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Stress is the body's physiological reaction to a dangerous or threatening situation, leading to a state of alertness. This reaction is necessary for developing an effective adaptive response to stress and maintaining the body's homeostasis. Chronic stress, caused mainly by social stress, is what primarily affects the world's population. In the last decades, the emergence of psychological disorders in humans has become more frequent, and one of the symptoms that can be observed is aggressiveness. In the brain, stress can cause neuronal circuit alterations related to the action of hormones in the central nervous system. Leptin, for example, is a hormone capable of acting in brain regions and neuronal circuits important for behavioral and emotional regulation. This study investigated the correlation between chronic social stress, neuroendocrine disorders, and individual behavioral changes. Then, leptin and its receptors' anatomical distribution were evaluated in the brains of mice subjected to a protocol of chronic social stress. The model of spontaneous aggression (MSA) is based on grouping young mice and posterior regrouping of the same animals as adults. According to the regrouping social stress, we categorized the mice into i) harmonic, ii) attacked, and iii) aggressive animals. For leptin hormone evaluation, we quantified plasma and brain concentrations by ELISA and evaluated its receptor and isoform expression by western blotting. Moreover, we verified whether stress or changes in leptin levels interfered with the animal's body weight. Only attacked animals showed reduced plasma leptin concentration and weight gain, besides a higher expression of the high-molecular-weight leptin receptor in the amygdala and the low-molecular-weight receptor in the hippocampal region. Aggressive animals showed a reduction in the cerebral concentration of leptin in the hippocampus and a reduced high-and low-molecular-weight leptin receptor expression in the amygdala. The harmonic animals showed a reduction in the cerebral concentration of leptin in the pituitary and a reduced expression of the high-molecular-weight leptin receptor in the amygdala. We then suggest that leptin and its receptors' expression in plasma and specific brain areas are involved in how individuals react in stressful situations, such as regrouping stress in MSA.
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Leptina , Receptores de Leptina , Adulto , Animales , Ratones , Peso Corporal , Leptina/metabolismo , Conducta Social , Estrés Psicológico/metabolismoRESUMEN
OBJECTIVE: The objective of this study was to determine how arch form and interproximal contact size displace mandibular teeth subjected to an anterior component of force (ACF). METHODS: Nine finite element models (FEM) of the mandibular arch were developed using Ansys® v. 16.0 software. They were designed to evaluate the effects of three arch forms (triangular, oval, and square) and three contact sizes (point-to-point, 1 mm diameter, and 2 mm diameter). All nine models were subjected to an ACF of 53.8 N (5486 gm). Three-dimensional tooth rotations and displacements of the mandibular teeth were evaluated, from the right first molar to the left first molar. RESULTS: Arch form had a greater effect on tooth movements than contact size. Triangular arches and point-to-point contacts produced the greatest displacements and rotations of teeth. Oval arches with 2 mm wide interproximal contact points showed the greatest stability. The right first premolar showed the greatest displacements in all of the models. CONCLUSIONS: Arch form and contact size affect interproximal tooth stability. Teeth are least stable in narrow arches with point-to-point interproximal contacts, and most stable in wider arches with larger contacts.
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Diente Molar , Programas Informáticos , Análisis de Elementos Finitos , Técnicas de Movimiento DentalRESUMEN
ABSTRACT Objective: The objective of this study was to determine how arch form and interproximal contact size displace mandibular teeth subjected to an anterior component of force (ACF). Methods: Nine finite element models (FEM) of the mandibular arch were developed using Ansys® v. 16.0 software. They were designed to evaluate the effects of three arch forms (triangular, oval, and square) and three contact sizes (point-to-point, 1 mm diameter, and 2 mm diameter). All nine models were subjected to an ACF of 53.8 N (5486 gm). Three-dimensional tooth rotations and displacements of the mandibular teeth were evaluated, from the right first molar to the left first molar. Results: Arch form had a greater effect on tooth movements than contact size. Triangular arches and point-to-point contacts produced the greatest displacements and rotations of teeth. Oval arches with 2 mm wide interproximal contact points showed the greatest stability. The right first premolar showed the greatest displacements in all of the models. Conclusions: Arch form and contact size affect interproximal tooth stability. Teeth are least stable in narrow arches with point-to-point interproximal contacts, and most stable in wider arches with larger contacts.
