Biology subjects

Restrepo, A.

Publications and source records attributed to Restrepo, A..

6 recordsLinked to original sources

bioRxiv2026

Preclinical evaluation of a natural extract-based oral nanoformulation from Eucalyptus tereticornis for potential use in treating type 2 diabetes mellitus.

The acute, subacute, and subchronic oral toxicities, as well as the combined chronic toxicity and carcinogenicity, of a nanotechnology-based formulation derived from a natural extract of Eucalyptus tereticornis leaves were investigated. This nanoformulation demonstrates anti-obesogenic and potentially anti-diabetic properties. Our study aims to conduct preclinical tests to evaluate the chemical formulation. To assess acute toxicity, rats received a single oral dose of 2000 mg/kg of the nanoformulation. In the subacute trial, mice were treated with approximately 1180 mg/kg of the nanoformulation for 28 days. In the combined chronic toxicity and carcinogenicity study, the nanoformulation was administered daily at approximately 590 mg/kg for 10 months. At the end of the experiment, hematological, biochemical, and histopathological assessments were conducted. Throughout the acute, subacute, subchronic, and chronic/carcinogenicity studies, animals showed no toxic effects from the treatment or the vehicle. No histopathological lesions, such as degeneration or cell death in the liver, kidney, or gastrointestinal tract, were observed. Treatments did not cause any clinical changes, and there were no significant differences in weight, hematological, or biochemical parameters. Therefore, the nanoformulation did not produce toxic effects in the animals.

pharmacology and toxicology↗

bioRxiv2024

Identification of nuclear pore proteins at plasmodesmata

Plasmodesmata (PD) mediate intercellular exchange of small molecules, RNAs and proteins between plant cells with an apparent exclusion limit for passive non-specific transport, and transport of specific cargo mediated by mediators. PD and nuclear pore complexes (NPC) are nanometer sized micropores with strikingly similar properties. Cargo translocation through NPC is mediated by phase separating FG-nucleoporins (FG-NUP). Here, bioinformatics, proteomics and fluorescence imaging identified FG-NUPs at PD. Transient expression of GFP fusions at low and intermediate expression levels supported dual localization of 12 NUPs to NPC and PD. Structured illumination microscopy detected the transmembrane anchor NUP CPR5 close to orifices of PD. cpr5 mutants showed reduced intercellular short-root (SHR) transport. However, transport defects cannot be excluded due to indirect effects in the mutants. Identification of FG-NUPs at PD is consistent with the recruitment of NUPs to form a PD pore gating complex consistent with phase separation domains as diffusion barriers at PD. Further analyses will be required to determine whether NUPs are bona fide PD components, or accumulate at PD in certain conditions, or may serve intermediate NPC storage.

cell biology↗

bioRxiv2022

Neotropical birds and mammals show divergent behaviour responses to human pressure

Human presence and habitat disturbance (together human pressure hereafter) can generate a deep fear in animals and this can influence their behaviour. Altered animal behaviour, such as shifts in diel activity patterns, affect many species and species interactions, which can induce changes in individual fitness, species-level population persistence, evolutionary dynamics, and ecosystem-level biodiversity. However, whether dial activity behavioural responses to human pressure are consistent among key functional groups has been poorly studied. For example, while medium to large mammal species tend to become more nocturnal in areas with high human pressure, its unclear if sympatric/co-occurring birds display similar or opposite patterns. This is an important knowledge gap because synchronous or opposing guild-level shifts can shape consequences for food-web dynamics (predation and competition), stability of interaction networks and ecosystem functioning. Here we used information from camera trapping along a gradient of human pressure in the Colombian Llanos region to assess diel activity changes in birds and mammals. We found that the diel activity of over 45% of the bird and 50% of the mammals assessed significantly changed where there was higher human pressures, with mammals becoming more nocturnal and birds more diurnal. The opposing behavioural responses to humans among vertebrate functional groups has significant repercussions for the fields of community ecology, including intraguild predation and competition, and may be a significant ecosystem-level conservation consideration.

