difference augmented vs routine = 0 [95% confidence interval: -5, 10]). TBI participants assigned to augmented energy received more energy with a similar protein than the routine group. Gastrointestinal tolerance was similar between groups. CONCLUSION: While patients admitted after a TBI received enteral nutrition for an extended period, an increased exposure to augmented energy did not affect survivors' quality-of-life scores.

Multi-qubit gates and Schrödinger cat states in an optical clock.

Many-particle entanglement is a key resource for achieving the fundamental precision limits of a quantum sensor1. Optical atomic clocks2, the current state of the art in frequency precision, are a rapidly emerging area of focus for entanglement-enhanced metrology3-6. Augmenting tweezer-based clocks featuring microscopic control and detection7-10 with the high-fidelity entangling gates developed for atom-array information processing11,12 offers a promising route towards making use of highly entangled quantum states for improved optical clocks. Here we develop and use a family of multi-qubit Rydberg gates to generate Schrödinger cat states of the Greenberger-Horne-Zeilinger (GHZ) type with up to nine optical clock qubits in a programmable atom array. In an atom-laser comparison at sufficiently short dark times, we demonstrate a fractional frequency instability below the standard quantum limit (SQL) using GHZ states of up to four qubits. However, because of their reduced dynamic range, GHZ states of a single size fail to improve the achievable clock precision at the optimal dark time compared with unentangled atoms13. Towards overcoming this hurdle, we simultaneously prepare a cascade of varying-size GHZ states to perform unambiguous phase estimation over an extended interval14-17. These results demonstrate key building blocks for approaching Heisenberg-limited scaling of optical atomic clock precision.

Branch retinal vein occlusion and peripheral nonperfusion associated with astrocytic hamartoma of the optic nerve head in a patient with tuberous sclerosis.

PURPOSE: To report a case of branch retinal vein occlusion (BRVO) causing retinal neovascularization (NV) and vitreous hemorrhage associated with astrocytic hamartoma (AH) involving the optic nerve head in a patient with tuberous sclerosis complex (TSC). We review the natural history of the clinical presentation and posit its etiology. METHODS: Electronic health records were reviewed for patient history and demographics and multimodal ophthalmic imaging including fundus photography, fluorescein angiography, and optical coherence tomography (OCT). RESULTS: Neovascularization emanating superiorly and inferiorly from a large AH of the optic nerve head was identified as the cause of a longstanding vitreous hemorrhage. Retinal nonperfusion was also found in superior peripheral quadrants, most notably distal to the superior NV. OCT was useful in visualizing small retinal AH in the fellow eye that was otherwise undetected on prior dilated fundus examinations. The patient was treated with intravitreal anti-VEGF and superior sectoral PRP in the involved eye. CONCLUSION: BRVO and associated NV may represent rare vision-threatening sequela of AH in TSC and manifested in this case with diffuse peripheral retinal nonperfusion secondary to BRVO-induced ischemia. OCT is a valuable resource in identifying and monitoring AH of the retina.

Effect of packaging with versus without candy-oriented marketing themes on the appeal and sensory attributes of flavoured e-cigarettes.

SIGNIFICANCE: E-cigarettes with candy-themed marketing are implicated in decisions to first try e-cigarettes but have unknown effects on the experience of vaping. We compared adults' perceived appeal and sensory attributes after self-administering flavoured e-cigarettes in experimentally manipulated packaging with candy-themed versus standard marketing. We also assessed effect modification by salt vs free-base nicotine formulation. METHODS: Adults who currently used e-cigarettes and/or cigarettes (N=72; age M(SD)=31.4 (12.8) years) completed single-puff self-administrations from eight individually-packaged pods containing fruit or dessert-flavoured e-liquid via staff-guided video sessions. For each e-liquid flavour, we custom-manufactured packaging with standard (eg, 'mango'; mango fruit image) and candy (eg, 'mango gummy bear'; gummy bear image) marketing versions, which we varied within-subject (four pods candy; four pods standard). After participants opened the package and vaped the pod inside, they rated its sensory attributes and appeal (0-100 scale). Participants were randomised between subjects to salt or free-base ~2.3% nicotine in all pods. RESULTS: Marketing theme had no significant main effects on outcomes. Marketing theme × nicotine formulation interactions were significant; candy-themed (vs standard) packaging elevated composite appeal (Bdifference [estimated mean difference between marketing themes]=7.7), liking (Bdifference=8.4), and sweetness (Bdifference=5.7) ratings in free-base but not salt nicotine formulations. Marketing theme did not affect smoothness, harshness and bitterness ratings regardless of nicotine formulation. CONCLUSION: Candy-themed marketing may heighten the appeal and sweet sensory experience of vaping flavoured free-base nicotine e-cigarettes. While marketing restrictions are predominantly intended to prevent e-cigarette initiation, candy-themed marketing restrictions could also prevent persistent use by lowering the appeal of flavoured free-base nicotine e-cigarettes.