RESUMO Objetivo: O objetivo deste estudo foi determinar como o formato da arcada e o tamanho do contato interproximal deslocam os dentes inferiores submetidos a um componente anterior de força (CAF). Métodos: Nove modelos de elementos finitos (MEF) da arcada inferior foram desenvolvidos utilizando o software Ansys® v. 16.0. Eles foram projetados para avaliar os efeitos de três formatos de arcada (triangular, oval e quadrado) e três tamanhos de contato interproximal (ponto a ponto, 1 mm de diâmetro e 2 mm de diâmetro). Todos os nove modelos foram submetidos a um CAF de 53,8 N (5486 gm). Foram avaliados tridimensionalmente as rotações dentárias e os deslocamentos dos dentes inferiores, do primeiro molar direito ao primeiro molar esquerdo. Resultados: A forma da arcada teve um efeito maior no movimento dos dentes do que o tamanho do contato interproximal. Arcadas triangulares e contatos ponto a ponto produziram os maiores deslocamentos e rotações dos dentes. Arcadas ovais com pontos de contato interproximal de 2 mm de largura apresentaram maior estabilidade. O primeiro pré-molar direito apresentou os maiores deslocamentos em todos os modelos. Conclusões: O formato da arcada e o tamanho do contato interproximal afetam a estabilidade dos dentes. Os dentes foram menos estáveis nas arcadas estreitas com contatos interproximais ponto a ponto, e mais estáveis nas arcadas mais largas com contatos maiores.
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PURPOSE: To investigate the effect of systemic arterial blood pressure (BP) on rates of progressive structural damage over time in glaucoma. DESIGN: Retrospective cohort study. PARTICIPANTS: A total of 7501 eyes of 3976 subjects with glaucoma or suspected of glaucoma followed over time from the Duke Glaucoma Registry. METHODS: Linear mixed models were used to investigate the effects of BP on the rates of retinal nerve fiber layer (RNFL) loss from spectral-domain OCT (SD-OCT) over time. Models were adjusted for intraocular pressure (IOP), gender, race, diagnosis, central corneal thickness (CCT), follow-up time, and baseline disease severity. MAIN OUTCOME MEASURE: Effect of mean arterial pressure (MAP), systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) on rates of RNFL loss over time. RESULTS: A total of 157 291 BP visits, 45 408 IOP visits, and 30 238 SD-OCT visits were included. Mean rate of RNFL change was -0.70 µm/year (95% confidence interval, -0.72 to -0.67 µm/year). In univariable models, MAP, SAP, and DAP during follow-up were not significantly associated with rates of RNFL loss. However, when adjusted for mean IOP during follow-up, each 10 mmHg reduction in mean MAP (-0.06 µm/year; P = 0.007) and mean DAP (-0.08 µm/year; P < 0.001) but not SAP (-0.01 µm/year; P = 0.355) was associated with significantly faster rates of RNFL thickness change over time. The effect of the arterial pressure metrics remained significant after additional adjustment for baseline age, diagnosis, sex, race, follow-up time, disease severity, and corneal thickness. CONCLUSIONS: When adjusted for IOP, lower MAP and DAP during follow-up were significantly associated with faster rates of RNFL loss, suggesting that levels of systemic BP may be a significant factor in glaucoma progression.