ecology↗

bioRxiv2022

Axo-vascular coupling mediated by oligodendrocytes

The high energy requirements of the cortical gray matter are met by the precise cooperation of neurons, glia, and vascular cells in a process known as neurovascular coupling (NVC). In contrast, the existence and significance of NVC in white matter (WM) are still debated and basic regulatory mechanisms are unknown. We recently discovered that oligodendrocytes sense the spiking axons activity via NMDA receptors and regulate their cell surface expression of glucose transporter GLUT1 allowing an increase in glycolytic metabolism that enables lactate release to metabolically support the axons. Here, we show for the mouse optic nerve (ON), a model WM tract, that the vascular support is also dynamically controlled. Axonal spiking activity induces small vessel dilations which are sustained for more than 20 minutes upon the ending of electrical stimulation. Pharmacological inhibition shows that the electrically evoked dilation is mediated by the prostaglandin E2 receptor EP4 and can be modulated by the oxygen concentration, as has been shown in the grey matter. Importantly, we found in ONs from conditional mouse mutants that oligodendroglial NMDA receptors are required for this type of neurovascular response, demonstrating a critical role of oligodendrocytes in coupling axonal activity to pericyte function. Reminiscent of NVC in cortical slices, the "axo-vascular" response is slower and may represent a more rudimentary form of neurovascular coupling.

neuroscience↗

bioRxiv2019

Associations between Processing Speed and Psychopathology in a Transdiagnostic, Pediatric Sample

ObjectiveThe present study sought to examine the relationships between processing speed (PS), mental health disorders, and learning disorders. Prior work has tended to explore relationships between PS deficits and individual diagnoses (i.e., anxiety, autism, ADHD, depressive) in isolation of one another, often relying on relatively modest sample sizes. In contrast, the present work simultaneously investigated associations between PS deficits and these diagnoses, along with specific learning disabilities (i.e., reading, math), in a large-scale, transdiagnostic, community self-referred sample.\n\nMethodA total of 843 children, ages 8-16 were included from the Healthy Brain Network (HBN) Biobank. Given the presence of four PS tasks in HBN, principal component analysis (PCA) was employed to create a composite measure that represented the shared variance of the four PS tasks, referred to as PC1. Intraclass correlation coefficient (ICC) between the four PS measures, as well as PC1, were calculated to assess reliability. We then used multiple linear regression models to assess specific relationships between PS deficits and psychiatric diagnoses.\n\nResultsICCs were moderate between WISC-V tasks (0.663), and relatively modest between NIH Toolbox Pattern Comparison and other PS scales (0.14-0.27). Regression analyses revealed specific significant relationships between PS and reading and math disabilities, ADHD-inattentive type (ADHD-I), and ADHD-combined type (ADHD-C). Secondary analyses accounting for inattention dimensionally diminished associations with ADHD-C, but not ADHD-I or specific learning disability subtypes. The present study did not find a significant relationship with Autism Spectrum Disorder after accounting for inattentive symptoms. Consistent with prior work, demographic variables, including sex, socioeconomic status, and motor control exhibited independent relationships with PC1 as well.\n\nDiscussionThis study provided a comprehensive examination of PS, mental health disorders, and learning disabilities through a transdiagnostic approach. Implications for understanding how PS interacts with a highly heterogeneous childhood sample, as well as the need for increased focus on detection of affected populations are discussed.

developmental biology↗

bioRxiv2017

The Healthy Brain Network Biobank: An open resource for transdiagnostic research in pediatric mental health and learning disorders

Technological and methodological innovations are equipping researchers with unprecedented capabilities for detecting and characterizing pathologic processes in the developing human brain. As a result, ambitions to achieve clinically useful tools to assist in the diagnosis and management of mental health and learning disorders are gaining momentum. To this end, it is critical to accrue large-scale multimodal datasets that capture a broad range of commonly encountered clinical psychopathology. The Child Mind Institute has launched the Healthy Brain Network (HBN), an ongoing initiative focused on creating and sharing a biobank of data from 10,000 New York area participants (ages 5-21). The HBN Biobank houses data about psychiatric, behavioral, cognitive, and lifestyle phenotypes, as well as multimodal brain imaging (resting and naturalistic viewing fMRI, diffusion MRI, morphometric MRI), electroencephalography, eye-tracking, voice and video recordings, genetics, and actigraphy. Here, we present the rationale, design and implementation of HBN protocols. We describe the first data release (n = 664) and the potential of the biobank to advance related areas (e.g., biophysical modeling, voice analysis).

neuroscience↗