Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Sensors (Basel) ; 23(1)2023 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-36617127

RESUMEN

Predicting the trajectories of surrounding vehicles is an essential task in autonomous driving, especially in a highway setting, where minor deviations in motion can cause serious road accidents. The future trajectory prediction is often not only based on historical trajectories but also on a representation of the interaction between neighbouring vehicles. Current state-of-the-art methods have extensively utilized RNNs, CNNs and GNNs to model this interaction and predict future trajectories, relying on a very popular dataset known as NGSIM, which, however, has been criticized for being noisy and prone to overfitting issues. Moreover, transformers, which gained popularity from their benchmark performance in various NLP tasks, have hardly been explored in this problem, presumably due to the accumulative errors in their autoregressive decoding nature of time-series forecasting. Therefore, we propose MALS-Net, a Multi-Head Attention-based LSTM Sequence-to-Sequence model that makes use of the transformer's mechanism without suffering from accumulative errors by utilizing an attention-based LSTM encoder-decoder architecture. The proposed model was then evaluated in BLVD, a more practical dataset without the overfitting issue of NGSIM. Compared to other relevant approaches, our model exhibits state-of-the-art performance for both short and long-term prediction.


Asunto(s)
Conducción de Automóvil , Benchmarking , Suministros de Energía Eléctrica , Movimiento (Física) , Factores de Tiempo
2.
Environ Monit Assess ; 195(7): 886, 2023 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-37358657

RESUMEN

Bangladesh, the largest delta in the world, is situated over the flow of more than 700 rivers. The Ganges is a transboundary river, and it takes the Padma after meeting Jamuna near Aricha. The Padma River's morphology and hydraulic parameters are so dynamic that it erodes a large portion of land every year. However, the situation of erosion has been very threatening since 2014 which is almost the same period when the construction of the Padma Bridge started. Our Study on the erosion-accretion rate and bar dynamics of the selected reach of Padma River shows that the downstream right bank of this river lost around 134.85 sq. km of land between 2003 and 2021. The total bar area has also increased to 76.8%. Land use land classification (LULC) analysis was done for the years 2003, 2009, 2015, and 2021 to predict how the river might act in the future. For this prediction, artificial neural network (ANN) system has been used, and the predicted land use map was generated for 2027. The current kappa validation was 0.869, and the accuracy of the prediction was 87.05%. This study aims at analyzing the current morphological condition and its connection to the construction of the Padma Bridge and also predicts how the lower Padma River might act in near future. According to the study findings, in absence of prompt and appropriate measures, this country is highly susceptible to experiencing catastrophic consequences.


Asunto(s)
Monitoreo del Ambiente , Ríos , Bangladesh
3.
Soft Matter ; 17(41): 9293-9314, 2021 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-34647568

RESUMEN

In hydrodynamics, the event of dynamic bubble growth in a pure liquid under tensile pressure is known as cavitation. The same event can also be observed in soft materials (e.g., elastomers and hydrogels). However, for soft materials, bubble/cavity growth is either defined as cavitation if the bubble growth is elastic and reversible or as fracture if the cavity growth is by material failure and irreversible. In any way, bubble growth can cause damage to soft materials (e.g., tissue) by inducing high strain and strain-rate deformation. Additionally, a high-strength pressure wave is generated upon the collapse of the bubble. Therefore, it is crucial to identify the critical condition of spontaneous bubble growth in soft materials. Experimental and theoretical observations have agreed that the onset of bubble growth in soft materials requires higher tensile pressure than pure water. The extra tensile pressure is required since the cavitating bubble needs to overcome the elastic and surface energy in soft materials. In this manuscript, we developed two models to study and quantify the extra tensile pressure for different gelatin concentrations. Both the models are then compared with the existing cavitation onset criteria of rubber-like materials. Validation is done with the experimental results of threshold tensile pressure for different gelatin concentrations. Both models can moderately predict the extra tensile pressure within the intermediate range of gelatin concentrations (3-7% [w/v]). For low concentration (∼1%), the network's non-affinity plays a significant role and must be incorporated. On the other hand, for higher concentrations (∼10%), the entropic deformation dominates, and the strain energy formulation is not adequate.

4.
J Food Sci Technol ; 56(4): 2267-2277, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30996460

RESUMEN

This study was planned to characterize the physicochemical and antioxidant properties, and microbiological quality of honey obtained from the sandbar pumpkin field. In this study, four sugar supplemented and one control (without sugar fed) honey sample was used. Results revealed that all samples exhibited appropriate maturity considering their low moisture content (~ 19%) and high total solids (~ 80%) and TSS (~ 79%). Total acidity (< 40 meq/kg) and pH (~ 4.5) directed the absenteeism of detrimental fermentation. Ash (~ 0.29%) and electrical conductivity (~ 700 µS/cm) were reasonable and distinctive of dark yellowish-brown honey, which is buttressed by color attributes. Reducing sugars, glucose, fructose, and sucrose values ranged from 68.98 to 75.82%, 26.01 to 33.84%, 34.93 to 38.70%, and 1.74 to 5.96%, respectively. Proline (~ 400 mg/kg), HMF (< 40 mg/kg) and diastase action (~ 14° Gothe) were found within accepted limits, and also possesses good antioxidants in terms of total phenol (~ 160 mg GAE/100 g), total flavonoid (4.67-6.25 mg CE/100 g), and DPPH-RSA (30.65-35.97%). The microbial study revealed that the total viable count ranged between 33.33 and 27.66 CFU/g, while yeasts and mold count varied between 14.33 and 12 CFU/g. Principle component analysis (PCA) results revealed that all the studied parameters could be used effectively to discriminate the honey sample. The overall results signpost a new information regarding the quality i.e. processing, maturity, freshness and composition of honey obtained from the sandbar pumpkin field.

5.
Artículo en Inglés | MEDLINE | ID: mdl-27562181

RESUMEN

BACKGROUND: The evaluation of the QT interval in the presence of left bundle branch block (LBBB) is associated with the challenge to discriminate native QT interval from the prolongation due to the increase in QRS duration. The newest formula to evaluate QT interval in the presence of LBBB suggests: modified QT during LBBB = measured QT interval minus 50% of LBBB duration. The purpose of this study is therefore to validate the abovementioned formula in the clinical setting. METHODS: Validation in two separate groups of patients: Patients who alternated between narrow QRS and intermittent LBBB and patients with narrow QRS who developed LBBB after transcatheter aortic valve implantation (TAVI). RESULTS: The acquired mean native QTc intervals and those calculated by the presented formula displayed no significant differences (p > .99 and p > .75). CONCLUSIONS: In this study we proved for the first time the validity and applicability of the experimentally acquired formula for the evaluation of the QT interval in the presence of LBBB in a clinical setting.


Asunto(s)
Bloqueo de Rama/fisiopatología , Electrocardiografía/métodos , Fascículo Atrioventricular/fisiopatología , Humanos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento
6.
Ann Noninvasive Electrocardiol ; 20(6): 609-11, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25631624

RESUMEN

Q waves can regularly be observed in the 12-lead electrocardiogram either due to heart axis underlying pathology such as subacute myocardial infarction, myocardial scar, or accessory pathways. Rarely, other entities such as circumscribed hypertrophy can induce significant Q wave and represent an important differential diagnosis especially in younger patients. In the setting of atypical chest pain determination of the correct diagnosis can be challenging. Therefore, circumscribed hypertrophy should be taken into account to avoid unnecessary invasive procedures.


Asunto(s)
Electrocardiografía , Hipertrofia Ventricular Izquierda/diagnóstico , Hipertrofia Ventricular Izquierda/etiología , Adulto , Cicatriz/diagnóstico , Femenino , Humanos , Infarto del Miocardio/diagnóstico
7.
Scand J Gastroenterol ; 49(12): 1432-40, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25319588

