Highly reliable LC-MS lipidomics database for efficient human plasma profiling based on NIST SRM 1950.

Liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS)-based methods have become the gold standard methodology for the comprehensive profiling of the human plasma lipidome. However, both the complexity of lipid chemistry and LC-HRMS-associated data pose challenges to the characterization of this biological matrix. In accordance with the current consensus of quality requirements for LC-HRMS lipidomics data, we aimed to characterize the NIST® Standard Reference Material for Human Plasma (SRM 1950) using an LC-ESI(+/-)-MS method compatible with high-throughput lipidome profiling. We generated a highly curated lipid database with increased coverage, quality, and consistency, including additional quality assurance procedures involving adduct formation, within-method m/z evaluation, retention behavior of species within lipid chain isomers, and expert-driven resolution of isomeric and isobaric interferences. As a proof-of-concept, we showed the utility of our in-house LC-MS lipidomic database -consisting of 592 lipid entries- for the fast, comprehensive, and reliable lipidomic profiling of the human plasma from healthy human volunteers. We are confident that the implementation of this robust resource and methodology will have a significant impact by reducing data redundancy and the current delays and bottlenecks in untargeted plasma lipidomic studies.

Calling for Action: The Need of Large-Scale Cohorts to Uncover the Cardiovascular Risk in Non-Sleepy Obstructive Sleep Apnea.

Since randomized clinical trials currently do not support continuous positive airway pressure treatment of asymptomatic obstructive sleep apnea (OSA) we proposed the Obesity, Symptoms, and CARdiovascular assessment (OSCAR) algorithm to aid clinicians in the management of asymptomatic low-risk moderate-severe OSA, focusing on weight loss, symptoms and cardiovascular disease (CVD) risk assessment. Exploiting the data of the Sleep Heart Health Study we selected subjects with a body mass index (BMI) < 30 Kg/m2, no history of CVD or sleepiness and compared 552 patients with moderate-severe OSA (OSCAR(-)) to 916 individuals without OSA (No-OSA). After adjusting for age, gender, and BMI, there was no significant difference in the risk of major adverse cardiovascular events (MACE) between OSCAR(-) and No-OSA (1.05; 95%CI 0.81-1.37). The study suggests that low-risk moderate-severe OSA patients may not have a greater risk of MACE compared to those without OSA and highlights the need for further research on this topic.

The Effect of Obstructive Sleep Apnea on Subclinical Target Organ Damage in Patients With Resistant Hypertension.

INTRODUCTION: Among all patients with hypertension, those with resistant hypertension (RH) have the highest rates of subclinical organ damage (SOD). The prevalence of obstructive sleep apnea (OSA) is high in RH patients, and it could contribute to SOD. We aimed to investigate how OSA and its treatment are related to SOD in a large cohort of RH patients. METHODS: This is an ancillary analysis to the SARAH study, a multicentre observational cohort aiming to evaluate the impact of OSA on RH. Individuals with RH who were undergoing a sleep study and have information on at least one of the SOD variables (vascular, cardiac or renal damage) were selected. Patients were followed-up for three years. RESULTS: In total, 503 subjects were included. The participants were predominantly male, obese, and the median (IQR) apnea-hypopnea index (AHI) was 15.5 (7.90-31.5)events/h. No differences in the presence of vascular or cardiac damage were observed between OSA and non-OSA patients. A lower estimated glomerular filtration rate (eGFR) was observed in participants with OSA than in those without OSA, with an adjusted effect of -8.69mL/min/1.73m2 (-13.59, -3.79; p value<0.001). Kidney damage was also greater in subjects with OSA, with an adjusted OR (95% CI) of 1.77 (1.09, 2.87; p value=0.02). The eGFR showed a linear dose-response relationship with OSA severity. Among patients treated with CPAP, lower eGFR values were observed in noncompliant subjects. CONCLUSIONS: OSA could contribute to worsening renal function in patients with RH. No compliance with CPAP was associated with lower values of eGFR.

Comparing anticoagulant rodenticide exposure in barn owl (Tyto alba) and common kestrel (Falco tinnunculus): A biomonitoring study in an agricultural region of southeastern Spain.

