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The malfunctioning of the heating, ventilating, and air conditioning (HVAC) system is considered to be one of the main challenges in modern buildings. Due to the complexity of the building management system (BMS) with operational data input from a large number of sensors used in HVAC system, the faults can be very difficult to detect in the early stage. While numerous fault detection and diagnosis (FDD) methods with the use of statistical modeling and machine learning have revealed prominent results in recent years, early detection remains a challenging task since many current approaches are unfeasible for diagnosing some HVAC faults and have accuracy performance issues. In view of this, this study presents a novel hybrid FDD approach by combining random forest (RF) and support vector machine (SVM) classifiers for the application of FDD for the HVAC system. Experimental results demonstrate that our proposed hybrid random forest-support vector machine (HRF-SVM) outperforms other methods with higher prediction accuracy (98%), despite that the fault symptoms were insignificant. Furthermore, the proposed framework can reduce the significant number of sensors required and work well with the small number of faulty training data samples available in real-world applications.
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Aire Acondicionado , Máquina de Vectores de Soporte , Calefacción , Aprendizaje Automático , Modelos EstadísticosRESUMEN
BACKGROUND: Capillary hemangiomas of the skin and soft tissue are a common entity, while capillary hemangiomas of the central nervous system are an extremely rare pathology. There are less than 20 published cases of intradural lesions involving the cauda equina. CASE PRESENTATION: Herein, we describe a young patient with a capillary hemangioma of the cauda equina that underwent successful surgical resection. CONCLUSION: Natural history and post-operative follow-up for patients with spinal intradural capillary hemangioma are uncertain. This is the sole case to have not recurred at 12 months which underwent gross total resection and had a high proliferative index.
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Cauda Equina/patología , Hemangioma Capilar/patología , Recurrencia Local de Neoplasia/patología , Neoplasias del Sistema Nervioso Periférico/patología , Adulto , Diagnóstico Diferencial , Hemangioma Capilar/diagnóstico , Humanos , Imagen por Resonancia Magnética , Masculino , Recurrencia Local de Neoplasia/diagnóstico , Neoplasias del Sistema Nervioso Periférico/diagnósticoRESUMEN
Coronavirus disease 2019 (COVID-19) infection has now reached a pandemic state, affecting more than a million patients worldwide. Predictors of disease outcomes in these patients need to be urgently assessed to decrease morbidity and societal burden. Lactate dehydrogenase (LDH) has been associated with worse outcomes in patients with viral infections. In this pooled analysis of 9 published studies (n = 1532 COVID-19 patients), we evaluated the association between elevated LDH levels measured at earliest time point in hospitalization and disease outcomes in patients with COVID-19. Elevated LDH levels were associated with a ~6-fold increase in odds of developing severe disease and a ~16-fold increase in odds of mortality in patients with COVID-19. Larger studies are needed to confirm these findings.
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Betacoronavirus , Infecciones por Coronavirus/enzimología , L-Lactato Deshidrogenasa/sangre , Pandemias , Neumonía Viral/enzimología , Biomarcadores/sangre , Proteína C-Reactiva/metabolismo , COVID-19 , Infecciones por Coronavirus/epidemiología , Salud Global , Humanos , Neumonía Viral/epidemiología , SARS-CoV-2 , Índice de Severidad de la Enfermedad , Tasa de Supervivencia/tendenciasRESUMEN
BACKGROUND: Symptoms of Temporomandibular Disorders (TMD) could affect oral health-related quality of life (OHRQoL) and psychological distress. OBJECTIVE: This study aims to determine the prevalence of TMD symptoms, and impact of type and number of TMD symptoms on OHRQoL and psychological states among Asian military personnel. METHOD: The study was conducted across 12 military dental centres using self-administered questionnaire comprising demographical data, DC/TMD symptom questionnaire, OHIP-14 and DASS-21. A total of 3028 personnel, aged between 18-65 years old, were invited to participate with an acceptance rate of 90.5%. Data analysis was done using non-parametric tests, regression analysis and Spearman correlation (P < 0.05). RESULTS: Out of 2043 subjects (1998 males; 45 females, mean age 24.18 ± 7.18 years), 36.32% (n = 742) reported at least one TMD symptom. Significant differences in summary OHIP-14, depression, anxiety and stress scores were observed between subjects with and without TMD symptoms. Significant differences in OHIP-14 and DASS-21 scores were observed between dissimilar type and number of TMD symptoms in the TMD group. Those with headaches and 2-3 symptoms have substantially poorer OHRQoL and greater psychological distress. Associations between number of TMD symptoms, quality of life, depression, anxiety and stress were significant but weak (r = 0.19-0.40). CONCLUSIONS: Symptoms of Temporomandibular Disorders were prevalent among Asian military population. Significant differences in OHRQoL and psychological states were observed between subjects with and without TMD symptoms. Specific type and number of TMD symptoms impacted OHRQoL and psychological states differently. Associations between number of TMD symptoms and quality of life, depression, anxiety and stress were significant but weak.
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Pueblo Asiatico/psicología , Personal Militar/psicología , Salud Bucal/estadística & datos numéricos , Calidad de Vida , Estrés Psicológico/epidemiología , Trastornos de la Articulación Temporomandibular/epidemiología , Trastornos de la Articulación Temporomandibular/psicología , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Prevalencia , Singapur/epidemiología , Estrés Psicológico/etiología , Estrés Psicológico/fisiopatología , Estrés Psicológico/psicología , Trastornos de la Articulación Temporomandibular/fisiopatología , Adulto JovenRESUMEN
BACKGROUND AND PURPOSE: The management of unruptured brain arteriovenous malformations (ubAVMs) remains controversial despite ARUBA trial (A Randomized Trial of Unruptured Brain Arteriovenous Malformation), a controlled trial that suggested superiority of conservative management over intervention. However, microsurgery occurred in only 14.9% of ARUBA intervention cases, raising concerns about the study's generalizability. Our purpose was to evaluate whether, in a larger ARUBA-eligible ubAVM population, microsurgery produces acceptable outcomes. METHODS: Demographic data, AVM characteristics, and treatment outcomes were evaluated in 155 ARUBA-eligible bAVMs treated with microsurgery between 1994 and 2014. Outcomes were rates of early disabling deficits and permanent disabling deficits with modified Rankin Scale score ≥3 or any permanent neurological deficits with modified Rankin Scale score ≥1. Covariates associated with outcomes were determined by regression analysis. RESULTS: Of 977 AVM patients, 155 ARUBA-eligible patients had microsurgical resection (71.6% surgery only and 25.2% with preoperative embolization). Mean follow-up was 36.1 months. Complete obliteration was achieved in 94.2% after initial surgery and 98.1% on final angiography. Early disabling deficits and permanent disabling deficits occurred in 12.3% and 4.5%, respectively, whereas any permanent neurological deficit (modified Rankin Scale score ≥1) occurred in 16.1%. Among ubAVM of Spetzler-Martin grades 1 and 2, complete obliteration occurred in 99.2%, with early disabling deficits and permanent disabling deficits occurring in 9.3% and 3.4%, respectively. Major bleeding was the only significant predictor of early disabling deficits on multivariate analysis (P<0.001). CONCLUSIONS: Microsurgery in this cohort produced less disabling deficits than ARUBA with similar morbidity and AVM obliteration as other cohort series. This disparity between our results and ARUBA suggests that future controlled trials should focus on the safety and efficacy of microsurgery with or without adjunctive embolization in carefully selected ubAVM patients.
