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BACKGROUND AND PURPOSE: Transvenous embolization has emerged as a novel technique for treating selected brain AVMs with high reported occlusion rates. However, it requires anatomic and technical skills to be successful and to ensure patient safety. Therefore, training and testing are essential for preparing clinicians to perform these procedures. Our aim was to develop and test a novel, patient-specific brain AVM in vitro model for transvenous embolization by using 3D printing technology. MATERIALS AND METHODS: We developed a brain AVM in vitro model based on real patient data by using stereolithography resin 3D printing. We created a closed pulsed circuit with flow passing from the arterial side to the venous side, and we tested the effect of mean arterial pressure on retrograde nidal filling with contrast injections. Transvenous embolization simulations were conducted for each of the 12 identical models divided into 2 groups (2×6). This involved the use of an ethylene-vinyl alcohol liquid embolic agent injected through microcatheters either without or with a coil in the vein (groups 1 and 2, respectively). RESULTS: Retrograde contrast advance to nidus was directly related to lower mean arterial pressure. Transvenous embolization tests with a liquid embolic agent adequately reproduced the usual embolization plug and push technique. We found no differences between the 2 group conditions, and additional venous coil neither increased nidus penetration nor reduced injection time in the model (57.6 versus 61.2% nidus occlusion rate, respectively). CONCLUSIONS: We were able to develop and test a functional in vitro brain AVM model for transvenous embolization by using 3D printing to emulate its conditions and characteristics. Better contrast penetration was achieved with less mean arterial pressure, and no embolization advantage was found by adding coil to the vein in this model.
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Embolização Terapêutica , Malformações Arteriovenosas Intracranianas , Impressão Tridimensional , Humanos , Embolização Terapêutica/métodos , Malformações Arteriovenosas Intracranianas/terapia , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Modelos AnatômicosRESUMO
La enfermedad de Parkinson y Alzheimer son las enfermedades neurodegenerativas más frecuentes a nivel mundial. Tienen etiología multifactorial, entre ellas, la genética; y son motivo de interés en la investigación científica actual. Se realizó una revisión narrativa con el objetivo de determinar las alteraciones genéticas asociadas a estas patologías, además su influencia en la evolución y respuesta al tratamiento de ellas. Se consultaron artículos originales, revisiones bibliográficas, sistemáticas, metaanálisis en inglés y español, con fecha de publicación entre el 1 enero de 2018 y el 20 de mayo de 2023, en bases como PubMed y Medline. Se utilizaron los términos MeSH «Alzheimer Disease¼, «Parkinson Disease¼, «Drug Therapy¼ y «Mutations¼. El riesgo hereditario para la enfermedad de Parkinson suele ser poligenético, sin embargo, existen genes relacionados con mutaciones monogénicas. Se identifican alteraciones en genes de α-sinucleína, glucocerebrosidasa y quinasa 2 rica en leucina que se relacionan con mayor riesgo de desarrollar Parkinson, además de variaciones en el cuadro clínico y edad de inicio de síntomas. En cuanto a la enfermedad de Alzheimer, las alteraciones en los genes de la proteína precursora amiloide, presenilina 1 y 2 se relacionan con la forma familiar de la enfermedad; por otra parte, las de apolipoproteína E4 se han identificado en la forma esporádica, por lo que se consideran como el factor de riesgo genético más importante para su desarrollo
Parkinson's and Alzheimer's are the most frequent neurodegenerative diseases worldwide. They have a multifactorial etiology, including genetics, and are of interest in current scientific research. A narrative review was carried out with the aim of determining the genetic alterations associated with these pathologies, as well as their influence on their evolution and response to treatment. Original articles, literature reviews, systematic reviews, meta-analyses in English and Spanish, with publication date between January 1, 2018 and May 20, 2023, were consulted in databases such as PubMed and Medline. MeSH terms "Alzheimer Disease", "Parkinson Disease", "Drug Therapy" and "Mutation" were used. Hereditary risk for Parkinson's disease is usually polygenetic, however, there are genes related to monogenic mutations. Alterations in α-synuclein, glucocerebrosidase and leucine-rich kinase 2 genes have been identified that are related to an increased risk of developing Parkinson's disease, in addition to variations in the clinical picture and age of symptom onset. As for Alzheimer's disease, alterations in the genes of the amyloid precursor protein, presenilin 1 and 2 are related to the familial form of the disease; on the other hand, those of apolipoprotein E4 have been identified in the sporadic form, and are therefore considered to be the most important genetic risk factor for its development