Second-generation anticoagulant rodenticides (SGARs) are commonly used for rodent control, affecting various non-target wildlife species. Here, blood samples from common kestrels (Falco tinnunculus, n = 70 chicks) and barn owls (Tyto alba, n = 54 chicks and 12 adults) from Southeastern Spain were analysed using HPLC-TQ. SGAR prevalence was 68.6% in kestrel chicks, 50% in barn owl chicks and 100% in adult barn owls, with multiple SGARs in both species. Prothrombin time analysis in barn owls revealed a positive correlation with blood ΣSGARs, suggesting a potential adverse effect on coagulation. Analysis of variables potentially influencing SGAR prevalence indicated that, for kestrels, it was only related to the extent of artificial surface, showing no differences across study sites. In owlets, the highest prevalence occurred in the most urbanized study site, with human population density being a key factor. This study highlights species-specific differences in SGAR exposure, likely influenced by ecological traits. Barn owls probably encounter contaminated prey near anthropized areas, with widespread SGAR use and higher presence of target rodents. Conversely, kestrels, hunting a variety of prey often near human settlements, face consistently elevated exposure from multiple sources. Understanding these variations is crucial for effective conservation and minimizing SGAR impact on non-target wildlife.

A comprehensive assessment of care competence and maternal experience of first antenatal care visits in Mexico: Insights from the baseline survey of an observational cohort study.

BACKGROUND: Comprehensive antenatal care (ANC) must prioritize competent, evidence-based medical attention to ensure a positive experience and value for its users. Unfortunately, there is scarce evidence of implementing this holistic approach to ANC in low- and middle-income countries, leading to gaps in quality and accountability. This study assessed care competence, women's experiences during the first ANC visit, and the factors associated with these care attributes. METHODS AND FINDINGS: The study analyzed cross-sectional baseline data from the maternal eCohort study conducted in Mexico from August to December 2023. The study adapted the Quality Evidence for Health System Transformation (QuEST) network questionnaires to the Mexican context and validated them through expert group and cognitive interviews with women. Pregnant women aged 18 to 49 who had their first ANC visit with a family physician were enrolled in 48 primary clinics of the Instituto Mexicano del Seguro Social across 8 states. Care competence and women's experiences with care were the primary outcomes. The statistical analysis comprised descriptive statistics, multivariable linear and Poisson regressions. A total of 1,390 pregnant women were included in the study. During their first ANC visit, women received only 67.7% of necessary clinical actions on average, and 52% rated their ANC experience as fair or poor. Women with previous pregnancies (adjusted regression coefficient [aCoef.] -3.55; (95% confidence intervals [95% CIs]): -4.88, -2.22, p < 0.001), at risk of depression (aCoef. -3.02; 95% CIs: -5.61, -0.43, p = 0.023), those with warning signs (aCoef. -2.84; 95% CIs: -4.65, -1.03, p = 0.003), common pregnancy discomforts (aCoef. -1.91; 95% CIs: -3.81, -0.02, p = 0.048), or those who had a visit duration of less than 20 minutes (<15 minutes: aCoef. -7.58; 95% CIs: -10.21, -4.95, p < 0.001 and 15 to 19 minutes: aCoef. -2.73; 95% CIs: -4.79, -0.67, p = 0.010) and received ANC in the West and Southeast regions (aCoef. -5.15; 95% CIs: -7.64, -2.66, p < 0.001 and aCoef. -5.33; 95% CIs: -7.85, -2.82, p < 0.001, respectively) had a higher probability of experiencing poorer care competence. Higher care competence (adjusted prevalence ratio [aPR] 1.004; 95% CIs:1.002, 1.005, p < 0.001) and receiving care in a small clinic (aPR 1.19; 95% CIs: 1.06, 1.34, p = 0.003) compared to a medium-sized clinic were associated with a better first ANC visit experience, while common pregnancy discomforts (aPR 0.94; 95% CIs: 0.89, 0.98, p = 0.005) and shorter visit length (aPR 0.94; 95% CIs: 0.88, 0.99, p = 0.039) were associated with lower women's experience. The primary limitation of the study is that participants' responses may be influenced by social desirability bias, leading them to provide socially acceptable responses. CONCLUSIONS: We found important gaps in adherence to ANC standards and that care competence during the first ANC visit is an important predictor of positive user experience. To inform quality improvement efforts, IMSS should institutionalize the routine monitoring of ANC competencies and ANC user experience. This will help identify poorly performing facilities and providers and address gaps in the provision of evidence-based and women-centered care.

