Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 440
Filtrar
1.
J Neurointerv Surg ; 16(10): 957-958, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39288973
2.
bioRxiv ; 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39229094

RESUMEN

Nascent polypeptide chains (NCs) are extruded from the ribosome through an exit tunnel (ET) traversing the large ribosomal subunit. The ET's irregular and chemically complex wall allows for various NC-ET interactions. Translational arrest peptides (APs) bind in the ET to induce translational arrest, a property that can be exploited to study NC-ET interactions by Force Profile Analysis (FPA). We employed FPA and molecular dynamics (MD) simulations to investigate how individual residues placed in a glycine-serine repeat segment within an AP-stalled NC interact with the ET to exert a pulling force on the AP and release stalling. Our results indicate that large and hydrophobic residues generate a pulling force on the NC when placed ≳10 residues away from the peptidyl transfer center (PTC). Moreover, an asparagine placed 12 residues from the PTC makes a specific stabilizing interaction with the tip of ribosomal protein uL22 that reduces the pulling force on the NC, while a lysine or leucine residue in the same position increases the pulling force. Finally, the MD simulations suggest how the Mannheimia succiniproducens SecM AP interacts with the ET to promote translational stalling.

3.
Interv Neuroradiol ; : 15910199241279009, 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39262342

RESUMEN

BACKGROUND: The benefit of intravenous thrombolysis (IVT) is well established. We aim to study the benefits of IVT in acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) who underwent unsuccessful mechanical thrombectomy (MT). METHODS: We included AIS patients who underwent MT for anterior circulation LVO with failed recanalization (modified treatment in cerebral ischemia [mTICI] score ≤ 2A). Patients who received IVT prior to MT were compared to those who received MT alone. Propensity score matching using demographic, clinical, radiographic and procedural variables was used to match patients with and without IVT. The primary outcome was favorable 90-day good functional outcome (defined as modified Rankin scale of 0-2), and secondary outcomes included intracranial hemorrhage (ICH), symptomatic ICH (sICH), and 90-day mortality. RESULTS: Totally, 610 AIS patients with unsuccessful MT were included. After propensity matching, 219 patients were identified in each group. Median age was 70 years and 73 years in the IVT + MT and MT alone groups, respectively. In the IVT + MT group, final mTICI scores of 0, 1, and 2A were achieved in 92 (42.0%), 33 (15.1%), and 94 (42.9%) patients, respectively, versus 76 (34.7%), 29 (13.2%), and 114 (52.1%) in the MT alone group. The IVT + MT group had greater odds of 90-day good functional outcome (adjusted odds ratio 2.54, 95% confidence interval 1.53-4.32). There were no significant differences in secondary outcomes. CONCLUSIONS: IVT is associated with improved functional outcomes in AIS patients with LVO despite unsuccessful MT.

4.
J Neurointerv Surg ; 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39179373

RESUMEN

BACKGROUND: A combination of intravenous (IVT) or intra-arterial (IAT) thrombolysis with mechanical thrombectomy (MT) for acute ischemic stroke due to large vessel occlusion (AIS-LVO) has been investigated. However, there is limited data on patients who receive both IVT and IAT compared with IVT alone before MT. METHODS: STAR data from 2013 to 2023 was utilized. We performed propensity score matching between the two groups. The primary outcomes were symptomatic intracranial hemorrhage (sICH) and 90-day modified Rankin Scale (mRS) score 0-2. Secondary outcomes included successful recanalization (modified treatment in cerebral infarction (mTICI) ≥2B, ≥2C), early neurological improvement, any intracranial hemorrhage (ICH), and 90-day mortality. RESULTS: A total of 2454 AIS-LVO patients were included. Propensity matching yielded 190 well-matched patients in each group. No significant differences were observed between the groups in either ICH or sICH (odds ratio (OR): 0.80, 95% confidence interval (CI) 0.51-1.24, P=0.37; OR: 0.60, 95% CI 0.29 to 1.24, P=0.21, respectively). Rates of successful recanalization and early neurological improvement (ENI) were significantly lower in MT+IVT + IAT. mRS 0-1 and mortality were not significantly different between the two groups. However, the MT+IVT + IAT group demonstrated superior rates of good functional outcomes (90-day mRS 0-1) compared with patients in the MT+IVT group who had mTICI ≤2B, (OR: 2.18, 95% CI 1.05 to 3.99, P=0.04). CONCLUSION: The combined use of IAT and IVT thrombolysis in AIS-LVO patients undergoing MT is safe. Although the MT+IVT+ IAT group demonstrated lower rates of recanalization and early neurological improvement, long-term functional outcomes were favorable in this group suggesting a potential delayed benefit of IAT.

5.
J Neurointerv Surg ; 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39137967

RESUMEN

BACKGROUND: The optimal duration for dual antiplatelet therapy (DAPT) after stent-assisted coiling (SAC) of intracranial aneurysms is unclear. Longer-term therapy may reduce thrombotic complications but increase the risk of bleeding complications. METHODS: A retrospective review of prospectively maintained data at 12 institutions was conducted on patients with unruptured intracranial aneurysms who underwent SAC between January 1, 2016 and December 31, 2020, and were followed ≥6 months postprocedure. The type and duration of DAPT, stent(s) used, outcome, length of follow-up, complication rates, and incidence of significant in-stent stenosis (ISS) were collected. RESULTS: Of 556 patients reviewed, 450 met all inclusion criteria. Nine patients treated with DAPT <29 days after SAC and 11 treated for 43-89 days were excluded from the final analysis as none completed their prescribed duration of treatment. Eighty patients received short-term DAPT. There were no significant differences in the rate of thrombotic complications during predefined periods of risk in the short, medium, or long-term treatment groups (1/80, 1.3%; 2/188, 1.1%; and 0/162, 0%, respectively). Similarly, no differences were found in the rate of hemorrhagic complications during period of risk in any group (0/80, 0%; 3/188, 1.6%; and 1/162, 0.6%, respectively). Longer duration DAPT did not reduce ISS risk in any group. CONCLUSIONS: Continuing DAPT >42 days after SAC did not reduce the risk of thrombotic complications or in-stent stenosis, although the risk of additional hemorrhagic complications remained low. It may be reasonable to discontinue DAPT after 42 days following non-flow diverting SAC of unruptured intracranial aneurysms.

6.
Interv Neuroradiol ; : 15910199241273839, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39140967

RESUMEN

BACKGROUND: Whereas mechanical thrombectomy (MT) has become standard-of-care treatment for patients with salvageable brain tissue after acute stroke caused by large-vessel occlusions, the results of MT in patients with medium-vessel occlusions (MEVOs), particularly in the posterior cerebral artery (PCA), are not well known. METHODS: Using data from the international Stroke Thrombectomy and Aneurysm Registry (STAR), we assessed presenting characteristics and clinical outcomes for patients who underwent MT for primary occlusions in the P2 PCA segment. As a subanalysis, we compared the PCA MeVO outcomes with STAR's anterior circulation MeVO outcomes, namely middle cerebral artery (MCA) M2 and M3 segments. RESULTS: Of the 9812 patients in STAR, 43 underwent MT for isolated PCA MeVOs. The patients' median age was 69 years (interquartile range 61-79), and 48.8% were female. The median NIH Stroke Scale score was 9 (range 6-17). After recanalization, 67.4% of patients achieved successful recanalization (modified treatment in cerebral infarction score [mTICI] ≥ 2b), with a first-pass success rate of 44.2%, and 39.6% achieved a modified Rankin score of 0-2 at 90 days. Nine patients (20.9%) had died by the 90-day follow-up. In comparison with M2 and M3 MeVOs, there were no differences in presenting characteristics among the three groups. Patients with PCA MeVOs were less likely to undergo intra-arterial thrombolysis (4.7% PCA vs. 10.1% M2 vs. 16.2% M3, p = 0.046) or to achieve successful recanalization (mTICI ≥ 2b, 67.4%, 86.7%, 82.3%, respectively, p < 0.001); however, there were no differences in the rates of successful first-pass recanalization (44.2%, 49.8%, 52.3%, respectively, p = 0.65). CONCLUSIONS: We describe the STAR experience performing MT in patients with PCA MeVOs. Our analysis supports that successful first-pass recanalization can be achieved in PCA MEVOs at a rate similar to that in MCA MeVOs, although further study and possible innovation may be necessary to improve successful PCA MeVO recanalization rates.