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El SalvadorRESUMO
BACKGROUND: Brain arteriovenous malformations (bAVM) are complex vascular diseases. Several models have been used to simulate endovascular treatments; thus in vitro models have not been widely employed because it has been difficult to recreate realistic phantoms of this disease. OBJECTIVE: To describe the development and evaluate the preliminary experience of a novel bAVM in vitro model for endovascular embolization using millifluidic three-dimensional (3D) printing technology. METHODS: We designed a bAVM phantom starting from simple to more complex designs, composed of a nidus, feeding arteries and draining vein. We recreate the design by using millifluidic technology with stereolithography 3D printing. Structural and functional tests were performed using angiographic images and computer flow dynamics. Treatment simulations with ethylene vinyl alcohol were tested using two different microcatheter position techniques. A Likert-scale questionnaire was applied to perform a qualitative evaluation of the model. RESULTS: We developed a realistic model of a bAVM with hollow channels. The structural evaluation showed a high precision of the 3D printing process. Embolization tests with the liquid agent gave similar sensations and material behaviour as in vivo cases. There were no significant differences between microcatheter position techniques, thus we observed a trend for better nidus filling with a deeper in-nidus position technique. CONCLUSIONS: We were able to create and test a novel bAVM in vitro model with stereolithography 3D printing in resin. It showed a high capacity for simulating endovascular embolization characteristics, with an excellent user experience. It could be potentially used for training and testing of bAVM embolizations.
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Glucokinase (GCK) is the pancreatic ß-cell glucose sensor, and its kinetics are key to that purpose. A slow transition step, displayed as non-hyperbolic kinetics, and a low affinity for glucose characterize GCK. Mutations in GCK associated with maturity-onset diabetes of the young type 2 (MODY2) previously described reduce the functionality of the human pancreatic ß-cell, leading to diabetic clinical phenotypes. We present a kinetic characterization of the G448D mutation identified in a MODY2 patient, which is one of the first mutations to exhibit increased functionality. This mutant displays increased activity, high affinity for both Mg2+ -ATP and glucose, hyperbolic kinetics and increased phosphorylation potential. Hyperbolic kinetics and assays in the presence of glycerol indicate that G448D lacks the slow transition step crucial for the pancreatic ß-cell glucose sensor function.
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Diabetes Mellitus Tipo 2 , Glucoquinase , Humanos , Glucoquinase/genética , Mutação , Diabetes Mellitus Tipo 2/genética , GlucoseRESUMO
BACKGROUND: Aneurysm recurrence remains a challenge when coiling cerebral aneurysms. Development of next generation coils has focused on accelerating thrombus maturation and increasing coil packing density. Ultra low density shape memory polymer is a novel embolic material designed for this purpose. The polymer is crimped over a platinum-tungsten coil for catheter delivery and self-expands to a predefined volume on contact with blood. METHODS: This prospective study in humans evaluated aneurysms 5-16 mm (inclusive) in diameter that were indicated for endovascular coil embolization. At least 70% coil volume was required to be shape memory polymer coils. Patients were followed-up according to standard of care for 12 months. RESULTS: Nine patients (89% women, mean age 55.8±11.7 years) were treated with shape memory polymer coils and completed 12 months of follow-up. Aneurysms were all unruptured and were in the ophthalmic segment of the internal carotid artery (n=7), posterior communicating artery, and anterior cerebral artery A1-A2 segment. Aneurysms were a mean of 7.8±2.9 mm in diameter (range 5.2-14.9 mm). The mean packing density based on unexpanded polymer was 17±6%. Packing density based on expanded polymer was 43±13%. At 12 months, no recurrence had occurred, and a Raymond-Roy occlusion classification of 1 (n=5) or 2 (n=4) was observed. No serious adverse events related to the study device occurred over the 12 months after the procedure. CONCLUSIONS: Shape memory polymer coils were safe and effective in treating intracranial aneurysms over 12 months in this first study in human subjects.
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Embolização Terapêutica , Aneurisma Intracraniano , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Masculino , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/terapia , Aneurisma Intracraniano/etiologia , Seguimentos , Estudos Prospectivos , Chile , Resultado do Tratamento , Embolização Terapêutica/métodos , Polímeros , Estudos RetrospectivosRESUMO
In the context of fiscal reform in Costa Rica (value added tax revision), the definition of a new basic tax basket, "canasta básica tributaria" (CBT) in Spanish, incorporating nutritional criteria is underway in the country. In this study, price elasticities of major food categories were analyzed using a Quadratic Almost Ideal Demand System (QUAIDS) model. Data from the 2018 National Survey of Household Income and Expenditures was used. Measuring price elasticities is essential because it allows: knowing the extent to which food demand reacts to price changes, anticipating changes in the quantities demanded as a result of fiscal policy changes, measuring potential substitution and complementary effects between food groups, and potential nutritional effects of fiscal policies. As a result, it helps providing recommendations on the content of a CBT with nutritional criteria. Results show that the food categories with the most elastic demand are "Bread and cereals," soft drinks and "Milk, cheese and eggs." Substitution effects exist between the following groups: "Fruits" and "Oils and fats," "Fruits" and "Bread and cereals," and between "Milk, cheese and eggs" and "Oils and fats." For this last food category and for the one which includes sweets and chocolates, the consumption decreases when the price of "Bread and cereals" increases. They are complementary goods. These relations between food groups need to be taken into account when defining a national CBT with nutritional criteria and with the objective of promoting the consumption of healthier food groups while disincentivizing the consumption of the unhealthy ones. Lastly, it is important that the consumption of the healthiest foods within each food group be fiscally promoted. Clinical Trial Registration: JEL codes: D12, H3, I18.
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Domain swapping is a mechanism of protein oligomerization by which two or more subunits exchange structural elements to generate an intertwined complex. Numerous studies support a diversity of swapping mechanisms in which structural elements can be exchanged at different stages of the folding pathway of a subunit. Here, we used single-molecule optical tweezers technique to analyze the swapping mechanism of the forkhead DNA-binding domain of human transcription factor FoxP1. FoxP1 populates folded monomers in equilibrium with a swapped dimer. We generated a fusion protein linking two FoxP1 domains in tandem to obtain repetitive mechanical folding and unfolding trajectories. Thus, by stretching the same molecule several times, we detected either the independent folding of each domain or the elusive swapping step between domains. We found that a swapped dimer can be formed directly from fully or mostly folded monomer. In this situation, the interaction between the monomers in route to the domain-swapped dimer is the rate-limiting step. This approach is a useful strategy to test the different proposed domain swapping mechanisms for proteins with relevant physiological functions.
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Pinças Ópticas , Dobramento de Proteína , Fatores de Transcrição Forkhead/metabolismo , Humanos , Substâncias Macromoleculares , Domínios Proteicos , Proteínas , Proteínas Repressoras/metabolismoRESUMO
BACKGROUND: Social cognition is critically compromised across neurodegenerative diseases, including the behavioral variant frontotemporal dementia (bvFTD), Alzheimer's disease (AD), and Parkinson's disease (PD). However, no previous study has used social cognition and other cognitive tasks to predict diagnoses of these conditions, let alone reporting the brain correlates of prediction outcomes. OBJECTIVE: We performed a diagnostic classification analysis using social cognition, cognitive screening (CS), and executive function (EF) measures, and explored which anatomical and functional networks were associated with main predictors. METHODS: Multiple group discriminant function analyses (MDAs) and ROC analyses of social cognition (facial emotional recognition, theory of mind), CS, and EF were implemented in 223 participants (bvFTD, AD, PD, controls). Gray matter volume and functional connectivity correlates of top discriminant scores were investigated. RESULTS: Although all patient groups revealed deficits in social cognition, CS, and EF, our classification approach provided robust discriminatory characterizations. Regarding controls, probabilistic social cognition outcomes provided the best characterization for bvFTD (together with CS) and PD, but not AD (for which CS alone was the best predictor). Within patient groups, the best MDA probabilities scores yielded high classification rates for bvFTD versus PD (98.3%, social cognition), AD versus PD (98.6%, social cognitionâ+âCS), and bvFTD versus AD (71.7%, social cognitionâ+âCS). Top MDA scores were associated with specific patterns of atrophy and functional networks across neurodegenerative conditions. CONCLUSION: Standardized validated measures of social cognition, in combination with CS, can provide a dimensional classification with specific pathophysiological markers of neurodegeneration diagnoses.
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Doença de Alzheimer , Demência Frontotemporal , Programas de Rastreamento , Doença de Parkinson , Cognição Social , Idoso , Doença de Alzheimer/classificação , Doença de Alzheimer/patologia , Atrofia/patologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Função Executiva , Feminino , Demência Frontotemporal/classificação , Demência Frontotemporal/patologia , Substância Cinzenta/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Testes de Estado Mental e Demência/estatística & dados numéricos , Pessoa de Meia-Idade , Doenças Neurodegenerativas/diagnóstico , Doença de Parkinson/classificação , Doença de Parkinson/patologia , América do SulRESUMO
The modelling of biological structures has allowed great advances in Engineering, Biology, and Medicine. In turn, these advances are seen from the design of footwear and sports accessories, to the design of prostheses, accessories and rehabilitation treatments. The reproduction of the various tissues has gone through an important evolution thanks to the development of computer systems and programs. However, knowledge of the medical-biological and engineering areas continues to be required, and it involves a considerable investment of time and resources. The resulting biomodels still require great precision. The present work shows a methodology that allows to optimize computational resources and reduce elaboration time of biomodels. Through this methodology, it is possible to generate a biomodel of high biofidelity of a human knee. This biomodel is constituted by hard tissues (cortical and trabecular bones) and soft tissues (ligaments and meniscus) resulting in the modelling of the lower third of the femur, the tibial plateaus, the anterior cruciate ligament, posterior cruciate ligament, external lateral ligament, interior lateral ligaments, and the meniscus. With this model and methodology, it is possible to perform numerical analyses that will provide results very similar to those of real life. As, the methodology allows to assign the mechanical properties to each tissue and the anatomical structure.
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Imageamento Tridimensional , Joelho/diagnóstico por imagem , Impressão Tridimensional , Análise de Elementos Finitos , Humanos , Ligamentos/diagnóstico por imagem , Imageamento por Ressonância MagnéticaRESUMO
In the lingual orthodontic technique, there are two paradigms regarding the type of wire used. Regardless of the material or gauge, some orthodontists choose to use the straight wire and resin and bond it to the surface of the tooth; they call it compensations. Other orthodontists prefer to bend the wire, giving it a mushroom shape. There is no specific indication for the use of each type of wire, so orthodontists use them according to their criteria. The present study establishes the bases so that it is possible to find the indications for each type of wire. A clinical trial of a lingual orthodontic patient was used. To carry out the comparative study, a straight arch was placed in his right arch and a mushroom arch in the left arch. Using 3D imaging, a high-biofidelity biomodel of the patient's mandible was generated, with which the FEM analysis was performed, which allowed comparing the reactions of the mandibular bone and appliances with the different arches. It was found that, on the side with the straight arch, there were greater deformations, and in the mushroom arch, there were greater stresses. With this, it is possible to find which clinical cases in each type of wire are indicated.
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BACKGROUND: Mechanical Thrombectomy (MT) is the standard of care for treatment of large vessel occlusion stroke. Until the beginning of 2020 MT was not funded nor widely implemented at the public healthcare level in Chile. OBJECTIVE: To describe the results of a pilot program created to provide access to public MT in Santiago - Chile. METHODS: Analysis from a prospectively collected database of MT cases performed between September 2017 and September 2019 in one center. A stroke network was developed with a single MT capable stroke center and five primary stroke centers. The primary efficacy endpoint was the rate of functional independence (mRS 0-2) at 90 days. Successful reperfusion was defined as 2 b-3 according to the thrombolysis in cerebral infarction scale. Safety outcomes include the rates of symptomatic intracranial hemorrhage and 90-day mortality. RESULTS: A total of 100 patients were treated over the study period. Their mean age was 62.8 ± 11.8 years and median baseline National Institute of Health Stroke Scale (NIHSS) measurement was 17. Seventy-seven percent of the patients received intra venous thrombolysis. Successful reperfusion was achieved in 95% of the cases. NIHSS at 24 hours showed a median drop of 7 points from baseline (p < 0.00001) and 50% of the follow-up patients were functionally independent at 90 days. Symptomatic Intracerebral hemorrhage occurred in 5% of the patients and 90-day all case mortality was 11%. CONCLUSIONS: We demonstrated the feasibility of a publicly funded MT program in Chile, with similar results as other international randomized control trials.
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Isquemia Encefálica , Acidente Vascular Cerebral , Idoso , Chile , Atenção à Saúde , Humanos , América Latina , Pessoa de Meia-Idade , Projetos Piloto , Estudos Retrospectivos , Acidente Vascular Cerebral/terapia , Trombectomia , Resultado do TratamentoRESUMO
BACKGROUND: With the global population aging and life expectancy increasing, dementia has turned a priority in the health care system. In Chile, dementia is one of the most important causes of disability in the elderly and the most rapidly growing cause of death in the last 20 years. Cognitive complaint is considered a predictor for cognitive and functional decline, incident mild cognitive impairment, and incident dementia. The GERO cohort is the Chilean core clinical project of the Geroscience Center for Brain Health and Metabolism (GERO). The objective of the GERO cohort is to analyze the rate of functional decline and progression to clinical dementia and their associated risk factors in a community-dwelling elderly with subjective cognitive complaint, through a population-based study. We also aim to undertake clinical research on brain ageing and dementia disorders, to create data and biobanks with the appropriate infrastructure to conduct other studies and facilitate to the national and international scientific community access to the data and samples for research. METHODS: The GERO cohort aims the recruitment of 300 elderly subjects (> 70 years) from Santiago (Chile), following them up for at least 3 years. Eligible people are adults not diagnosed with dementia with subjective cognitive complaint, which are reported either by the participant, a proxy or both. Participants are identified through a household census. The protocol for evaluation is based on a multidimensional approach including socio-demographic, biomedical, psychosocial, neuropsychological, neuropsychiatric and motor assessments. Neuroimaging, blood and stool samples are also obtained. This multidimensional evaluation is carried out in a baseline and 2 follow-ups assessments, at 18 and 36 months. In addition, in months 6, 12, 24, and 30, a telephone interview is performed in order to keep contact with the participants and to assess general well-being. DISCUSSION: Our work will allow us to determine multidimensional risks factors associated with functional decline and conversion to dementia in elderly with subjective cognitive complain. The aim of our GERO group is to establish the capacity to foster cutting edge and multidisciplinary research on aging in Chile including basic and clinical research. TRIAL REGISTRATION: NCT04265482 in ClinicalTrials.gov. Registration Date: February 11, 2020. Retrospectively Registered.
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Alcoolismo , Disfunção Cognitiva , Atividades Cotidianas , Idoso , Chile/epidemiologia , Cognição , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/epidemiologia , Estudos de Coortes , Estudo de Associação Genômica Ampla , Humanos , Masculino , Glicoproteínas de Membrana , Testes Neuropsicológicos , Projetos Piloto , Qualidade de Vida , Receptores ImunológicosRESUMO
Experimental research on living beings faces several obstacles, which are more than ethical and moral issues. One of the proposed solutions to these situations is the computational modelling of anatomical structures. The present study shows a methodology for obtaining high-biofidelity biomodels, where a novel imagenological technique is used, which applies several CAM/CAD computer programs that allow a better precision for obtaining a biomodel, with highly accurate morphological specifications of the molar and tissues that shape the biomodel. The biomodel developed is the first lower molar subjected to a basic chewing simulation through the application of the finite element method, resulting in a viable model, able to be subjected to various simulations to analyse molar biomechanical characteristics, as well as pathological conditions to evaluate restorative materials and develop treatment plans. When research is focused in medical and dental investigation aspects, numerical analyses could allow the implementation of several tools commonly used by mechanical engineers to provide new answers to old problems in these areas. With this methodology, it is possible to perform high-fidelity models no matter the size of the anatomical structure, nor the complexity of its structure and internal tissues. So, it can be used in any area of medicine.
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Tomografia Computadorizada de Feixe Cônico/estatística & dados numéricos , Imageamento Tridimensional/métodos , Modelos Dentários , Dente Molar/anatomia & histologia , Dente Molar/diagnóstico por imagem , Fenômenos Biomecânicos , Biologia Computacional , Simulação por Computador , Desenho Assistido por Computador , Humanos , Imageamento Tridimensional/estatística & dados numéricos , Modelos Biológicos , Dente Molar/fisiologia , SoftwareRESUMO
BACKGROUND: Recently, five randomized controlled trials confirmed the efficacy and safety of endovascular treatment with or without intravenous thrombolysis in acute ischemic stroke with large-vessel occlusion. AIM: To report patients with ischemic stroke treated with endovascular methods. MATERIAL AND METHODS: Retrospective analysis of 104 patients aged 61 ± 15 years (54% males) with ischemic stroke who received endovascular treatment at a single medical center between 2009 and 2017. RESULTS: Sixty one percent were treated with intravenous thrombolysis plus endovascular procedures and 39% with endovascular procedures alone. The median door-to needle time was 61 minutes and door-to femoral puncture was 135 minutes. The median National Institute of Health Stroke Scale (NIHSS) scores on admission, 24 hours later and at discharge were 12,4 and 1 points, respectively. Middle cerebral artery was occluded in 60% of cases. Other frequent localizations where distal carotid artery in 17% and vertebro-basilar artery in 14%. Thrombolysis in cerebral infarction (TICI) scale flow score after the procedure was 3 or 2b in 58% of cases and significantly correlated with NIHSS scores at 24 hours and discharge. Fifty percent of patients had a mRankin score < = 1 and ten patients died (9.6%). Eight percent had a symptomatic intracerebral hemorrhage. CONCLUSIONS: The clinical improvement of these patients 24 hours after the procedure and at discharge demonstrate the effectiveness of endovascular treatment in ischemic stroke. The presence neurologists able to interpret multimodal images at the emergency room, the use of local guidelines, the availability of an experienced neuro-interventional team engaged with the workflow and the use of stent retrievers are strongly associated with good outcomes.
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Isquemia Encefálica/terapia , Procedimentos Endovasculares/métodos , Acidente Vascular Cerebral/terapia , Terapia Trombolítica/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Isquemia Encefálica/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Índice de Gravidade de Doença , Estatísticas não Paramétricas , Acidente Vascular Cerebral/diagnóstico por imagem , Fatores de Tempo , Tempo para o Tratamento , Resultado do Tratamento , Adulto JovemRESUMO
Background: Recently, five randomized controlled trials confirmed the efficacy and safety of endovascular treatment with or without intravenous thrombolysis in acute ischemic stroke with large-vessel occlusion. Aim: To report patients with ischemic stroke treated with endovascular methods. Material and Methods: Retrospective analysis of 104 patients aged 61 ± 15 years (54% males) with ischemic stroke who received endovascular treatment at a single medical center between 2009 and 2017. Results: Sixty one percent were treated with intravenous thrombolysis plus endovascular procedures and 39% with endovascular procedures alone. The median door-to needle time was 61 minutes and door-to femoral puncture was 135 minutes. The median National Institute of Health Stroke Scale (NIHSS) scores on admission, 24 hours later and at discharge were 12,4 and 1 points, respectively. Middle cerebral artery was occluded in 60% of cases. Other frequent localizations where distal carotid artery in 17% and vertebro-basilar artery in 14%. Thrombolysis in cerebral infarction (TICI) scale flow score after the procedure was 3 or 2b in 58% of cases and significantly correlated with NIHSS scores at 24 hours and discharge. Fifty percent of patients had a mRankin score < = 1 and ten patients died (9.6%). Eight percent had a symptomatic intracerebral hemorrhage. Conclusions: The clinical improvement of these patients 24 hours after the procedure and at discharge demonstrate the effectiveness of endovascular treatment in ischemic stroke. The presence neurologists able to interpret multimodal images at the emergency room, the use of local guidelines, the availability of an experienced neuro-interventional team engaged with the workflow and the use of stent retrievers are strongly associated with good outcomes.
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Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Terapia Trombolítica/métodos , Isquemia Encefálica/terapia , Acidente Vascular Cerebral/terapia , Procedimentos Endovasculares/métodos , Fatores de Tempo , Índice de Gravidade de Doença , Isquemia Encefálica/diagnóstico por imagem , Estudos Retrospectivos , Análise de Variância , Resultado do Tratamento , Estatísticas não Paramétricas , Acidente Vascular Cerebral/diagnóstico por imagem , Tempo para o TratamentoRESUMO
Background Brain arteriovenous malformations (AVMs) are complex vascular lesions. Endovascular treatment results are usually measured by calculating the volume reduction of the lesions. Nevertheless, vascular flow quantification seems a more physiologically accurate way of measuring endovascular results. We evaluated the use of parametric color coding (PCC) with digital subtraction angiography (DSA), in order to determine the feasibility of PCC to detect and measure the impact of AVM endovascular treatment-induced changes using real-time hemodynamic parameters. Methods and results Supratentorial brain AVM treatment was evaluated in 29 patients over the course of 38 sessions. Using regions of interest (ROIs) at the carotid siphon, arterial feeder, drainage vein and venous sinus, we found significant increase in time to peak (TTP) values at the arterial feeder, drainage vein and venous sinus. We compared TTP in four different embolization volume groups: I (0-25%), II (26-50%), III (51-75%) and IV (76-100%). We found significant differences between groups and a moderate correlation between embolization percentages, as well as an increase in TTP at the main vein ROI; but not in the arterial side or sinus. Conclusions Brain AVM endovascular treatment results can be quantified in vivo with PCC. PCC is capable of detecting hemodynamic changes after brain AVM endovascular treatment, that may reflect flow drop, and it is correlated with volume embolization.
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Embolização Terapêutica/métodos , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Malformações Arteriovenosas Intracranianas/terapia , Adulto , Angiografia Digital , Angiografia Cerebral , Feminino , Hemodinâmica/fisiologia , Humanos , Malformações Arteriovenosas Intracranianas/fisiopatologia , Masculino , Interpretação de Imagem Radiográfica Assistida por Computador , Estudos Retrospectivos , Resultado do TratamentoRESUMO
A nitrifying consortium was kinetically, stoichiometrically and molecularly characterized via the in situ pulse respirometric method and pyrosequencing analysis before and after the addition of m-cresol (25 mg C L-1) in a sequencing batch reactor (SBR). Five important kinetic and stoichiometric parameters were determined: the maximum oxygen uptake rate, the maximum nitrification rate, the oxidation yield, the biomass growth yield, and the substrate affinity constant. An inhibitory effect was observed in the nitrification process with a recovery of this by up to eight SBR cycles after m-cresol was added to the system. However, full recovery of the nitrification process was not observed, as the maximum oxygen uptake rate was 25% lower than that of the previous operation without m-cresol addition. Furthermore, the pyrosequencing analyses of the nitrifying consortium after the addition of only two pulses of 25 mg C L-1 m-cresol showed an important microbial community change represented by a decrease in the nitrifying populations and an increase in the populations degrading phenolic compounds.
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Bactérias/metabolismo , Reatores Biológicos , Cresóis/farmacologia , Esgotos , Bactérias/genética , Biodegradação Ambiental , Biomassa , NitrificaçãoRESUMO
BACKGROUND: Functional recovery after aneurysmal subarachnoid hemorrhage (SAH) remains a significant problem. We tested a novel therapeutic approach with long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) to assess the safety and feasibility of an effectiveness trial. METHODS: We conducted a multicentre, parallel, randomized, open-label pilot trial. Patients admitted within 72 hours after SAH with modified Fisher scale scores of 3 or 4 who were selected for scheduled aneurysm clipping were allocated to receive either n-3 PUFA treatment (parenteral perioperative: 5 days; oral: 8 weeks) plus usual care or usual care alone. Exploratory outcome measures included major postoperative intracranial bleeding complications (PIBCs), cerebral infarction caused by delayed cerebral ischemia, shunt-dependent hydrocephalus, and consent rate. The computed tomography evaluator was blinded to the group assignment. RESULTS: Forty-one patients were randomized, but one patient had to be excluded after allocation. Twenty patients remained for intention to treat analysis in each trial arm. No PIBs (95% confidence interval [CI]: 0.00 to 0.16) or other unexpected harm were observed in the intervention group (IG). No patient suspended the intervention due to side effects. There was a trend towards improvements in all benefit-related outcomes in the IG. The overall consent rate was 0.91 (95% CI: 0.78 to 0.96), and there was no consent withdrawal. CONCLUSIONS: Although the balance between the benefit and harm of the intervention appears highly favourable, further testing on SAH patients is required. We recommend proceeding with amendments in a dose-finding trial to determine the optimal duration of parenteral treatment.
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A siphon is a device that is used to drain a container, with water rising inside a hose in the form of an inverted U and then going down towards a discharge point placed below the initial water level. The siphon is the first of a number of inventions of the ancients documented about 2.000 years ago by Hero of Alexandria in his treatise Pneumatics, and although the explanation given by Hero was essentially correct, there is nowadays a controversy about the underlying mechanism that explains the working of this device. Discussions concerning the physics of a siphon usually refer to concepts like absolute negative pressures, the strength of liquid's cohesion and the possibility of a siphon working in vacuum or in the presence of bubbles. Torricelli understood the working principle of the barometer and the impossibility of pumping water out of wells deeper than 10.33 m. Following Torricelli's ideas it would also not be possible to build a siphon that drives pure water to ascend higher than 10.33 m. In this work, we report the first siphon that drives water (with surfactant) to ascend higher than the Torricellian limit. Motivated by the rising of sap in trees, we built a 15.4 m siphon that shows that absolute negative pressures are not prohibited, that cohesion plays an important role in transmitting forces through a fluid, and that surfactants can help to the transport of water in a metastable regime of negative pressures.
Assuntos
Modelos Teóricos , Pressão , ÁguaRESUMO
Background: Early mobilization in intensive care units (ICU) provides respiratory, neurological and cardiovascular benefits in hospitalized patients. However, the orthostatic effects of changing from a supine to a sitting position may interfere with cerebral hemodynamics of patients with aneurysmal subarachnoid hemorrhage (aSAH). Aim: To describe the changes in mean cerebral blood flow velocity (MCBFV) in supine and sitting position, in adult patients with aSAH, with asymptomatic vasospasm (AVS) or without vasospasm (VS) at a neurosurgical ICU. Material and Methods: Descriptive case series study in 21 patients with aSAH, both with and without VS. They were positioned in a supine 30° position and then seated at the edge of bed for six minutes. MCBFV was measured by transcranial Doppler (TCD), and hemodynamic variables in both positions were registered. After this basal assessment and for 21 days after the episode of SAH, patients were seated once a day and signs of VS were recorded. Results: No significant changes in MCBFV or hemodynamic variables were detected during position changes, except for an increase in heart rate in the sitting position. No patient with AVS at the onset, had symptomatic VS during the 21 days of follow up when patients were seated. Among patients with a normal MCBFV at baseline, five patients (24%) had VS at a mean of three days after the first time that they were seated on the edge of bed. Conclusions: Sitting patients at the edge of the bed is a safe mobilization alternative for patients who suffered aSAH who did not have VS or had AVS.