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Malformaciones Arteriovenosas Intracraneales/diagnóstico , Malformaciones Arteriovenosas Intracraneales/cirugía , Microcirugia/métodos , Complicaciones Posoperatorias/diagnóstico , Adolescente , Adulto , Niño , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Masculino , Microcirugia/efectos adversos , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/efectos adversos , Procedimientos Neuroquirúrgicos/métodos , Complicaciones Posoperatorias/etiología , Estudios Prospectivos , Estudios Retrospectivos , Adulto JovenRESUMEN
Integrating the genotype with epigenetic marks holds the promise of better understanding the biology that underlies the complex interactions of inherited and environmental components that define the developmental origins of a range of disorders. The quality of the in utero environment significantly influences health over the lifecourse. Epigenetics, and in particular DNA methylation marks, have been postulated as a mechanism for the enduring effects of the prenatal environment. Accordingly, neonate methylomes contain molecular memory of the individual in utero experience. However, interindividual variation in methylation can also be a consequence of DNA sequence polymorphisms that result in methylation quantitative trait loci (methQTLs) and, potentially, the interaction between fixed genetic variation and environmental influences. We surveyed the genotypes and DNA methylomes of 237 neonates and found 1423 punctuate regions of the methylome that were highly variable across individuals, termed variably methylated regions (VMRs), against a backdrop of homogeneity. MethQTLs were readily detected in neonatal methylomes, and genotype alone best explained â¼25% of the VMRs. We found that the best explanation for 75% of VMRs was the interaction of genotype with different in utero environments, including maternal smoking, maternal depression, maternal BMI, infant birth weight, gestational age, and birth order. Our study sheds new light on the complex relationship between biological inheritance as represented by genotype and individual prenatal experience and suggests the importance of considering both fixed genetic variation and environmental factors in interpreting epigenetic variation.
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Metilación de ADN , Ambiente , Epigénesis Genética , Interacción Gen-Ambiente , Heterogeneidad Genética , Genotipo , Transcriptoma , Biología Computacional/métodos , Islas de CpG , Epigenómica/métodos , Femenino , Humanos , Recién Nacido , Masculino , Polimorfismo de Nucleótido Simple , Embarazo , Sitios de Carácter Cuantitativo , Factores de RiesgoRESUMEN
Despite claims concerning biological mechanisms sub-serving infant attention, little experimental work examines its underpinnings. This study examines how candidate polymorphisms from the cholinergic (CHRNA4 rs1044396) and dopaminergic (COMT rs4680) systems, respectively indicative of parietal and prefrontal/anterior cingulate involvement, are related to 6-month-olds' (n=217) performance during a visual expectation eye-tracking paradigm. As previous studies suggest that both cholinergic and dopaminergic genes may influence susceptibility to the influence of other genetic and environmental factors, we further examined whether these candidate genes interact with one another and/or with early caregiving experience in predicting infants' visual attention. We detected an interaction between CHRNA4 genotype and observed maternal sensitivity upon infants' orienting to random stimuli and a CHRNA4-COMT interaction effect upon infants' orienting to patterned stimuli. Consistent with adult research, we observed a direct effect of COMT genotype on anticipatory looking to patterned stimuli. Findings suggest that CHRNA4 genotype may influence susceptibility to other attention-related factors in infancy. These interactions may account for the inability to establish a link between CHRNA4 and orienting in infant research to date, despite developmental theorizing suggesting otherwise. Moreover, findings suggest that by 6months, dopamine, and relatedly, the prefrontal cortex/anterior cingulate, may be important to infant attention.