RESUMEN

OBJECTIVE: Ulcerative colitis (UC) is generally considered a disease of the Caucasian populations in developed countries, but its incidence is increasing rapidly in many developing countries, including the Middle East. The objective of this study was to determine the clinical epidemiology of UC in Arabs. MATERIAL AND METHODS: This cross-sectional medical record-based descriptive study collected sociodemographic and clinical information on 182 Arab patients with UC in Kuwait. Age at diagnosis, extent and severity of disease were determined according to the Montreal classification. results: Among the 182 patients, 91 (50.0%) were males. The median age at diagnosis was 28.5 years. Family history of UC was reported by 26 (14.3%) patients. The extent of the disease was limited to the rectum in 34 (18.7%) patients, left sided in 67 (36.8%) and pan colitis in 81 (44.5%). At the time of inclusion in the study, 127 (69.8%) patients were in clinical remission, 53 (29.1%) had mild-to-moderate disease and 2 (1.1%) had severe colitis. Younger age at diagnosis and non-smoking were associated with more extensive colitis. The majority of patients were treated with mesalamine, steroids and immunomodulators, while biologic therapy and surgery were needed in 5% and 4% of the patients, respectively. CONCLUSIONS: UC presents more commonly at younger age among Arabs in Kuwait. Extensive disease at presentation is associated with younger age at diagnosis and absence of tobacco smoking. There also appears to be less need for surgery and biologic therapy for the disease in this population.


Asunto(s)
Árabes , Colitis Ulcerosa/etnología , Adolescente , Adulto , Anciano , Niño , Preescolar , Colitis Ulcerosa/diagnóstico , Colitis Ulcerosa/etiología , Colitis Ulcerosa/terapia , Estudios Transversales , Femenino , Humanos , Incidencia , Kuwait/epidemiología , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Factores de Riesgo , Índice de Severidad de la Enfermedad , Adulto Joven
8.
J Interv Card Electrophysiol ; 66(4): 857-863, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35107720

RESUMEN

PURPOSE: The cephalic vein cutdown (CVC) and the subclavian puncture (SP) is the most common access for pacemaker implantation. The purpose of this study was to compare the peri-/postoperative complications of these approaches. METHODS: A retrospective analysis of the quality assurance data of the state of North Rhine-Westphalia was performed to evaluate the peri-/postoperative complications of first pacemaker implantation according to the venous access. The primary endpoint was defined as the occurrence of one of the following: asystole, ventricular fibrillation, pneumothorax, hemothorax, pericardial effusion, pocket hematoma, lead dislocation, lead dysfunction, postoperative wound infection or other complication requiring intervention. Descriptive analysis was done via absolute, relative frequencies and Odds Ratio. Fisher's exact test was used for comparison of the both study groups. RESULTS: From 139,176 pacemaker implantations from 2010 to 2014, 15,483 cases were excluded due to other/double access. The median age was 78 years and the access used was CVC for 75,251 cases (60.8%) and SP for 48,442 cases (39.2%). The implanted devices were mainly dual-chamber pacemakers (73.9% in the CVC group and 78.4% in the SP group), followed by single-chamber pacemakers VVI (24.9% and 19.9% in the CVC and SP group respectively). There were significantly fewer peri/postoperative complications in the CVC group compared to the SP group (2.49% vs. 3.64%, p = 0.0001, OR 1.47; 95% CI 1.38-1.57). CONCLUSIONS: CVC as venous access for pacemaker implantation has significantly fewer peri/postoperative complications than SP and appears to be an advantageous technique.


Asunto(s)
Marcapaso Artificial , Vena Subclavia , Humanos , Anciano , Incisión Venosa/métodos , Estudios Retrospectivos , Punciones
9.
Ann Hepatol ; 11(2): 186-93, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22345335

RESUMEN

BACKGROUND: Approximately one-third of patients with chronic hepatitis C virus infection have persistently normal liver enzymes reflected by a normal serum alanine transaminase (ALT). Data with regards the efficacy and safety of treatment in patients chronically infected with Hepatitis C virus genotype 4 and normal serum ALT are limited. AIM: To evaluate the efficacy and safety of peginterferon alfa-2b plus ribavirin combination therapy in this population. MATERIAL AND METHODS: Twenty-two patients with chronic hepatitis C virus genotype 4 infection were enrolled in an open-labeled, uncontrolled pilot study. All patients had biopsy proven chronic hepatitis and persistently normal serum ALT levels. Patients were treated with subcutaneous peginterferon alfa-2b at a dose of 1.5 µg/kg body weight once per week plus oral ribavirin (15 mg/kg/day) for 48 weeks. Patients were followed for 24 weeks post-treatment. RESULTS: Sixteen patients out of twenty two completed the study (9 [40.9%] females, mean age 43.8 years). The ALT level were normal in all patients, with a mean of 38.6 U/L. Sustained viral response was achieved in 13 patients (59%), 4 patients (18.1%) were non-responders and 2 patients (9%) relapsed while 1 patient had a viral breakthrough during treatment. Two patients (9%) discontinued the treatment because of adverse events. CONCLUSIONS: Combination therapy of pegylated interferon-alpha2b and ribavirin is safe and resulted in a sustained virological response in a significant number of patients with chronic Hepatitis C, genotype 4, and persistently normal serum ALT.


Asunto(s)
Alanina Transaminasa/sangre , Antivirales/uso terapéutico , Hepacivirus/genética , Hepatitis C Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Polietilenglicoles/uso terapéutico , Ribavirina/uso terapéutico , Adolescente , Adulto , Biomarcadores , Quimioterapia Combinada , Femenino , Genotipo , Hepatitis C Crónica/enzimología , Humanos , Interferón alfa-2 , Masculino , Persona de Mediana Edad , Proyectos Piloto , ARN Viral/sangre , Proteínas Recombinantes/uso terapéutico , Resultado del Tratamiento , Carga Viral/efectos de los fármacos
10.
Front Bioeng Biotechnol ; 10: 904818, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36277388

RESUMEN

In this manuscript, we have studied the microstructure of the axonal cytoskeleton and adopted a bottom-up approach to evaluate the mechanical responses of axons. The cytoskeleton of the axon includes the microtubules (MT), Tau proteins (Tau), neurofilaments (NF), and microfilaments (MF). Although most of the rigidity of the axons is due to the MT, the viscoelastic response of axons comes from the Tau. Early studies have shown that NF and MF do not provide significant elasticity to the overall response of axons. Therefore, the most critical aspect of the mechanical response of axons is the microstructural topology of how MT and Tau are connected and construct the cross-linked network. Using a scanning electron microscope (SEM), the cross-sectional view of the axons revealed that the MTs are organized in a hexagonal array and cross-linked by Tau. Therefore, we have developed a hexagonal Representative Volume Element (RVE) of the axonal microstructure with MT and Tau as fibers. The matrix of the RVE is modeled by considering a combined effect of NF and MF. A parametric study is done by varying fiber geometric and mechanical properties. The Young's modulus and spacing of MT are varied between 1.5 and 1.9 GPa and 20-38 nm, respectively. Tau is modeled as a 3-parameter General Maxwell viscoelastic material. The failure strains for MT and Tau are taken to be 50 and 40%, respectively. A total of 4 RVEs are prepared for finite element analysis, and six loading cases are inspected to quantify the three-dimensional (3D) viscoelastic relaxation response. The volume-averaged stress and strain are then used to fit the relaxation Prony series. Next, we imposed varying strain rates (between 10/sec to 50/sec) on the RVE and analyzed the axonal failure process. We have observed that the 40% failure strain of Tau is achieved in all strain rates before the MT reaches its failure strain of 50%. The corresponding axonal failure strain and stress vary between 6 and 11% and 5-19.8 MPa, respectively. This study can be used to model macroscale axonal aggregate typical of the white matter region of the brain tissue.

11.
Front Cardiovasc Med ; 9: 981985, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36119735

RESUMEN

Introduction: The Electrical storm (ES) subsumes a state of electrical instability of the heart, which manifests itself in repeated and potentially fatal ventricular arrhythmias (VA). We examine the long-term effects of substrate modification with regards to mortality, ventricular tachycardia (VT) recurrences and hospitalization depending on age, gender, heart function, scare location, VT documentation, postprocedural electrical stimulation (PES) and induced VTs. Methods: From 08/2008 and 09/2019 160 consecutive patients admitted for ES ablation via electroanatomical mapping were followed up until 04/2021. Results: 50/160 patients showed VT recurrences after 13.8 ± 21.7 (0.0-80.3) months, with a characteristic steep curve directly after ES and then a rapid decline leading to a plateau (first month 10/50 (20%), first year 35/50 VT recurrences (70%) Mortality rates followed a similar pattern also the initial decline was not as steep. 42 patients died during the observation period (26%) after 16.6 ± 16.1 (0.0-67.9) months after ablation day (first month (n = 7, 16.7%) first year (n = 21, 50%). Gender, age, scare localization, missing VT documentation did not worsen outcome. Induction of >3 VTs and lack of PES due to hemodynamic instability significantly decreased effectiveness. Finding the entry significantly increased long-term effects. Conclusion: Ablation of ES is safe and feasible independent of a variety of factors. Employing more sophisticated tools to understand the reentry mechanism will further improve the long-term outcome.

12.
Biomolecules ; 11(4)2021 04 07.
Artículo en Inglés | MEDLINE | ID: mdl-33917073

RESUMEN

Existent literature has limitations regarding the mechanical behavior of axonal cytoskeletal components in a high strain rate scenario, which is mainly due to limitations regarding the structure of some components such as tau protein and neurofilaments (NF). This study performs molecular dynamics (MD) simulations on NFs to extract their strain rate-dependent behavior. It is found that they are highly stretchable and show multiple stages of unfolding. Furthermore, NFs show high tensile stiffness. Also, viscoelastic modeling shows that they correspond to simplified viscoelastic models. This study effectively enhances the existent axonal models focusing on axonal injury.


Asunto(s)
Filamentos Intermedios/química , Simulación de Dinámica Molecular , Citoesqueleto , Filamentos Intermedios/metabolismo , Resistencia a la Tracción , Proteínas tau/química
13.
Inflamm Intest Dis ; 6(3): 123-131, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34722642

RESUMEN

OBJECTIVES: Despite the recent findings of the rising incidence of inflammatory bowel disease (IBD) in Arab countries, there are limited data on the characteristics of IBD patients and the disease course in the Arab world. This systematic review aimed to investigate the incidence and epidemiology of IBD in the Arab world. MATERIAL AND METHODS: We conducted a systematic literature review that utilized a comprehensive search of PubMed, Cochrane Central, SCOPUS, Google Scholar, and Web of Science from their inception till August 2020. We included cross-sectional, prospective, and retrospective studies that examined the prevalence and/or epidemiological characteristics of IBD in Arab countries. RESULTS: A total of 16 studies that examined IBD in Saudi Arabia, Egypt, Kuwait, the United Arab Emirates, Bahrain, Lebanon, and Oman were included. Generally, the included studies covered the period from the early 1990s to the late 2010s. A total of 1,627 ulcerative colitis (UC) patients and 1,588 Crohn's disease (CD) patients were included in this systematic review. The mean age at diagnosis ranged from 24.13 to 43.6 years in adult cases and from 4.5 to 16 years in pediatric cases. In most of the included studies, the majority of patients were male. The quantitative analysis revealed a pooled incidence rate of 2.33 (95% confidence interval [CI] 1.2-3.4) per 100,000 persons per year for UC in the Arab world. Likewise, the pooled incidence rate for CD in the Arab world was 1.46 (95% CI 1.03-1.89) per 100,000 persons per year. CONCLUSION: There is a growing incidence of IBD in the Arab world, while IBD patients from Arab countries may present with some different characteristics, compared to their counterparts in Europe.

14.
Biomolecules ; 12(1)2021 12 22.
Artículo en Inglés | MEDLINE | ID: mdl-35053158

RESUMEN

The perineuronal net (PNN) region of the brain's extracellular matrix (ECM) surrounds the neural networks within the brain tissue. The PNN is a protective net-like structure regulating neuronal activity such as neurotransmission, charge balance, and action potential generation. Shock-induced damage of this essential component may lead to neuronal cell death and neurodegenerations. The shock generated during a vehicle accident, fall, or improvised device explosion may produce sufficient energy to damage the structure of the PNN. The goal is to investigate the mechanics of the PNN in reaction to shock loading and to understand the mechanical properties of different PNN components such as glycan, GAG, and protein. In this study, we evaluated the mechanical strength of PNN molecules and the interfacial strength between the PNN components. Afterward, we assessed the PNN molecules' damage efficiency under various conditions such as shock speed, preexisting bubble, and boundary conditions. The secondary structure altercation of the protein molecules of the PNN was analyzed to evaluate damage intensity under varying shock speeds. At a higher shock speed, damage intensity is more elevated, and hyaluronan (glycan molecule) is most likely to break at the rigid junction. The primary structure of the protein molecules is least likely to fail. Instead, the molecules' secondary bonds will be altered. Our study suggests that the number of hydrogen bonds during the shock wave propagation is reduced, which leads to the change in protein conformations and damage within the PNN structure. As such, we found a direct connection between shock wave intensity and PNN damage.


Asunto(s)
Matriz Extracelular/metabolismo , Modelos Neurológicos , Red Nerviosa/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Neuronas/metabolismo , Animales , Humanos
15.
Biomolecules ; 11(9)2021 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-34572521

RESUMEN

Microtubule-associated protein (MAP) tau is a cross-linking molecule that provides structural stability to axonal microtubules (MT). It is considered a potential biomarker for Alzheimer's disease (AD), dementia, and other neurological disorders. It is also a signature protein for Traumatic Brain Injury (TBI) assessment. In the case of TBI, extreme dynamic mechanical energies can be felt by the axonal cytoskeletal members. As such, fundamental understandings of the responses of single tau protein, polymerized tau protein, and tau-microtubule interfaces under high-rate mechanical forces are important. This study attempts to determine the high-strain rate mechanical behavior of single tau, dimerized tau, and tau-MT interface using molecular dynamics (MD) simulation. The results show that a single tau protein is a highly stretchable soft polymer. During deformation, first, it significantly unfolds against van der Waals and electrostatic bonds. Then it stretches against strong covalent bonds. We found that tau acts as a viscoelastic material, and its stiffness increases with the strain rate. The unfolding stiffness can be ~50-500 MPa, while pure stretching stiffness can be >2 GPa. The dimerized tau model exhibits similar behavior under similar strain rates, and tau sliding from another tau is not observed until it is stretched to >7 times of original length, depending on the strain rate. The tau-MT interface simulations show that very high strain and strain rates are required to separate tau from MT suggesting Tau-MT bonding is stronger than MT subunit bonding between themselves. The dimerized tau-MT interface simulations suggest that tau-tau bonding is stronger than tau-MT bonding. In summary, this study focuses on the structural response of individual cytoskeletal components, namely microtubule (MT) and tau protein. Furthermore, we consider not only the individual response of a component, but also their interaction with each other (such as tau with tau or tau with MT). This study will eventually pave the way to build a bottom-up multiscale brain model and analyze TBI more comprehensively.


Asunto(s)
Microtúbulos/metabolismo , Simulación de Dinámica Molecular , Multimerización de Proteína , Desplegamiento Proteico , Estrés Mecánico , Proteínas tau/metabolismo
16.
J Interv Card Electrophysiol ; 61(2): 415-419, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32725360

RESUMEN

PURPOSE: We sought to establish the technical feasibility of VT-mapping with high-density catheters in patients with Mitraclips, requiring a hemodynamic support. METHODS: A 73-year-old man with ischemic cardiomyopathy and reduced left ventricular ejection fraction (LVEF ~ 20%) was presented due to syncope and adequate shock of his ICD. Due to severe mitral valve regurgitation (MR), two Mitraclips were implanted earlier. The decision for catheter ablation was made in line with current guidelines. Given the increased PAAINESD score, the use of hemodynamic support was required. To employ an Impella pump via the retrograde transaortic approach, LV-mapping and VT-ablation were necessary to be performed via the transseptal approach, which was challenging due to the presence of Mitraclips. The MV passage with the steerable sheath was guided by a quadripolar catheter and 3D transoesophageal echo (TEE). After the 12F steerable sheath had passed the MV, the quadripolar catheter was exchanged by a high-density (HD) Grid® catheter. Hereafter, the Impella pump was placed retrogradely in the LV, and voltage-mapping of the LV and ablation was performed. RESULTS: At the end of the procedure, the Impella pump could be removed in stable hemodynamic conditions. The follow-up after 3, 6, and 12 months showed no new VT episodes. CONCLUSIONS: This case demonstrates the feasibility of the transseptal approach of VT mapping used HD Grid catheter and retrograde hemodynamic support with Impella Pump for VT treatment in patients after Mitraclips implantation. To avoid a damage of the MV and Mitraclips, 3D-TEE is advisable.


Asunto(s)
Ablación por Catéter , Taquicardia Ventricular , Anciano , Catéteres , Hemodinámica , Humanos , Masculino , Volumen Sistólico , Taquicardia Ventricular/cirugía , Resultado del Tratamiento , Función Ventricular Izquierda
17.
J Mech Behav Biomed Mater ; 113: 104149, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33125954

RESUMEN

Phosphorylation has been hypothesized to alter the ability of tau protein to bind with microtubules (MT), and pathological level of phosphorylation can incorporate formation of Paired Helical Filaments (PHF) in affected tau. Study of the effect of phosphorylation on different domains of tau (projection domain, microtubule binding sites and N-terminus tail) is important to obtain insight about tau neuropathology. In an earlier study, we have already obtained the mechanical properties and behavior of single tau and dimerized tau and observed tau-MT interaction for normal level of phosphorylation. This study attempts to obtain insights on the effect of phosphorylation on different domains of tau, using molecular dynamics (MD) simulation with the aid of CHARMM force field under high strain rate. It also determines the effect of residue focused phosphorylation on tau-MT interaction and tau accumulation tendency. The results show that for single tau protein, unfolding stiffness does not differ significantly due to phosphorylation, but stretching stiffness can be much higher than the normally phosphorylated protein. For dimerized tau protein, the stretching required to separate the protein forming the dimer is similar for phosphorylation in individual domains but is significantly less in case of phosphorylation in all domains. For tau-MT interaction simulations, it is found that for normal phosphorylation, the tau separation from MT occurs at higher strain for phosphorylation in projection domain and N-terminus tail, and earlier for phosphorylation in all domains altogether than the normal phosphorylation state. The residue focused phosphorylation study also shows that tau separates earlier from MT and shows stronger accumulation tendency at the phosphorylated state, while preserving the highly stretchable and flexible characteristic of tau. This study provides important insight on mechanochemical phenomena relevant to traumatic brain injury (TBI) scenario, where the result of mechanical loading and posttranslational modification as well as conformation decides the mechanical behavior.


Asunto(s)
Enfermedad de Alzheimer , Proteínas tau , Enfermedad de Alzheimer/metabolismo , Humanos , Microtúbulos/metabolismo , Simulación de Dinámica Molecular , Ovillos Neurofibrilares/metabolismo , Fosforilación
18.
Hepatol Int ; 15(4): 912-921, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33822317

RESUMEN

BACKGROUND AND AIMS: The Middle East (ME) has a high prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), driven by obesity and type-2 diabetes mellitus (T2DM). Studies in Saudi Arabia (KSA) and United Arab Emirates (UAE) predict an escalating impact of NAFLD/NASH, particularly advanced fibrosis due to NASH (AF-NASH), increasing cases of cirrhosis, liver cancer and death. The scale of this burden in other ME countries is unknown with no reports of NAFLD/NASH healthcare resource utilization (HCRU) or costs. We estimated the clinical and economic burden of NAFLD/NASH in KSA, UAE and Kuwait. METHODS: Markov models populated with country-specific obesity and T2DM prevalence data estimated numbers and progression of NAFLD/NASH patients from 2018 to 2030. Model inputs, assumptions and outputs were collected from literature, national statistics, and expert consensus. RESULTS: Over 13 years, the KSA model estimated cases increasing as follows: patients with fibrosis F0-3 doubled to 2.5 m, compensated and decompensated cirrhosis and hepatocellular carcinoma trebled to 212,000; liver failure or transplant patients increased four-fold to 4,086 and liver-related death escalated from < 10,000 to > 200,000. Similar trends occurred in UAE and Kuwait. Discounted lifetime costs of NASH standard-care increased totaling USD40.41 bn, 1.59 bn and 6.36 bn in KSA, UAE (Emiratis only) and Kuwait, respectively. NASH-related costs in 2019 comprised, respectively, 5.83%, 5.80% and 7.66% of national healthcare spending. CONCLUSIONS: NASH, especially AF-NASH, should be considered a higher priority in ME Public Health policy. Our analyses should inform health policy makers to mitigate the enormity of this escalating regional burden.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Carcinoma Hepatocelular/epidemiología , Costo de Enfermedad , Humanos , Kuwait/epidemiología , Neoplasias Hepáticas/epidemiología , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Arabia Saudita/epidemiología , Emiratos Árabes Unidos/epidemiología
19.
Virol J ; 7: 111, 2010 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-20509964

RESUMEN

Genotypes (A to H) of hepatitis B virus (HBV) influence liver disease progression and response to antiviral therapy in HBV-infected patients. Several methods have been developed for rapid genotyping of HBV strains. However, some of these methods may not be suitable for developing countries. The performance of INNO-LiPA HBV Genotyping assay (LiPA), direct DNA sequencing and subtractive PCR-RFLP of genotype-specific HBV genome regions were evaluated for accurately determining the HBV genotypes by analyzing sera (n = 80) samples from chronic HBV patients. Both, LiPA and DNA sequencing identified 63, 4 and 13 HBV strains as belonging to genotype D, genotype A and mixed genotype A and D, respectively. On the contrary, the PCR-RFLP-based method correctly identified all 4 genotype A but only 56 of 63 genotype D strains. Seven genotype D strains yielded indeterminate results. DNA sequence comparisons showed that a single nucleotide change in the target region generated an additional restriction site for Nla IV that compromised the accuracy of this method. Furthermore, all the mixed genotype A and D strains were identified only as genotype A strains. The data show that the PCR-RFLP-based method incorrectly identified some genotype D strains and failed to identify mixed genotype infections while LiPA and DNA sequencing yielded accurate results.


Asunto(s)
Virus de la Hepatitis B/genética , Hepatitis B/virología , Hibridación de Ácido Nucleico/métodos , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo de Longitud del Fragmento de Restricción , Análisis de Secuencia de ADN/métodos , Secuencia de Bases , Sondas de ADN/genética , ADN Viral/genética , Genotipo , Virus de la Hepatitis B/química , Virus de la Hepatitis B/clasificación , Virus de la Hepatitis B/aislamiento & purificación , Humanos , Datos de Secuencia Molecular , Alineación de Secuencia , Proteínas Virales/química , Proteínas Virales/genética
20.
Ann Hepatol ; 9(2): 156-60, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20526008

RESUMEN

BACKGROUND: Hepatitis C is endemic in the Middle East where genotype 4 accounts for most cases. Data regarding the safety and efficacy of peginterferon plus ribavirin for the treatment of chronic hepatitis C in children and adolescents, particularly those infected with genotype 4 is limited. Aim. To evaluate the efficacy and tolerability of peginterferon alfa-2b in combination with ribavirin in adolescents chronically infected with HCV genotype 4. PATIENTS AND METHODS: In an open-labeled, uncontrolled pilot study, 12 adolescents (range14-17 years) were treated with subcutaneous peginterferon alfa-2b at a dose of 1.5 mg/kg body weight once per week plus oral ribavirin (15 mg/kg/day) for 48 weeks. Patients were followed for 24 weeks post-treatment. All patients had biopsy proven hepatitis without cirrhosis. RESULTS: One patient withdrew from the study due to developing insulin dependent diabetes mellitus 4 months into treatment. The remaining patients received at least 80% of the prescribed dose of pegylated interferon and ribavirin. Sustained viral response was observed in 9 patients (75%). The most frequent side effect was flu like illness which was reported in all patients. Sixty seven percent had leucopenia, but only one individual required adjuvant therapy with hematologic growth factor. Four patients had anemia requiring ribavirin dose reduction. One patient developed hypothyroidism. CONCLUSION: Combination treatment of peginterferon alfa-2b with ribavirin appears to be efficacious and relatively safe in adolescents with chronic hepatitis C genotype 4.B.


Asunto(s)
Antivirales/uso terapéutico , Hepacivirus/genética , Hepatitis C Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Polietilenglicoles/uso terapéutico , Ribavirina/uso terapéutico , Adolescente , Factores de Edad , Antivirales/efectos adversos , Biopsia , Quimioterapia Combinada , Femenino , Genotipo , Hepatitis C Crónica/diagnóstico , Humanos , Interferón alfa-2 , Interferón-alfa/efectos adversos , Kuwait , Masculino , Proyectos Piloto , Polietilenglicoles/efectos adversos , Proteínas Recombinantes , Ribavirina/efectos adversos , Factores de Tiempo , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA