Happy faces selectively increase the excitability of cortical neurons innervating frowning muscles of the mouth.

Although facial muscles are heavily involved in emotional expressions, there is still a lack of evidence about the role of face primary motor cortex (face M1) in the processing of facial recognition and expression. This work investigated the effects of the passive viewing of different facial expressions on face M1 and compared data with those obtained from the hand M1. Thirty healthy subjects were randomly assigned to two groups undergoing transcranial magnetic stimulation (TMS) of face or hand M1. In both groups, short-latency intracortical inhibition (SICI) and intracortical facilitation (ICF) were probed in the depressor anguli oris (DAO) and first dorsal interosseous (FDI) muscles 300 ms after presentation of a picture of a face that expressed happy, sad or neutral emotions. Statistical analysis of SICI showed a non-significant effect of muscle (F1,28 = 1.903, p = 0.179), but a significant effect of emotion (F2,56 = 6.860, p = 0.004) and a significant interaction between muscle and emotion (F2,56 = 5.072, p = 0.015). Post hoc analysis showed that there was a significant reduction of SICI in the DAO muscle after presentation of a face with a happy expression compared with a neutral face (p < 0.001). In the FDI, a significant difference was observed between neutral and sad expressions (p = 0.010) No clear differences in ICF were detected. The different responses of face and hand muscles to emotional stimuli may be due to their functional roles in emotional expression versus protection of the body.

Use of Electroencephalography Brain-Computer Interface Systems as a Rehabilitative Approach for Upper Limb Function After a Stroke: A Systematic Review.

BACKGROUND: Brain-computer interface (BCI) systems have been suggested as a promising tool for neurorehabilitation. However, to date, there is a lack of homogeneous findings. Furthermore, no systematic reviews have analyzed the degree of validation of these interventions for upper limb (UL) motor rehabilitation poststroke. OBJECTIVES: The study aims were to compile all available studies that assess an UL intervention based on an electroencephalography (EEG) BCI system in stroke; to analyze the methodological quality of the studies retrieved; and to determine the effects of these interventions on the improvement of motor abilities. TYPE: This was a systematic review. LITERATURE SURVEY: Searches were conducted in PubMed, PEDro, Embase, Cumulative Index to Nursing and Allied Health, Web of Science, and Cochrane Central Register of Controlled Trial from inception to September 30, 2015. METHODOLOGY: This systematic review compiles all available studies that assess UL intervention based on an EEG-BCI system in patients with stroke, analyzing their methodological quality using the Critical Review Form for Quantitative Studies, and determining the grade of recommendation of these interventions for improving motor abilities as established by the Oxford Centre for Evidence-based Medicine. The articles were selected according to the following criteria: studies evaluating an EEG-based BCI intervention; studies including patients with a stroke and hemiplegia, regardless of lesion origin or temporal evolution; interventions using an EEG-based BCI to restore functional abilities of the affected UL, regardless of the interface used or its combination with other therapies; and studies using validated tools to evaluate motor function. SYNTHESIS: After the literature search, 13 articles were included in this review: 4 studies were randomized controlled trials; 1 study was a controlled study; 4 studies were case series studies; and 4 studies were case reports. The methodological quality of the included papers ranged from 6 to 15, and the level of evidence varied from 1b to 5. The articles included in this review involved a total of 141 stroke patients. CONCLUSIONS: This systematic review suggests that BCI interventions may be a promising rehabilitation approach in subjects with stroke. LEVEL OF EVIDENCE: II.

Entrenamiento de las señales corticales a través de un sistema BMI-EEG, evolución e intervención. A propósito de un caso / Training cortical signals by means of a BMI-EEG system, its evolution and intervention. A case report

Introducción. En los últimos años están incorporándose nuevas tecnologías en el tratamiento fisioterapéutico de pacientes con ictus, como las interfaces cerebro-máquina -brain-machine interface (BMI)-, capaces de detectar la intención de movimiento analizando las señales corticales por medio de diferentes técnicas, como la electroencefalografía (EEG). Estas señales se traducen en comandos con el fin de realizar una función. Caso clínico. Varón de 40 años con ictus de dos meses de evolución, en el cual se empleó un dispositivo BMI-EEG. La intención de movimiento del sujeto se analizó calculando la desincronización relacionada con el evento. La función motora del miembro superior fue evaluada con la escala de Fügl-Meyer, y el nivel de satisfacción del paciente, mediante el cuestionario QUEST 2.0. La intervención se llevó a cabo sin dificultad siendo el fisioterapeuta la interfaz. Conclusiones. Los sistemas BMI-EEG detectan cambios corticales en un sujeto con ictus subagudo. Estos cambios son coherentes con los cambios observados en escalas clínicas (AU)

Introduction. In the last years, new technologies such as the brain-machine interfaces (BMI) have been incorporated in the rehabilitation process of subjects with stroke. These systems are able to detect motion intention, analyzing the cortical signals using different techniques such as the electroencephalography (EEG). This information could guide different interfaces such as robotic devices, electrical stimulation or virtual reality. Case report. A 40 years-old man with stroke with two months from the injury participated in this study. We used a BMI based on EEG. The subject’s motion intention was analyzed calculating the event-related desynchronization. The upper limb motor function was evaluated with the Fügl-Meyer Assessment and the participant’s satisfaction was evaluated using the QUEST 2.0. The intervention using a physical therapist as an interface was carried out without difficulty. Conclusions. The BMI systems detect cortical changes in a subacute stroke subject. These changes are coherent with the evolution observed using the Fügl-Meyer Assessment (AU)

The role of the gastrointestinal epithelium as a possible pathway for the transfer of nutrients to the embryo's circulation.

The endodermal cells of the human yolk sac (YS) produce non-nucleated erythrocytes (NNEs) and numerous serum proteins that are transiently storage within the YS cavity. After their transfer via the vitelline duct to the embryo gastrointestinal lumen, the nutrients' final fate is unknown. With the aim of investigate how erythroid cells and nutrients are conveyed to embryo circulation, we studied, using a morphological and immunohistochemical approach, the embryo anatomy and the serum protein α-fetoprotein (AFP) presence, in 15 human embryos and their YS, collected from tubal pregnancies from 4 to 8 wpf. We observed at 5 wpf, a strong AFP staining in the endodermal cells of the YS, thereafter AFP was only present in the YS cavity and the gastrointestinal lumen. During 7 wpf, AFP expression declined and disappeared, concomitant with YS regression. Between 5 and 7 wpf, NNEs were observed in the gastrointestinal cavity, where they accumulate in the stomach. Here, the cells were attached to the endodermal epithelial cells or were free in the lumen. By scanning electron microscopy, we identified signs of NNEs phagocytized by endodermal cells. Those NNEs free in the lumen, after hemolysis, were probably removed by endocytosis (cell debris). Taking all together, we postulate that after reaching the endodermal epithelial cells of the stomach, nutrients are transferred to the embryo by a phagocytic/endocytic mechanism that is operative until the end of 6 wpf. After absorption, NNEs are probably degraded within phagosomes, nutrients delivered to the cell cytoplasm and then transported towards the embryonic circulation.

Quantitative description of the morphology and ossification center in the axial skeleton of 20-week gestation formalin-fixed human fetuses using magnetic resonance images.

OBJECTIVES: Human tissues are usually studied using a series of two-dimensional visualizations of in vivo or cutout specimens. However, there is no precise anatomical description of some of the processes of human fetal development. The purpose of our study is to develop a quantitative description of the normal axial skeleton by means of high-resolution three-dimensional magnetic resonance (MR) images, collected from six normal 20-week-old human fetuses fixed in formaldehyde. METHODS: Fetuses were collected after spontaneous abortion and subsequently fixed with formalin. They were imaged using a 1.5 T MR scanner with an isotropic spatial resolution of 200 µm. The correct tissue discrimination between ossified and cartilaginous bones was confirmed by comparing the images achieved by MR scans and computerized axial tomographies. The vertebral column was segmented out from each image using a specially developed semi-automatic algorithm. RESULTS: Vertebral body dimensions and inter-vertebral distances were larger in the lumbar region, in agreement with the beginning of the ossification process from the thoracolumbar region toward the sacral and cephalic ends. CONCLUSION: In this article, we demonstrate the feasibility of using MR images to study the ossification process in formalin-fixed fetal tissues. A quantitative description of the ossification centers of vertebral bodies and arches is presented.

CXCR7 protein is not expressed on human or mouse leukocytes.

Since the discovery that CXCR7 binds to CXCL12/SDF-1α, the role of CXCR7 in CXCL12-mediated biological processes has been under intensive scrutiny. However, there is no consensus in the literature on the expression of CXCR7 protein by peripheral blood cells. In this study we analyzed human and mouse leukocytes and erythrocytes for CXCR7 protein expression, using a competitive CXCL12 binding assay as well as by flow cytometry and immunohistochemistry using multiple CXCR7 Abs. CXCR7(-/-) mice were used as negative controls. Together, these methods indicate that CXCR7 protein is not expressed by human peripheral blood T cells, B cells, NK cells, or monocytes, or by mouse peripheral blood leukocytes. CXCR7 protein is, however, expressed on mouse primitive erythroid cells, which supply oxygen to the embryo during early stages of development. These studies therefore suggest that, whereas CXCR7 protein is expressed by primitive RBCs during murine embryonic development, in adult mammals CXCR7 protein is not expressed by normal peripheral blood cells.

Two different pathways for the transport of primitive and definitive blood cells from the yolk sac to the embryo in humans.

During the early human embryonic period nutrients and blood cells are temporarily provided by the extraembryonic yolk sac (YS). The YS before week six is involved not only in primitive but also in definitive erythropoiesis. While the destiny of primitive erythroid cells that fill the blood vessels of the YS is well known, the final destination of erythrocytes present in the endodermal vesicular system is unknown. In the present study we have investigated, step by step, the destiny of the erythrocytes present in the endodermal vesicles during the embryonic period. Twelve human YSs and their corresponding yolk stalks were analyzed between weeks 4 and 7 of embryonic age by light and scanning electron microscopy. It is shown that erythrocytes (according to their size and morphological features) located within the endodermal vesicles of the YS wall are pulled out through endodermal pits into the YS cavity, from where they reach the lumen of the primitive gut of the embryo through the vitelline duct, a temporary pathway communicating both compartments. During the study period no erythrocytes were seen within the embryo's vascular network where only primitive erythroblasts were identified. Our results indicate that the vitelline duct plays an important transient role as a pathway for the transport of nutrients and blood cells between the YS and the embryo before week five of embryonic development that ends just at the time when YS-embryo circulation becomes established.

Budding and direct division of adult human erythrocytes in serum-free cultures.

This paper documents the budding and division process of human erythrocytes in vitro using time-lapse light microscopy of hanging-drop preparations. The erythrocytes were prepared from normal adult human peripheral blood. Red blood cells showed cytoplasmic budding, segmentation, and direct division with delayed addition of erythropoietin in serum-free Dulbecco's modified Eagle's medium/nutrient mixture F-12 Ham. These observations are thought to be useful for developing model of definitive erythropoiesis and simple expansion of human erythrocytes.

Embryonic erythropoiesis in human yolk sac: two different compartments for two different processes.

The wall of 12 yolk sacs (YSs) from 17- to 50-day-old human embryos was examined by light, scanning, and transmission electron microscopy to identify the ontogeny of embryonic erythropoiesis. Initial formation of blood island with the generation of erythroid and endothelial cells was seen in the mesenchymal layer in embryos aged 17 days. A network of blood vessels containing abundant erythroblasts was identified in the YS walls of embryos aged approximately 24 days. At this age, erythroblasts were also identified within the embryo body. Primitive erythroblasts were the only cells present within the embryo and its YS until the end of week 5. These cells first appeared in the mesenchymal vascular plexus of the YS wall, and were then observed in the liver and other tissues of the embryo. At embryonic week 5, two compartments were identified in the YS wall; a mesodermal one in which blood vessels were formed, and an endodermal compartment in which erythrocytes were present within the endodermal vesicles. Erythrocytes were small non-nucleated cells similar to adult erythrocytes. Transmission electron microscopic observation focused on the endodermal vesicles confirmed the presence of definitive erythrocytes only at such extra vascular location. At this age, there were no definitive erythrocytes detected within the embryo. Erythrocytes started to be identified in embryonic blood vessels from week 7 onward. These findings provide information not previously described about YS erythropoiesis during early human development.

Histochemical study of the definitive erythropoietic foci in the chicken yolk sac.

It is well known that avian yolk sac is involved in both primitive and definitive erythropoiesis during embryonic development. Definitive erythropoiesis is first detected at about 4-5 days incubation and its maximum activity is reached between day 10 and 15 of incubation, ending between days 18 and 20 of incubation. We confirmed the definitive erythropoietic foci in the chicken yolk sac throughout the 5th to 19th day of incubation by histochemical light and electron microscopy. The definitive erythropoietic foci were observed in the yolk sac endodermal layer from day 5 until day 19, just before hatching. Ultrastructurally, definitive erythropoietic foci were observed extravascularly in the yolk sac endodermal cell layer in direct contact with the vitellolysis zone. These findings provide a basis for clarifying definitive erythropoiesis in vertebrates.

Presence of erythrocytes in the villous trophoblast cell layer of normal first trimester and term human placentae.

Light and electron microscopic examination of first-trimester and term human placental tissues were performed to identify erythrocytes containing hemoglobin in the villous trophoblast cell layer. Erythrocytes were not identified in chorionic villous epithelium at week 7 of gestation. These cells first appeared in the villous cytotrophoblast at week 8, and continued to be present in the villous cytotrophoblast until week 9, as shown by benzidine staining. At week 12 gestation, a cluster of erythrocytes was present in a villous syncytial sprout. At 40 and 41 weeks gestation, erythrocytes were located in the villous cytotrophoblast cell layer. Electron microscopic observations focused on the cytoplasm of villous cytotrophoblast at week 8, the syncytial sprout at week 12 and the cytotrophoblast cell layer at term, confirmed the presence of erythrocytes at an extravascular location, as observed by light microscopy.

Migration of human and mouse primordial germ cells and colonization of the developing ovary: an ultrastructural and cytochemical study.

This review is an account of the origin and migratory events of primordial germ cells until their settlement in the gonad before sexual differentiation in the human as well as mice. In this context, the morphodynamic characteristics of the migration of the primordial germ cells, the macromolecular characteristics of the extracellular matrix of the migratory pathway, and the factors involved in the germ cell guidance have been analyzed and discussed in the light of recent advances in this field, by means of immunocytochemical procedures. The events prior to gonadal morphogenesis and the origin of the somatic cell content of the human gonadal primordium have been also analyzed. In particular, evidences are presented showing that cells derived from the coelomic epithelium and mesenchyme are at the origin of the somatic components of the gonadal primordium, and that a mesonephric cell contribution to the generation of somatic cell components of the genital ridge in humans should be discarded due to the morphological stability of the different nephric structures during the period preceding the sexual differentiation of the gonad.

Modulation of hyaluronan in the migratory pathway of mouse primordial germ cells.

In the present report we followed the distribution of hyaluronan during the phases of separation, migration, and colonization of the primordial germ cell migratory process. Hyaluronan was detected by the use of two cytochemical methods: (1) ruthenium hexammine trichloride (RHT) associated with enzymatic treatment with hyaluronate lyase and (2) a binding specific probe for hyaluronan. After RHT treatment the proteoglycans and/or glycosaminoglycans were observed as a meshwork formed by electron-dense granules connected by thin filaments. After enzymatic digestion, no filaments could be detected in the migratory pathway. Quantitative analysis showed a close correlation between cell migration and the concentration of RHT-positive filaments. It was also shown that high amounts of hyaluronan were expressed in the separation phase and migration phases whereas during the colonization phase the amount of hyaluronan was clearly diminished. This study showed that the presence of primordial germ cells in each compartment of the migratory pathway was always accompanied by a high expression of hyaluronan. These results indicate that hyaluronan is an important molecule in the migratory process, providing the primordial germ cells with a hydrated environment that facilitates their movement toward the genital ridges.

Reconstrucción tridimensional de la mano de un embrión humano de 43 días: evaluación experimental, teoría y metodología / Three-dimensional reconstruction of the hand of a human embryo of 43 days: experimental evaluation, theory and methodology

El avance tecnológico en la práctica obstétrica y particularmente en el campo de la ultrasonografía ha dejado en evidencia el impacto que la visualización del dinámico desarrollo de la gestación ha tenido, en el conocimiento de los fenomenos que ocurren durante la vida intrauterina. En esta perspectiva y dada la demanda creciente de información, particularmente del desarrollo embrionario, la reconstrucción tridimensional virtual desde secciones bidimensionales se presenta como una nueva opci¢n y una herramienta util al conocimiento del desarrollo de estructuras complejas durante la morfogénesis. En este trabajo se presentan material, métodos, y resultados experimentales que se obtuvieron al desarrollar un sistema computacional interactivo para la reconstrucción tridimensional de la mano de un embrión humano de 43 días a partir de cortes seriados. Se describen los componentes principales del ambiente virtual, las principales técnicas de generación de actores tridimensionales y en especial la técnica Marching Cubes empleada para la generación de superficie de la piel y de la estructura esquelética de la mano. Se discute el problema de registración de imagenes, describiendo la técnica de registraci¢n de puntos rígidos empleada y se presenta un método alternativo de registración secundaria para solucionar problemas derivados por la distancia existente entre los puntos fiduciales y la muestra en estudio. Se presentan además, los resultados obtenidos de la aplicación de la técnica Data Cutting e interpolación trilineal para la obtención de cortes virtuales sagitales, axiales y coronales. Sobre la base de los resultados obtenidos, se proponen futuras aplicaciones incorporando técnicas de textura y de visualización en función del tiempo. Se enfatiza la importancia de la interdisciplina en el logro de estos objetivos

El concepto de normalidad durante el desarrollo preimplantación del huevo humano: análisis ultraestructural de cuatro embriones / Normality concept during human egg preimplantation development: structural analysis of 4 embryos

Se analizó la ultraestructura de 4 huevos humanos al estado de: pronúcleo, dos, cuatro y siete células. Los embriones, se recogieron después de lavado de trompas de Falopio, desde mujeres sanas y de probada fertilidad que habían solicitado ser esterilizadas quirúrgicamente. Las intervenciones se realizaron a diferentes lapsos de tiempo después de detectado el pico de LH en plasma. Después de la colecta, los huevos se prepararon para microscopía electrónica de acuerdo a las técnicas convencionales. Los huevos cursaban un proceso de desarrollo normal al momento de la colecta. Tanto la morfología de los huevos y sus anexos, como las características ultraestructurales de los organelos citoplasmáticos, correspondían a huevos con un desarrollo aparentemente normal. Entre las características más relevantes estaban: la presencia de fragmentos citoplasmáticos en el espacio perivitelino, la distribución espacial de los organelos citoplasmáticos en los blastómeros, la estrecha relación entre el retículo endoplasmático liso y las mitocondrias, la actividad de yemación de la membrana nuclear y finalmente la organización estructural del nucléolo. Este trabajo presenta a nivel ultraestructural algunas características únicas que pueden tener relación con la ontogénesis de los organelos celulares y diferenciación celular. Además, se revelan detalles estructurales que pueden tener una expresión a nivel de microscopía óptica y pueden servir para una mejor evaluación de especímenes vivos en programas de fecundación in vitro