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Presión Sanguínea/fisiología , Glaucoma/diagnóstico , Glaucoma/fisiopatología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Presión Arterial/fisiología , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Presión Intraocular/fisiología , Masculino , Persona de Mediana Edad , Fibras Nerviosas/patología , Hipertensión Ocular/fisiopatología , Sistema de Registros , Células Ganglionares de la Retina/patología , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Tonometría OcularRESUMEN
Aggression is defined as hostile behavior that results in psychological damage, injury and even death among individuals. When aggression presents itself in an exacerbated and constant way, it can be considered escalating or pathological. The association between social stress and the emergence of exacerbated aggressiveness is common and is suggested to be interconnected through very complex neurobiological factors. For example, alterations in the expression of the dopaminergic receptors D1 and D2, reactive oxygen species (ROS) and the c-Fos protein in the cortex have been observed. Our objective was to analyze which factors are involved at the neurobiological level in the highly aggressive response of Swiss Webster adult male mice in a vivarium. In this work, we investigated the relationship among dopaminergic receptors, the production of ROS and the expression of c-Fos. Mice with exacerbated aggression were identified by the model of spontaneous aggression (MSA) based on the grouping of young mice and the regrouping of the same animals in adulthood. During the regrouping, we observed different categories of behavior resulting from social stress, such as (i) highly aggressive animals, (ii) defeated animals, and (iii) harmonic groups. To evaluate the dopaminergic system and the c-Fos protein, we quantified the expression of D1 and D2 dopaminergic receptors by Western blotting and fluorescence immunohistochemistry and that of the c-Fos protein by fluorescence immunohistochemistry. The possible production of ROS was also evaluated through the dihydroethidium (DHE) assay. The results showed that aggressive and subordinate mice showed a reduction in the expression of the D1 receptor, and no significant difference in the expression of the D2 receptor was observed between the groups. In addition, aggressive mice exhibited increased production of ROS and c-Fos protein. Based on our results, we suggest that exacerbated aggression is associated with social stress, dysregulation of the dopaminergic system and exacerbated ROS production, which leads to a state of cellular oxidative stress. The overexpression of c-Fos due to social stress suggests an attempt by the cell to produce antioxidant agents to reduce the toxic cellular concentration of ROS.
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PURPOSE: To investigate the impact of intraocular pressure (IOP) control on rates of change of spectral-domain OCT (SD-OCT) retinal nerve fiber layer (RNFL) thickness in a large clinical population. DESIGN: Retrospective cohort study. PARTICIPANTS: A total of 85 835 IOP measurements and 60 223 SD-OCT tests from 14 790 eyes of 7844 patients. METHODS: Data were extracted from the Duke Glaucoma Registry, a large database of electronic medical records of patients with glaucoma and suspected disease followed over time at the Duke Eye Center and satellite clinics. All records from patients with a minimum of 6 months of follow-up and at least 2 good-quality SD-OCT scans and 2 clinical visits with Goldmann applanation tonometry were included. Eyes were categorized according to the frequency of visits with IOP below cutoffs of 21 mmHg, 18 mmHg, and 15 mmHg over time. Rates of change for global RNFL thickness were obtained using linear mixed models and classified as slow if change was slower than -1.0 µm/year; moderate if between -1.0 and -2.0 µm/year; and fast if faster than -2.0 µm/year. Multivariable models were adjusted for age, gender, race, diagnosis, central corneal thickness, follow-up time, and baseline disease severity. MAIN OUTCOME MEASURES: Rates of change in SD-OCT RNFL thickness according to levels of IOP control. RESULTS: Eyes had a mean follow-up of 3.5±1.9 years. Average rate of change in RNFL thickness was -0.68±0.59 µm/year. Each 1 mmHg higher mean IOP was associated with 0.05 µm/year faster RNFL loss (P < 0.001) after adjustment for potentially confounding variables. For eyes that had fast progression, 41% of them had IOP <21 mmHg in all visits during follow-up, whereas 20% of them had all visits with IOP <18 mmHg, but only 9% of them had all visits with IOP <15 mmHg. CONCLUSIONS: Intraocular pressure was significantly associated with rates of progressive RNFL loss in a large clinical population. Eyes with stricter IOP control over follow-up visits had a smaller chance of exhibiting fast deterioration. Our findings may assist clinicians in establishing target pressures in clinical practice.
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Glaucoma/diagnóstico , Presión Intraocular/fisiología , Vigilancia de la Población/métodos , Células Ganglionares de la Retina/patología , Tomografía de Coherencia Óptica/métodos , Tonometría Ocular/métodos , Campos Visuales , Anciano , Femenino , Estudios de Seguimiento , Glaucoma/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) patients can progress to cirrhosis. In these, there is a compensated stage in which esophageal varices can exist. However, no more than 20% of these patients have varices needing treatment (VNT). OBJECTIVE: Evaluate the accuracy of non-invasive models to predict esophageal varices, as well as their performance to avoid esophagogastroduodenoscopy (EGD) with a risk of missing VNT of less than 5%, in Brazilian patients with compensated advanced chronic liver disease (cACLD) secondary to NAFLD. METHODS: Twenty-one patients with biopsy-proven cACLD secondary to NAFLD were submitted to liver stiffness measurement (LSM) by transient elastography (TE), and data were collected to measure platelet count/spleen diameter ratio (PSR), LSM-spleen diameter to platelet ratio score (LSPS), varices risk score (VRS), Baveno VI, Expanded Baveno VI and NAFLD cirrhosis criteria. RESULTS: The mean age was 61 (±6.6) years, and 81% were female; 14% presented VNT. For detection of VNT, LSPS and VRS performed excellently, with an area under receiver operating characteristic (AUROC) of 0.961 for both. LSM presented an AUROC of 0.889 and a cutoff point of 21.8â¯kPa. LSPS and VRS enabled sparing 75-80% of EGDs for VNT, with no risk of missing varices. Expanded Baveno VI enabled sparing 71% of EGDs, with 4.8% risk of missing VNT. CONCLUSION: LSPS and VRS performed excellently in both predicting VNT and sparing EGD, and Expanded Baveno VI showed good performance in sparing EGDs, with acceptable risk of missing VNT. An LSM cutoff point was established and had good performance.
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Várices Esofágicas y Gástricas/diagnóstico , Várices Esofágicas y Gástricas/etiología , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Anciano , Brasil , Enfermedad Crónica , Estudios Transversales , Diagnóstico por Imagen de Elasticidad , Endoscopía del Sistema Digestivo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recuento de Plaquetas , Valor Predictivo de las Pruebas , Curva ROCRESUMEN
Bone presents different systemic functionalities as calcium phosphate reservoir, organ protection, among others. For that reason, the bone health conditions are essential to keep in equilibrium the metabolism of several body systems. Different technologies exist to diagnose bone conditions with invasive methods based on ionizing radiation. Therefore, there is a challenge to develop new ways to evaluate bone alterations in a noninvasive form. This study shows the assessment of a piezo-actuated device acting on a human tooth for the bio-monitoring of bone alterations. The bone diagnosis is performed by applying the electromechanical impedance technique (EMI), commonly used in structural health monitoring. For the experimental tests, five bone samples were prepared, and one was chosen as the monitoring. All samples were put in a decalcifying substance (TBD1 acid-base) at different times to emulate localized bone mineral alterations. Bone reductions were computed by using X-ray micro-computed tomography analyzing the morphometry. Electrical resistance measurements (piezo-device) were taken for the monitoring specimen meanwhile it was partially decalcified during 8520 seconds. In the frequency spectrum, several observation windows showed that the bone alterations gradually changed the electrical resistance signals which were quantified statistically. Results evidenced that the bone density changes are correlated with the electrical resistance measurements; these changes presented an exponential behavior as much as in the calculated index, and bone mineral reduction. The results demonstrated that bone alterations exhibit linear dependence with the computed statistical indexes. This result confirms that it is possible to observe the bone changes from the teeth as a future application.
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[This corrects the article DOI: 10.1007/s13534-020-00170-9.].
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PURPOSE: To compare the diagnostic performance of human gradings vs predictions provided by a machine-to-machine (M2M) deep learning (DL) algorithm trained to quantify retinal nerve fiber layer (RNFL) damage on fundus photographs. DESIGN: Evaluation of a machine learning algorithm. METHODS: An M2M DL algorithm trained with RNFL thickness parameters from spectral-domain optical coherence tomography was applied to a subset of 490 fundus photos of 490 eyes of 370 subjects graded by 2 glaucoma specialists for the probability of glaucomatous optical neuropathy (GON), and estimates of cup-to-disc (C/D) ratios. Spearman correlations with standard automated perimetry (SAP) global indices were compared between the human gradings vs the M2M DL-predicted RNFL thickness values. The area under the receiver operating characteristic curves (AUC) and partial AUC for the region of clinically meaningful specificity (85%-100%) were used to compare the ability of each output to discriminate eyes with repeatable glaucomatous SAP defects vs eyes with normal fields. RESULTS: The M2M DL-predicted RNFL thickness had a significantly stronger absolute correlation with SAP mean deviation (rho=0.54) than the probability of GON given by human graders (rho=0.48; P < .001). The partial AUC for the M2M DL algorithm was significantly higher than that for the probability of GON by human graders (partial AUC = 0.529 vs 0.411, respectively; P = .016). CONCLUSION: An M2M DL algorithm performed as well as, if not better than, human graders at detecting eyes with repeatable glaucomatous visual field loss. This DL algorithm could potentially replace human graders in population screening efforts for glaucoma.
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Aprendizaje Profundo , Glaucoma de Ángulo Abierto/diagnóstico , Fibras Nerviosas/patología , Enfermedades del Nervio Óptico/diagnóstico , Examen Físico , Células Ganglionares de la Retina/patología , Anciano , Algoritmos , Área Bajo la Curva , Estudios Transversales , Femenino , Fondo de Ojo , Glaucoma de Ángulo Abierto/diagnóstico por imagen , Gonioscopía , Humanos , Presión Intraocular/fisiología , Masculino , Persona de Mediana Edad , Enfermedades del Nervio Óptico/diagnóstico por imagen , Fotograbar , Curva ROC , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Trastornos de la Visión/diagnóstico , Pruebas del Campo Visual/métodos , Campos Visuales/fisiologíaRESUMEN
Bone is a dynamic biological tissue that acts as the primary rigid support of the body. Several systemic factors are responsible for pathologies that negatively affect its structural attributes. Although the bone is in continuous renewal by osteogenesis, metabolic diseases are the most common affectations that alter its natural equilibrium. Different techniques based on ionizing radiation are used for the bone diagnosis restrictively. However, if these are not used adequately, the application could present risks for human health. In this paper, it is proposed and explored a new technique to apply an early-stage diagnosis of bone variations. The technique evaluates bone structural conditions from the teeth (used as probes) by applying a structural health monitoring (SHM) methodology. An experimental procedure is described to identify the stiffness variations produced by mechanical drillings done in prepared bone samples. The identification is carried out applying the electromechanical impedance technique (EMI) through a piezo-actuated device in the frequency spectrum 5-20kHz. Three bone samples with incorporated teeth (three teeth, two teeth, and one tooth) were prepared to emulate a mandibular portion of alveolar bone-PDL (periodontal ligament)-tooth system. Piezo-device was attached to the crown of the tooth with an orthodontic bracket allowing the teeth to act as probes. The electrical resistance measurements were computed with an electrical decoupling approach that improved the detection of the drillings; it was due to the increment of the sensitivity of the signals. The results showed that the bone mass reduction is correlated with statistical indices obtained in specific frequency intervals of the electrical resistance. This work suggests the possibility of a future application addressed to a bone diagnosis in a non-invasive way.
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Densidad Ósea , Diente , Impedancia Eléctrica , Humanos , Mandíbula/diagnóstico por imagen , Ligamento Periodontal , Diente/diagnóstico por imagenRESUMEN
OBJECTIVE: To determine the impact of damaging genetic variation in proangiogenic pathways on placental function, complications of pregnancy, fetal growth, and clinical outcomes in pregnancies with fetal congenital heart defect. STUDY DESIGN: Families delivering a baby with a congenital heart defect requiring surgical repair in infancy were recruited. The placenta and neonate were weighed and measured. Hemodynamic variables were recorded from a third trimester (36.4 ± 1.7 weeks) fetal echocardiogram. Exome sequencing was performed on the probands (N = 133) and consented parents (114 parent-child trios, and 15 parent-child duos) and the GeneVetter analysis tool used to identify damaging coding sequence variants in 163 genes associated with the positive regulation of angiogenesis (PRA) (GO:0045766). RESULTS: In total, 117 damaging variants were identified in PRA genes in 133 congenital heart defect probands with 73 subjects having at least 1 variant. Presence of a damaging PRA variant was associated with increased umbilical artery pulsatility index (mean 1.11 with variant vs 1.00 without; P = .01). The presence of a damaging PRA variant was also associated with lower neonatal length and head circumference for age z score at birth (mean -0.44 and -0.47 with variant vs 0.23 and -0.05 without; P = .01 and .04, respectively). During median 3.1 years (IQR 2.0-4.1 years) of follow-up, deaths occurred in 2 of 60 (3.3%) subjects with no PRA variant and in 9 of 73 (12.3%) subjects with 1 or more PRA variants (P = .06). CONCLUSIONS: Damaging variants in proangiogenic genes may impact placental function and are associated with impaired fetal growth in pregnancies involving a fetus with congenital heart defect.
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Proteínas Angiogénicas/genética , Desarrollo Fetal/genética , Variación Genética/genética , Cardiopatías Congénitas/genética , Complicaciones del Embarazo/etiología , Estudios de Casos y Controles , Femenino , Cardiopatías Congénitas/diagnóstico , Cardiopatías Congénitas/cirugía , Humanos , Recién Nacido , Masculino , EmbarazoRESUMEN
This study exposes the assessment of a piezo-actuated sensor for monitoring elastic variations (change in Young's modulus) of a host structure in which it is attached. The host structure is monitored through a coupling interface connected to the piezo-actuated device. Two coupling interfaces were considered (an aluminum cone and a human tooth) for the experimental tests. Three different materials (aluminum, bronze and steel) were prepared to emulate the elastic changes in the support, keeping the geometry as a fixed parameter. The piezo device was characterized from velocity frequency response functions in pursuance to understand how vibration modes stimulate the electrical resistance through electrical resonance peaks of the sensor. An impedance-based analysis (1â»20 kHz) was performed to correlate elastic variations with indexes based on root mean square deviation (RMSD) for two observation windows (9.3 to 9.7 kHz and 11.1 to 11.5 kHz). Results show that imposed elastic variations were detected and quantified with the electrical resistance measurements. Moreover, it was demonstrated that the sensitivity of the device was influenced by the type of coupling interface since the cone was more sensitive than the tooth in both observation windows. As a final consideration, results suggest that bio-structures (fruits and bone, among others) could be studied since these can modify naturally its elastic properties.
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Introducción: La fibrilación auricular es un serio problema de salud y los paísescentroamericanos no escapan de este flagelo. Objetivo: Caracterizar la fibrilación auricular, precisar sus variables clínico-epidemiológicas y determinar el riesgo de accidente cerebrovascular, a partir del uso dela escala CHA 2 DS 2 -VASc. Método: Se realizó un estudio descriptivo y prospectivo en 107 pacientes que in-gresaron, con diagnóstico de fibrilación auricular, en el servicio de Medicina Interna del Hospital Nacional San Rafael de la ciudad de Santa Tecla, La Libertad, El Salvador; en el período de enero a julio de 2013. Se analizaron las variables clínico-epidemiológicas, se realizó ecocardiograma a todos los pacientes y se calculó la escala de riesgo CHA 2 DS 2 -VASc. Se utilizaron métodos para establecer las relacio-nes entre las variables. Resultados: Más de la mitad de los pacientes con fibrilación auricular (57,0 por ciento; p=0,015) son mujeres, el 51,4 por ciento tiene color blanco de piel y una edad media de 74,7 ± 13,8 años. El 80,4 por ciento de los pacientes tiene una fibrilación auricular no asociada a valvulopatía. Predominaron la hipertensión arterial (54,2 por ciento), las cardiopatías isquémica (28,0 por ciento) e hipertensiva (23,4 por ciento), la miocardiopatía dilatada (24,3 por ciento) y la fibrilación auricular permanente (49,5 por ciento). Conclusiones: La menor fracción de eyección y el mayor diámetro diastólico del ventrículo izquierdo se relacionaron con la fibrilación auricular. La mayoría de los pacientes presenta un riesgo elevado de accidente cerebrovascular, las variables que se le asocian son: la mayor edad, el sexo femenino y el mayor grosor del septum interventricular(AU)
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Humanos , Adulto , Fibrilación Atrial , Accidente Cerebrovascular , AnticoagulantesRESUMEN
OBJECTIVE: To determine the effects of occlusion on maximum bite force of growing subjects. MATERIALS AND METHODS: Incisor and first molar bite force of children and adolescents was evaluated. Four cohorts were measured annually for 3 years, starting at approximately 7, 9, 12, and 15 years of age, respectively. The initial sample included 182 females and 198 males; there were 130 subjects with normal occlusion, 111 with Class I malocclusion, and 139 with Class II malocclusion. Multilevel analyses were performed to model the growth changes and compare groups. RESULTS: Maximum bite force increased significantly (P < .05) over time. Incisal forces peaked at 14.3 and 15.3 years of age for females and males, respectively. Maximum molar bite force peaked at 16 years for both males and females. Subjects with normal occlusion had significantly higher bite force than subjects with malocclusion. Maximum molar bite force exhibited a significant testing effect, with forces increasing 2.6 kg each year that the tests were repeated. CONCLUSIONS: Malocclusion has a detrimental effect on bite force. Changes in maximum bite force are also due to age, sex, and repeated testing.
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Fuerza de la Mordida , Maloclusión , Adolescente , Niño , Oclusión Dental , Femenino , Humanos , Incisivo , Masculino , Diente MolarRESUMEN
Advancing biomedical knowledge is crucial to the understanding of disease pathophysiology, diagnosis, treatment, and the maintenance of health. Whereas collaborative pursuits among basic and translational scientists, clinical researchers, and clinicians should advance biomedical progress and its translation to better medicine. The field of obstetrics and gynecology and its subspecialties has not escaped this problem. Obstetrics and gynecology specialists and subspecialists have limited opportunities to interact with translational or basic investigators, and cross-fertilization and collaborations are further challenged by the current healthcare and funding climate. This opinion manuscript focuses on the field of maternal-fetal medicine, serving as an example that illustrates the risks and opportunities that might exist within our obstetrics and gynecology academic community. A Pregnancy Task Force recently sought to identify ways to overcome hurdles related to research training, and ensure a sufficient pool of physician-scientists pursuing pertinent questions in the field. The group discussed strategies to promote a culture of intellectual curiosity and research excellence, securing additional resources for trainees, and attracting current and next generation basic, translational, and clinical scholars to our field. Recommendations encompassed activities within annual academic meetings, training initiatives, and additional funding opportunities. Inferences from these discussions can be made to all obstetrics and gynecology subspecialty areas.
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Investigación Biomédica , Ginecología/educación , Obstetricia/educación , Conducta Cooperativa , Femenino , HumanosRESUMEN
Introducción: La hipertensión arterial constituye un importante problema de salud a nivel mundial. La prehipertensión es una categoría que se ha estudiado poco en los jóvenes. Objetivo: Determinar los factores asociados a la prehipertensión arterial en jóvenes entre 20 a 25 años de edad. Método: Se realizó un estudio descriptivo y transversal a un universo constituido por 257 estudiantes de segundo año de medicina. Por muestreo aleatorio simple se escogieron 134 jóvenes entre 20 a 25 años de edad, correspondientes al curso académico 2009-2010. Resultados: Se observó una prevalencia de prehipertensión arterial de 27,6 por ciento. Los del sexo masculino (51,5 por ciento) y de color de piel blanca (59,7 por ciento) fueron los más afectados. El ambiente familiar, el antecedente personal de bajo peso al nacer (OR=2,3; p=0.179) y la edad gestacional menor de 37 semanas (OR=2,5; p=0.187) no influyeron en la posibilidad de presentar cifras prehipertensivas en los jóvenes de esta muestra. Conclusiones: El índice de masa corporal elevado (OR=34,1; p<0.001), los antecedentes familiares de hipertensión arterial (OR=12; p<0.01) y la obesidad familiar (χ2=11,19; p=0.001), fueron los factores más fuertemente asociados a la prehipertensión arterial en estos jóvenes(AU)
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Humanos , Masculino , Femenino , Adulto Joven , Hipertensión , Factores de Riesgo , Estudios Transversales/métodos , Epidemiología DescriptivaRESUMEN
INTRODUCTION: The purposes of this study were to determine (1) how masticatory performance changes with age, (2) whether masticatory performance differs between the sexes, and (3) whether patterns of masticatory performance differ among subjects with various types of malocclusion. METHODS: A total of 450 children and adolescents (244 boys, 206 girls) were assigned to 4 age cohorts (ages 6, 9, 12, and 15 years) and followed for 3 consecutive years. The subjects were selected based on having about equal numbers of boys and girls, and about equal numbers of subjects with normal occlusion and Class I and Class II malocclusions. Masticatory performance was assessed by using the artificial food CutterSil (Heraeus Kulze, South Bend, Ind). The peer assessment rating index was used to quantify the severity of the malocclusions. RESULTS: Median particle size (MPS) decreased significantly from 6 to 17 years of age. There were no statistically significant differences in MPS between the 3 occlusal groups, but there were significant sex differences, with girls having smaller MPS than boys. Multilevel analysis showed greater decreases in MPS between 6 and 9 years, and after 12 years of age, than between 9 and 12 years of age. There were no significant correlations between MPS and the weighted peer assessment rating index. MPS showed significant intercorrelations between measures of MPS obtained at years 1, 2, and 3, with correlations tending to be highest for the oldest age cohort. CONCLUSIONS: Masticatory performance improves with age, and the changes appear to be influenced by the loss of the deciduous teeth during the late mixed dentition phase of dental development. Although there are limited sex differences in masticatory performance among subjects 6 to 17 years of age, mild forms of Class I and Class II malocclusions have little or no effect on masticatory performance.
Asunto(s)
Masticación/fisiología , Adolescente , Factores de Edad , Algoritmos , Niño , Estudios de Cohortes , Oclusión Dental , Dentición Mixta , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Maloclusión Clase I de Angle/clasificación , Maloclusión Clase I de Angle/fisiopatología , Maloclusión Clase II de Angle/clasificación , Maloclusión Clase II de Angle/fisiopatología , Modelos Dentales , Tamaño de la Partícula , Factores Sexuales , SiliconasRESUMEN
INTRODUCTION: This study provides reference data and evaluates the potential of using regression models to predict maxillary and mandibular arch widths. METHODS: A total of 473 Colombian mestizos, aged 5 to 17 years, with normal occlusions and malocclusions (Class I and Class II Division 1) were evaluated. Arch widths and tooth sizes were measured on each subject's dental casts. Anthropometric measurements of body size, facial breadth, and facial height were used, along with tooth sizes, to develop multiple regressions for predicting arch widths. RESULTS: Analyses showed that Class II subjects had significantly (P < 0.05) narrower anterior maxillary widths than those with normal occlusion or Class I malocclusion. Class I subjects had narrower interpremolar widths than those with normal occlusion or Class II malocclusion. Boys had significantly (P < 0.001) wider arches than girls, especially in the posterior aspects. Older children had significantly wider arches than younger children, with intermolar and interpremolar widths having the largest and smallest age effects, respectively. Regression analyses of subjects with normal occlusion showed that 2 to 5 variables combined to explain 36% to 64% of the variation in arch widths, with the sizes of the maxillary incisors and bigonial width explaining most of the variation. CONCLUSIONS: When applied to subjects with malocclusion, the predictions indicate transverse deficiencies in the premolar region of Class I subjects and deficiencies in the anterior maxilla of Class II subjects. Predictions based on Pont's index, the Schwarz analysis, or the McNamara rule of thumb were biased and less reliable than those based on the regressions.