RESUMO
The establishment of the embryonic dorsoventral axis in Xenopus occurs when the radial symmetry around the egg's animal-vegetal axis is broken to give rise to the typical symmetry of Bilaterians. We have previously shown that the Notch1 protein is ventrally enriched during early embryogenesis in Xenopus laevis and zebrafish and exerts ventralizing activity through ß-Catenin destabilization and the positive regulation of ventral center genes in X. laevis. These findings led us to further investigate when these asymmetries arise. In this work, we show that the asymmetrical distribution of Notch1 protein and mRNA precedes cortical rotation and even fertilization in X. laevis. Moreover, we found that in unfertilized eggs transcripts encoded by the ventralizing gene bmp4 are also asymmetrically distributed in the animal hemisphere and notch1 transcripts accumulate consistently on the same side of the eccentric maturation point. Strikingly, a Notch1 asymmetry orthogonal to the animal-vegetal axis appears during X. laevis oogenesis. Thus, we show for the first time a maternal bias in the distribution of molecules that are later involved in ventral patterning during embryonic axialization, strongly supporting the hypothesis of a dorsoventral prepattern or intrinsic bilaterality of Xenopus eggs before fertilization.
RESUMO
Dogs bring many benefits to our society but, if not properly managed, they can be detrimental for humans, livestock and wildlife. We highlight the increasing problems associated with free-ranging dogs using examples from two regions of the world where this issue is pervasive, India and South America. In these regions, free-ranging dogs spread diseases, injure people, harm biodiversity, and negatively impact human livelihoods. We discuss why mitigating these deleterious effects can be extremely complicated because there are diverse challenges such as: (a) a lack of or inappropriate legislations concerning free-ranging dog management and human-dog interactions, (b) unregulated intentional and unintentional feeding of free-ranging dogs, (c) limitations of animal shelters, (d) non-responsible ownership, and (e) uncontrolled dog populations. As the management of animal species is usually shaped by differing interests, existing policies and regulations, views and social influence of stakeholders, power asymmetries between interested parties is yet another challenge in this regard. We need evidence-based legislations and strong institutions (e.g., public health and conservation institutions) that are capable of implementing governance principles and managing the complexities of this socio-ecological system by taking science-based decisions, and balancing power asymmetries to promote consensus.
Assuntos
Animais Selvagens , Ecossistema , Animais , Humanos , Cães , Consenso , Biodiversidade , PropriedadeRESUMO
Radiologists routinely analyze hippocampal asymmetries in magnetic resonance (MR) images as a biomarker for neurodegenerative conditions like epilepsy and Alzheimer's Disease. However, current clinical tools rely on either subjective evaluations, basic volume measurements, or disease-specific models that fail to capture more complex differences in normal shape. In this paper, we overcome these limitations by introducing NORHA, a novel NORmal Hippocampal Asymmetry deviation index that uses machine learning novelty detection to objectively quantify it from MR scans. NORHA is based on a One-Class Support Vector Machine model learned from a set of morphological features extracted from automatically segmented hippocampi of healthy subjects. Hence, in test time, the model automatically measures how far a new unseen sample falls with respect to the feature space of normal individuals. This avoids biases produced by standard classification models, which require being trained using diseased cases and therefore learning to characterize changes produced only by the ones. We evaluated our new index in multiple clinical use cases using public and private MRI datasets comprising control individuals and subjects with different levels of dementia or epilepsy. The index reported high values for subjects with unilateral atrophies and remained low for controls or individuals with mild or severe symmetric bilateral changes. It also showed high AUC values for discriminating individuals with hippocampal sclerosis, further emphasizing its ability to characterize unilateral abnormalities. Finally, a positive correlation between NORHA and the functional cognitive test CDR-SB was observed, highlighting its promising application as a biomarker for dementia.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Hipocampo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Doença de Alzheimer/diagnóstico por imagem , BiomarcadoresRESUMO
The objectives of this study were: (a) to determine asymmetries, both lower limb (LL) and upper limb (UL), in Chilean older adults, and (b) to relate asymmetries to FA in both LL and UL. Forty-one older adults voluntarily participated in this study (mean ± standard deviation [SD]: age 72.0 ± 8.0 years, LL asymmetries 13.78 ± 14.87%, UL asymmetries 10.70 ± 8.85%, FA 40.35 ± 16.26 points). The variables were: (1) asymmetries of LL and UL, assessed through a force platform and handgrip, respectively; (2) FA, assessed through the Latin American Group for Maturity (GDLAM) and the GDLAM index of autonomy (GI) protocol. The relationship between the variables was performed through Spearman's correlation. The analysis showed that 39% of the participants presented asymmetries above 15% in the LL. Likewise, this 39% of older adults presented a lower FA than their peers with asymmetries below 15% in the LL (≤15%: 35.64 ± 12.26 points vs. >15%: 47.69 ± 19.23 points, p = 0.003). The analysis showed a small correlation between LL and GI asymmetries (r = 0.27, p = 0.07) and a small but negative correlation between UL and GI (r = -0.21). The mean values of asymmetries of both LL and UL are within 'normal' parameters. However, several older adults were identified as being at risk. In parallel, older adults who presented a higher level of asymmetries in LL showed a lower level of FA.