7.
J Stroke Cerebrovasc Dis ; 33(10): 107922, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39128501

RESUMEN

OBJECTIVES: Vasospasm is a complication of aneurysmal subarachnoid hemorrhage (aSAH) that can change the trajectory of recovery and is associated with morbidity and mortality. Earlier detection of vasospasm could improve patient outcomes. Our objective is to evaluate the accuracy of smartphone-based quantitative pupillometry in the detection of radiographic vasospasm and delayed cerebral ischemia (DCI) after aSAH. MATERIALS AND METHODS: We prospectively collected pupillary light reflex (PLR) parameters from patients with aSAH admitted to a neurocritical care unit at a single hospital twice daily using quantitative smartphone pupillometry recordings. PLR parameters included: Maximum pupil diameter, minimum pupil diameter, percent change in pupil diameter, latency in beginning of pupil constriction to light, mean constriction velocity, maximum constriction velocity, and mean dilation velocity. Two-tailed t-tests for independent samples were performed to determine changes in average concurrent PLR parameter values between the following comparisons: (1) patients with and without radiographic vasospasm (defined by angiography with the need for endovascular intervention) and (2) patients with and without DCI. RESULTS: 49 subjects with aSAH underwent 323 total PLR recordings. For PLR recordings taken with (n=35) and without (n=241) radiographic vasospasm, significant differences were observed in MIN (35.0 ± 7.5 pixels with vasospasm versus 31.6 ± 6.2 pixels without; p=0.002). For PLR recordings taken with (n=43) and without (n=241) DCI, significant differences were observed in MAX (48.9 ± 14.3 pixels with DCI versus 42.5 ± 9.2 pixels without; p<0.001). CONCLUSIONS: Quantitative smartphone pupillometry has the potential to be used to detect radiographic vasospasm and DCI after aSAH.


Asunto(s)
Valor Predictivo de las Pruebas , Reflejo Pupilar , Teléfono Inteligente , Hemorragia Subaracnoidea , Vasoespasmo Intracraneal , Humanos , Hemorragia Subaracnoidea/complicaciones , Hemorragia Subaracnoidea/fisiopatología , Hemorragia Subaracnoidea/diagnóstico , Vasoespasmo Intracraneal/etiología , Vasoespasmo Intracraneal/diagnóstico , Vasoespasmo Intracraneal/diagnóstico por imagen , Vasoespasmo Intracraneal/fisiopatología , Masculino , Persona de Mediana Edad , Femenino , Estudios Prospectivos , Anciano , Adulto , Reproducibilidad de los Resultados , Pupila/fisiología , Factores de Tiempo , Técnicas de Diagnóstico Oftalmológico/instrumentación , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/fisiopatología , Isquemia Encefálica/etiología , Isquemia Encefálica/complicaciones
8.
Ann Biomed Eng ; 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39095638

RESUMEN

PURPOSE: Flow diverting stents (FDS) are used to treat cerebral aneurysms, by promoting thrombosis and occlusion of the aneurysm sac. However, retreatment is required in some cases, and the biologic basis behind treatment outcome is not known. The goal of this study was to understand how changes in hemodynamic flow after FDS placement affect aneurysmal endothelial cell (EC) activity. METHODS: Three-dimensional models of patient-specific aneurysms were created to quantify the EC response to FDS placement. Computational fluid dynamic simulations were used to determine the hemodynamic impact of FDS. Two identical models were created for each patient; into one a FDS was inserted. Each model was then populated with human carotid ECs and subjected to patient-specific pulsatile flow for 24 h. ECs were isolated from aneurysm dome from each model and bulk RNA sequencing was performed. RESULTS: Paired untreated and treated models were created for four patients. Aneurysm dome EC analysis revealed 366 (2.6%) significant gene changes between the untreated and FDS conditions, out of 13909 total expressed genes. Gene set enrichment analysis of the untreated models demonstrated enriched gene ontology terms related to cell adhesion, growth/tensile activity, cytoskeletal organization, and calcium ion binding. In the FDS models, enriched terms were related to cellular proliferation, ribosomal activity, RNA splicing, and protein folding. CONCLUSION: Treatment of cerebral aneurysms with FDS induces significant EC gene transcription changes related to aneurysm hemodynamics in patient-specific in vitro 3D-printed models subjected to pulsatile flow. Further investigation is needed into the relationship between transcriptional change and treatment outcome.

9.
J Neurointerv Surg ; 2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39084853

RESUMEN

BACKGROUND: Nickel hypersensitivity is the most common metal related allergy. Nickel containing alloys are frequently used in endovascular devices. The use of intracranial stents in patients with nickel hypersensitivity appears to be safe, but these small series only evaluated arterial stent placement. This case series aimed to assess the safety of intracranial venous stent placement in patients with documented nickel allergy. METHODS: In this retrospective multicenter case series, patients with idiopathic intracranial hypertension and documented nickel allergy underwent treatment with a permanently implanted nickel containing stent in the dural venous sinuses. RESULTS: Nine patients with nickel allergy were included. All patients reported clinical improvement in their idiopathic intracranial hypertension symptoms. Of the five patients who had follow-up intracranial venous imaging, all stents remained patent. No patients experienced intraoperative, postoperative, or long term procedure related complications, with follow-up ranging from 1.8 weeks to 49.1 months. CONCLUSION: In this limited case series, the use of nickel containing stents in intracranial venous sinuses in patients with nickel allergy did not result in any allergic reaction or adverse outcome.

10.
Transl Stroke Res ; 2024 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-39037513

RESUMEN

Chinese population have a high prevalence of unruptured intracranial aneurysm (UIA). Clinical and imaging risk factors predicting UIA growth or rupture are poorly understood in the Chinese population due to the lack of large-scale longitudinal studies, and the treatment decision for UIA patients was challenging. Develop a decision tree (DT) model for UIA instability, and validate its performance in multi-center studies. Single-UIA patients from two prospective, longitudinal multicenter cohort studies were analyzed, and set as the development cohort and validation cohort. The primary endpoint was UIA instability (rupture, growth, or morphological change). A DT was established within the development cohort and validated within the validation cohort. The performance of clinicians in identifying unstable UIAs before and after the help of the DT was compared using the area under curve (AUC). The development cohort included 1270 patients with 1270 UIAs and a follow-up duration of 47.2 ± 15.5 months. Aneurysm instability occurred in 187 (14.7%) patients. Multivariate Cox analysis revealed hypertension (hazard ratio [HR], 1.54; 95%CI, 1.14-2.09), aspect ratio (HR, 1.22; 95%CI, 1.17-1.28), size ratio (HR, 1.31; 95%CI, 1.23-1.41), bifurcation configuration (HR, 2.05; 95%CI, 1.52-2.78) and irregular shape (HR, 4.30; 95%CI, 3.19-5.80) as factors of instability. In the validation cohort (n = 106, 12 was unstable), the DT model incorporating these factors was highly predictive of UIA instability (AUC, 0.88 [95%CI, 0.79-0.97]), and superior to existing UIA risk scales such as PHASES and ELAPSS (AUC, 0.77 [95%CI, 0.67-0.86] and 0.76 [95%CI, 0.66-0.86], P < 0.001). Within all 1376 single-UIA patients, the use of the DT significantly improved the accuracy of junior neurosurgical clinicians to identify unstable UIAs (AUC from 0.63 to 0.82, P < 0.001). The DT incorporating hypertension, aspect ratio, size ratio, bifurcation configuration and irregular shape was able to predict UIA instability better than existing clinical scales in Chinese cohorts. CLINICAL TRIAL REGISTRATION: IARP-CP cohort were included (unique identifier: ChiCTR1900024547. Published July 15, 2019. Completed December 30, 2020), with 100-Project phase-I cohort (unique identifier: NCT04872842, Published May 5, 2021. Completed November 8, 2022) as the development cohort. The 100-Project phase-II cohort (unique identifier: NCT05608122. Published November 8, 2022) as the validation cohort.

11.
J Neurointerv Surg ; 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38991734

RESUMEN

BACKGROUND: With transradial access (TRA) being more progressively used in neuroendovascular procedures, we compared TRA with transfemoral access (TFA) in middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH). METHODS: Consecutive patients undergoing MMAE for cSDH at 14 North American centers (2018-23) were included. TRA and TFA groups were compared using propensity score matching (PSM) controlling for: age, sex, concurrent surgery, previous surgery, hematoma thickness and side, midline shift, and pretreatment antithrombotics. The primary outcome was access site and overall complications, and procedure duration; secondary endpoints were surgical rescue, radiographic improvement, and technical success and length of stay. RESULTS: 872 patients (median age 73 years, 72.9% men) underwent 1070 MMAE procedures (54% TFA vs 46% TRA). Access site hematoma occurred in three TFA cases (0.5%; none required operative intervention) versus 0% in TRA (P=0.23), and radial-to-femoral conversion occurred in 1% of TRA cases. TRA was more used in right sided cSDH (58.4% vs 44.8%; P<0.001). Particle embolics were significantly higher in TFA while Onyx was higher in TRA (P<0.001). Following PSM, 150 matched pairs were generated. Particles were more utilized in the TFA group (53% vs 29.7%) and Onyx was more utilized in the TRA group (56.1% vs 31.5%) (P=0.001). Procedural duration was longer in the TRA group (median 68.5 min (IQR 43.1-95) vs 59 (42-84); P=0.038), and radiographic success was higher in the TFA group (87.3% vs 77.4%; P=0.036). No differences were noted in surgical rescue (8.4% vs 10.1%, P=0.35) or technical failures (2.4% vs 2%; P=0.67) between TFA and TRA. Sensitivity analysis in the standalone MMAE retained all associations but differences in procedural duration. CONCLUSIONS: In this study, TRA offered comparable outcomes to TFA in MMAE for cSDH in terms of access related and overall complications, technical feasibility, and functional outcomes. Procedural duration was slightly longer in the TRA group, and radiographic success was higher in the TFA group, with no differences in surgical rescue rates.

12.
World Neurosurg ; 189: e435-e441, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38908685

RESUMEN

BACKGROUND: The definitive impact of onset to arterial puncture time (OPT) on 90-day mortality after endovascular thrombectomy (EVT) in patients with acute ischemic stroke (AIS) caused by anterior circulation large vessel occlusion (LVO) remains unknown. The present study aimed to evaluate the influence of OPT on 90-day mortality in anterior circulation AIS-LVO patients who underwent EVT. METHODS: Data from 33 international centers were retrospectively analyzed. The receiver operating characteristic curve analysis was used to identify a cutoff for OPT. A propensity score-matched analysis was performed. The primary outcome was 90-day mortality (modified Rankin Scale [mRS] 6). Secondary outcomes included mortality at discharge, 90-day good outcome (mRS 0-2), 90-day poor outcome (mRS 5-6), successful recanalization (defined as postprocedure modified Thrombolysis in Cerebral Infarction scale ≥2b), and intracranial hemorrhage. RESULTS: A total of 2842 AIS-LVO patients with EVT were included. The cutoff for OPT for 90-day mortality was 180 min. Of these 378 patients had OPT <180 min and 378 patients had OPT ≥180 min in the propensity score-matched cohort (n = 756). Patients with OPT <180 min were less likely to have 90-day mortality (odds ratio [OR] 0.70, 95% confidence interval [CI] 0.51-0.96) and poor outcome (OR 0.71, 95% CI 0.53-0.96), and more likely to have 90-day good outcome (OR 1.55, 95% CI 1.16-2.08). Other outcomes showed no significant differences. CONCLUSIONS: This study showed that OPT <180 min was less related to 90-day mortality and poor outcome, and more to 90-day good outcome in AIS-LVO patients who underwent EVT.


Asunto(s)
Procedimientos Endovasculares , Puntaje de Propensión , Sistema de Registros , Trombectomía , Humanos , Femenino , Masculino , Procedimientos Endovasculares/métodos , Trombectomía/métodos , Anciano , Persona de Mediana Edad , Estudios Retrospectivos , Accidente Cerebrovascular Isquémico/cirugía , Accidente Cerebrovascular Isquémico/mortalidad , Anciano de 80 o más Años , Resultado del Tratamiento , Tiempo de Tratamiento
13.
J Neurol Sci ; 462: 123054, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38889600

RESUMEN

BACKGROUND: The outcomes of endovascular thrombectomy (EVT) for medium vessel occlusions (MeVOs) of specific vascular territories remain unknown. We aimed to investigate EVT outcomes by MeVO locations using the data from an ongoing international multicenter registry. METHODS: Patients with isolated MeVO who underwent EVT between January 2013 and December 2022 were retrospectively analyzed. Isolated MeVO was defined as an occlusion of the A2 or A3 (A2/A3), M2 or M3, and P2 or P3 (P2/P3). Outcomes included a 90-day modified Rankin score (mRS) of 0-2, successful recanalization (modified Thrombolysis in Cerebral Infarction score ≥ 2b), early neurological deterioration (END) or improvement (ENI), and 90-day mortality. END was defined as a worsening of ≥4 points from the baseline National Institutes of Health Stroke Scale (NIHSS) score within 24 h of EVT, while ENI was defined as an improvement of ≥4 points from the baseline NIHSS score within 24 h of EVT. RESULTS: 1744 MeVOs included. Compared to M2 occlusions (n = 1542, 88.4%), A2/A3 (n = 36, 2.1%) occlusions had lower odds of 90-day mRS 0-2 (adjusted odds ratio [aOR] 0.30, 95% confidence interval [CI] 0.11-0.80), and P2/P3 occlusions (n = 49, 2.8%) had lower odds of successful recanalization (aOR 0.19, 95% CI 0.07-0.50), and higher odds of END (aOR 3.53, 95% CI 1.35-9.25). Other outcomes showed no significant differences. CONCLUSIONS: A2/A3 occlusions were more likely to have worse outcomes compared to M2 occlusions after EVT for patients with isolated MeVOs.


Asunto(s)
Procedimientos Endovasculares , Trombectomía , Humanos , Masculino , Femenino , Trombectomía/métodos , Anciano , Procedimientos Endovasculares/métodos , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Sistema de Registros , Anciano de 80 o más Años
14.
J Clin Epidemiol ; 173: 111428, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38897481

RESUMEN

Consensus statements can be very influential in medicine and public health. Some of these statements use systematic evidence synthesis but others fail on this front. Many consensus statements use panels of experts to deduce perceived consensus through Delphi processes. We argue that stacking of panel members toward one particular position or narrative is a major threat, especially in absence of systematic evidence review. Stacking may involve financial conflicts of interest, but nonfinancial conflicts of strong advocacy can also cause major bias. Given their emerging importance, we describe here how such consensus statements may be misleading, by analyzing in depth a recent high-impact Delphi consensus statement on COVID-19 recommendations as a case example. We demonstrate that many of the selected panel members and at least 35% of the core panel members had advocated toward COVID-19 elimination (Zero-COVID) during the pandemic and were leading members of aggressive advocacy groups. These advocacy conflicts were not declared in the Delphi consensus publication, with rare exceptions. Therefore, we propose that consensus statements should always require rigorous evidence synthesis and maximal transparency on potential biases toward advocacy or lobbyist groups to be valid. While advocacy can have many important functions, its biased impact on consensus panels should be carefully avoided.

15.
J Chem Theory Comput ; 20(12): 5215-5224, 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38842599

RESUMEN

We model the autoionization of water by determining the free energy of hydration of the major intermediate species of water ions. We represent the smallest ions─the hydroxide ion OH-, the hydronium ion H3O+, and the Zundel ion H5O2+─by bonded models and the more extended ionic structures by strong nonbonded interactions (e.g., the Eigen H9O4+ = H3O+ + 3(H2O) and the Stoyanov H13O6+ = H5O2+ + 4(H2O)). Our models are faithful to the precise QM energies and their components to within 1% or less. Using the calculated free energies and atomization energies, we compute the pKa of pure water from first principles as a consistency check and arrive at a value within 1.3 log units of the experimental one. From these calculations, we conclude that the hydronium ion, and its hydrated state, the Eigen cation, are the dominant species in the water autoionization process.

16.
Ann Biomed Eng ; 52(9): 2417-2439, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38758460

RESUMEN

The Circle of Willis (CoW) is a ring-like network of blood vessels that perfuses the brain. Flow in the collateral pathways that connect major arterial inputs in the CoW change dynamically in response to vessel narrowing or occlusion. Vasospasm is an involuntary constriction of blood vessels following subarachnoid hemorrhage (SAH), which can lead to stroke. This study investigated interactions between localization of vasospasm in the CoW, vasospasm severity, anatomical variations, and changes in collateral flow directions. Patient-specific computational fluid dynamics (CFD) simulations were created for 25 vasospasm patients. Computed tomographic angiography scans were segmented capturing the anatomical variation and stenosis due to vasospasm. Transcranial Doppler ultrasound measurements of velocity were used to define boundary conditions. Digital subtraction angiography was analyzed to determine the directions and magnitudes of collateral flows as well as vasospasm severity in each vessel. Percent changes in resistance and viscous dissipation were analyzed to quantify vasospasm severity and localization of vasospasm in a specific region of the CoW. Angiographic severity correlated well with percent changes in resistance and viscous dissipation across all cerebral vessels. Changes in flow direction were observed in collateral pathways of some patients with localized vasospasm, while no significant changes in flow direction were observed in others. CFD simulations can be leveraged to quantify the localization and severity of vasospasm in SAH patients. These factors as well as anatomical variation may lead to changes in collateral flow directions. Future work could relate localization and vasospasm severity to clinical outcomes like the development of infarct.


Asunto(s)
Circulación Cerebrovascular , Círculo Arterial Cerebral , Modelos Cardiovasculares , Vasoespasmo Intracraneal , Humanos , Círculo Arterial Cerebral/fisiopatología , Círculo Arterial Cerebral/diagnóstico por imagen , Vasoespasmo Intracraneal/fisiopatología , Vasoespasmo Intracraneal/diagnóstico por imagen , Femenino , Masculino , Persona de Mediana Edad , Hidrodinámica , Anciano , Circulación Colateral , Adulto
17.
Neurosurgery ; 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38758725

RESUMEN

BACKGROUND AND OBJECTIVES: This study aimed to compare outcomes of low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) patients with stroke who underwent mechanical thrombectomy (MT) within 6 hours or 6 to 24 hours after stroke onset. METHODS: A retrospective cohort study was conducted using data from a large multicenter international registry from 2013 to 2023. Patients with low ASPECTS (2-5) who underwent MT for anterior circulation intracranial large vessel occlusion were included. A propensity matching analysis was conducted for patients presented in the early (<6 hours) vs late (6-24 hours) time window after symptom onset or last known normal. RESULTS: Among the 10 229 patients who underwent MT, 274 met the inclusion criteria. 122 (44.5%) patients were treated in the late window. Early window patients were older (median age, 74 years [IQR, 63-80] vs 66.5 years [IQR, 54-77]; P < .001), had lower proportion of female patients (40.1% vs 54.1%; P = .029), higher median admission National Institutes of Health Stroke Scale score (20 [IQR, 16-24] vs 19 [IQR, 14-22]; P = .004), and a higher prevalence of atrial fibrillation (46.1% vs 27.3; P = .002). Propensity matching yielded a well-matched cohort of 84 patients in each group. Comparing the matched cohorts showed there was no significant difference in acceptable outcomes at 90 days between the 2 groups (odds ratio = 0.90 [95% CI = 0.47-1.71]; P = .70). However, the rate of symptomatic ICH was significantly higher in the early window group compared with the late window group (odds ratio = 2.44 [95% CI = 1.06-6.02]; P = .04). CONCLUSION: Among patients with anterior circulation large vessel occlusion and low ASPECTS, MT seems to provide a similar benefit to functional outcome for patients presenting <6 hours or 6 to 24 hours after onset.

