Ipsilateral dual cannulation is associated with wound complications following veno-arterial ECMO decannulation.

BACKGROUND: Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is a well-established treatment for severe cardio-pulmonary failure. The use of large bore cannulas in the femoral vessels for an extended period has been associated with significant wound complications. There is a lack of data analyzing risk factors that can mitigate such complications. The primary purpose of this study was to identify modifiable risk factors associated with femoral wound complications after VA ECMO decannulation. METHODS: Retrospective analysis of wound complications in patients following VA ECMO decannulation from 2014-2021 at a single academic institution were analyzed. Wound complications were defined as wound infection, dehiscence, or those wounds that were deliberately opened to promote healing by secondary intention. RESULTS: Sixty patients underwent decannulation of VA ECMO with operative repair of the femoral artery. Fifteen patients were identified to have wound complications, eight (53%) of these had infection. Fourteen (93%) patients had wound dehiscence or had their wound purposely opened at bedside. Univariate analysis revealed no association of access-related complication with higher Body Mass Index (BMI, 28.3 vs. 32.7 kg/m2, P=0.110) but here was a trend in having more wound complications in individuals with COVID-19 infection (6.7% vs. 26.7%, P=0.058). Patients that had dual cannulation with the arterial and venous cannulas in the same groin had significantly more wound complications compared to single cannulation arterial and venous cannulas in separate groins (57.8% vs. 93.3%; P=0.012). Multivariate analysis revealed same side cannulation (OR 18.05, 95% CI 1.44-226.18, P=0.025) and COVID-19 infection (OR 18.18, 95% CI 1.50-220.66, P=0.023) were independent predictors of wound complications. CONCLUSIONS: Wound complications after VA ECMO decannulation is associated with COVID-19 infection and having venous and arterial cannulas in the same groin. We recommend that the arterial and venous cannulation be placed in different groins in patients that require VA ECMO.

Quality of life of patients after kidney transplant: ADHERE Brazil multicenter cross-sectional study.

BACKGROUND: Quality of life (QoL) is a measure to evaluate kidney transplant (KT) results. AIM: To describe the QoL profile in a larger sample of Brazilian patients who underwent KT according to age, sex, and access to KT. METHODS: We conducted a secondary data analysis of the ADHERE BRAZIL multicenter cross-sectional study including 1105 patients from 20 centers, considering KT access region and transplant activity. QoL was assessed by the WHOQOL-BREF. Data was compared using Generalized Estimating Equations. RESULTS: Overall, 58.5 % of the patients were men, mean age of 47.6 ± 12.6 years. The general QoL score was 81 ± 15.1, 58.6 ± 11.6 for physical, 65.5 ± 11.4 for psychological, 68.3 ± 17.1 for social relationships, and 64.2 ± 13.3 for environmental domain. Higher QoL scores were observed in men compared to women in three WHOQOL-BREF domains: psychological (OR:2.62; CI, 1.29 ̶ 3.95, p < 0.0001), social relationships (OR:3.21; CI, 1.2 ̶ 5.23, p = 0.002) and environmental (OR:3.79; CI:2.23 ̶ 5.35, p < 0.0001). Younger patients (18-44 years) had higher scores in the psychological (OR:-2.69; CI, -4.13 ̶ -1.25; p < 0.001; OR:-3.52; CI, -5.39 ̶ -1.66; p < 0.001) and social (OR:-3.46; CI, -5.64 ̶ -1.27; p = 0.002; OR:-7.17; CI, -10 ̶ -4.35; p < 0.0001) domains than older ones (45-59 and > 60 years, respectively). Patients from higher KT access region had higher scores in environmental domain (OR:3.53; CI, 0.28 ̶ 6.78; p = 0.033). CONCLUSIONS: Featuring the results of KT under patient view, the physical and social relationships domains were the most and least affected, respectively. Lower QoL subgroups (females and age > 45 years) should be targeted in future multi-professional interventions.

Generating cysteine-trypsin cleavage sites with 2-chloroacetamidine capping.

An electrophilic arginine mimetic, 2-chloroacetamidine (CAM), was deployed to enable trypsin-mediated proteolysis at cysteine residues and to enhance mass spectrometry-based proteomic detection of cysteine-containing peptides. Illustrating the value of the CAM-capping strategy, proteogenomic analysis using a two-stage false discovery rate (FDR) search revealed >50% enhanced coverage of missense variants, when compared to established workflows.

Development of novel tools for dissection of central versus peripheral dopamine D2-like receptor signaling in dysglycemia.

Dopamine (DA) D2-like receptors in both the central nervous system (CNS) and the periphery are key modulators of metabolism. Moreover, disruption of D2-like receptor signaling is implicated in dysglycemia. Yet, the respective metabolic contributions of CNS versus peripheral D2-like receptors including D2 (D2R) and D3 (D3R) receptors remain poorly understood. To address this, we developed new pharmacological tools, D2-like receptor agonists with diminished and delayed blood-brain barrier capability, to selectively manipulate D2R/D3R signaling in the periphery. We designated bromocriptine methiodide (BrMeI), a quaternary methiodide analogue of D2R/D3R agonist and diabetes drug bromocriptine, as our lead compound based on preservation of D2R/D3R binding and functional efficacy. We then used BrMeI and unmodified bromocriptine to dissect relative contributions of CNS versus peripheral D2R/D3R signaling in treating dysglycemia. Systemic administration of bromocriptine, with unrestricted access to CNS and peripheral targets, significantly improved both insulin sensitivity and glucose tolerance in obese, dysglycemic mice in vivo. In contrast, metabolic improvements were attenuated when access to bromocriptine was restricted either to the CNS through intracerebroventricular administration or delayed access to the CNS via BrMeI. Our findings demonstrate that the coordinated actions of both CNS and peripheral D2-like receptors are required for correcting dysglycemia. Ultimately, the development of a first-generation of drugs designed to selectively target the periphery provides a blueprint for dissecting mechanisms of central versus peripheral DA signaling and paves the way for novel strategies to treat dysglycemia.

A Divergent Platelet Transcriptome in Patients with Lipedema and Lymphedema.

Lipedema and lymphedema are physically similar yet distinct diseases that are commonly misdiagnosed. We previously reported that lipedema and lymphedema are associated with increased risk for venous thromboembolism (VTE). The underlying etiology of the prothrombotic profile observed in lipedema and lymphedema is unclear, but may be related to alterations in platelets. Our objective was to analyze the platelet transcriptome to identify biological pathways that may provide insight into platelet activation and thrombosis. The platelet transcriptome was evaluated in patients with lymphedema and lipedema, then compared to control subjects with obesity. Patients with lipedema were found to have a divergent transcriptome from patients with lymphedema. The platelet transcriptome and impacted biological pathways in lipedema were surprisingly similar to weight-matched comparators, yet different when compared to overweight individuals with a lower body mass index (BMI). Differences in the platelet transcriptome for patients with lipedema and lymphedema were found in biological pathways required for protein synthesis and degradation, as well as metabolism. Key differences in the platelet transcriptome for patients with lipedema compared to BMI-matched subjects involved metabolism and glycosaminoglycan processing. These inherent differences in the platelet transcriptome warrant further investigation, and may contribute to the increased risk of thrombosis in patients with lipedema and lymphedema.

Unveiling Trichosporon austroamericanum sp. nov.: A Novel Emerging Opportunistic Basidiomycetous Yeast Species.

During an epidemiological survey, a potential novel species within the basidiomycetous yeast genus Trichosporon was observed. The clinical strain was obtained from a urine sample taken from a Brazilian kidney transplant recipient. The strain was molecularly identified using the intergenic spacer (IGS1) ribosomal DNA locus and a subsequent phylogenetic analysis showed that multiple strains that were previously reported by other studies shared an identical IGS1-genotype most closely related to that of Trichosporon inkin. However, none of these studies provided an in-depth characterization of the involved strains to describe it as a new taxon. Here, we present the novel clinically relevant yeast for which we propose the name Trichosporon austroamericanum sp. nov. (holotype CBS H-24937). T. austroamericanum can be distinguished from other siblings in the genus Trichosporon using morphological, physiological, and phylogenetic characters.

Direct antiglobulin test in the differential diagnosis of ABO hemolytic disease of the newborn: an important tool with high negative predictive value.

BACKGROUND: Hemolysis due to ABO incompatibility is an important differential diagnosis in newborns presenting with jaundice. Clinical studies evaluating ABO hemolytic disease of fetus and newborn (ABO-HDFN) question the diagnostic value of the direct antiglobulin test (DAT) in this situation. GOALS: To determine the clinical and laboratorial findings associated with the occurrence of ABO-HDFN and to evaluate the accuracy of DAT as a diagnostic tool. METHODS: This was a nested case control study with a cohort of 4122 newborns. Clinical and immunohematological data were retrieved from medical files including clinical and laboratorial factors associated with ABO-HDFN. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of positive DAT were calculated. RESULTS: Among the 4122 newborns, 44 had the diagnosis of ABO-HDFN. Positive DAT, group O mother and group A newborn were significantly associated with the occurrence of neonatal jaundice and this association persisted in a multivariable model (p-value <0.001). DAT presented 65.85 % sensitivity, 96.28 % specificity, 16.9 % PPV and 99.6 % NPV for the diagnosis of ABO-HDFN. There were no cases of positive DAT in cases other than O/A and O/B incompatibilities. The newborn hemoglobin was significantly lower in O/A incompatibility (p-value <0.001). CONCLUSION: Positive DAT, mother of group O and newborn of group A are independent risk factors associated with ABO-HDFN. DAT exhibited high NPV for the diagnosis of this complication. Thus, performing DAT in newborns with O/A and O/B incompatibilities is a cost-effective strategy that can be applied as routine by blood banks.

Chemical composition and sensory profiling of coffees treated with asparaginase to decrease acrylamide formation during roasting.

Acrylamide is an amide formed in the Maillard reaction, with asparagine as the primary amino acid precursor. The intake of large amounts of acrylamide has induced genotoxic and carcinogenic effects in hormone-sensitive tissues of animals. The enzime asparaginase is one of the most effective methods for lowering the formation of acrylamide in foods such as potatoes. However, the reported sensory outcomes for coffee have been unsatisfactory so far. This study aimed to produce coffees with reduced levels of acrylamide by treating them with asparaginase while retaining their original sensory and bioactive profiles. Three raw samples of Coffea arabica, including two specialty coffees, and one of Coffea canephora were treated with 1000, 2000, and 3000 ASNU of the enzyme. Asparagine and bioactive compounds (chlorogenic acids-CGA, caffeine, and trigonelline) were quantified in raw and roasted beans by HPLC and LC-MS, while the determination of acrylamide and volatile organic compounds was performed in roasted beans by CG-MS. Soluble solids, titratable acidity, and pH were also determined. Professional cupping by Q-graders and consumer sensory tests were also conducted. Results were analyzed by ANOVA-Fisher, MFA, PCA and Cluster analyses, with significance levels set at p ≤ 0.05. Steam treatment alone decreased acrylamide content by 18.4%, on average, and 6.1% in medium roasted arabica and canefora coffees. Average reductions of 32.5-56.0% in acrylamide formation were observed in medium roasted arabica beans when 1000-3000 ASNU were applied. In the canefora sample, 59.4-60.7% reductions were observed. However, steam treatment primarily caused 17.1-26.7% reduction of total CGA and lactones in medium roasted arabica samples and 13.9-22.0% in canefora sample, while changes in trigonelline, caffeine, and other evaluated chemical parameters, including the volatile profiles were minimal. Increasing enzyme loads slightly elevated acidity. The only sensory changes observed by Q-graders and or consumers in treated samples were a modest increase in acidity when 3000 ASNU was used in the sample with lower acidity, loss of mild off-notes in control samples, and increased perception of sensory descriptors. The former was selected given the similarity in chemical outcomes among beans treated with 2000 and 3000 ASNU loads.

In Vitro Digestion and Intestinal Absorption of Mycotoxins Due to Exposure from Breakfast Cereals: Implications for Children's Health.

Breakfast cereals play a crucial role in children's diets, providing essential nutrients that are vital for their growth and development. Children are known to be more susceptible than adults to the harmful effects of food contaminants, with mycotoxins being a common concern in cereals. This study specifically investigated aflatoxin B1 (AFB1), enniatin B (ENNB), and sterigmatocystin (STG), three well-characterized mycotoxins found in cereals. The research aimed to address existing knowledge gaps by comprehensively evaluating the bioaccessibility and intestinal absorption of these three mycotoxins, both individually and in combination, when consumed with breakfast cereals and milk. The in vitro gastrointestinal method revealed patterns in the bioaccessibility of AFB1, ENNB, and STG. Overall, bioaccessibility increased as the food progressed from the stomach to the intestinal compartment, with the exception of ENNB, whose behavior differed depending on the type of milk. The ranking of overall bioaccessibility in different matrices was as follows: digested cereal > cereal with semi-skimmed milk > cereal with lactose-free milk > cereal with soy beverage. Bioaccessibility percentages varied considerably, ranging from 3.1% to 86.2% for AFB1, 1.5% to 59.3% for STG, and 0.6% to 98.2% for ENNB. Overall, the inclusion of milk in the ingested mixture had a greater impact on bioaccessibility compared to consuming the mycotoxins as a single compound or in combination. During intestinal transport, ENNB and STG exhibited the highest absorption rates when ingested together. This study highlights the importance of investigating the combined ingestion and transport of these mycotoxins to comprehensively assess their absorption and potential toxicity in humans, considering their frequent co-occurrence and the possibility of simultaneous exposure.

Chemoproteomics Identifies State-Dependent and Proteoform-Selective Caspase-2 Inhibitors.

Caspases are a highly conserved family of cysteine-aspartyl proteases known for their essential roles in regulating apoptosis, inflammation, cell differentiation, and proliferation. Complementary to genetic approaches, small-molecule probes have emerged as useful tools for modulating caspase activity. However, due to the high sequence and structure homology of all 12 human caspases, achieving selectivity remains a central challenge for caspase-directed small-molecule inhibitor development efforts. Here, using mass spectrometry-based chemoproteomics, we first identify a highly reactive noncatalytic cysteine that is unique to caspase-2. By combining both gel-based activity-based protein profiling (ABPP) and a tobacco etch virus (TEV) protease activation assay, we then identify covalent lead compounds that react preferentially with this cysteine and afford a complete blockade of caspase-2 activity. Inhibitory activity is restricted to the zymogen or precursor form of monomeric caspase-2. Focused analogue synthesis combined with chemoproteomic target engagement analysis in cellular lysates and in cells yielded both pan-caspase-reactive molecules and caspase-2 selective lead compounds together with a structurally matched inactive control. Application of this focused set of tool compounds to stratify the functions of the zymogen and partially processed (p32) forms of caspase-2 provide evidence to support that caspase-2-mediated response to DNA damage is largely driven by the partially processed p32 form of the enzyme. More broadly, our study highlights future opportunities for the development of proteoform-selective caspase inhibitors that target nonconserved and noncatalytic cysteine residues.

Monomeric Esterase: Insights into Cooperative Behavior, Hysteresis/Allokairy.

Herein, we present a novel esterase enzyme, Ade1, isolated from a metagenomic library of Amazonian dark earths soils, demonstrating its broad substrate promiscuity by hydrolyzing ester bonds linked to aliphatic groups. The three-dimensional structure of the enzyme was solved in the presence and absence of substrate (tributyrin), revealing its classification within the α/ß-hydrolase superfamily. Despite being a monomeric enzyme, enzymatic assays reveal a cooperative behavior with a sigmoidal profile (initial velocities vs substrate concentrations). Our investigation brings to light the allokairy/hysteresis behavior of Ade1, as evidenced by a transient burst profile during the hydrolysis of substrates such as p-nitrophenyl butyrate and p-nitrophenyl octanoate. Crystal structures of Ade1, coupled with molecular dynamics simulations, unveil the existence of multiple conformational structures within a single molecular state (E̅1). Notably, substrate binding induces a loop closure that traps the substrate in the catalytic site. Upon product release, the cap domain opens simultaneously with structural changes, transitioning the enzyme to a new molecular state (E̅2). This study advances our understanding of hysteresis/allokairy mechanisms, a temporal regulation that appears more pervasive than previously acknowledged and extends its presence to metabolic enzymes. These findings also hold potential implications for addressing human diseases associated with metabolic dysregulation.

Investigating the individual and mixture cytotoxicity of co-occurring aflatoxin B1, enniatin B, and sterigmatocystin on gastric, intestinal, hepatic, and renal cellular models.

This study investigates the individual and combined effects of the mycotoxins, Aflatoxin B1 (AFB1), Enniatin B (ENNB) and Sterigmatocystin (STG), on the cellular viability of gastric (NCI-N87), intestinal (Caco-2), hepatic (Hep-G2) and renal (Hek-293) cells, shedding light on synergistic or antagonistic effects using a constant ratio combination design proposed by Chou-Talalay. These toxins are prevalent in cereal-based foods, frequently consumed by children which raises concerns about their exposure to these mycotoxins. This population is particularly vulnerable to the effects of these toxins due to their underdeveloped organs and incompletely structured physiological processes. Results showed that ENB was the most toxic of the three mycotoxins across all cell lines, while STG and AFB1 showed lower toxicity. The combination of ENNB + STG was found to be the most potent in terms of binary mixtures. In regard to ternary combinations, Caco-2 cells are more sensitive to the tested mycotoxins, whereas NCI-N87 cells show lower levels of cell damage. Worrying dose reduction values (>10-fold) were found for ENNB in binary and ternary combinations at low exposure levels. These findings are significant for establishing initial reference values, which play a pivotal role in estimating reference doses that are subsequently incorporated into the broader risk assessment process.

Factors Associated With Physical Inactivity of Recipients of a Kidney Transplant: Results From the ADHERE BRAZIL Multicenter Study.

OBJECTIVE: Physical activity is recommended for recipients of a kidney transplant. However, ADHERE BRAZIL study found a high prevalence (69%) of physical inactivity in Brazilian recipients of a kidney transplant. To tackle this behavior, a broad analysis of barriers is needed. This study aimed to identify factors (patient and transplant center levels) associated with physical inactivity among recipients of a kidney transplant. METHODS: This was a subproject of the ADHERE BRAZIL study, a cross-sectional, multicenter study of 1105 recipients of a kidney transplant from 20 kidney transplant centers. Using a multistage sampling method, patients were proportionally and randomly selected. Applying the Brief Physical Activity Assessment questionnaire, patients were classified as physically active (≥150 min/wk) or physically inactive (<150 min/wk). On the basis of an ecological model, 34 factors associated with physical inactivity were analyzed by sequential logistic regression. RESULTS: At the patient level, physical inactivity was associated with smoking (odds ratio = 2.43; 95% CI = 0.97-6.06), obesity (odds ratio = 1.79; 95% CI = 1.26-2.55), peripheral vascular disease (odds ratio = 3.18; 95% CI = 1.20-8.42), >3 posttransplant hospitalizations (odds ratio = 1.58; 95% CI = 1.17-2.13), family income of >1 reference salary ($248.28 per month; odds ratio = 0.66; 95% CI = 0.48-0.90), and student status (odds ratio = 0.58; 95% CI = 0.37-0.92). At the center level, the correlates were having exercise physiologists in the clinical team (odds ratio = 0.54; 95% CI = 0.46-0.64) and being monitored in a teaching hospital (undergraduate students) (odds ratio = 1.47; 95% CI = 1.01-2.13). CONCLUSIONS: This study identified factors associated with physical inactivity after kidney transplantation that may guide future multilevel behavioral change interventions for physical activity. IMPACT: In a multicenter sample of recipients of a kidney transplant with a prevalence of physical inactivity of 69%, we found associations between this behavior and patient- and center-level factors. At the patient level, the chance of physical inactivity was positively associated with smoking, obesity, and patient morbidity (peripheral vascular disease and hospitalization events after kidney transplantation). Conversely, a high family income and a student status negatively correlated with physical inactivity. At the center level, the presence of a dedicated professional to motivate physical activity resulted in a reduced chance of physical inactivity. A broad knowledge of barriers associated with physical inactivity can allow us to identify patients at a high risk of not adhering to the recommended levels of physical activity.

A review of air pollution as a driver of cardiovascular disease risk across the diabetes spectrum.

The prevalence of diabetes is estimated to reach almost 630 million cases worldwide by the year 2045; of current and projected cases, over 90% are type 2 diabetes. Air pollution exposure has been implicated in the onset and progression of diabetes. Increased exposure to fine particulate matter air pollution (PM2.5) is associated with increases in blood glucose and glycated hemoglobin (HbA1c) across the glycemic spectrum, including normoglycemia, prediabetes, and all forms of diabetes. Air pollution exposure is a driver of cardiovascular disease onset and exacerbation and can increase cardiovascular risk among those with diabetes. In this review, we summarize the literature describing the relationships between air pollution exposure, diabetes and cardiovascular disease, highlighting how airborne pollutants can disrupt glucose homeostasis. We discuss how air pollution and diabetes, via shared mechanisms leading to endothelial dysfunction, drive increased cardiovascular disease risk. We identify portable air cleaners as potentially useful tools to prevent adverse cardiovascular outcomes due to air pollution exposure across the diabetes spectrum, while emphasizing the need for further study in this particular population. Given the enormity of the health and financial impacts of air pollution exposure on patients with diabetes, a greater understanding of the interventions to reduce cardiovascular risk in this population is needed.

Association of performance in medical residency selection with a psychiatric diagnosis, and depressive and anxiety symptoms.

OBJECTIVE: Few studies have focused on medical students and residents' mental health impact on medical residency selection (MRS) performance. The authors evaluated the association of performance in MRS with depressive and anxiety symptoms and with a reported psychiatric diagnosis (rPD). METHODS: The authors enrolled candidates after the second round of MRS examinations at a Brazilian Medical School. Performance was assessed by final grade. Depressive and anxiety symptoms were assessed by the Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) and the State-Trait Anxiety Inventory (STAI). The authors performed mediation analysis and multiple linear regression analysis to investigate the impact of rPD, state and trait anxiety, and depressive symptom severity on performance. RESULTS: 515 of the 643 MRS candidates (80.1%) participated in the study. Higher age, attending a preparatory course for MRS, rPD, and the number of MRS applications that year were associated with poorer performance. In mediation analysis, trait anxiety was associated with a direct effect on performance and an indirect effect mediated by rPD. CONCLUSION: The data suggest that psychiatric diagnosis is associated with poorer performance on MRS, regardless of current symptoms of anxiety and depression. Additionally, increased levels of trait anxiety may negatively impact performance, directly and indirectly.

Evaluating the human neurotoxicity and toxicological interactions impact of co-occurring regulated and emerging mycotoxins.

Mycotoxins can inflict harmful effects on diverse organs, and mounting evidence indicates their potential involvement in human neurodegenerative diseases. Given the common occurrence of these toxins in food, there is an increasing demand for a comprehensive assessment of their combined toxicity to enhance our understanding of their potential hazards. This research investigates mycotoxin exposure from widely consumed cereal-based products, including enniatin B (ENNB), sterigmatocystin (STG), aflatoxin B1 (AFB1), cyclopiazonic acid (CPZ), citrinin (CIT), and ochratoxin A (OTA). Employing the median-effect equation based on Chou and Talalay's mass-action law, we assessed their cytotoxicity in human SH-SY5Y neuronal cells. Notably, ENNB displayed the highest neurotoxicity (IC50 = 3.72 µM), followed by OTA (9.10 µM) and STG (9.99 µM). The combination of OTA + STG exhibited the highest toxicity (IC50 = 3.77 µM), while CPZ + CIT showed the least detrimental effect. Approximately 70 % of tested binary combinations displayed synergistic or additive effects, except for ENNB + STG, ENNB + AFB1, and CPZ + CIT, which showed antagonistic interactions. Intriguingly, the senary combination displayed moderate antagonism at the lowest exposure and moderate synergism at higher doses. OTA exhibited predominantly synergistic interactions, comprising approximately 90 %, a noteworthy finding considering its prevalence in food. Conversely, ENNB interactions tended to be antagonistic. The most remarkable synergy occurred in the STG and CIT combination, enabling a 50-fold reduction in CIT dosage for an equivalent toxic effect. These findings highlight the biological relevance of robust synergistic interactions, emphasizing the need to assess human exposure hazards accurately, particularly considering frequent mycotoxin co-occurrence in environmental and food settings.

Higher-order functional brain networks and anterior cingulate glutamate + glutamine (Glx) in antipsychotic-naïve first episode psychosis patients.

Human connectome studies have provided abundant data consistent with the hypothesis that functional dysconnectivity is predominant in psychosis spectrum disorders. Converging lines of evidence also suggest an interaction between dorsal anterior cingulate cortex (dACC) cortical glutamate with higher-order functional brain networks (FC) such as the default mode (DMN), dorsal attention (DAN), and executive control networks (ECN) in healthy controls (HC) and this mechanism may be impaired in psychosis. Data from 70 antipsychotic-medication naïve first-episode psychosis (FEP) and 52 HC were analyzed. 3T Proton magnetic resonance spectroscopy (1H-MRS) data were acquired from a voxel in the dACC and assessed correlations (positive FC) and anticorrelations (negative FC) of the DMN, DAN, and ECN. We then performed regressions to assess associations between glutamate + glutamine (Glx) with positive and negative FC of these same networks and compared them between groups. We found alterations in positive and negative FC in all networks (HC > FEP). A relationship between dACC Glx and positive and negative FC was found in both groups, but when comparing these relationships between groups, we found contrasting associations between these variables in FEP patients compared to HC. We demonstrated that both positive and negative FC in three higher-order resting state networks are already altered in antipsychotic-naïve FEP, underscoring the importance of also considering anticorrelations for optimal characterization of large-scale functional brain networks as these represent biological processes as well. Our data also adds to the growing body of evidence supporting the role of dACC cortical Glx as a mechanism underlying alterations in functional brain network connectivity. Overall, the implications for these findings are imperative as this particular mechanism may differ in untreated or chronic psychotic patients; therefore, understanding this mechanism prior to treatment could better inform clinicians.Clinical trial registration: Trajectories of Treatment Response as Window into the Heterogeneity of Psychosis: A Longitudinal Multimodal Imaging Study, NCT03442101 . Glutamate, Brain Connectivity and Duration of Untreated Psychosis (DUP), NCT02034253 .