Interactions of Obstructive Sleep Apnea With the Pathophysiology of Cardiovascular Disease, Part 1: JACC State-of-the-Art Review.

The American Heart Association considers sleep health an essential component of cardiovascular health, and sleep is generally a time of cardiovascular quiescence, such that any deviation from normal sleep may be associated with adverse cardiovascular consequences. Many studies have shown that both impaired quantity and quality of sleep, particularly with obstructive sleep apnea (OSA) and comorbid sleep disorders, are associated with incident cardiometabolic consequences. OSA is associated with repetitive episodes of altered blood gases, arousals, large negative swings in intrathoracic pressures, and increased sympathetic activity. Recent studies show that OSA is also associated with altered gut microbiota, which could contribute to increased risk of cardiovascular disease. OSA has been associated with hypertension, atrial fibrillation, heart failure, coronary artery disease, stroke, and excess cardiovascular mortality. Association of OSA with chronic obstructive lung disease (overlap syndrome) and morbid obesity (obesity hypoventilation syndrome) increases the odds of mortality.

The Antitumour Mechanisms of Carotenoids: A Comprehensive Review.

Carotenoids, known for their antioxidant properties, have garnered significant attention for their potential antitumour activities. This comprehensive review aims to elucidate the diverse mechanisms by which carotenoids exert antitumour effects, focusing on both well-established and novel findings. We explore their role in inducing apoptosis, inhibiting cell cycle progression and preventing metastasis by affecting oncogenic and tumour suppressor proteins. The review also explores the pro-oxidant function of carotenoids within cancer cells. In fact, although their overall contribution to cellular antioxidant defences is well known and significant, some carotenoids can exhibit pro-oxidant effects under certain conditions and are able to elevate reactive oxygen species (ROS) levels in tumoural cells, triggering mitochondrial pathways that would lead to cell death. The final balance between their antioxidant and pro-oxidant activities depends on several factors, including the specific carotenoid, its concentration and the redox environment of the cell. Clinical trials are discussed, highlighting the conflicting results of carotenoids in cancer treatment and the importance of personalized approaches. Emerging research on rare carotenoids like bacterioruberin showcases their superior antioxidant capacity and selective cytotoxicity against aggressive cancer subtypes, such as triple-negative breast cancer. Future directions include innovative delivery systems, novel combinations and personalized treatments, aiming to enhance the therapeutic potential of carotenoids. This review highlights the promising yet complex landscape of carotenoid-based cancer therapies, calling for continued research and clinical exploration.

Exploring Dietary Interventions in Autism Spectrum Disorder.

Autism spectrum disorder (ASD) involves social communication difficulties and repetitive behaviors, and it has a growing prevalence worldwide. Symptoms include cognitive impairments, gastrointestinal (GI) issues, feeding difficulties, and psychological problems. A significant concern in ASD is food selectivity, leading to nutrient deficiencies. Common GI issues in ASD, such as constipation and irritable bowel syndrome, stem from abnormal gut flora and immune system dysregulation. Sensory sensitivities and behavioral challenges exacerbate these problems, correlating with neurological symptom severity. Children with ASD also exhibit higher oxidative stress due to low antioxidant levels like glutathione. Therapeutic diets, including ketogenic, high-antioxidant, gluten-free and casein-free, and probiotic-rich diets, show potential in managing ASD symptoms like behavior, communication, GI issues, and oxidative stress, though the evidence is limited. Various studies have focused on different populations, but there is increasing concern about the impact among children. This review aims to highlight the food preferences of the ASD population, analyze the effect of the physicochemical and nutritional properties of foods on the selectivity in its consumption, GI problems, and antioxidant deficiencies in individuals with ASD, and evaluate the effectiveness of therapeutic diets, including diets rich in antioxidants, gluten-free and casein-free, ketogenic and essential fatty acids, and probiotic-rich diets in managing these challenges.

Treatment of OSA and its Impact on Cardiovascular Disease, Part 2: JACC State-of-the-Art Review.

Many studies have shown an association of obstructive sleep apnea (OSA) with incident cardiovascular diseases, particularly when comorbid with insomnia, excessive sleepiness, obesity hypoventilation syndrome, and chronic obstructive pulmonary disease. Randomized controlled trials (RCTs) have demonstrated that treatment of OSA with positive airway pressure devices (CPAP) improves systemic hypertension, particularly in those with resistant hypertension who are adherent to CPAP. However, large RCTs have not shown long-term benefits of CPAP on hard cardiovascular outcomes, but post hoc analyses of these RCTs have demonstrated improved hard outcomes in those who use CPAP adequately. In theory, low CPAP adherence and patient selection may have contributed to neutral results in intention-to-treat analyses. Only by further research into clinical, translational, and basic underlying mechanisms is major progress likely to continue. This review highlights the various treatment approaches for sleep disorders, particularly OSA comorbid with various other disorders, the potential reasons for null results of RCTs treating OSA with CPAP, and suggested approaches for future trials.

Effect of mesenchymal stem cells on the host response in severe community-acquired pneumonia.

Mesenchymal stem cells (MSC) have immune regulatory properties that may ameliorate pathophysiological processes in sepsis. We determined the effect of allogeneic adipose-derived MSCs (Cx611) on the host response during sepsis due to community-acquired bacterial pneumonia (CABP) by measuring 29 plasma biomarkers and blood transcriptomes at six time points in 82 patients randomised to two intravenous infusions of Cx611 or placebo. Cx611 treatment enhanced several endothelial cell and procoagulant response plasma biomarkers, and led to increased expression of pathways related to innate immunity, haemostasis and apoptosis. Cx611 infusion in sepsis due to CABP is associated with broad host response alterations.

Outcomes with non-small cell lung cancer and brain-only metastasis.

Background: We evaluated outcomes in non-small cell lung cancer (NSCLC) patients who presented with brain-only metastatic (BOM) disease overall and by EGFR/ALK mutation status. Methods: We analyzed clinico-demographic, treatment and survival data for all NSCLC patients who presented to our center between 2014 and 2016 with BOM as their first presentation of metastatic disease. Differences in overall survival (OS) were evaluated using log-rank tests for NSCLC wildtype (NSCLCwt) versus NSCLC with an ALK-rearrangement/EGFR-mutation (NSCLCmut+). Results: Of 109 patients with BOM, median age was 68 years; 51 % were female; 69 % Caucasian; 76 % ever-smoker; 76 % adenocarcinoma; and 25 % NSCLCmut+. While 41 patients (38 %) had subsequent brain-only progressive disease (PD), 22 (20 %) developed extracranial metastases. A higher proportion of NSCLCmut+ (vs -wt) subsequently progressed outside the brain (37 % vs 15 %, p = 0.03). Median time-to-first-extracranial-metastases was 8.5 (NSCLCmut+) vs 21.0 months (NSCLCwt; p = 0.23).With 17.7 months median follow-up, median-OS was 15.9 months [95%CI: 11.5-21.3; all patients]; 12.3 [7.4-18.4; NSCLCwt] and 38.9 [21.3-not reached (NR); NSCLCmut+] (p = 0.09). In 33 of 80 patients with de novo BOM, the primary tumor was treated with surgery or radiotherapy. In patients with NSCLCwt, there was no OS benefit associated with local lung tumor treatment (p = 0.68), whereas in NSCLCmut + pts, local lung tumor treatment correlated with greater OS (median-OS NR vs 21.5 months; p = 0.05). Conclusion: In patients with NSCLCwt with BOM, we observed a -predominant pattern of brain-only secondary progression, however patients with NSCLCmut + more often progressed extracranially. In patients with NSCLCmut+ and BOM, definitive primary tumor treatment correlated with improved survival.

Factors Influencing Feeding Decisions in Children With Bronchiolitis on High-Flow Nasal Cannula.

BACKGROUND AND OBJECTIVES: High-flow nasal cannula (HFNC) is used in up to 50% of children admitted with bronchiolitis. Consensus recommendations for feeding these children have not been established, and there is variability in practice. We sought to identify factors influencing feeding decisions for general care patients admitted with bronchiolitis on HFNC from a national sample of interdisciplinary care team members. METHODS: In this qualitative study, we conducted semi-structured virtual interviews with care team members involved in making feeding decisions at 10 US hospitals from June 2022 to March 2023. Eligible participants included 1 nurse, respiratory therapist, speech language pathologist, and physician from each site. Interviews were audio-recorded, transcribed, and conducted until reaching sufficiency. Three researchers analyzed transcript data using content analysis guided by the Systems Engineering Initiative for Patient Safety 2.0 model. RESULTS: We interviewed 29 participants, including 19 nurses, respiratory therapists, and speech language pathologists and 10 physicians. Participants identified 11 factors influencing feeding decisions related to hospital work systems and processes outlined in the Systems Engineering Initiative for Patient Safety model, including people (child and parent characteristics, care team experience), tools and technology (guideline, protocol, ordersets), organization (institutional culture, education), environment (time of day, care location), task (interventions to optimize feeding), and process (clinical assessment, feeding trial, communication). CONCLUSIONS: Our findings suggest that feeding decisions are driven by factors related to the child, care team experience, institutional tools, and culture. These key factors may inform local improvement efforts to decrease variation in feeding children with bronchiolitis requiring HFNC.

Obstructive sleep apnea and hypertension; critical overview.

Obstructive sleep apnea (OSA) and hypertension are two important modifiable risk factors for cardiovascular disease and mortality. Numerous studies have highlighted the interplay between these two conditions. We provide a critical review of the current literature on the role of the OSA as a risk factor for hypertension and its effect on blood pressure (BP). We discuss several key topics: the effect of OSA on nocturnal BP, BP response to continuous positive airway pressure (CPAP) treatment, CPAP effect on BP in refractory hypertension, the role of OSA in BP variability (BPV), and maladaptive cardiac remodeling mediated by OSA's effect on BP. Finally, we discuss the unique aspects of ethnicity and social determinants of health on OSA with a focus on Asian populations and the disparity in BP control and cardiovascular outcomes.

Current and Future Implications of Lymphedema Surgery in Head and Neck Reconstruction.

In this study, the authors shed light on the underappreciated realm of head and neck lymphedema (HNL) amid the backdrop of significant advancements in extremity lymphedema management. Despite its prevalence and impact, HNL has long been overlooked, attributed to its subtle symptom presentation and lack of awareness among primary care providers. The study delves into the unique challenges associated with diagnosing and treating HNL, emphasizing the predominance of internal swelling over external manifestations. The authors advocate for the refinement and standardization of outcome measures and the integration of innovative techniques such as indocyanine green lymphography and patient-reported outcomes.

Proneurogenic actions of follicle-stimulating hormone on neurospheres derived from ovarian cortical cells in vitro.

BACKGROUND: Neural stem and progenitor cells (NSPCs) from extra-neural origin represent a valuable tool for autologous cell therapy and research in neurogenesis. Identification of proneurogenic biomolecules on NSPCs would improve the success of cell therapies for neurodegenerative diseases. Preliminary data suggested that follicle-stimulating hormone (FSH) might act in this fashion. This study was aimed to elucidate whether FSH promotes development, self-renewal, and is proneurogenic on neurospheres (NS) derived from sheep ovarian cortical cells (OCCs). Two culture strategies were carried out: (a) long-term, 21-days NS culture (control vs. FSH group) with NS morphometric evaluation, gene expression analyses of stemness and lineage markers, and immunolocalization of NSPCs antigens; (b) NS assay to demonstrate FSH actions on self-renewal and differentiation capacity of NS cultured with one of three defined media: M1: positive control with EGF/FGF2; M2: control; and M3: M2 supplemented with FSH. RESULTS: In long-term cultures, FSH increased NS diameters with respect to control group (302.90 ± 25.20 µm vs. 183.20 ± 7.63 on day 9, respectively), upregulated nestin (days 15/21), Sox2 (day 21) and Pax6 (days 15/21) and increased the percentages of cells immunolocalizing these proteins. During NS assays, FSH stimulated NSCPs proliferation, and self-renewal, increasing NS diameters during the two expansion periods and the expression of the neuron precursor transcript DCX during the second one. In the FSH-group there were more frequent cell-bridges among neighbouring NS. CONCLUSIONS: FSH is a proneurogenic hormone that promotes OCC-NSPCs self-renewal and NS development. Future studies will be necessary to support the proneurogenic actions of FSH and its potential use in basic and applied research related to cell therapy.

Social Media Use, Emotional Investment, Self-Control Failure, and Addiction in Relation to Mental and Sleep Health in Hispanic University Emerging Adults.

The number of social media users has increased dramatically in recent years. Common correlates of social media use may be poor mental and sleep health which are pressing issues among emerging adults and Hispanic groups. This study investigated the relationships between five different forms of social media use and mental and sleep health in Hispanic university emerging adults. Hispanic university emerging adults (n = 358) completed a survey assessing sociodemographics, overall social media use frequency, nighttime in-bed social media use, social media addiction, social media self-control failure, emotional investment in social media, depression, anxiety, stress, and sleep quality. Findings demonstrated that social media addiction and social media self-control failure were positively associated with stress and poor sleep quality. Emotional investment in social media was positively associated with depression. Findings may suggest that Hispanic university emerging adults may use social media emotionally and problematically to cope with negative affect and poor sleep quality, or that negative affect and poor sleep quality stem from using social media emotionally and problematically. The clinical implications of these results are discussed. Prospective studies are warranted to assess temporality.

Ovarioleukodystrophy Due to EIF2B Genes: Systematic Review and Case Report.

Leukodystrophies comprise a spectrum of genetic disorders affecting white matter (WM) formation in the central nervous system (CNS), of which vanishing white matter disease (VWMD) is one. VWMD presents with progressive neurological deterioration and a variety of manifestations. Ovarioleukodystrophy, a subtype of VWMD, exhibits a distinctive clinical profile encompassing both CNS WM alterations and ovarian dysfunction. Variants in genes of the eukaryotic translation initiation factor 2B (EIF2B) complex affect the full form and are implicated in VWMD, including ovarioleukodystrophy. This work aimed to systematically review all published cases of ovarioleukodystrophy associated with variants in the EIF2B1-5 gene complex based on the first case identified in a Mexican population. We performed a systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines of published cases of ovarioleukodystrophy associated with the EIF2B gene complex, including a newly identified case from Mexico. We identified 207 publications using PUBMED, SCOPUS, and PMC databases. One hundred fifty-one publications were eliminated due to duplicates, titles, abstracts, or other reasons, while 56 publications were revised, of which 29 were eliminated because they dealt with other genes or non-human research, and 27 reports were assessed for eligibility. Finally, 14 reports describing ovarian involvement, neuroimaging, and molecular variants were included. Our review identified 20 cases worldwide, with a median age of onset of 19 years. Clinical features included WM involvement, ovarian abnormalities, gait disturbances, epilepsy, cognitive and language impairment, and other neurological manifestations. Neuroimaging showed characteristic WM changes, highlighting the importance of MRI in diagnosis. Missense variants predominated among the identified genetic mutations, especially in the EIF2B4 and EIF2B5 genes. Ovarioleukodystrophy is an ultra-rare disorder with a wide range of clinical manifestations and ovarian changes. Gynecological evaluation is crucial in suspected cases of ovarioleukodystrophy, as ovarian manifestations may precede neurological symptoms. The role of MRI is crucial in the diagnostic approach to this entity. Continued collaborative efforts are essential to elucidate genotype-phenotype correlations, improve clinical management, and promote therapeutic advances for this rare disorder.

Conservation, alteration, and redistribution of mammalian striatal interneurons.

Mammalian brains vary in size, structure, and function, but the extent to which evolutionarily novel cell types contribute to this variation remains unresolved1-4. Recent studies suggest there is a primate-specific population of striatal inhibitory interneurons, the TAC3 interneurons5. However, there has not yet been a detailed analysis of the spatial and phylogenetic distribution of this population. Here, we profile single cell gene expression in the developing pig (an ungulate) and ferret (a carnivore), representing 94 million years divergence from primates, and assign newborn inhibitory neurons to initial classes first specified during development6. We find that the initial class of TAC3 interneurons represents an ancestral striatal population that is also deployed towards the cortex in pig and ferret. In adult mouse, we uncover a rare population expressing Tac2, the ortholog of TAC3, in ventromedial striatum, prompting a reexamination of developing mouse striatal interneuron initial classes by targeted enrichment of their precursors. We conclude that the TAC3 interneuron initial class is conserved across Boreoeutherian mammals, with the mouse population representing Th striatal interneurons, a subset of which expresses Tac2. This study suggests that initial classes of telencephalic inhibitory neurons are largely conserved and that during evolution, neuronal types in the mammalian brain change through redistribution and fate refinement, rather than by derivation of novel precursors early in development.