18.
World J Oncol ; 15(3): 348-354, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38751697

RESUMEN

Multiple myeloma (MM), a malignancy involving plasma cells, disproportionately affects older adults with an average age of diagnosis of about 70 years. Oftentimes, the therapies used in the treatment of MM are associated with a risk for immunotoxicity, lowering the ability of the immune system to fight off opportunistic infections. This is an important relationship for clinicians to realize as the incidence of opportunistic infections in myeloma patients is increasing. As an example, we present a case of a patient with MM who subsequently developed a cryptococcal infection. Our paper will highlight the key details of the case as well as shed light on the importance of understanding the immunodeficiencies in this patient population. We highlight important aspects of the current literature related to MM and relate them to the associated case.

19.
J Neurosurg ; : 1-10, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38820616

RESUMEN

OBJECTIVE: The placement of flow-diverting devices has become a common method of treating unruptured intracranial aneurysms of the internal carotid artery. The progressive improvement of aneurysm occlusion after treatment-with low complication and rupture rates-has led to a dilemma regarding the management of aneurysms in which occlusion has not occurred within 6-24 months. The authors aimed to identify clinical consensus regarding management of intracranial aneurysms displaying persistent filling 6-24 months after flow diversion and to ascertain questions that may drive future investigation. METHODS: An international panel of 67 experts was invited to participate in a multistep Delphi consensus process on the treatment of intracranial aneurysms after failed flow diversion. RESULTS: Of the 67 experts invited, 23 (34%) participated. Qualitative analysis of an initial survey with open-ended questions resulted in 51 statements regarding management of aneurysms showing persistent filling after flow diversion. The statements were grouped into 8 categories, and in the second round, respondents rated the degree of their agreement with each statement on a 5-point Likert scale. Flow diverters with surface modifiers did not influence administration of dual-antiplatelet therapy according to 83%. Consensus was also reached regarding the definition of treatment failure at specific time points, including at 6 months if there is aneurysm growth or persistent rapid flow through the entirety of the aneurysm (96%), at 12 months if there is aneurysm growth or symptom onset (78%), and at 24 months if there is persistent filling regardless of size and filling characteristics (74%). Although experts agreed that the degree of intimal hyperplasia or in-device stenosis could not be ascertained by noninvasive imaging alone (83%), only 65% chose digital subtraction angiography as the preferred modality. At 6 and 12 months, retreatment is preferred if there is persistent filling with aneurysm growth (96%, 96%), device malposition (48%, 87%), or a history of subarachnoid hemorrhage (65%, 70%), respectively, and at 24 months if there is persistent filling without reduction in aneurysm size (74%). Experts favored treatment with an additional flow diverter (87%) over aneurysm clipping, applying the same principles for follow-up (83%) and treatment failure (91%) as for the first flow diverter. CONCLUSIONS: The authors present the consensus practices of experts in the management of intracranial aneurysms without occlusion 6-24 months after treatment with a flow-diverting device.

20.
Neurosurg Clin N Am ; 35(3): 287-291, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38782521

RESUMEN

Idiopathic intracranial hypertension is defined by headaches and a decline in visual acuity due to increased intracranial pressure. Treatment options historically included weight loss, acetazolamide, and/or cerebrospinal fluid diversion surgery. Recent understanding of the contributions of dural venous sinus hypertension and stenosis has led to venous sinus stenting as a treatment option.


Asunto(s)
Seudotumor Cerebral , Humanos , Acetazolamida/uso terapéutico , Senos Craneales/cirugía , Hipertensión Intracraneal/terapia , Seudotumor Cerebral/cirugía , Seudotumor Cerebral/terapia , Stents
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA