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1.
Bio Protoc ; 14(13): e5028, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-39007159

RESUMO

Mitochondria are vital organelles essential for cellular functions, but their lipid composition and response to stressors are not fully understood. Recent advancements in lipidomics reveal insights into lipid functions, especially their roles in metabolic perturbations and diseases. Previous methods have focused on the protein composition of mitochondria and mitochondrial-associated membranes. The advantage of our technique is that it combines organelle isolation with targeted lipidomics, offering new insights into the composition and dynamics of these organelles in pathological conditions. We developed a mitochondria isolation protocol for L6 myotubes, enabling lipidomics analysis of specific organelles without interference from other cellular compartments. This approach offers a unique opportunity to dissect lipid dynamics within mitochondria and their associated ER compartments under cellular stress. Key features • Analysis and quantification of lipids in mitochondria-ER fraction through liquid chromatography-tandem mass spectrometry-based lipidomics (LC-MS/MS lipidomics). • LC-MS/MS lipidomics provide precise and unbiased information on the lipid composition in in vitro systems. • LC-MS/MS lipidomics facilitates the identification of lipid signatures in mammalian cells.

2.
Phys Ther Sport ; 68: 71-79, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38968787

RESUMO

BACKGROUND: Lower limb injury rates have increased dramatically in line with increased female sport participation levels. Muscle strength is a modifiable lower limb injury risk factor, guiding performance monitoring and rehabilitation. OBJECTIVES: The aim of this study was to investigate the test-retest reliability of isokinetic and isometric lower limb peak torque to body mass of muscles acting on the hip, knee, and ankle in female team sport athletes. It was hypothesised the test-retest reliability would be good (intraclass correlation coefficients (ICC) ≥ 0.75). METHODS: Thirty-eight female athletes (Australian Rules Football = 18, netball = 12, soccer = 8) aged 16-35 years participated in this study. Participants performed isokinetic (60°/s and 120°/s) and isometric testing on a Biodex Isokinetic Dynamometer on three separate days. RESULTS: Poor to good reliability was demonstrated for all joint movements (ICC = 0.38-0.88) with small to moderate effect sizes (0.00-0.43) and typical errors (5.65-24.49). CONCLUSION: Differences in peak torque to body mass were observed between sessions one and two and/or one and three, demonstrating a learning effect. Therefore, three testing sessions, and/or the inclusion of a familiarisation session, is recommended for future assessments in populations unfamiliar with dynamometry.

3.
JIMD Rep ; 65(4): 249-254, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38974616

RESUMO

Familial chylomicronemia syndrome (FCS) is a rare inherited disorder characterized by severe hypertriglyceridemia, posing a heightened risk of acute pancreatitis. Recently, Volanesorsen, an APOC3 antisense oligonucleotide, gained approval for FCS treatment in the UK. Caution is advised during pregnancy due to limited safety data, although animal studies show no toxicity/teratogenicity. Two case scenarios are presented: In the first case, a patient with FCS continued Volanesorsen injections without having thrombocytopenia during an unplanned pregnancy until third trimester, maintaining triglyceride control. Upon discovering the pregnancy at 38 weeks, Volanesorsen was ceased, and a low-fat diet reinstated. Despite a heightened risk of pancreatitis, no episodes of pancreatitis occurred during the pregnancy. In the second case, stopping Volanesorsen before conception led to elevated triglycerides, and an episode of acute pancreatitis at 22 weeks, despite strict very low-fat diet and fibrate therapy from 14 weeks. At 23 weeks, Volanesorsen was reintroduced concurrently with regular therapeutic plasma exchange. No further episodes of pancreatitis occurred. In both case, fetal health was maintained throughout pregnancy, fetal scans revealed no anomalies, and planned C-sections delivered healthy babies without congenital issues. Both babies are well and developing normally at 24 and 19 months.

4.
A A Pract ; 18(7): e01811, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38976513

RESUMO

While Title VI of the Civil Rights Act of 1964 mandates use of interpreters for patients with limited English proficiency, significant disparities persist in intensive postsurgical care. We present the case of a 60-year-old Vietnamese-speaking man with a Type A aortic dissection requiring postoperative mechanical ventilation and stroke care. Despite use of a remote video interpreter, our language-discordant nursing and physician providers faced challenges in managing agitation and delirium and assessing neurological function. This case highlights the need for adequate interpretation equipment, linguistic diversity among providers, and interventions to promote and enable consistent certified and professional medical interpreter use.


Assuntos
Delírio , Acidente Vascular Cerebral , Humanos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/complicações , Agitação Psicomotora , Proficiência Limitada em Inglês , Complicações Pós-Operatórias , Dissecção Aórtica/cirurgia , Respiração Artificial
6.
bioRxiv ; 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39026740

RESUMO

Enhancers are key drivers of gene regulation thought to act via 3D physical interactions with the promoters of their target genes. However, genome-wide depletions of architectural proteins such as cohesin result in only limited changes in gene expression, despite a loss of contact domains and loops. Consequently, the role of cohesin and 3D contacts in enhancer function remains debated. Here, we developed CRISPRi of regulatory elements upon degron operation (CRUDO), a novel approach to measure how changes in contact frequency impact enhancer effects on target genes by perturbing enhancers with CRISPRi and measuring gene expression in the presence or absence of cohesin. We systematically perturbed all 1,039 candidate enhancers near five cohesin-dependent genes and identified 34 enhancer-gene regulatory interactions. Of 26 regulatory interactions with sufficient statistical power to evaluate cohesin dependence, 18 show cohesin-dependent effects. A decrease in enhancer-promoter contact frequency upon removal of cohesin is frequently accompanied by a decrease in the regulatory effect of the enhancer on gene expression, consistent with a contact-based model for enhancer function. However, changes in contact frequency and regulatory effects on gene expression vary as a function of distance, with distal enhancers (e.g., >50Kb) experiencing much larger changes than proximal ones (e.g., <50Kb). Because most enhancers are located close to their target genes, these observations can explain how only a small subset of genes - those with strong distal enhancers - are sensitive to cohesin. Together, our results illuminate how 3D contacts, influenced by both cohesin and genomic distance, tune enhancer effects on gene expression.

7.
medRxiv ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39040186

RESUMO

Immunoparalysis is a significant concern in patients with sepsis and critical illness, potentially leading to increased risk of secondary infections. This study aimed to perform a longitudinal assessment of immune function over the initial two weeks following the onset of sepsis and critical illness. We compared ex vivo stimulated cytokine release to traditional markers of immunoparalysis, including monocyte Human Leukocyte Antigen (mHLA)-DR expression and absolute lymphocyte count (ALC). A total of 64 critically ill patients were recruited in a tertiary care academic medical setting, including 31 septic and 33 non-septic patients. Results showed that while mHLA-DR expression significantly increased over time, this was primarily driven by the non-septic subset of critically ill patients. ALC recovery was more prominent in septic patients. Ex vivo stimulation revealed significant increases in TNF and IL-6 production over time in septic patients. However, IFNγ production varied with the stimulant used and did not show significant recovery when normalized to cell count. No significant correlation was found between mHLA-DR expression and other immunoparalysis biomarkers. These findings suggest the need for more nuanced immune monitoring approaches beyond the traditional 'sepsis' versus 'non-sepsis' classifications in critically ill patients. It also provided further evidence of a potential window for targeted immunotherapeutic interventions in the first week of critical illness.

8.
Drug Alcohol Depend Rep ; 11: 100243, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38948428

RESUMO

Background: As the US opioid-involved morbidity and mortality increase, uptake and implementation of evidence-based interventions remain key policy responses. Respond to Prevent was a multi-component, randomized trial implemented in four states and two large pharmacy chains with the aim of improving the pharmacy's capacity to provide naloxone, dispense buprenorphine, and sell nonprescription syringes (NPS). We sought to provide context and assess how policies and organizational practices affect communities and pharmacies across the study states. Methods: Using a multi-method approach we: 1) conducted an environmental scan of published literature and online materials spanning January 2015 to June 2021, 2) created timelines of key events pertaining to those policies and practices and 3) conducted semi-structured interviews with stakeholders (key informants) at the state and local levels (N=36) to provide further context for the policies and practices we discovered. Results: Key informants discussed state policies, pharmacy policies and local practices that facilitated access to naloxone, buprenorphine and NPSs. Interviewees from all states spoke about the impact of naloxone standing orders, active partnerships with community-based harm reduction organizations, and some federal and state policies like Medicaid coverage for naloxone and buprenorphine, and buprenorphine telehealth permissions as key facilitators. They also discussed patient stigma, access in rural settings, and high cost of medications as barriers. Conclusion: Findings underscore the important role harm reduction-related policies play in boosting and institutionalizing interventions in communities and pharmacies while also identifying structural barriers where more focused state and local attention is needed.

9.
bioRxiv ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38948883

RESUMO

Traumatic social experiences redefine socially motivated behaviors to enhance safety and survival. Although many brain regions have been implicated in signaling a social threat, the mechanisms by which global neural networks regulate such motivated behaviors remain unclear. To address this issue, we first combined traditional and modern behavioral tracking techniques in mice to assess both approach and avoidance, as well as sub-second behavioral changes, during a social threat learning task. We were able to identify previously undescribed body and tail movements during social threat learning and recognition that demonstrate unique alterations into the behavioral structure of social motivation. We then utilized inter-regional correlation analysis of brain activity after a mouse recognizes a social threat to explore functional communication amongst brain regions implicated in social motivation. Broad brain activity changes were observed within the nucleus accumbens, the paraventricular thalamus, the ventromedial hypothalamus, and the nucleus of reuniens. Inter-regional correlation analysis revealed a reshaping of the functional connectivity across the brain when mice recognize a social threat. Altogether, these findings suggest that reshaping of functional brain connectivity may be necessary to alter the behavioral structure of social motivation when a social threat is encountered.

10.
Biofouling ; 40(7): 377-389, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38955544

RESUMO

Biofouling on marine surfaces causes immense material and financial harm for maritime vessels and related marine industries. Previous reports have shown the effectiveness of amphiphilic coating systems based on poly(dimethylsiloxane) (PDMS) against such marine foulers. Recent studies on biofouling mechanisms have also demonstrated acidic microenvironments in biofilms and stronger adhesion at low-pH conditions. This report presents the design and utilization of amphiphilic polymer coatings with buffer functionalities as an active disruptor against four different marine foulers. Specifically, this study explores both neutral and zwitterionic buffer systems for marine coatings, offering insights into coating design. Overall, these buffer systems were found to improve foulant removal, and unexpectedly were the most effective against the diatom Navicula incerta.


Assuntos
Biofilmes , Incrustação Biológica , Diatomáceas , Dimetilpolisiloxanos , Incrustação Biológica/prevenção & controle , Diatomáceas/fisiologia , Dimetilpolisiloxanos/química , Animais , Soluções Tampão , Propriedades de Superfície , Concentração de Íons de Hidrogênio
11.
J Crit Care ; 83: 154857, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38996498

RESUMO

BACKGROUND: The Sequential Organ Failure Assessment (SOFA) score monitors organ failure and defines sepsis but may not fully capture factors influencing sepsis mortality. Socioeconomic and demographic impacts on sepsis outcomes have been highlighted recently. OBJECTIVE: To evaluate the prognostic value of SOFA scores against demographic and social health determinants for predicting sepsis mortality in critically ill patients, and to assess if a combined model increases predictive accuracy. METHODS: The study utilized retrospective data from the MIMIC-IV database and prospective external validation from the Penn State Health cohort. A Random Forest model incorporating SOFA scores, demographic/social data, and the Charlson Comorbidity Index was trained and validated. FINDINGS: In the MIMIC-IV dataset of 32,970 sepsis patients, 6,824 (20.7%) died within 30 days. A model including demographic, socioeconomic, and comorbidity data with SOFA scores improved predictive accuracy beyond SOFA scores alone. Day 2 SOFA, age, weight, and comorbidities were significant predictors. External validation showed consistent performance, highlighting the importance of delta SOFA between days 1 and 3. CONCLUSION: Adding patient-specific demographic and socioeconomic information to clinical metrics significantly improves sepsis mortality prediction. This suggests a more comprehensive, multidimensional prognostic approach is needed for accurate sepsis outcome predictions.

12.
Acta Med Philipp ; 58(10): 93-98, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38939418

RESUMO

Background: Teachers in medicine do not only teach scientific facts about health and disease to their learners but they are also looked up to as role models. Little is known about the qualities of consultant-faculty members who are regarded as role models by Filipino internal medicine residents. Objective: This study aimed to determine the reasons why consultant-faculty members are considered role models by Filipino internal medicine residents. Methods: A cross-sectional survey was conducted among internal medicine residents at a tertiary national university hospital in the Philippines. Participants were asked to give the reasons for citing consultant-faculty members who they consider as role models. Results: There were 81 residents who participated (93% response rate) who gave a total of 332 qualities as reasons for citing them as role models. The most commonly cited quality category was those of personal qualities (35.84% of all responses). This was followed by academic, clinical, teaching, leadership and research qualities. Physical qualities were the least cited (0.30% of all responses). Across the four batches of residents, personal qualities were consistently cited the most number of times, while physical qualities were consistently cited the least. Conclusion: Filipino internal medicine residents identified personal qualities as the most frequent reason for considering their consultant-faculty as role models.

13.
Blood Adv ; 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38941537

RESUMO

While intensive induction chemotherapy (IC) remains the standard of care for younger patients with acute myeloid leukemia (AML), data from older patients shows that hypomethylating agents + venetoclax (HMA/VEN) can lead to durable remissions among patients with NPM1 mutations. Whether IC or HMA/VEN is superior in patients ≥60 years-old with NPM1-mutant AML is unknown. To compare IC and HMA/VEN, we performed an international, multicenter retrospective cohort study of patients with newly diagnosed, NPM1-mutant AML.We included 221 patients (147 IC, 74 HMA/VEN) with previously untreated NPM1-mutant AML. Composite complete remission (cCR; defined as CR + CR with incomplete count recovery [CRi]) rate was similar for IC and HMA/VEN (cCR: 85% vs. 74%; p=0.067). While OS was favorable with IC in unselected patients compared to HMA/VEN (24-month OS 59% [95% CI: 52-69%] vs. 38% [95% CI 27-55%]; p=0.013), it was not statistically different among patients 60-75 years-old (60% [95% CI 52-70%] vs. 44% [95% CI 29-66%]; p=0.069) and patients who received an allogeneic stem cell transplant (70% [95% CI: 58-85%] vs. 66% [95% CI: 44-100%]; p=0.56). Subgroup analyses suggested that patients with normal cytogenetics (24-month OS with IC 65% [95% 56-74%] vs. 40% [95% CI: 26-60%] with HMA/VEN; p=0.009) and without FLT3-ITD mutations might benefit from IC compared with HMA/VEN (24-month OS: 68% [95% CI: 59-79%] vs. 43% [95% CI: 29-63%]; p=0.008). In multivariable analysis, OS was not statistically different for patients treated with IC and HMA/VEN (hazard ratio for death HMA/VEN vs. IC: 0.71; 95% CI: 0.40-1.27; p=0.25).

14.
Crit Care Explor ; 6(7): e1106, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38916619

RESUMO

OBJECTIVES: While cytokine response patterns are pivotal in mediating immune responses, they are also often dysregulated in sepsis and critical illness. We hypothesized that these immunological deficits, quantifiable through ex vivo whole blood stimulation assays, may be indicative of subsequent organ dysfunction. DESIGN: In a prospective observational study, adult septic patients and critically ill but nonseptic controls were identified within 48 hours of critical illness onset. Using a rapid, ex vivo assay based on responses to lipopolysaccharide (LPS), anti-CD3/anti-CD28 antibodies, and phorbol 12-myristate 13-acetate with ionomycin, cytokine responses to immune stimulants were quantified. The primary outcome was the relationship between early cytokine production and subsequent organ dysfunction, as measured by the Sequential Organ Failure Assessment score on day 3 of illness (SOFAd3). SETTING: Patients were recruited in an academic medical center and data processing and analysis were done in an academic laboratory setting. PATIENTS: Ninety-six adult septic and critically ill nonseptic patients were enrolled. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Elevated levels of tumor necrosis factor and interleukin-6 post-endotoxin challenge were inversely correlated with SOFAd3. Interferon-gamma production per lymphocyte was inversely related to organ dysfunction at day 3 and differed between septic and nonseptic patients. Clustering analysis revealed two distinct immune phenotypes, represented by differential responses to 18 hours of LPS stimulation and 4 hours of anti-CD3/anti-CD28 stimulation. CONCLUSIONS: Our rapid immune profiling technique offers a promising tool for early prediction and management of organ dysfunction in critically ill patients. This information could be pivotal for early intervention and for preventing irreversible organ damage during the acute phase of critical illness.


Assuntos
Estado Terminal , Insuficiência de Múltiplos Órgãos , Sepse , Humanos , Estudos Prospectivos , Sepse/imunologia , Sepse/sangue , Masculino , Feminino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/imunologia , Insuficiência de Múltiplos Órgãos/diagnóstico , Idoso , Escores de Disfunção Orgânica , Adulto , Citocinas/sangue , Citocinas/metabolismo , Estudos de Coortes , Valor Preditivo dos Testes , Lipopolissacarídeos/farmacologia
16.
Artigo em Inglês | MEDLINE | ID: mdl-38844340

RESUMO

BACKGROUND: There is a need for biomarkers of disease progression and therapeutic response in multiple sclerosis (MS). This study aimed to identify cerebrospinal fluid (CSF) lipids that differentiate MS from other neuroinflammatory conditions and correlate with Expanded Disability Status Scale (EDSS) scores, gadolinium-enhancing lesions or inflammatory mediators. METHODS: Lipids and inflammatory cytokines/chemokines were quantified with liquid chromatography-tandem mass spectrometry and multiplex ELISA, respectively, in CSF from people with untreated MS, neuromyelitis optica spectrum disorder (NMOSD), other inflammatory neurological diseases and non-inflammatory neurological diseases (NIND). Analytes were compared between groups using analysis of variance, and correlations were assessed with Pearson's analysis. RESULTS: Twenty-five sphingolipids and four lysophosphatidylcholines were significantly higher in NMOSD compared with MS and NIND cases, whereas no lipids differed significantly between MS and NIND. A combination of three sphingolipids differentiated NMOSD from MS with the area under the curve of 0.92 in random forest models. Ninety-four lipids, including those that differentiated NMOSD from MS, were positively correlated with macrophage migration inhibitory factor (MIF) and 37 lipids were positively correlated with CSF protein in two independent MS cohorts. EDSS was inversely correlated with cholesterol ester CE(16:0) in both MS cohorts. In contrast, MIF and soluble triggering receptor expressed on myeloid cells 2 were positively associated with EDSS. CONCLUSIONS: CSF sphingolipids are positively correlated with markers of neuroinflammation and differentiate NMOSD from MS. The inverse correlation between EDSS and CE(16:0) levels may reflect poor clearance of cholesterol released during myelin break-down and warrants further investigation as a biomarker of therapeutic response.

17.
MSMR ; 31(5): 16-23, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38857490

RESUMO

The Department of Defense Global Respiratory Pathogen Surveillance Program conducts continuous surveillance for influenza, severe acute respiratory syndrome 2 (SARS-CoV-2), and other respiratory pathogens at 104 sentinel sites across the globe. These sites submitted 65,475 respiratory specimens for clinical diagnostic testing during the 2021-2022 surveillance season. The predominant influenza strain was influenza A(H3N2) (n=777), of which 99.9% of strains were in clade 3C.2a1b.2a2. A total of 21,466 SARSCoV-2-positive specimens were identified, and 12,225 of the associated viruses were successfully sequenced. The Delta variant predominated at the start of the season, until December 2021, when Omicron became dominant. Most circulating SARS-CoV-2 viruses were subsequently held by Omicron sublineages BA.1, BA.2, and BA.5 during the season. Clinical manifestation, obtained through a self-reported questionnaire, found that cough, sinus congestion, and runny nose complaints were the most common symptoms presenting among all pathogens. Sentinel surveillance can provide useful epidemiological data to supplement other disease monitoring activities, and has become increasingly useful with increasing numbers of individuals utilizing COVID-19 rapid self-test kits and reductions in outpatient visits for routine respiratory testing.


Assuntos
COVID-19 , Infecções Respiratórias , SARS-CoV-2 , Vigilância de Evento Sentinela , Humanos , Estados Unidos/epidemiologia , Masculino , Feminino , COVID-19/epidemiologia , Adulto , Pessoa de Meia-Idade , Adolescente , Adulto Jovem , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Criança , Idoso , Influenza Humana/epidemiologia , Pré-Escolar , Lactente , Militares/estatística & dados numéricos , Estações do Ano , Família Militar/estatística & dados numéricos , Recém-Nascido , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Serviços de Saúde Militar/estatística & dados numéricos
18.
PLoS One ; 19(6): e0305015, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38905248

RESUMO

INTRODUCTION: Advances have been made in understanding the aetiology of functional neurological disorder (FND); however, its pathophysiological mechanisms have not been definitively demonstrated. Evidence suggests interacting roles for altered emotional processing and interoception, elevated autonomic arousal, and dissociation, but there is limited evidence demonstrating their causal influence on specific FND symptoms. Our superordinate aim is to elucidate potentially shared and distinct aetiological factors and mechanisms in two common FND subtypes, functional seizures (FS) and functional motor symptoms (FMS). METHODS: This study has a multimodal, mixed between- and within-groups design. The target sample is 50 individuals with FS, 50 with FMS, 50 clinical controls (anxiety/depression), and 50 healthy controls. Potential aetiological factors (e.g., adverse life events, physical/mental health symptoms, dissociative tendencies, interoceptive insight/sensibility) will be assessed with a detailed medical history interview and self-report questionnaires. A laboratory session will include a neurocognitive battery, psychophysiological testing, cardiac interoception and time estimation tasks and an isometric handgrip task. A subsample will undergo magnetic resonance imaging, including structural, resting-state and task-based scans combined with psychophysiological recording. Remote monitoring with ecological momentary assessment and wearables will measure variability in FND symptoms and their potential predictors/correlates for ≥2 weeks in patients' daily lives. Longitudinal follow-ups at 3, 6, and 12-months will monitor longer-term outcomes in the clinical groups. DISCUSSION: This study employs multimodal research methods to rigorously examine several putative mechanisms in FND, at subjective/experiential, behavioural, and physiological levels. The study will test causal hypotheses about the role of altered emotional processing, autonomic arousal, dissociation and interoception in the initiation or exacerbation of FND symptoms, directly comparing these processes in FS and FMS to healthy and clinical controls. This is the first study of its kind, with potential to reveal important targets for prevention and treatment of FND in future.


Assuntos
Convulsões , Humanos , Convulsões/fisiopatologia , Convulsões/psicologia , Adulto , Masculino , Feminino , Pessoa de Meia-Idade , Imageamento por Ressonância Magnética , Adulto Jovem , Interocepção/fisiologia , Adolescente , Estudos de Casos e Controles
19.
Acta Crystallogr C Struct Chem ; 80(Pt 7): 331-336, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38940368

RESUMO

Methyl 2-acetamido-2-deoxy-ß-D-glucopyranosyl-(1→4)-2-acetamido-2-deoxy-ß-D-glucopyranoside (methyl ß-chitobioside), (IV), crystallizes from aqueous methanol at room temperature to give a structure (C17H30N2O22·CH3OH) containing conformational disorder in the exocyclic hydroxymethyl group of one of its ßGlcNAc residues. As observed in other X-ray structures of disaccharides containing ß-(1→4) O-glycosidic linkages, inter-residue hydrogen bonding between O3H of the ßGlcNAc bearing the OCH3 aglycone and O5 of the adjacent ßGlcNAc is observed based on the 2.79 Šinternuclear distance between the O atoms. The structure of (IV) was compared to that determined previously for 2-acetamido-2-deoxy-ß-D-glucopyranosyl-(1→4)-2-acetamido-2-deoxy-ß-D-glucopyranose (ß-chitobiose), (III). The O-glycosidic linkage torsion angles, phi (φ) and psi (ψ), in (III) and (IV) differ by 6-8°. The N-acetyl side chain conformation in (III) and (IV) shows some context dependence, with the C1-C2-N-Ccar torsion angle 10-15° smaller for the ßGlcNAc residue involved in the internal O-glycosidic linkage. In (IV), conformational disorder is observed in the exocyclic hydroxymethyl (-CH2OH) group in the ßGlcNAc residue bearing the OCH3 aglycone, and a fitting of the electron density indicates an approximate 50:50 distribution of the gauche-gauche (gg) and gauche-trans (gt) conformers in the lattice. Similar behavior is not observed in (III), presumably due to the different packing structure in the vicinity of the -CH2OH substituent that affects its ability to hydrogen bond to proximal donors/acceptors. Unlike (IV), a re-examination of the previously reported electron density of (III) revealed conformational disorder in the N-acetyl side chain attached to the reducing-end ßGlcNAc residue caused by rotation about the C2-N bond.

20.
Glia ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38899762

RESUMO

The neurometabolic disorder succinic semialdehyde dehydrogenase (SSADH) deficiency leads to great neurochemical imbalances and severe neurological manifestations. The cause of the disease is loss of function of the enzyme SSADH, leading to impaired metabolism of the principal inhibitory neurotransmitter GABA. Despite the known identity of the enzymatic deficit, the underlying pathology of SSADH deficiency remains unclear. To uncover new mechanisms of the disease, we performed an untargeted integrative analysis of cerebral protein expression, functional metabolism, and lipid composition in a genetic mouse model of SSADH deficiency (ALDH5A1 knockout mice). Our proteomic analysis revealed a clear regional vulnerability, as protein alterations primarily manifested in the hippocampus and cerebral cortex of the ALDH5A1 knockout mice. These regions displayed aberrant expression of proteins linked to amino acid homeostasis, mitochondria, glial function, and myelination. Stable isotope tracing in acutely isolated brain slices demonstrated an overall maintained oxidative metabolism of glucose, but a selective decrease in astrocyte metabolic activity in the cerebral cortex of ALDH5A1 knockout mice. In contrast, an elevated capacity of oxidative glutamine metabolism was observed in the ALDH5A1 knockout brain, which may serve as a neuronal compensation of impaired astrocyte glutamine provision. In addition to reduced expression of critical oligodendrocyte proteins, a severe depletion of myelin-enriched sphingolipids was found in the brains of ALDH5A1 knockout mice, suggesting degeneration of myelin. Altogether, our study highlights that impaired astrocyte and oligodendrocyte function is intimately linked to SSADH deficiency pathology, suggesting that selective targeting of glial cells may hold therapeutic potential in this disease.

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