Assuntos
Força da Mão , Extremidade Superior , Humanos , Idoso , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Chile , Extremidade InferiorRESUMO
BACKGROUND: People with Parkinson's disease (PwPD) showed impairments of balance control which can be aggravated by the presence of higher interlateral postural asymmetry caused by a distinct dopaminergic loss in the substantia nigra between cerebral hemispheres. RESEARCH QUESTION: We evaluate asymmetries between the more and the less affected leg in PwPD in responses to unanticipated stance perturbations. METHODS: Sixteen 16 PwPD participated in the experiment that consisted of recovering a stable upright stance, keeping the feet in place, in response to a perturbation caused by a sudden release of a load equivalent to 7 % of the participant's body mass. Anterior displacement and velocity of the center of pressure (CoP), the latency of gastrocnemius medialis muscle (GM) activation onset, rate of GM activation, and normalized magnitude of muscular activation were analyzed. RESULTS: Analysis revealed significantly rate (pâ¯=â¯0.04) and magnitude (pâ¯=â¯0.02) higher activation of GM in the less affected limb. No significant effects of the leg were found for GM activation latency or CoP-related variables. SIGNIFICANCE: There is a higher contribution of the less affected leg in automatic postural responses in PwPD.
Assuntos
Doença de Parkinson , Postura , Pé/fisiologia , Humanos , Perna (Membro)/fisiologia , Músculo Esquelético/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologiaRESUMO
Axon-dendrite formation is a crucial milestone in the life history of neurons. During this process, historically referred as "the establishment of polarity," newborn neurons undergo biochemical, morphological and functional transformations to generate the axonal and dendritic domains, which are the basis of neuronal wiring and connectivity. Since the implementation of primary cultures of rat hippocampal neurons by Gary Banker and Max Cowan in 1977, the community of neurobiologists has made significant achievements in decoding signals that trigger axo-dendritic specification. External and internal cues able to switch on/off signaling pathways controlling gene expression, protein stability, the assembly of the polarity complex (i.e., PAR3-PAR6-aPKC), cytoskeleton remodeling and vesicle trafficking contribute to shape the morphology of neurons. Currently, the culture of hippocampal neurons coexists with alternative model systems to study neuronal polarization in several species, from single-cell to whole-organisms. For instance, in vivo approaches using C. elegans and D. melanogaster, as well as in situ imaging in rodents, have refined our knowledge by incorporating new variables in the polarity equation, such as the influence of the tissue, glia-neuron interactions and three-dimensional development. Nowadays, we have the unique opportunity of studying neurons differentiated from human induced pluripotent stem cells (hiPSCs), and test hypotheses previously originated in small animals and propose new ones perhaps specific for humans. Thus, this article will attempt to review critical mechanisms controlling polarization compiled over decades, highlighting points to be considered in new experimental systems, such as hiPSC neurons and human brain organoids.
RESUMO
SUMMARY: The purpose of this study was to investigate the effect of age on peak torque (PT) relative strength measures of knee extensors (KE) and knee flexors (KF), bilateral strength ratio (Q:Q, H:H), and ipsilateral strength ratio (H:Q) in youth elite male football players.Elite male players (n = 70) from four age categories (U16: n = 20, U17: n = 20, U19: n = 15, U21: n = 15) performed isokinetic strength tests using a Cybex dynamometer. Results show a significant effect of age on PTKE (F3,142 = 4.54, p = 0.005, = 0.09) and PTKF (age: F3,142 = 3.07, p = 0.030, = 0.06). No significant effect of age on unilateral (F3,142 = 1.05, p = 0.375, = 0.02) or ipsilateral strength ratio (F3,142 = 2.63, p = 0.053, = 0.06) was found. Results revealed significant differences in PTKE for nondominant limbs between U16 and U21. Higher bilateral differences were detected for flexors (H:H = 7.94-11.47 %, Q:Q = 7.97-9.29 %) compared to extensors. Our study showed that 17-year-old players have levels of strength similar to U19 players. A higher bilateral difference of knee flexors than extensors was found, suggesting that more attention should be paid to knee flexors. No effect of laterality was found for strength and strength asymmetries. Future research should also focus on ipsilateral strength ratio in late stage of maturation.
RESUMEN: El objetivo de este estudio fue investigar el efecto de la edad en las medidas de fuerza relativa de torque máximo (TM) de los extensores de rodilla (ER) y flexores de rodilla (FR), la relación de fuerza bilateral (Q: Q, H: H) y la relación de fuerza ipsilateral (H: Q) en jugadores de fútbol masculino de élite en 70 sujetos de cuatro categorías de edad (U16: n = 20, U17: n = 20, U19: n = 15, U21: n = 15). Se realizaron pruebas de fuerza isocinética utilizando un dinamómetro Cybex. Los resultados mos- traron un efecto significativo de la edad en TMER (F3,142 = 4,54, p = 0,005, = 0,09) y TMFR (edad: age: F3,142 = 3,07, p = 0,030, = 0,06). No se observó efecto significativo alguno de la edad sobre la fuerza unilateral (F3,142 = 1,05, p = 0,375, = 0,02) o relación de fuerza ipsilateral (F3,142 = 2,63, p = 0,053, = 0,06). Los resultados indicaron diferencias significativas en TMER para miembros no dominantes entre U16 y U21. Se detectaron mayo- res diferencias bilaterales para los flexores (H:H = 7,94-11,47%, Q:Q = 7,97-9,29 %) en comparación con los extensores. Nues- tro estudio mostró que los jugadores de 17 años tienen niveles de fuerza similares a la de los jugadores sub-19. Se observó una mayor diferencia bilateral de flexores de rodilla que de extensores, lo que sugiere que se debe prestar más atención a los flexores de rodilla. No se encontró un efecto de lateralidad para fuerza y asimetrías de fuerza. Los estudios futuros también deben centrarse en la relación de fuerza ipsilateral en la etapa tardía de maduración.
Assuntos
Humanos , Masculino , Adolescente , Futebol , Força Muscular/fisiologia , Cinética , Estudos Transversais , Fatores Etários , Torque , Articulação do Joelho , Lateralidade FuncionalRESUMO
Many studies have highlighted evidence of lateralized behaviours in vertebrates and invertebrates, indicating that cerebral lateralization might not be uniquely human. Flamingos, as highly social species, might represent an interesting model in the study of lateralization, as this trait appears to be useful in gregarious animals. This study aims to investigate the presence of lateralized behaviours in zoo flamingos. The subjects of this study were 41 greater flamingos (Phoenicopterus roseus) and 29 Chilean flamingos (Phoenicopterus chilensis). Ten 20-minute observation sessions per subject were carried out, using focal animal sampling method. Bouts of side preferences were recorded for foraging, neck resting and preening. Moreover, bouts and duration of leg use for postural support during unipedal standing (leg stance) were also collected. Results highlighted a group-level right-side preference for foraging in the whole sample as well as within each species. Within greater flamingos, group-level right-side preferences were also reported for neck resting and leg stance. Differences between the two flocks were found, with greater flamingos displaying right preferences to a greater extent than Chilean flamingos. Males showed a more pronounced right preference than females for some categories. This study adds to previous literature highlighting the presence of group-level behavioural lateralization in flamingos.
Assuntos
Animais de Zoológico , Lateralidade Funcional , Animais , Aves , Feminino , Humanos , Masculino , Pescoço , DescansoRESUMO
The aim of this study was to compare body composition (BC) and morphological symmetry differences among elite athletes (n = 132) in six martial arts (judo, karate, fencing, wrestling, taekwondo, kickboxing). Multivariate analysis of variances (MANOVA) was used to compare the following variables: absolute (FFM) and relative (FFMrel) value of fat free mass, percentage of fat mass (FMp), bone mass, protein mass, basal metabolic rate, absolute (TBW) and percentual (TBWp) value of total body water, segmental proportion of muscle mass, phase angle, and percent-age differences between the upper and lower limbs. MANOVA revealed significant differences in BC among the groups (λ = 0.01, F104, 256 = 10.01, p< 0.01, ηp2 = 0.67). No significant differences were observed for FMp, FFMrel, and TBWp (p>0.05). In all other BC variables, significant differences were detected (p<0.05). The comparison of paired differences between limbs revealed significantly greater fluid volume in the preferred arm compared to the non-preferred arm in karate and fencing athletes. Significant differences (p<0.05) in favour of the preferred leg in all combat athletes were detected. This study revealed morphological differences among practitioners of different martial arts and between paired limbs.
El objetivo de este estudio fue comparar la composición corporal (CC) y las diferencias de simetría morfológica entre atletas de élite (n = 132) en seis artes marciales (judo, karate, esgrima, lucha, taekwondo, kickboxing). Se utilizó el análisis multivariado de varianzas (MANOVA) para comparar las siguientes variables: valor absoluto (FFM) y relativo (FFMrel) de la masa libre de grasa, porcentaje de masa grasa (FMp), masa ósea, masa proteica, tasa metabólica basal, absoluto (TBW) y el valor porcentual (TBWp) de líquido corporal total, la proporción segmentaria de la masa muscular, el ángulo de fase y las diferencias porcentuales entre los miembros superiores e inferiores. MANOVA reveló diferencias significativas en BC entre los grupos (λ = 0,01, F104, 256 = 10,01, p <0,01, ηp2 = 0,67). No se observaron diferencias significativas para FMp, FFMrel y TBWp (p>0,05). En todas las demás variables de BC, se detectaron diferencias significativas (p<0,05). La comparación de las diferencias pareadas entre los miembros reveló un volumen de líquido significativamente mayor en el brazo dominante en comparación con el brazo no dominante en karate y atletas de esgrima. Se detectaron diferencias significativas (p<0,05) a favor de la pierna dominante en todos los atletas de combate. Este estudio reveló diferencias morfológicas entre los practicantes de diferentes artes marciales y entre las miembros emparejadas.
Assuntos
Humanos , Masculino , Composição Corporal , Artes Marciais , Extremidades/anatomia & histologia , Antropometria , Tecido Adiposo , Análise MultivariadaRESUMO
O texto a seguir trata da origem e desenvolvimento do sistema de pós-graduação no Brasil, desde sua implementação na década de 1960 até os dias de hoje. Para isso, realiza-se uma análise especialmente dos seis Planos Nacionais de Pós-Graduação. Percebe-se que a despeito de um incremento regular no número de programas e na produção científica, ao longo do referido período analisado, reproduz-se igualmente as assimetrias e desigualdades regionais e espaciais. Tais assimetrias geram impactos interessantes para se pensar no futuro da produção científica no país, sobretudo aqueles ligados à lógica que privilegia programas de pós-graduação localizados nas regiões sul, sudeste e o Distrito Federal.
The following text deals with the origin and development of the postgraduate system in Brazil, from its implementation in the 1960s to the present day. For this, an analysis is made especially of the National Postgraduate Plans. In spite of a regular increase in the number of programs and scientific production, over the period analyzed, regional and spatial asymmetries and inequalities are also reproduced asymmetries and inequalities is also intensified. Such asymmetries generate interesting impacts to think about the future of scientific production in the country, especially those linked to the logic that favors graduate programs located in the south, southeast regions and the Federal District.
El texto siguiente trata del origen y desarrollo del sistema de postgrado en Brasil, desde su implementación en la década de 1960 hasta la actualidad. Para ello se realiza un análisis especialmente de los Planes Nacionales de Postgrado. Se percibe que, a pesar de un incremento regular en el número de programas y en la producción científica, durante el período analizado, son reproducidas las asimetrías y desigualdades regionales y espaciales. Tales asimetrías generan impactos interesantes para pensar en el futuro de la producción científica en el país, especialmente aquellos vinculados a la lógica que favorece los programas de posgrado ubicados en las regiones sur, sureste y el Distrito Federal.