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1.
Chem Rev ; 123(23): 13209-13290, 2023 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-37862151

RESUMEN

Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.


Asunto(s)
Surfactantes Pulmonares , Recién Nacido , Humanos , Surfactantes Pulmonares/química , Surfactantes Pulmonares/metabolismo , Fosfolípidos/química , Tensoactivos , Tensión Superficial , Fenómenos Químicos
2.
Stroke ; 55(7): 1808-1817, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38913799

RESUMEN

BACKGROUND: Tandem lesions consist of cervical internal carotid artery (ICA) stenosis or occlusion, most commonly of atherosclerosis or dissection etiology, plus a large vessel occlusion. In this study, we compare outcomes in patients with atherosclerosis versus dissection of the cervical ICA. METHODS: This multicenter retrospective cohort study includes data from tandem lesion patients who underwent endovascular treatment from 2015 to 2020. Atherosclerosis was defined as ICA stenosis/occlusion associated with a calcified lesion and dissection by the presence of a tapered or flame-shaped lesion and intramural hematoma. Primary outcome: 90-day functional independence (modified Rankin Scale score, 0-2); secondary outcomes: 90-day favorable shift in the modified Rankin Scale score, modified Thrombolysis in Cerebral Infarction score 2b-3, modified Thrombolysis in Cerebral Infarction score 2c-3, symptomatic intracranial hemorrhage, parenchymal hematoma type 2, petechial hemorrhage, distal embolization, early neurological improvement, and mortality. Analysis was performed with matching by inverse probability of treatment weighting. RESULTS: We included 526 patients (68 [59-76] years; 31% females); 11.2% presented dissection and 88.8%, atherosclerosis. Patients with dissection were younger, had lower rates of hypertension, hyperlipidemia, diabetes, and smoking history. They also exhibited higher rates of ICA occlusion, multiple stents (>1), and lower rates of carotid self-expanding stents. After matching and adjusting for covariates, there were no differences in 90-day functional independence. The rate of successful recanalization was significantly lower in the dissection group (adjusted odds ratio, 0.38 [95% CI, 0.16-0.91]; P=0.031), which also had significantly higher rates of distal emboli (adjusted odds ratio, 2.53 [95% CI, 1.15-5.55]; P=0.021). There were no differences in other outcomes. Acute ICA stenting seemed to increase the effect of atherosclerosis in successful recanalization. CONCLUSIONS: This study reveals that among patients with acute stroke with tandem lesions, cervical ICA dissection is associated with higher rates of distal embolism and lower rates of successful recanalization than atherosclerotic lesions. Using techniques to minimize the risk of distal embolism may mitigate this contrast. Further prospective randomized trials are warranted to fully understand these associations.


Asunto(s)
Procedimientos Endovasculares , Humanos , Femenino , Persona de Mediana Edad , Masculino , Anciano , Estudios Retrospectivos , Procedimientos Endovasculares/métodos , Disección de la Arteria Carótida Interna/diagnóstico por imagen , Disección de la Arteria Carótida Interna/cirugía , Disección de la Arteria Carótida Interna/terapia , Estenosis Carotídea/cirugía , Estenosis Carotídea/complicaciones , Resultado del Tratamiento , Embolia
3.
J Am Chem Soc ; 146(3): 1860-1873, 2024 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-38215281

RESUMEN

Biotin synthase (BioB) is a member of the Radical SAM superfamily of enzymes that catalyzes the terminal step of biotin (vitamin B7) biosynthesis, in which it inserts a sulfur atom in desthiobiotin to form a thiolane ring. How BioB accomplishes this difficult reaction has been the subject of much controversy, mainly around the source of the sulfur atom. However, it is now widely accepted that the sulfur atom inserted to form biotin stems from the sacrifice of the auxiliary 2Fe-2S cluster of BioB. Here, we bioinformatically explore the diversity of BioBs available in sequence databases and find an unexpected variation in the coordination of the auxiliary iron-sulfur cluster. After in vitro characterization, including the determination of biotin formation and representative crystal structures, we report a new type of BioB utilized by virtually all obligate anaerobic organisms. Instead of a 2Fe-2S cluster, this novel type of BioB utilizes an auxiliary 4Fe-5S cluster. Interestingly, this auxiliary 4Fe-5S cluster contains a ligated sulfide that we propose is used for biotin formation. We have termed this novel type of BioB, Type II BioB, with the E. coli 2Fe-2S cluster sacrificial BioB representing Type I. This surprisingly ubiquitous Type II BioB has implications for our understanding of the function and evolution of Fe-S clusters in enzyme catalysis, highlighting the difference in strategies between the anaerobic and aerobic world.


Asunto(s)
Proteínas de Escherichia coli , Proteínas Hierro-Azufre , Escherichia coli/metabolismo , Biotina/química , Proteínas de Escherichia coli/química , Azufre/química , Sulfurtransferasas/metabolismo , Proteínas Hierro-Azufre/química
4.
Stroke ; 54(5): 1392-1402, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36789774

RESUMEN

Scientific advances have informed many aspects of acute stroke care but have also highlighted the complexity and heterogeneity of cerebrovascular diseases. While practice guidelines are essential in supporting the clinical decision-making process, they may not capture the nuances of individual cases. Personalized stroke care in ICU has traditionally relied on integrating clinical examinations, neuroimaging studies, and physiologic monitoring to develop a treatment plan tailored to the individual patient. However, to realize the potential of precision medicine in stroke, we need advances and evidence in several critical areas, including data capture, clinical phenotyping, serum biomarker development, neuromonitoring, and physiology-based treatment targets. Mathematical tools are being developed to analyze the multitude of data and provide clinicians with real-time information and personalized treatment targets for the critical care management of patients with cerebrovascular diseases. This review summarizes research advances in these areas and outlines principles for translating precision medicine into clinical practice.


Asunto(s)
Medicina de Precisión , Accidente Cerebrovascular , Humanos , Medicina de Precisión/métodos , Monitoreo Fisiológico/métodos , Cuidados Críticos/métodos
5.
Stroke ; 54(11): 2832-2841, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37795593

RESUMEN

BACKGROUND: Neuroimaging is essential for detecting spontaneous, nontraumatic intracerebral hemorrhage (ICH). Recent data suggest ICH can be characterized using low-field magnetic resonance imaging (MRI). Our primary objective was to investigate the sensitivity and specificity of ICH on a 0.064T portable MRI (pMRI) scanner using a methodology that provided clinical information to inform rater interpretations. As a secondary aim, we investigated whether the incorporation of a deep learning (DL) reconstruction algorithm affected ICH detection. METHODS: The pMRI device was deployed at Yale New Haven Hospital to examine patients presenting with stroke symptoms from October 26, 2020 to February 21, 2022. Three raters independently evaluated pMRI examinations. Raters were provided the images alongside the patient's clinical information to simulate real-world context of use. Ground truth was the closest conventional computed tomography or 1.5/3T MRI. Sensitivity and specificity results were grouped by DL and non-DL software to investigate the effects of software advances. RESULTS: A total of 189 exams (38 ICH, 89 acute ischemic stroke, 8 subarachnoid hemorrhage, 3 primary intraventricular hemorrhage, 51 no intracranial abnormality) were evaluated. Exams were correctly classified as positive or negative for ICH in 185 of 189 cases (97.9% overall accuracy). ICH was correctly detected in 35 of 38 cases (92.1% sensitivity). Ischemic stroke and no intracranial abnormality cases were correctly identified as blood-negative in 139 of 140 cases (99.3% specificity). Non-DL scans had a sensitivity and specificity for ICH of 77.8% and 97.1%, respectively. DL scans had a sensitivity and specificity for ICH of 96.6% and 99.3%, respectively. CONCLUSIONS: These results demonstrate improvements in ICH detection accuracy on pMRI that may be attributed to the integration of clinical information in rater review and the incorporation of a DL-based algorithm. The use of pMRI holds promise in providing diagnostic neuroimaging for patients with ICH.


Asunto(s)
Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular Isquémico/complicaciones , Tomografía Computarizada por Rayos X , Hemorragia Cerebral/complicaciones , Accidente Cerebrovascular/diagnóstico , Imagen por Resonancia Magnética
6.
Stroke ; 54(10): 2522-2533, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37602387

RESUMEN

BACKGROUND: We aimed to describe the safety and efficacy of mechanical thrombectomy (MT) with or without intravenous thrombolysis (IVT) for patients with tandem lesions and whether using intraprocedural antiplatelet therapy influences MT's safety with IVT treatment. METHODS: This is a subanalysis of a pooled, multicenter cohort of patients with acute anterior circulation tandem lesions treated with MT from 16 stroke centers between January 2015 and December 2020. Primary outcomes included symptomatic intracranial hemorrhage (sICH) and parenchymal hematoma type 2. Additional outcomes included hemorrhagic transformation, successful reperfusion (modified Thrombolysis in Cerebral Infarction score 2b-3), complete reperfusion (modified Thrombolysis in Cerebral Infarction score 3), favorable functional outcome (90-day modified Rankin Scale score 0-2), excellent functional outcome (90-day modified Rankin Scale score 0-1), in-hospital mortality, and 90-day mortality. RESULTS: Of 691 patients, 512 were included (218 underwent IVT+MT and 294 MT alone). There was no difference in the risk of sICH (adjusted odds ratio [aOR], 1.22 [95% CI, 0.60-2.51]; P=0.583), parenchymal hematoma type 2 (aOR, 0.99 [95% CI, 0.47-2.08]; P=0.985), and hemorrhagic transformation (aOR, 0.95 [95% CI, 0.62-1.46]; P=0.817) between the IVT+MT and MT alone groups after adjusting for confounders. Administration of IVT was associated with an increased risk of sICH in patients who received intravenous antiplatelet therapy (aOR, 3.04 [95% CI, 0.99-9.37]; P=0.05). The IVT+MT group had higher odds of a 90-day modified Rankin Scale score 0 to 2 (aOR, 1.72 [95% CI, 1.01-2.91]; P=0.04). The odds of successful reperfusion, complete reperfusion, 90-day modified Rankin Scale score 0 to 1, in-hospital mortality, or 90-day mortality did not differ between the IVT+MT versus MT alone groups. CONCLUSIONS: Our study showed that the combination of IVT with MT for tandem lesions did not increase the overall risk of sICH, parenchymal hematoma type 2, or overall hemorrhagic transformation independently of the cervical revascularization technique used. However, intraprocedural intravenous antiplatelet therapy during acute stent implantation might be associated with an increased risk of sICH in patients who received IVT before MT. Importantly, IVT+MT treatment was associated with a higher rate of favorable functional outcomes at 90 days.


Asunto(s)
Isquemia Encefálica , Trombolisis Mecánica , Accidente Cerebrovascular , Humanos , Terapia Trombolítica/efectos adversos , Terapia Trombolítica/métodos , Inhibidores de Agregación Plaquetaria/uso terapéutico , Resultado del Tratamiento , Trombectomía/métodos , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/cirugía , Hemorragias Intracraneales/etiología , Hemorragias Intracraneales/complicaciones , Infarto Cerebral/etiología , Hematoma/complicaciones , Trombolisis Mecánica/métodos , Isquemia Encefálica/terapia , Fibrinolíticos/efectos adversos
7.
Neurocrit Care ; 2023 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-38158481

RESUMEN

BACKGROUND: The Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase II randomized controlled trial used a tier-based management protocol based on brain tissue oxygen (PbtO2) and intracranial pressure (ICP) monitoring to reduce brain tissue hypoxia after severe traumatic brain injury. We performed a secondary analysis to explore the relationship between brain tissue hypoxia, blood pressure (BP), and interventions to improve cerebral perfusion pressure (CPP). We hypothesized that BP management below the lower limit of autoregulation would lead to cerebral hypoperfusion and brain tissue hypoxia that could be improved with hemodynamic augmentation. METHODS: Of the 119 patients enrolled in the Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase II trial, 55 patients had simultaneous recordings of arterial BP, ICP, and PbtO2. Autoregulatory function was measured by interrogating changes in ICP and PbtO2 in response to fluctuations in CPP using time-correlation analysis. The resulting autoregulatory indices (pressure reactivity index and oxygen reactivity index) were used to identify the "optimal" CPP and limits of autoregulation for each patient. Autoregulatory function and percent time with CPP outside personalized limits of autoregulation were calculated before, during, and after all interventions directed to optimize CPP. RESULTS: Individualized limits of autoregulation were computed in 55 patients (mean age 38 years, mean monitoring time 92 h). We identified 35 episodes of brain tissue hypoxia (PbtO2 < 20 mm Hg) treated with CPP augmentation. Following each intervention, mean CPP increased from 73 ± 14 mm Hg to 79 ± 17 mm Hg (p = 0.15), and mean PbtO2 improved from 18.4 ± 5.6 mm Hg to 21.9 ± 5.6 mm Hg (p = 0.01), whereas autoregulatory function trended toward improvement (oxygen reactivity index 0.42 vs. 0.37, p = 0.14; pressure reactivity index 0.25 vs. 0.21, p = 0.2). Although optimal CPP and limits remained relatively unchanged, there was a significant decrease in the percent time with CPP below the lower limit of autoregulation in the 60 min after compared with before an intervention (11% vs. 23%, p = 0.05). CONCLUSIONS: Our analysis suggests that brain tissue hypoxia is associated with cerebral hypoperfusion characterized by increased time with CPP below the lower limit of autoregulation. Interventions to increase CPP appear to improve autoregulation. Further studies are needed to validate the importance of autoregulation as a modifiable variable with the potential to improve outcomes.

8.
J Stroke Cerebrovasc Dis ; 32(12): 107438, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37883826

RESUMEN

OBJECTIVES: Intravenous (IV) periprocedural antiplatelet therapy (APT) for patients undergoing acute carotid stenting during mechanical thrombectomy (MT) is not fully investigated. We aimed to compare the safety profile of IV low dose cangrelor versus IV glycoprotein IIb/IIIa (GP-IIb/IIIa) inhibitors in patients with acute tandem lesions (TLs). MATERIALS AND METHODS: We retrospectively identified all cases of periprocedural administration of IV cangrelor or GP-IIb/IIIa inhibitors during acute TLs intervention from a multicenter collaboration. Patients were divided in two groups according to the IV APT regimen at the time of MT procedure: 1) cangrelor and 2) GP-IIb/IIIa inhibitors (tirofiban and eptifibatide). Safety outcomes included rates of symptomatic intracranial hemorrhage (sICH), parenchymal hematoma type 1 and 2 (PH1-PH2), and hemorrhagic infarction type 1 and 2 (HI1-HI2). RESULTS: Sixty-three patients received IV APT during MT, 30 were in the cangrelor group, and 33 were in the GP-IIb/IIIa inhibitors group. There were no significant differences in the rates of sICH (3.3% vs. 12.1%, aOR=0.21, 95%CI 0.02-2.18, p=0.229), HI1-HI2 (21.4% vs 42.4%, aOR=0.21, 95%CI 0.02-2.18, p=0.229), and PH1-PH2 (17.9% vs. 12.1%, aOR=1.63, 95%CI 0.29-9.83, p=0.577) between both treatment groups. However, there was a trend toward reduced hemorrhage rates with cangrelor. Cangrelor was associated with increased odds of complete reperfusion (aOR=5.86; 95%CI 1.57-26.62;p=0.013). CONCLUSIONS: In this retrospective non-randomized cohort study, our findings suggest that low dose cangrelor has similar safety and increased rate of complete reperfusion compared to IV GP-IIb/IIIa inhibitors. Further prospective studies are warranted to confirm this association.


Asunto(s)
Hemorragias Intracraneales , Inhibidores de Agregación Plaquetaria , Humanos , Inhibidores de Agregación Plaquetaria/uso terapéutico , Estudios Retrospectivos , Estudios de Cohortes , Hemorragias Intracraneales/tratamiento farmacológico , Glicoproteínas , Resultado del Tratamiento
9.
Stroke ; 53(4): 1074-1084, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35291822

RESUMEN

High blood pressure (BP) is common after ischemic stroke and associated with a poor functional outcome and increased mortality. The conundrum then arises on whether to lower BP to improve outcome or whether this will worsen cerebral perfusion due to aberrant cerebral autoregulation. A number of large trials of BP lowering have failed to change outcome whether treatment was started prehospital in the community or hospital. Hence, nuances on how to manage high BP are likely, including whether different interventions are needed for different causes, the type and timing of the drug, how quickly BP is lowered, and the collateral effects of the drug, including on cerebral perfusion and platelets. Specific scenarios are also important, including when to lower BP before, during, and after intravenous thrombolysis and endovascular therapy/thrombectomy, when it may be necessary to raise BP, and when antihypertensive drugs taken before stroke should be restarted. This narrative review addresses these and other questions. Although further large trials are ongoing, it is increasingly likely that there is no simple answer. Different subgroups of patients may need to have their BP lowered (eg, before or after thrombolysis), left alone, or elevated.


Asunto(s)
Isquemia Encefálica , Hipertensión , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Antihipertensivos , Presión Sanguínea/fisiología , Isquemia Encefálica/tratamiento farmacológico , Humanos , Hipertensión/tratamiento farmacológico , Hipertensión/etiología , Resultado del Tratamiento
10.
Stroke ; 53(4): 1216-1225, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34781705

RESUMEN

BACKGROUND: Elevated blood pressure after endovascular thrombectomy (EVT) has been associated with an increased risk of hemorrhagic transformation and poor functional outcomes. However, the optimal hemodynamic management after EVT remains unknown, and the blood pressure course in the acute phase of ischemic stroke has not been well characterized. This study aimed to identify patient subgroups with distinct blood pressure trajectories after EVT and study their association with radiographic and functional outcomes. METHODS: This multicenter retrospective cohort study included consecutive patients with anterior circulation large-vessel occlusion ischemic stroke who underwent EVT. Repeated time-stamped blood pressure data were recorded for the first 72 hours after thrombectomy. Latent variable mixture modeling was used to separate subjects into five groups with distinct postprocedural systolic blood pressure (SBP) trajectories. The primary outcome was functional status, measured on the modified Rankin Scale 90 days after stroke. Secondary outcomes included hemorrhagic transformation, symptomatic intracranial hemorrhage, and death. RESULTS: Two thousand two hundred sixty-eight patients (mean age [±SD] 69±15, mean National Institutes of Health Stroke Scale 15±7) were included in the analysis. Five distinct SBP trajectories were observed: low (18%), moderate (37%), moderate-to-high (20%), high-to-moderate (18%), and high (6%). SBP trajectory group was independently associated with functional outcome at 90 days (P<0.0001) after adjusting for potential confounders. Patients with high and high-to-moderate SBP trajectories had significantly greater odds of an unfavorable outcome (adjusted odds ratio, 3.5 [95% CI, 1.8-6.7], P=0.0003 and adjusted odds ratio, 2.2 [95% CI, 1.5-3.2], P<0.0001, respectively). Subjects in the high-to-moderate group had an increased risk of symptomatic intracranial hemorrhage (adjusted odds ratio, 1.82 [95% CI, 1-3.2]; P=0.04). No significant association was found between trajectory group and hemorrhagic transformation. CONCLUSIONS: Patients with acute ischemic stroke demonstrate distinct SBP trajectories during the first 72 hours after EVT that have differing associations with functional outcome. These findings may help identify potential candidates for future blood pressure modulation trials.


Asunto(s)
Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Anciano , Anciano de 80 o más Años , Presión Sanguínea/fisiología , Isquemia Encefálica/complicaciones , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/cirugía , Procedimientos Endovasculares/efectos adversos , Humanos , Persona de Mediana Edad , Estudios Retrospectivos , Accidente Cerebrovascular/etiología , Trombectomía/efectos adversos , Resultado del Tratamiento
11.
Eur J Neurol ; 29(3): 771-781, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34821437

RESUMEN

BACKGROUND AND PURPOSE: The Blood Pressure Target in Acute Ischemic Stroke to Reduce Hemorrhage After Endovascular Therapy (BP TARGET) trial evaluated whether an intensive systolic blood pressure (SBP) target resulted in reduced rates of intracranial hemorrhage (ICH) after successful endovascular therapy (EVT) but did not assess the effect of blood pressure variability (BPV) on functional outcomes and ICH occurrence. We sought to evaluate this question in the BP TARGET trial. METHODS: We performed a post hoc analysis of the BP TARGET trial and included patients with at least 50% of blood pressure (BP) recordings during the first 24 h after EVT. BPV parameters were SBP and diastolic BP (DBP) coefficient of variation (CV), standard deviation (SD), maximum-minimum (max-min), successive variation (SV), and time rate. The primary outcome was favorable functional outcome (3-month modified Rankin Scale between 0 and 2); the secondary outcome was the rate of ICH at 24 h. RESULTS: We included 290 patients (mean number of BP measures = 30.4, SD = 8.0). BPV parameters (SBPSD , SBPmax-min , SBPCV ) were higher in the intensive SBP target group. Only DBP BPV parameters were associated with worse functional outcomes in the unadjusted model (DBPSD , DBPmax-min , DBPCV , and DBPSV ), but not after adjustment. Higher SBPmax-min was associated with worse functional outcomes in Thrombolysis in Cerebral Infarction 2B patients (odds ratio [OR] = 0.62, 95% confidence interval [CI] = 0.38-1.02), but not in patients with complete reperfusion (OR = 1.27, 95% CI = 0.80-2.02, p for heterogeneity (phet =0.037). None of the BPV parameters was associated with ICH, regardless of the randomization group or the reperfusion grade. CONCLUSIONS: BPV was significantly higher in the intensive SBP target group but was not associated with functional outcome or ICH.


Asunto(s)
Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Presión Sanguínea/fisiología , Infarto Cerebral , Humanos , Hemorragias Intracraneales , Oportunidad Relativa , Resultado del Tratamiento
12.
Proc Natl Acad Sci U S A ; 116(38): 19116-19125, 2019 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-31427514

RESUMEN

Cable bacteria of the family Desulfobulbaceae form centimeter-long filaments comprising thousands of cells. They occur worldwide in the surface of aquatic sediments, where they connect sulfide oxidation with oxygen or nitrate reduction via long-distance electron transport. In the absence of pure cultures, we used single-filament genomics and metagenomics to retrieve draft genomes of 3 marine Candidatus Electrothrix and 1 freshwater Ca. Electronema species. These genomes contain >50% unknown genes but still share their core genomic makeup with sulfate-reducing and sulfur-disproportionating Desulfobulbaceae, with few core genes lost and 212 unique genes (from 197 gene families) conserved among cable bacteria. Last common ancestor analysis indicates gene divergence and lateral gene transfer as equally important origins of these unique genes. With support from metaproteomics of a Ca. Electronema enrichment, the genomes suggest that cable bacteria oxidize sulfide by reversing the canonical sulfate reduction pathway and fix CO2 using the Wood-Ljungdahl pathway. Cable bacteria show limited organotrophic potential, may assimilate smaller organic acids and alcohols, fix N2, and synthesize polyphosphates and polyglucose as storage compounds; several of these traits were confirmed by cell-level experimental analyses. We propose a model for electron flow from sulfide to oxygen that involves periplasmic cytochromes, yet-unidentified conductive periplasmic fibers, and periplasmic oxygen reduction. This model proposes that an active cable bacterium gains energy in the anodic, sulfide-oxidizing cells, whereas cells in the oxic zone flare off electrons through intense cathodic oxygen respiration without energy conservation; this peculiar form of multicellularity seems unparalleled in the microbial world.


Asunto(s)
Proteínas Bacterianas/metabolismo , Evolución Biológica , Deltaproteobacteria/genética , Deltaproteobacteria/fisiología , Genoma Bacteriano , Proteoma/análisis , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Ciclo del Carbono , Movimiento Celular , Quimiotaxis , Citocromos/metabolismo , Deltaproteobacteria/clasificación , Transporte de Electrón , Sedimentos Geológicos/microbiología , Nitratos/metabolismo , Oxidación-Reducción , Oxígeno/metabolismo , Filogenia , Homología de Secuencia , Sulfuros/metabolismo
13.
Neurocrit Care ; 36(1): 46-51, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34494212

RESUMEN

BACKGROUND: Cerebral edema is associated with worse outcome after acute stroke; however, the minimum clinically relevant threshold remains unknown. This study aimed to identify the minimal degree of midline shift (MLS) that predicts outcome in a cohort encompassing a broad range of patients with acute stroke. METHODS: Patient-level data from six acute stroke clinical trials were combined with endovascular thrombectomy registries from two academic referral centers, generating a combined cohort of 1977 patients. MLS was extracted from the original trial data or measured on computed tomography or magnetic resonance imaging that was obtained a median of 47.0 h (interquartile range 27.0-75.1 h) after stroke onset. Logistic regression was performed to identify predictors of poor outcome and the minimal clinically relevant MLS threshold. RESULTS: The presence of MLS was a predictor of poor outcome, independent of baseline clinical and demographic factors (adjusted odds ratio 4.46, 95% confidence interval 3.56-5.59, p < 0.001). Examining the full range of MLS values identified, a value of greater than 3 mm was the critical threshold that significantly predicted poor outcome (adjusted odds ratio 3.20 [1.31-7.82], p = 0.011). CONCLUSIONS: These results show that the presence of MLS predicts poor outcome and, specifically, MLS value greater than 3 mm is an important threshold across a variety of clinical settings. These findings may have relevance for the design and interpretation of future trials for antiedema therapies.


Asunto(s)
Edema Encefálico , Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Edema Encefálico/complicaciones , Edema Encefálico/etiología , Isquemia Encefálica/complicaciones , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/terapia , Humanos , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/terapia , Trombectomía , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
14.
Biophys J ; 120(5): 877-885, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33515601

RESUMEN

Aggregates of misfolded α-synuclein are a distinctive feature of Parkinson's disease. Small oligomers of α-synuclein are thought to be an important neurotoxic agent, and α-synuclein aggregates exhibit prion-like behavior, propagating misfolding between cells. α-Synuclein is internalized by both passive diffusion and active uptake mechanisms, but how uptake varies with the size of the oligomer is less clear. We explored how α-synuclein internalization into live SH-SY5Y cells varied with oligomer size by comparing the uptake of fluorescently labeled monomers to that of engineered tandem dimers and tetramers. We found that these α-synuclein constructs were internalized primarily through endocytosis. Oligomer size had little effect on their internalization pathway, whether they were added individually or together. Measurements of co-localization of the α-synuclein constructs with fluorescent markers for early endosomes and lysosomes showed that most of the α-synuclein entered endocytic compartments, in which they were probably degraded. Treatment of the cells with the Pitstop inhibitor suggested that most of the oligomers were internalized by the clathrin-mediated pathway.


Asunto(s)
Lisosomas , alfa-Sinucleína , Transporte Biológico , Endocitosis , Humanos , Lisosomas/metabolismo , alfa-Sinucleína/metabolismo
15.
Stroke ; 52(3): 859-867, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33517702

RESUMEN

BACKGROUND AND PURPOSE: The mechanisms linking systemic inflammation to poor outcome in ischemic stroke are not fully understood. The authors investigated if peripheral inflammation following reperfusion therapy leads to an increase in cerebral edema (CED), thus hindering the clinical recovery. METHODS: We designed a single-center study conducted at Centro Hospitalar Universitário São João between 2017 and 2019. Inclusion criteria were being adult, having an anterior circulation acute ischemic stroke, and receiving reperfusion therapy. Neutrophil-to-lymphocyte, platelet-to-lymphocyte ratios, and the systemic inflammatory response syndrome criteria were determined. The presence and grade of CED were evaluated on the computed tomography performed 24 hours following event. The clinical outcomes included early neurological deterioration and functional dependence at 90 days. Adjusted odds ratio and 95% CI were obtained by ordinal and logistic regression models. Optimal cutoff values were defined using receiver operating characteristic analysis in the training cohort and validated in an independent data set. RESULTS: Five hundred fifty-three patients were included. Neutrophil-to-lymphocyte increased with higher degrees of CED at 24 hours (adjusted odds ratio, 1.34 [1.09-1.68], P<0.01) and was associated with early neurological deterioration (adjusted odds ratio, 1.30 [1.04-1.63], P<0.05) and poor functional status at 90 days (adjusted odds ratio, 1.79 [1.28-2.48], P<0.01). Platelet-to-lymphocyte was not associated with the outcomes. Systemic inflammatory response syndrome was related to CED due to altered white blood cell counts. Neutrophil-to-lymphocyte was the best predictor with an area under the curve around 0.7. Neutrophil-to-lymphocyte ≥7 had and accuracy, sensitivity, and specificity around 60%. CONCLUSIONS: Increased systemic inflammation is linked to the severity of CED early after reperfusion therapy in stroke. Easily obtained inflammatory markers convey early warning alerts for patients at risk of severe neurological complications with an impact on long-term functional outcome. CED quantification should be included as an end point in proof-of-concept trials in immunomodulation in stroke.


Asunto(s)
Linfocitos/citología , Neutrófilos/citología , Reperfusión/métodos , Accidente Cerebrovascular/sangre , Accidente Cerebrovascular/terapia , Adolescente , Adulto , Anciano , Plaquetas , Edema Encefálico/patología , Recuento de Células , Edema , Humanos , Inflamación , Recuento de Linfocitos , Persona de Mediana Edad , Oportunidad Relativa , Estudios Prospectivos , Curva ROC , Análisis de Regresión , Estudios Retrospectivos , Trombectomía/métodos , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Adulto Joven
16.
Stroke ; 52(9): e531-e535, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34311565

RESUMEN

BACKGROUND AND PURPOSE: High blood pressure (BP) variability after endovascular stroke therapy is associated with poor outcome. Conventional BP variability measures require long recordings, limiting their utility as a risk assessment tool to guide clinical decision-making. Here, we performed rapid assessment of BP variability by spectral analysis and evaluated its association with early clinical improvement and long-term functional outcomes. METHODS: We conducted a prospective study of 146 patients with anterior circulation ischemic stroke who underwent successful endovascular stroke therapy. Spectral analysis of 5-minute recordings of beat-to-beat BP was used to quantify BP variability. Outcomes included initial clinical response and modified Rankin Scale at 90 days. RESULTS: Increased BP variability at high frequencies was independently associated with poor functional outcome at 90 days (adjusted odds ratio [aOR], 1.85 [95% CI, 1.07-3.25], P=0.03; low-/high-frequency ratio aOR, 0.67 [95% CI, 0.46-0.92], P=0.02) and reduced likelihood of an early neurological recovery (aOR, 0.62 [95% CI, 0.44-0.91], P=0.01 and aOR, 1.37 [95% CI, 1.03-1.87], P=0.04, respectively). CONCLUSIONS: High-frequency BP oscillations after successful reperfusion may be harmful and associate with a decreased likelihood of neurological recovery and favorable functional outcomes. Rapid assessment of BP variability throughout the postreperfusion period is feasible and may allow for a more personalized BP management.


Asunto(s)
Presión Sanguínea/fisiología , Isquemia Encefálica/terapia , Accidente Cerebrovascular/terapia , Trombectomía , Humanos , Hipertensión/fisiopatología , Oportunidad Relativa , Estudios Prospectivos , Trombectomía/efectos adversos , Trombectomía/métodos , Resultado del Tratamiento
18.
Environ Microbiol ; 23(5): 2605-2616, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33760391

RESUMEN

Cable bacteria (CB) are Desulfobulbaceae that couple sulphide oxidation to oxygen reduction over centimetre distances by mediating electric currents. Recently, it was suggested that the CB clade is composed of two genera, Ca. Electronema and Ca. Electrothrix, with distinct freshwater and marine habitats respectively. However, only a few studies have reported CB from freshwater sediment, making this distinction uncertain. Here, we report novel data to show that salinity is a controlling factor for the diversity and the species composition within CB populations. CB sampled from a freshwater site (salinity 0.3) grouped into Ca. Electronema and could not grow under brackish conditions (salinity 21), whereas CB from a brackish site (salinity 21) grouped into Ca. Electrothrix and decreased by 93% in activity under freshwater conditions. On a regional scale (Baltic Sea), salinity significantly influenced species richness and composition. However, other environmental factors, such as temperature and quantity and quality of organic matter were also important to explain the observed variation. A global survey of 16S rRNA gene amplicon sequencing revealed that the two genera did not co-occur likely because of competitive exclusion and identified a possible third genus.


Asunto(s)
Deltaproteobacteria , Salinidad , Bacterias/genética , Deltaproteobacteria/genética , Filogenia , ARN Ribosómico 16S/genética
19.
Crit Care Med ; 49(5): 828-837, 2021 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-33591003

RESUMEN

OBJECTIVES: To test the hypothesis that admission hemoglobin levels are associated with outcome in primary, nontraumatic intracerebral hemorrhage. DESIGN: Individual patient data meta-analysis of three studies of intracerebral hemorrhage. SETTING: Two randomized clinical trials and one multiethnic observational study. PATIENTS: Patients with spontaneous, nontraumatic intracerebral hemorrhage. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Our exposure of interest was admission hemoglobin levels and the primary outcome was 3-month postintracerebral hemorrhage-dichotomized modified Rankin Scale (0-3 vs 4-6). Intermediate outcomes were admission hematoma volume and hematoma expansion defined as 6 mL or 33% increase in hemorrhage size on repeat CT. A total of 4,172 intracerebral hemorrhage patients were included in the study (mean age 63 [sd = 14]; female sex 1,668 [40%]). Each additional g/dL of admission hemoglobin was associated with 14% (odds ratio, 0.86; 95% CI, 0.82-0.91) and 7% (odds ratio, 0.93; 95% CI, 0.88-0.98) reductions in the risk of poor outcome in unadjusted and adjusted analyses, respectively. Dose-response analyses indicated a linear relationship between admission hemoglobin levels and poor outcome across the entire evaluated range (test-for-trend p < 0.001). No consistent associations were found between the admission hemoglobin levels and hematoma volume or hematoma expansion. CONCLUSIONS: Higher hemoglobin levels are associated with better outcome in intracerebral hemorrhage. Further research is needed to evaluate admission hemoglobin levels as both a therapeutic target and predictor of outcome.


Asunto(s)
Hemorragia Cerebral/metabolismo , Hemorragia Cerebral/fisiopatología , Hemoglobinas/metabolismo , Anciano , Hemorragia Cerebral/diagnóstico por imagen , Femenino , Sistema de Conducción Cardíaco/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Estudios Observacionales como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Tiempo
20.
New Phytol ; 232(5): 2138-2151, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-33891715

RESUMEN

Cable bacteria are sulfide-oxidising, filamentous bacteria that reduce toxic sulfide levels, suppress methane emissions and drive nutrient and carbon cycling in sediments. Recently, cable bacteria have been found associated with roots of aquatic plants and rice (Oryza sativa). However, the extent to which cable bacteria are associated with aquatic plants in nature remains unexplored. Using newly generated and public 16S rRNA gene sequence datasets combined with fluorescence in situ hybridisation, we investigated the distribution of cable bacteria around the roots of aquatic plants, encompassing seagrass (including seagrass seedlings), rice, freshwater and saltmarsh plants. Diverse cable bacteria were found associated with roots of 16 out of 28 plant species and at 36 out of 55 investigated sites, across four continents. Plant-associated cable bacteria were confirmed across a variety of ecosystems, including marine coastal environments, estuaries, freshwater streams, isolated pristine lakes and intensive agricultural systems. This pattern indicates that this plant-microbe relationship is globally widespread and neither obligate nor species specific. The occurrence of cable bacteria in plant rhizospheres may be of general importance to vegetation vitality, primary productivity, coastal restoration practices and greenhouse gas balance of rice fields and wetlands.


Asunto(s)
Ecosistema , Oxígeno , Bacterias/genética , Sedimentos Geológicos , Raíces de Plantas , ARN Ribosómico 16S/genética , Rizosfera
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