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Atención/fisiología , Catecol O-Metiltransferasa/genética , Desarrollo Infantil/fisiología , Función Ejecutiva/fisiología , Interacción Gen-Ambiente , Conducta Materna/fisiología , Orientación Espacial/fisiología , Receptores Nicotínicos/genética , Adulto , Femenino , Humanos , Lactante , MasculinoRESUMEN
PURPOSE: To evaluate the inter- and intraobserver reliability of the CADS score, a previously described facial nerve grading instrument for ophthalmic grading of facial nerve palsy. METHODS: This is a cross-sectional validation study. Two clinicians independently assessed and graded each patient on the same day, masked to each other's grading. Four parameters are assessed in the CADS scale: Cornea (0-3, ±a), static Asymmetry (0-2), Dynamic function (0-3), and Synkinesis (0-2). One clinician reassessed the patients and performed the grading again at a minimum time interval of 1 hour later. A weighted κ analysis was performed to determine inter- and intraobserver reliability using 95% bootstrapped bias-corrected and accelerated (BCa) confidence intervals (CIs). RESULTS: Thirty-three patients (27 women, mean age 51.7, range 23-80 years) with unilateral facial nerve palsy were graded. The overall interobserver reliability was 0.80 (95% BCa CI: 0.68-0.91) for cornea, 0.93 for resting asymmetry (95% BCa CI: 0.55-1.00), 0.80 for dynamic function (95% BCa CI: 0.50-0.96), and 0.88 (95% BCa CI: 0.71-0.96) for synkinesis. The overall intraobserver reliability was 0.93 for cornea (95% BCa CI: 0.83-0.98), 0.82 for resting asymmetry (95% BCa CI: 0.53-0.96), 0.92 for dynamic function (95% BCa CI: 0.72-1.00), and 0.98 for synkinesis (95% BCa CI: 0.84-1.00). CONCLUSION: The CADS grading scale demonstrates good interobserver reliability and very good intraobserver reliability. It incorporates all ophthalmic complications for facial nerve palsy and remains easy to use and refer to.
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Expresión Facial , Nervio Facial/fisiopatología , Parálisis Facial/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Parálisis Facial/fisiopatología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Curva ROC , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
The Holarctic tick Ixodes angustus is a competent vector for Borrelia burgdorferi, the etiologic agent of Lyme disease, and possibly Anaplasma phagocytophilum, the etiologic agent of granulocytic anaplasmosis, as well. From 2005 to 2013, we collected host-feeding I. angustus individuals from live-trapped small mammals and by flagging vegetation from 12 study sites in northern and central California, and tested for B. burgdorferi sensu lato, A. phagocytophilum, and Rickettsia spp. DNA by real-time PCR. Among 261 I. angustus collected (259 from hosts and two by flagging), the most common hosts were tree squirrels (20 % of ticks) and chipmunks (37 %). The PCR-prevalence for A. phagocytophilum and B. burgdorferi in ticks was 2 % and zero, respectively. The minimum infection prevalence on pooled DNA samples was 10 % for Rickettsia spp. DNA sequencing of the ompA gene identified this rickettsia as Candidatus Rickettsia angustus, a putative endosymbiont. A zero-inflated negative binomial mixed effects model was used to evaluate geographical and climatological predictors of I. angustus burden. When host species within study site and season within year were included in the model as nested random effects, all significant variables revealed that I. angustus burden increased as temperature decreased. Together with published data, these findings suggest that I. angustus is a host generalist, has a broad geographic distribution, is more abundant in areas with lower temperature within it's range, and is rarely infected with the pathogens A. phagocytophilum and B. burgdorferi.
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Anaplasma phagocytophilum/aislamiento & purificación , Borrelia burgdorferi/aislamiento & purificación , Clima , Ecosistema , Especificidad del Huésped , Ixodes/microbiología , Ixodes/fisiología , Animales , Proteínas Bacterianas/genética , California , Densidad de Población , Análisis de Secuencia de ADNRESUMEN
Anterior cervical discectomy and fusion (ACDF) and anterior lumbar interbody fusion (ALIF) are common surgical procedures for degenerative disc disease of the cervical and lumbar spine. Over the years, many bone graft options have been developed and investigated aimed at complimenting or substituting autograft bone, the traditional fusion substrate. Here, we summarise the historical context, biological basis and current best evidence for these bone graft options in ACDF and ALIF.
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Trasplante Óseo/métodos , Vértebras Cervicales/cirugía , Vértebras Lumbares/cirugía , Fusión Vertebral/métodos , Desarrollo Óseo , Trasplante de Médula Ósea/métodos , Sustitutos de Huesos , Trasplante Óseo/economía , Medicina Basada en la Evidencia , Terapia Genética , Humanos , Fusión Vertebral/economíaRESUMEN
Finding mucosal abnormalities (e.g., erythema, blood, ulcer, erosion, and polyp) is one of the most essential tasks during endoscopy video review. Since these abnormalities typically appear in a small number of frames (around 5% of the total frame number), automated detection of frames with an abnormality can save physician's time significantly. In this paper, we propose a new multi-texture analysis method that effectively discerns images showing mucosal abnormalities from the ones without any abnormality since most abnormalities in endoscopy images have textures that are clearly distinguishable from normal textures using an advanced image texture analysis method. The method uses a "texton histogram" of an image block as features. The histogram captures the distribution of different "textons" representing various textures in an endoscopy image. The textons are representative response vectors of an application of a combination of Leung and Malik (LM) filter bank (i.e., a set of image filters) and a set of Local Binary Patterns on the image. Our experimental results indicate that the proposed method achieves 92% recall and 91.8% specificity on wireless capsule endoscopy (WCE) images and 91% recall and 90.8% specificity on colonoscopy images.
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This review systematically explores the application of transformer-based models in EEG signal processing and brain-computer interface (BCI) development, with a distinct focus on ensuring methodological rigour and adhering to empirical validations within the existing literature. By examining various transformer architectures, such as the Temporal Spatial Transformer Network (TSTN) and EEG Conformer, this review delineates their capabilities in mitigating challenges intrinsic to EEG data, such as noise and artifacts, and their subsequent implications on decoding and classification accuracies across disparate mental tasks. The analytical scope extends to a meticulous examination of attention mechanisms within transformer models, delineating their role in illuminating critical temporal and spatial EEG features and facilitating interpretability in model decision-making processes. The discourse additionally encapsulates emerging works that substantiate the efficacy of transformer models in noise reduction of EEG signals and diversifying applications beyond the conventional motor imagery paradigm. Furthermore, this review elucidates evident gaps and propounds exploratory avenues in the applications of pre-trained transformers in EEG analysis and the potential expansion into real-time and multi-task BCI applications. Collectively, this review distils extant knowledge, navigates through the empirical findings, and puts forward a structured synthesis, thereby serving as a conduit for informed future research endeavours in transformer-enhanced, EEG-based BCI systems.
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Interfaces Cerebro-Computador , Electroencefalografía , Procesamiento de Señales Asistido por Computador , Humanos , Electroencefalografía/métodos , Encéfalo/fisiologíaRESUMEN
Objective: This article describes a case of polymicrobial Arcanobacterium haemolyticum pharyngitis and sinusitis complicated by intracranial complications and reviews similar cases in the literature. Case summary: A 21-year-old immunocompetent male presented with symptoms of sore throat, rhinorrhoea, lethargy, headache, and rash. Imaging demonstrated sinusitis, pre-septal sinusitis, peritonsillar abscess formation, subdural empyema and cerebritis. He was managed with endoscopic sinus surgery, craniotomy for evacuation of subdural empyema and antibiotics. Microbiological samples demonstrated growth of A. haemolyticum, strep. anginosus, and fusobacterium necrophorum. He subsequently developed a cerebral abscess requiring stereotactic needle drainage. After a prolonged course of antibiotics, the patient was discharge and made a good recovery. Discussion: A. haemolyticum is an uncommon cause of non-streptococcal pharyngitis that may occur alongside other microorganisms and is rarely associated with severe intracranial complications. This organism and its antibiotic susceptibility patterns should be considered in complicated upper respiratory tract infections in immunocompetent hosts. Penicillins and macrolide antibiotics form the mainstay of therapy for A. haemolyticum.
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Changes and advancements in technology have the potential to benefit older adults by promoting independence and increasing the ability to age in place. However, older adults are less likely to adopt new technology unless they see benefits to themselves. This study assessed the perceptions of 30 older adults in the Midwest concerning technology via three separate focus groups (i.e., independent apartment complex, a rural community, exercise program participants), which addressed a need in the literature (i.e., inclusion of oldest-old and rural individuals). The focus group questions included items such as what technology older adults currently used, desired improvements in technology, and the greatest challenges participants were facing or would face in the future. Overall, older adults were enthusiastic about learning new forms of technology that could help them maintain their independence and quality of life. Five themes emerged from all three focus groups: (a) Frustrations, Limitations, and Usability Concerns; (b) Transportation; (c) Help and Assistance; (d) Self-Monitoring; and (e) Gaming. The themes have important implications for future technology developed for older adults; in particular, older adults were willing and eager to adopt new technology when usefulness and usability outweighed feelings of inadequacy.
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Computadores , Actividades Cotidianas , Anciano , Anciano de 80 o más Años , Femenino , Enfermería Geriátrica , Humanos , Masculino , Persona de Mediana Edad , Calidad de VidaRESUMEN
The Brain Computer Interface (BCI) is the communication between the human brain and the computer. Electroencephalogram (EEG) is one of the biomedical signals which can be obtained by attaching electrodes to the scalp. Some EEG related applications can be developed to help disabled people, such as EEG based wheelchair or robotic arm. A hybrid BCI real-time control system is proposed to control a multi-tasks BCI robot. In this system, a sliding window based online data segmentation strategy is proposed to segment training data, which enable the system to learn the dynamic features when the subject's brain state transfer from a rest state to a task execution state. The features help the system achieve real-time control and ensure the continuity of executing actions. In addition, Common Spatial Pattern (CSP) can better extract the spatial features of these continuous actions from the dynamic data to ensure that multiple control commands are accurately classified. In the experiment, three subjects' EEG data is collected, trained and tested the performance and reliability of the proposed control system. The system records the robot's spending time, moving distance, and the number of objects pushing down. Experimental results are given to show the feasibility of the real-time control system. Compared to real-time remote controller, the proposed system can achieve similar performance. Thus, the proposed hybrid BCI real-time control system is able to control the robot in the real-time environment and can be used to develop robot-aided arm training methods based on neurological rehabilitation principles for stroke and brain injury patients.
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Interfaces Cerebro-Computador , Procedimientos Quirúrgicos Robotizados , Robótica , Humanos , Reproducibilidad de los Resultados , Electroencefalografía/métodosRESUMEN
BACKGROUND: Jugular foramen dural arteriovenous fistulas (DAVFs) are rare and challenging lesions. Described methods of treatment include embolization and microsurgical disconnection through a far lateral transcondylar approach. The authors present the case of a Borden type III jugular foramen DAVF, which was treated with a novel, less invasive retrosigmoid approach with intradural skeletonization and packing of the sigmoid sinus. OBSERVATIONS: The patient presented with headache and visual field deficit. Neuroimaging demonstrated a right temporal intracerebral hematoma with mass effect. This was due to a Borden type III jugular foramen DAVF with cortical venous reflux into the vein of Labbe secondary to recanalization of a previously thrombosed sigmoid sinus. Microsurgical disconnection was performed via a retrosigmoid approach, in which the sigmoid sinus was identified intradurally at the jugular foramen. The sigmoid sinus was isolated by drilling at the pre- and retrosigmoid spaces to permit packing and clip ligation. Postoperative angiography revealed complete occlusion of the DAVF. LESSONS: Jugular foramen DAVFs are rare entities, which have been traditionally treated through a far lateral transcondylar approach. An intradural retrosigmoid approach is a safe, less invasive alternative, which involves less soft tissue and bony dissection and does not have the associated morbidity of craniocervical instability and hypoglossal neuropathy.
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Research has advanced considerably since the first clinical trial of human mesenchymal stem cells (MSCs) in the early 1990s. During this period, our understanding of MSC biology and our ability to expand and manipulate these cells have provided hope for the repair of damaged tissues due to illness or injury. MSCs have conventionally been injected systemically or locally into target tissue; however, inconsistent cell homing and engraftment efficiencies represent a major bottleneck that has led to mixed results in clinical studies. To overcome these issues, MSCs have been pre-conditioned with biomolecules, genetically altered, or surface engineered to enhance their homing and engraftment capabilities. In parallel, a variety of cell-encapsulating materials have been designed to improve cell delivery and post-transplantation survival and function. In this review, we discuss the current strategies that have been employed on cultured MSCs to improve targeted cell delivery and retention for tissue repair. We also discuss the advances in injectable and implantable biomaterial technologies that drive the success of MSC-based therapies in regenerative medicine. Multi-faceted approaches combining cellular modification and cell-instructive material design can pave the way for efficient and robust stem cell transplantation for superior therapeutic outcomes.
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Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas , Humanos , Trasplante de Células Madre Mesenquimatosas/métodos , Materiales Biocompatibles/metabolismo , Medicina Regenerativa/métodosRESUMEN
Mesenchymal stem cells (MSCs) used for clinical applications require in vitro expansion to achieve therapeutically relevant numbers. However, conventional planar cell expansion approaches using tissue culture vessels are inefficient, costly, and can trigger MSC phenotypic and functional decline. Here we present a one-step dry plasma process to modify the internal surfaces of three-dimensional (3D) printed, high surface area to volume ratio (high-SA:V) porous scaffolds as platforms for stem cell expansion. To address the long-lasting challenge of uniform plasma treatment within the micrometre-sized pores of scaffolds, we developed a packed bed plasma immersion ion implantation (PBPI3) technology by which plasma is ignited inside porous materials for homogeneous surface activation. COMSOL Multiphysics simulations support our experimental data and provide insights into the role of electrical field and pressure distribution in plasma ignition. Spatial surface characterisation inside scaffolds demonstrates the homogeneity of PBPI3 activation. The PBPI3 treatment induces radical-containing chemical structures that enable the covalent attachment of biomolecules via a simple, non-toxic, single-step incubation process. We showed that PBPI3-treated scaffolds biofunctionalised with fibroblast growth factor 2 (FGF2) significantly promoted the expansion of MSCs, preserved cell phenotypic expression, and multipotency, while reducing the usage of costly growth factor supplements. This breakthrough PBPI3 technology can be applied to a wide range of 3D polymeric porous scaffolds, paving the way towards developing new biomimetic interfaces for tissue engineering and regenerative medicine.
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Dual antiplatelet therapy (DAPT) is standard treatment for endoluminal stent insertion, and complete resistance to DAPT is rare. A case of in-stent thrombosis occurring 3 hours after stent-assisted coiling of internal carotid artery aneurysm is presented despite compliance with DAPT. Platelet function tests (PFTs) revealed complete clopidogrel and prasugrel resistance.
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Cells can sense mechanical signals through cytoskeleton reorganization. We previously discovered the formation of omni-directional actin protrusions upon compression loading, namely compression-induced actin protrusions (CAPs), in human mesenchymal stem cells (MSCs) in 3D micro-tissues. Here, the regulatory roles of three RhoGTPases (CDC42, Rac1 and RhoA) in the formation of CAPs were investigated. Upon compression loading, extensive formation of CAPs was found, significantly associated with an upregulated mRNA expression of Rac1 only, but not CDC42, nor RhoA. Upon chemical inhibition of these RhoGTPase activity during compression, only Rac1 activity was significantly suppressed, associating with the reduced CAP formation. Silencing the upstream regulators of these RhoGTPase pathways including Rac1 by specific siRNA dramatically disrupted actin cytoskeleton, distorted cell morphology and aborted CAP formation. Silencing cortactin (CTTN), a downstream effector of the Rac1 pathway, induced a compensatory upregulation of Rac1, enabling the MSCs to respond to the compression loading stimulus in terms of CAP formation, although at a reduced number. The importance of Rac1 signalling in CAP formation and the corresponding upregulation of lamellipodial markers also suggest that these CAPs are lamellipodia in nature. This study delineates the mechanism of compression-induced cytoskeleton reorganization, contributing to rationalizing mechanical loading regimes for functional tissue engineering.