The formation and propagation of human Robertsonian chromosomes.

Robertsonian chromosomes are a type of variant chromosome found commonly in nature. Present in one in 800 humans, these chromosomes can underlie infertility, trisomies, and increased cancer incidence. Recognized cytogenetically for more than a century, their origins have remained mysterious. Recent advances in genomics allowed us to assemble three human Robertsonian chromosomes completely. We identify a common breakpoint and epigenetic changes in centromeres that provide insight into the formation and propagation of common Robertsonian translocations. Further investigation of the assembled genomes of chimpanzee and bonobo highlights the structural features of the human genome that uniquely enable the specific crossover event that creates these chromosomes. Resolving the structure and epigenetic features of human Robertsonian chromosomes at a molecular level paves the way to understanding how chromosomal structural variation occurs more generally, and how chromosomes evolve.

THOC1 complexes with SIN3A to regulate R-loops and promote glioblastoma progression.

Glioblastoma (GBM), the most common and aggressive malignant brain tumor in adults, has a median survival of 21 months. To identify drivers of GBM proliferation, we conducted a CRISPR-knockout screen, which revealed THO Complex 1 (THOC1) as a key driver. Knocking down THOC1 significantly reduced GBM cell viability across patient-derived xenograft (PDX) lines, enhancing survival (p<0.01) in primary PDX models. Conversely, overexpressing THOC1 in non-cancerous cells bolstered viability, decreasing survival and causing tumor engraftment in vivo (p<0.01). Further investigation revealed THOC1's robust interaction with SIN3A, a histone deacetylase complex. Histone deacetylation has been previously shown to prevent the buildup of R-loops, structures that form normally during transcription but can be lethal in excess. We found that THOC1-knockdown leads to elevated R-loop levels and reduced histone deacetylation levels. Next, to understand the networks specifically regulated by THOC1-mediated R-loop prevention, we conducted unbiased RNA-sequencing on control and THOC1-knockdown GBM cells. We found that THOC1's role in R-loop prevention primarily affects telomeres, critical regions for cell replication. We further show that THOC1-knockdown results in significantly increased telomeric R-loop levels and shortened telomeres. Ultimately, this study suggests that targeting THOC1 shows promise as a therapeutic strategy to disrupt the delicate R-loop landscape and undermine GBM's replicative potential.

High-throughput protein characterization by complementation using DNA barcoded fragment libraries.

Our ability to predict, control, or design biological function is fundamentally limited by poorly annotated gene function. This can be particularly challenging in non-model systems. Accordingly, there is motivation for new high-throughput methods for accurate functional annotation. Here, we used complementation of auxotrophs and DNA barcode sequencing (Coaux-Seq) to enable high-throughput characterization of protein function. Fragment libraries from eleven genetically diverse bacteria were tested in twenty different auxotrophic strains of Escherichia coli to identify genes that complement missing biochemical activity. We recovered 41% of expected hits, with effectiveness ranging per source genome, and observed success even with distant E. coli relatives like Bacillus subtilis and Bacteroides thetaiotaomicron. Coaux-Seq provided the first experimental validation for 53 proteins, of which 11 are less than 40% identical to an experimentally characterized protein. Among the unexpected function identified was a sulfate uptake transporter, an O-succinylhomoserine sulfhydrylase for methionine synthesis, and an aminotransferase. We also identified instances of cross-feeding wherein protein overexpression and nearby non-auxotrophic strains enabled growth. Altogether, Coaux-Seq's utility is demonstrated, with future applications in ecology, health, and engineering.

Clinical characterization, prognostic, and predictive values of HER2-low in patients with early breast cancer in the PALLAS trial (ABCSG-42/AFT-05/BIG-14-13/PrE0109).

BACKGROUND: Bidirectional crosstalk between HER2 and estrogen receptor (ER) pathways may influence outcomes and the efficacy of endocrine therapy (ET). Low HER2 expression levels (HER2-low) have emerged as a predictive biomarker in patients with breast cancer (BC). METHODS: PALLAS is an open, international, phase 3 study evaluating the addition of palbociclib for 2 years to adjuvant ET in patients with stage II-III ER-positive/HER2-negative BC. To assess the impact of HER2 expression on patient outcomes in the phase III PALLAS trial, we analyzed (1) the association between rate of HER2-low with demographic and clinicopathological parameters, (2) the prognostic value of HER2-low status on invasive disease-free survival (iDFS), distant relapse-free survival (DRFS), and overall survival (OS) and (3) HER2 expression's value as a predictive biomarker of response to palbociclib. HER2-low was defined as HER2 immunohistochemistry (IHC) 1 + or IHC 2 + with negative in situ hybridization (ISH). All pathologic evaluation was performed locally. Prognostic and predictive power of HER2 were assessed with Cox models. RESULTS: From the original PALLAS intention-to-treat population (N = 5753), 5304 patients (92.2%) were included in this analysis. Among these, 2254 patients (42.5%) were classified as having HER2 IHC 0 (HER2-0), and 3050 (57.5%) as having HER2-low disease (1838 with IHC 1 + and 1212 with IHC 2 +). Median follow-up was 59.8 months. HER2-low prevalence varied significantly across 21 participating countries (range 16.7% to 75.6%; p < 0.001) and was more frequent in patients enrolled in North America (63.1%) than in Europe (53.4%) or other regions (53.4%) (p < 0.001). HER2 status was not significantly associated with iDFS in a multivariable Cox model (hazard ratio 0.93, 95% confidence interval 0.81 - 1.06). No significant interaction was observed between treatment arm and HER2 status for iDFS (p = 0.43). Similar results were obtained for DRFS and OS. CONCLUSIONS: In this large, prospective, global patient cohort, no differences were observed in clinical parameters, prognosis, or differential benefit from palbociclib between HER2-0 and HER2-low tumors. Significant geographic variability was observed in the prevalence of HER2-low status, suggesting a high degree of variation in pathologic assessment of HER2 expression without impact on outcomes.

Complex genetic variation in nearly complete human genomes.

Diverse sets of complete human genomes are required to construct a pangenome reference and to understand the extent of complex structural variation. Here, we sequence 65 diverse human genomes and build 130 haplotype-resolved assemblies (130 Mbp median continuity), closing 92% of all previous assembly gaps and reaching telomere-to-telomere (T2T) status for 39% of the chromosomes. We highlight complete sequence continuity of complex loci, including the major histocompatibility complex (MHC), SMN1/SMN2, NBPF8, and AMY1/AMY2, and fully resolve 1,852 complex structural variants (SVs). In addition, we completely assemble and validate 1,246 human centromeres. We find up to 30-fold variation in α-satellite high-order repeat (HOR) array length and characterize the pattern of mobile element insertions into α-satellite HOR arrays. While most centromeres predict a single site of kinetochore attachment, epigenetic analysis suggests the presence of two hypomethylated regions for 7% of centromeres. Combining our data with the draft pangenome reference significantly enhances genotyping accuracy from short-read data, enabling whole-genome inference to a median quality value (QV) of 45. Using this approach, 26,115 SVs per sample are detected, substantially increasing the number of SVs now amenable to downstream disease association studies.

Medication Changes Among Older Drivers Involved in Motor Vehicle Crashes.

Importance: Although older adults may use potentially driver-impairing (PDI) medications that can produce psychomotor impairment, little is known about changes to PDI medication use among older adults from the time before to the time after a motor vehicle crash (MVC). Objective: To quantify use of and changes in PDI medications among older adults before and after an MVC. Design, Setting, and Participants: This cohort study used linked Medicare claims and police-reported MVC data on 154 096 person-crashes among 121 846 older drivers. Eligible persons were drivers aged 66 years or older, involved in a police-reported MVC in New Jersey from May 1, 2007, through December 31, 2017, and with continuous enrollment in Medicare fee-for-service Parts A and B for at least 12 months and Part D for at least 120 days prior to the MVC. Data were analyzed from January 2022 to May 2024. Main Outcomes and Measures: Use of benzodiazepines, nonbenzodiazepine hypnotics, opioid analgesics, and other PDI medications in the 120 days before and 120 days after the MVC. Because each person could contribute multiple MVCs during the study period if they met eligibility criteria, the unit of analysis was the number of person-crashes. The proportion of person-crashes after which PDI medications were started, discontinued, or continued was quantified as well. Results: Among 154 096 eligible person-crashes, the mean (SD) age of the drivers was 75.2 (6.7) years at the time of the MVC. Of 121 846 unique persons, 51.6% were women. In 80.0% of the person-crashes, drivers used 1 or more PDI medications before the crash, and in 81.0% of the person-crashes, drivers used 1 or more PDI medications after the crash. Use of benzodiazepines (8.1% before the crash and 8.8% after the crash), nonbenzodiazepine hypnotics (5.9% before the crash and 6.0% after the crash), and opioid analgesics (15.4% before the crash and 17.5% after the crash) was slightly higher after the MVC. After the MVC, drivers in 2.1% of person-crashes started benzodiazepines and 1.4% stopped benzodiazepines, drivers in 1.2% of person-crashes started nonbenzodiazepine hypnotics and 1.2% stopped nonbenzodiazepine hypnotics, and drivers in 8.4% of person-crashes started opioid analgesics and 6.3% stopped opioid analgesics. Conclusions and Relevance: This cohort study suggests that most older drivers involved in MVCs did not use fewer PDI medications after crashes than before crashes. Qualitative research of perceived risks vs benefits of PDI medications is necessary to understand the reasons why MVCs do not appear to motivate clinicians to deprescribe PDI medications as a strategy to avert potential harms, including additional MVCs.

Socioeconomic and medical determinants of state-level subjective cognitive decline in the United States.

INTRODUCTION: It is important to understand the socioeconomic and medical determinants of subjective cognitive decline (SCD) at a population level in the United States. METHODS: The primary outcomes are state-level rates of SCD and SCD-related functional impairment in adults aged ≥ 45, both measured in the Behavioral Risk Factor Surveillance System from 2016 to 2022. The exposures are state-level rates of poverty, unemployment, homelessness, college education, racial and ethnic minorities, uninsurance, smoking, hypertension, diabetes, and obesity as well as household income and physician density. RESULTS: The strongest state-level associations with rates of SCD were the prevalence of diabetes (rho = 0.64), hypertension (rho = 0.59), and poverty (rho = 0.58; all p < 0.001), and with SCD-related functional impairment were prevalence of poverty (rho = 0.71), diabetes (rho = 0.68), and hypertension (rho = 0.53; all p < 0.001). DISCUSSION: This study highlights critical links between SCD and socioeconomic and medical determinants in adults aged ≥ 45 in the United States, including the prevalence of poverty, diabetes, and hypertension. HIGHLIGHTS: State-level analysis reveals socioeconomic and medical risk factors for subjective cognitive decline (SCD) at a population level. The prevalence of poverty is a critical contributor to the state-level prevalence of SCD. The prevalence of diabetes and hypertension are also strong state-level determinants of SCD. Addressing the burden of cognitive decline at the population level necessitates targeting socioeconomic and medical factors.

Epigenetic control and inheritance of rDNA arrays.

Ribosomal RNA (rRNA) genes exist in multiple copies arranged in tandem arrays known as ribosomal DNA (rDNA). The total number of gene copies is variable, and the mechanisms buffering this copy number variation remain unresolved. We surveyed the number, distribution, and activity of rDNA arrays at the level of individual chromosomes across multiple human and primate genomes. Each individual possessed a unique fingerprint of copy number distribution and activity of rDNA arrays. In some cases, entire rDNA arrays were transcriptionally silent. Silent rDNA arrays showed reduced association with the nucleolus and decreased interchromosomal interactions, indicating that the nucleolar organizer function of rDNA depends on transcriptional activity. Methyl-sequencing of flow-sorted chromosomes, combined with long read sequencing, showed epigenetic modification of rDNA promoter and coding region by DNA methylation. Silent arrays were in a closed chromatin state, as indicated by the accessibility profiles derived from Fiber-seq. Removing DNA methylation restored the transcriptional activity of silent arrays. Array activity status remained stable through the iPS cell re-programming. Family trio analysis demonstrated that the inactive rDNA haplotype can be traced to one of the parental genomes, suggesting that the epigenetic state of rDNA arrays may be heritable. We propose that the dosage of rRNA genes is epigenetically regulated by DNA methylation, and these methylation patterns specify nucleolar organizer function and can propagate transgenerationally.

Deep Sequencing and Phenotyping in an Australian Tuberous Sclerosis Complex "No Mutations Identified" Cohort.

Tuberous sclerosis complex (TSC) is a variable multisystem disorder. The "no mutations identified" (NMI) group are reportedly phenotypically milder than those with an identified molecular cause, and often have mosaic or intronic variants not detected by standard sequencing methods. METHODS: We describe the phenotypes in an Australian TSC NMI group (n = 18) and a molecular testing strategy implementable in a diagnostic laboratory. Massively parallel sequencing (MPS) of the whole genomic regions of TSC1 and TSC2 was performed using DNA extracted from multiple tissue samples per participant. RESULTS: Our study showed that the phenotype in TSC NMI individuals can be similar to those with heterozygous, particularly TSC1, variants. Although neurodevelopmental outcomes can be less severe, the number of organ systems involved was similar to the non-mosaic groups. A diagnostic yield of 72% (13/18) was achieved, with the majority (10/13) being mosaic variants and the remainder heterozygous variants missed on previous testing. CONCLUSION: Testing DNA from multiple tissue samples allowed for validation of otherwise discarded low-level mosaic variants and detection of mosaic variants by MPS without excessive cost or the need for specialised techniques. Implementing this approach in a diagnostic setting is viable and allows optimal clinical care of patients with NMI TSC.

A multicentre point prevalence study of nocturnal hours awake and enteral pharmacological sleep aids in patients admitted to Australian and New Zealand intensive care units.

Objective: Critically ill patients suffer disrupted sleep. Hypnotic medications may improve sleep; however, local epidemiological data regarding the amount of nocturnal time awake and the use of such medications is needed. Design: Point prevalence study. Setting: Adult ICUs in Australia and New Zealand. Participants: All adult patients admitted to participating Intensive Care Units (ICUs) on the study day. Main outcome measures: Time awake overnight (22:00-06:00) was determined by structured nurse observation. The use of enterally administered sedative-hypnotic drugs prior to and during ICU admission was recorded, as was the use of a unit policy and non-pharmacological sleep promotion strategies. Results: Data were available for 532 patients admitted to 40 ICUs (median age 60 years, 336 (63.2%) male, and 222 (41.7%) invasively ventilated). Forty-eight patients (9.0%) received an enteral pharmacological sleep aid, of which melatonin (28, 5.2%) was most frequently used. Patients not invasively ventilated were observed to be awake overnight for a median of 4.0 h (interquartile range (IQR): 2.5, 5.5), with no difference in those receiving an enteral hypnotic (p = 0.9). Non-pharmacological sleep aids were reportedly not offered or available for 52% (earplugs) and 63% of patients (eye masks). Only 7 (17.5%) participating ICUs had a policy informing sleep-optimising interventions. Conclusions: Patients not receiving invasive ventilation appeared to spend many nocturnal hours awake. Pharmacological sleep aid administration was not associated with a greater observed time asleep. Most patients did not receive any non-pharmacological aid, and most ICUs did not have a local guideline or unit policy on sleep promotion.

Mechanisms of Polyethylene Terephthalate Pellet Fragmentation into Nanoplastics and Assimilable Carbons by Wastewater Comamonas.

Comamonadaceae bacteria are enriched on poly(ethylene terephthalate) (PET) microplastics in wastewaters and urban rivers, but the PET-degrading mechanisms remain unclear. Here, we investigated these mechanisms with Comamonas testosteroniKF-1, a wastewater isolate, by combining microscopy, spectroscopy, proteomics, protein modeling, and genetic engineering. Compared to minor dents on PET films, scanning electron microscopy revealed significant fragmentation of PET pellets, resulting in a 3.5-fold increase in the abundance of small nanoparticles (<100 nm) during 30-day cultivation. Infrared spectroscopy captured primarily hydrolytic cleavage in the fragmented pellet particles. Solution analysis further demonstrated double hydrolysis of a PET oligomer, bis(2-hydroxyethyl) terephthalate, to the bioavailable monomer terephthalate. Supplementation with acetate, a common wastewater co-substrate, promoted cell growth and PET fragmentation. Of the multiple hydrolases encoded in the genome, intracellular proteomics detected only one, which was found in both acetate-only and PET-only conditions. Homology modeling of this hydrolase structure illustrated substrate binding analogous to reported PET hydrolases, despite dissimilar sequences. Mutants lacking this hydrolase gene were incapable of PET oligomer hydrolysis and had a 21% decrease in PET fragmentation; re-insertion of the gene restored both functions. Thus, we have identified constitutive production of a key PET-degrading hydrolase in wastewater Comamonas, which could be exploited for plastic bioconversion.