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1.
Biochem Pharmacol ; 225: 116264, 2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38710334

RESUMO

The retrosplenial cortex (RSC) plays a central role in processing contextual fear conditioning. In addition to corticocortical and thalamocortical projections, the RSC receives subcortical inputs, including a substantial projection from the nucleus incertus in the pontine tegmentum. This GABAergic projection contains the neuropeptide, relaxin-3 (RLN3), which inhibits target neurons via its Gi/o-protein-coupled receptor, RXFP3. To assess this peptidergic system role in contextual fear conditioning, we bilaterally injected the RSC of adult rats with an adeno-associated-virus (AAV), expressing the chimeric RXFP3 agonist R3/I5 or a control AAV, and subjected them to contextual fear conditioning. The R3/I5 injected rats did not display any major differences to control-injected and naïve rats but displayed a significantly delayed extinction. Subsequently, we employed acute bilateral injections of the specific RXFP3 agonist peptide, RXFP3-Analogue 2 (A2), into RSC. While the administration of A2 before each extinction trial had no impact on the extinction process, treatment with A2 before each acquisition trial resulted in delayed extinction. In related anatomical studies, we detected an enrichment of RLN3-immunoreactive nerve fibers in deep layers of the RSC, and a higher level of co-localization of RXFP3 mRNA with vesicular GABA transporter (vGAT) mRNA than with vesicular glutamate transporter-1 (vGLUT1) mRNA across the RSC, consistent with an effect of RLN3/RXFP3 signalling on the intrinsic, inhibitory circuits within the RSC. These findings suggest that contextual conditioning processes in the RSC involve, in part, RLN3 afferent modulation of local inhibitory neurons that provides a stronger memory acquisition which, in turn, retards the extinction process.

2.
Nat Commun ; 15(1): 2379, 2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38493135

RESUMO

Respiratory syncytial virus (RSV) is the leading cause of hospitalisation for respiratory infection in young children. RSV disease severity is known to be age-dependent and highest in young infants, but other correlates of severity, particularly the presence of additional respiratory pathogens, are less well understood. In this study, nasopharyngeal swabs were collected from two cohorts of RSV-positive infants <12 months in Spain, the UK, and the Netherlands during 2017-20. We show, using targeted metagenomic sequencing of >100 pathogens, including all common respiratory viruses and bacteria, from samples collected from 433 infants, that burden of additional viruses is common (111/433, 26%) but only modestly correlates with RSV disease severity. In contrast, there is strong evidence in both cohorts and across age groups that presence of Haemophilus bacteria (194/433, 45%) is associated with higher severity, including much higher rates of hospitalisation (odds ratio 4.25, 95% CI 2.03-9.31). There is no evidence for association between higher severity and other detected bacteria, and no difference in severity between RSV genotypes. Our findings reveal the genomic diversity of additional pathogens during RSV infection in infants, and provide an evidence base for future causal investigations of the impact of co-infection on RSV disease severity.


Assuntos
Coinfecção , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Infecções Respiratórias , Lactente , Criança , Humanos , Pré-Escolar , Vírus Sincicial Respiratório Humano/genética , Infecções por Vírus Respiratório Sincicial/diagnóstico , Infecções por Vírus Respiratório Sincicial/epidemiologia , Hospitalização
3.
Small ; : e2311832, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38386283

RESUMO

The molecular foundations of epidermal cell wall mechanics are critical for understanding structure-function relationships of primary cell walls in plants and facilitating the design of bioinspired materials. To uncover the molecular mechanisms regulating the high extensibility and strength of the cell wall, the onion epidermal wall is stretched uniaxially to various strains and cell wall structures from mesoscale to atomic scale are characterized. Upon longitudinal stretching to high strain, epidermal walls contract in the transverse direction, resulting in a reduced area. Atomic force microscopy shows that cellulose microfibrils exhibit orientation-dependent rearrangements at high strains: longitudinal microfibrils are straightened out and become highly ordered, while transverse microfibrils curve and kink. Small-angle X-ray scattering detects a 7.4 nm spacing aligned along the stretch direction at high strain, which is attributed to distances between individual cellulose microfibrils. Furthermore, wide-angle X-ray scattering reveals a widening of (004) lattice spacing and contraction of (200) lattice spacing in longitudinally aligned cellulose microfibrils at high strain, which implies longitudinal stretching of the cellulose crystal. These findings provide molecular insights into the ability of the wall to bear additional load after yielding: the aggregation of longitudinal microfibrils impedes sliding and enables further stretching of the cellulose to bear increased loads.

4.
JACS Au ; 4(1): 177-188, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38274264

RESUMO

Plant cell walls are abundant sources of materials and energy. Nevertheless, cell wall nanostructure, specifically how pectins interact with cellulose and hemicelluloses to construct a robust and flexible biomaterial, is poorly understood. X-ray scattering measurements are minimally invasive and can reveal ultrastructural, compositional, and physical properties of materials. Resonant X-ray scattering takes advantage of compositional differences by tuning the energy of the incident X-ray to absorption edges of specific elements in a material. Using Tender Resonant X-ray Scattering (TReXS) at the calcium K-edge to study hypocotyls of the model plant, Arabidopsis thaliana, we detected distinctive Ca features that we hypothesize correspond to previously unreported Ca-Homogalacturonan (Ca-HG) nanostructures. When Ca-HG structures were perturbed by chemical and enzymatic treatments, cellulose microfibrils were also rearranged. Moreover, Ca-HG nanostructure was altered in mutants with abnormal cellulose, pectin, or hemicellulose content. Our results indicate direct structural interlinks between components of the plant cell wall at the nanoscale and reveal mechanisms that underpin both the structural integrity of these components and the molecular architecture of the plant cell wall.

5.
Behav Brain Res ; 462: 114874, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38266780

RESUMO

Contextual fear conditioning is a behavioral paradigm used to assess hippocampal-dependent memory in experimental animals. Perception of the context depends on activation of a distinct population of neurons in the hippocampus and in hippocampal-related areas that process discrete aspects of context perception. In the absence of any putatively associated cue, the context becomes the salient element that may warn of an upcoming aversive event; and in particular conditions, animals generalize this warning to any new or similar context. In this study we evaluated the effects of the number of sessions, the number of unconditioned stimuli per acquisition session and the distribution of extinction sessions to assess fear acquisition and extinction and determine under which conditions generalization occurred in adult, male rats. We observed that the organization and spacing of sessions were relevant factors in the acquisition and extinction of contextual fear memories. Extinction occurred with significantly greater robustness when sessions were spread over two days. Furthermore, results indicated that exposure to a single 0.3 mA, 0.5 s footshock in two different sessions could produce context-specific fear, while more acquisition sessions or more footshocks within a single session produced a generalization of the fear response to a new context. Notably, when generalization occurred, successive re-exposure to the generalized context produced extinction in a similar way to the paired exposure. Together, the present findings identify clear procedural and behavioral parameters amenable to neural systems analysis of three clinically relevant outcomes of contextual fear conditioning, i.e., memory acquisition, storage and extinction.


Assuntos
Extinção Psicológica , Medo , Ratos , Masculino , Animais , Extinção Psicológica/fisiologia , Medo/fisiologia , Memória/fisiologia , Condicionamento Clássico/fisiologia , Hipocampo/fisiologia
6.
J Cell Physiol ; 239(2): e31165, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38149820

RESUMO

Transforming growth factor (TGF)-ß1 is a multifunctional cytokine that plays important roles in health and disease. Previous studies have revealed that TGFß1 activation, signaling, and downstream cell responses including epithelial-mesenchymal transition (EMT) and apoptosis are regulated by the elasticity or stiffness of the extracellular matrix. However, tissues within the body are not purely elastic, rather they are viscoelastic. How matrix viscoelasticity impacts cell fate decisions downstream of TGFß1 remains unknown. Here, we synthesized polyacrylamide hydrogels that mimic the viscoelastic properties of breast tumor tissue. We found that increasing matrix viscous dissipation reduces TGFß1-induced cell spreading, F-actin stress fiber formation, and EMT-associated gene expression changes, and promotes TGFß1-induced apoptosis in mammary epithelial cells. Furthermore, TGFß1-induced expression of integrin linked kinase (ILK) and colocalization of ILK with vinculin at cell adhesions is attenuated in mammary epithelial cells cultured on viscoelastic substrata in comparison to cells cultured on nearly elastic substrata. Overexpression of ILK promotes TGFß1-induced EMT and reduces apoptosis in cells cultured on viscoelastic substrata, suggesting that ILK plays an important role in regulating cell fate downstream of TGFß1 in response to matrix viscoelasticity.


Assuntos
Matriz Extracelular , Transdução de Sinais , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal , Matriz Extracelular/metabolismo , Integrinas/metabolismo , Fator de Crescimento Transformador beta1/farmacologia , Fator de Crescimento Transformador beta1/metabolismo , Animais , Camundongos , Linhagem Celular , Elasticidade , Viscosidade
7.
Sci Rep ; 13(1): 20854, 2023 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-38012204

RESUMO

There are many surgical techniques (packing, Pringle maneuver, etc.) and hemostatic agents to manage hepatic bleeding in trauma surgery. This study compares the effectiveness of two different types of hemostatic agents, one is an active flowable hemostat and the other is a passive hemostat made of modified absorbable polymers [MAP]. Both surgical technique and hemostatic agents can be used together as a means of controlling bleeding. We have hypothesized that a single hemostatic agent might be as effective as a unique hemostatic surgical technique. Twenty swine were prospectively randomized to receive either active Flowable (Floseal) or passive MAP powder (PerClot) hemostatic agents. We used a novel severe liver injury model that caused exsanguinating hemorrhage. The main outcome measure was total blood loss volume. The total volume of blood loss, from hepatic injury to minute 120, was significantly lower in the Flowable group (407.5 cm3; IqR: 195.0-805.0 cm3) compared to MAP group (1107.5 cm3; IqR: 822.5 to 1544.5 cm3) (Hodges-Lehmann median difference: - 645.0 cm3; 95% CI: - 1144.0 to - 280.0 cm3; p = 0.0087). The rate of blood loss was significantly lower in the flowable group compared with the MAP group as measured from time of injury to minutes 3, 9, 12, and 120 (except for 6 min). The mean arterial pressure gradually recovered in the flowable group by 24 h, whereas in the MAP group, the mean arterial pressure was consistently stayed below baseline values. Kaplan-Meier survival analysis indicated similar rates of death between study groups (Logrank test p = 0.3395). Both the flowable and the MAP hemostatic agents were able to effectively control surgical bleeding in a novel severe liver injury model, however, the flowable gelatin-thrombin agent provided quicker and better bleed control.


Assuntos
Hemostáticos , Trombina , Animais , Suínos , Gelatina/uso terapêutico , Esponja de Gelatina Absorvível , Hemostáticos/uso terapêutico , Perda Sanguínea Cirúrgica/prevenção & controle , Fígado/lesões , Exsanguinação , Polímeros/uso terapêutico
8.
Front Plant Sci ; 14: 1212126, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37662163

RESUMO

Calcium is important for the growth and development of plants. It serves crucial functions in cell wall and cell membrane structure and serves as a secondary messenger in signaling pathways relevant to nutrient and immunity responses. Thus, measuring calcium levels in plants is important for studies of plant biology and for technology development in food, agriculture, energy, and forest industries. Often, calcium in plants has been measured through techniques such as atomic absorption spectrophotometry (AAS), inductively coupled plasma-mass spectrometry (ICP-MS), and electrophysiology. These techniques, however, require large sample sizes, chemical extraction of samples or have limited spatial resolution. Here, we used near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the calcium L- and K-edges to measure the calcium to carbon mass ratio with spatial resolution in plant samples without requiring chemical extraction or large sample sizes. We demonstrate that the integrated absorbance at the calcium L-edge and the edge jump in the fluorescence yield at the calcium K-edge can be used to quantify the calcium content as the calcium mass fraction, and validate this approach with onion epidermal peels and ICP-MS. We also used NEXAFS to estimate the calcium mass ratio in hypocotyls of a model plant, Arabidopsis thaliana, which has a cell wall composition that is similar to that of onion epidermal peels. These results show that NEXAFS spectroscopy performed at the calcium edge provides an approach to quantify calcium levels within plants, which is crucial for understanding plant physiology and advancing plant-based materials.

9.
Healthcare (Basel) ; 11(15)2023 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-37570430

RESUMO

JUSTIFICATION: Providing care to patients with several conditions and simultaneously taking several medications at home is inexorably growing in developed countries. This trend increases the chances of home caregivers experiencing diverse errors related with medication or care. OBJECTIVE: To determine the effectiveness of four different educational solutions compared to the natural intervention (absence of intervention) to provide a safer care at home by caregivers. METHOD: Prospective, parallel, and mixed research study with two phases. Candidates: Home-based caregivers caring a person with multiple comorbid conditions or polymedication who falls into one of the three profiles of patients defined for the study (oncology, cardiovascular, or pluripathological patients). First phase: Experts first answered an online survey, and then joined together to discuss the design and plan the content of educational solutions directed to caregivers including the identification of medication and home care errors, their causes, consequences, and risk factors. Second phase: The true experiment was performed using an inter- and intrasubject single-factor experimental design (five groups: four experimental groups against the natural intervention (control), with pre- and post-intervention and follow-up measures) with a simple random assignment, to determine the most effective educational solution (n = 350 participants). The participants will be trained on the educational solutions through 360 V, VR, web-based information, or psychoeducation. A group of professionals called the "Gold Standard" will be used to set a performance threshold for the caring or medication activities. The study will be carried out in primary care centers, hospitals, and caregivers' associations in the Valencian Community, Andalusia, Madrid, and Murcia. EXPECTED RESULTS: We expect to identify critical elements of risk management at home for caregivers and to find the most effective and optimal educational solution to reduce errors at home, increasing caregivers' motivation and self-efficacy whilst the impact of gender bias in this activity is reduced. TRIAL REGISTRATION: Clinical Trial NCT05885334.

10.
Front Neurosci ; 17: 1176587, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37234259

RESUMO

Introduction: The septal area provides a rich innervation to the hippocampus regulating hippocampal excitability to different behavioral states and modulating theta rhythmogenesis. However, little is known about the neurodevelopmental consequences of its alterations during postnatal development. The activity of the septohippocampal system is driven and/or modulated by ascending inputs, including those arising from the nucleus incertus (NI), many of which contain the neuropeptide, relaxin-3 (RLN3). Methods: We examined at the molecular and cellular level the ontogeny of RLN3 innervation of the septal area in postnatal rat brains. Results: Up until P13-15 there were only scattered fibers in the septal area, but a dense plexus had appeared by P17 that was extended and consolidated throughout the septal complex by P20. There was a decrease in the level of colocalization of RLN3 and synaptophysin between P15 and P20 that was reversed between P20 and adulthood. Biotinylated 3-kD dextran amine injections into the septum, revealed retrograde labeling present in the brainstem at P10-P13, but a decrease in anterograde fibers in the NI between P10-20. Simultaneously, a differentiation process began during P10-17, resulting in fewer NI neurons double-labeled for serotonin and RLN3. Discussion: The onset of the RLN3 innervation of the septum complex between P17-20 is correlated with the onset of hippocampal theta rhythm and several learning processes associated with hippocampal function. Together, these data highlight the relevance and need for further analysis of this stage for normal and pathological septohippocampal development.

11.
Brain Struct Funct ; 228(5): 1307-1328, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37173580

RESUMO

Nucleus incertus (NI) neurons in the pontine tegmentum give rise to ascending forebrain projections and express the neuropeptide relaxin-3 (RLN3) which acts via the relaxin-family peptide 3 receptor (RXFP3). Activity in the hippocampus and entorhinal cortex can be driven from the medial septum (MS), and the NI projects to all these centers, where a prominent pattern of activity is theta rhythm, which is related to spatial memory processing. Therefore, we examined the degree of collateralization of NI projections to the MS and the medial temporal lobe (MTL), comprising medial and lateral entorhinal cortex (MEnt, LEnt) and dentate gyrus (DG), and the ability of the MS to drive entorhinal theta in the adult rat. We injected fluorogold and cholera toxin-B into the MS septum and either MEnt, LEnt or DG, to determine the percentage of retrogradely labeled neurons in the NI projecting to both or single targets, and the relative proportion of these neurons that were RLN3-positive ( +). The projection to the MS was threefold stronger than that to the MTL. Moreover, a majority of NI neurons projected independently to either MS or the MTL. However, RLN3 + neurons collateralize significantly more than RLN3-negative (-) neurons. In in vivo studies, electrical stimulation of the NI induced theta activity in the MS and the entorhinal cortex, which was impaired by intraseptal infusion of an RXFP3 antagonist, R3(BΔ23-27)R/I5, particularly at ~ 20 min post-injection. These findings suggest that the MS plays an important relay function in the NI-induced generation of theta within the entorhinal cortex.


Assuntos
Córtex Entorrinal , Ritmo Teta , Ratos , Animais , Núcleos da Rafe , Lobo Temporal , Memória Espacial/fisiologia , Receptores de Peptídeos , Receptores Acoplados a Proteínas G
12.
Sci Rep ; 13(1): 5421, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-37012389

RESUMO

The primary cell wall is highly hydrated in its native state, yet many structural studies have been conducted on dried samples. Here, we use grazing-incidence wide-angle X-ray scattering (GIWAXS) with a humidity chamber, which enhances scattering and the signal-to-noise ratio while keeping outer onion epidermal peels hydrated, to examine cell wall properties. GIWAXS of hydrated and dried onion reveals that the cellulose ([Formula: see text]) lattice spacing decreases slightly upon drying, while the (200) lattice parameters are unchanged. Additionally, the ([Formula: see text]) diffraction intensity increases relative to (200). Density functional theory models of hydrated and dry cellulose microfibrils corroborate changes in crystalline properties upon drying. GIWAXS also reveals a peak that we attribute to pectin chain aggregation. We speculate that dehydration perturbs the hydrogen bonding network within cellulose crystals and collapses the pectin network without affecting the lateral distribution of pectin chain aggregates.


Assuntos
Celulose , Pectinas , Celulose/química , Pectinas/química , Incidência , Parede Celular/química , Membrana Celular , Plantas , Difração de Raios X
13.
Methods Enzymol ; 678: 121-144, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36641206

RESUMO

Resonant soft X-ray scattering (RSoXS), a technique that combines X-ray absorption spectroscopy and X-ray scattering, can probe the nano- and meso-scale structure of biological assemblies with chemical specificity. RSoXS experiments yield scattering data collected at several photon energies, for example across an elemental absorption edge of interest. Collecting a near-edge X-ray absorption fine structure (NEXAFS) spectrum complements RSoXS experiments and determines X-ray energies that are best suited for RSoXS measurements. The analysis of RSoXS data is similar in many ways to analysis of small angle X-ray scattering using hard X-rays, with an added dimension that includes an X-ray energy dependence. This chapter discusses procedures for predicting scattering contrast and thereby identifying energies suitable for RSoXS measurements using NEXAFS spectra, analyses of 2D RSoXS images through integration into 1D profiles, and strategies for elucidating the origin of RSoXS scattering features. It also discusses existing and potential methods for interpretation of RSoXS data to gain detailed structural insights into biological systems.


Assuntos
Fótons , Raios X , Espectroscopia por Absorção de Raios X
15.
Methods Enzymol ; 677: 357-383, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36410955

RESUMO

The complex structure of biological assemblies is crucial for function yet challenging to discern given the chemical similarities between constituent components. Hard X-ray techniques, for example, rely on small density differences between domains that lead to modest scattering intensities. Resonant soft X-ray scattering (RSoXS) uses X-rays below 2keV to access absorption edges of low-Z elements. In this way, RSoXS can enhance scattering contrast between domains of different chemical compositions or bonding motifs, thus providing structural information about specific chemical motifs. RSoXS is emerging as a technique applicable for biological systems, having been used to characterize protein structure in solution and polysaccharide organization in plant cell walls. Sample environment instrumentation, however, is challenging in the current state of the art, particularly with liquid samples. This chapter contains a brief introduction to RSoXS and current beamline capabilities, and provides methods to prepare, store, and mount biological samples for RSoXS characterization. Furthermore, key details during RSoXS and X-ray absorption data acquisition are highlighted and some future opportunities in RSoXS instrumentation for biological systems are discussed.


Assuntos
Proteínas , Síncrotrons , Raios X , Proteínas/química , Parede Celular
16.
Artigo em Inglês | MEDLINE | ID: mdl-36115554

RESUMO

We report here the community structure and functional analysis of the microbiome of the Alligator mississippiensis GI tract from the oral cavity through the entirety of the digestive tract. Although many vertebrate microbiomes have been studied in recent years, the archosaur microbiome has only been given cursory attention. In the oral cavity we used amplicon-based community analysis to examine the structure of the oral microbiome during alligator development. We found a community that diversified over time and showed many of the hallmarks we would expect of a stable oral community. This is a bit surprising given the rapid turnover of alligator teeth but suggests that the stable gumline microbes are able to rapidly colonize the emerging teeth. As we move down the digestive tract, we were able to use both long and short read sequencing approaches to evaluate the community using a shotgun metagenomics approach. Long read sequencing was applied to samples from the stomach/duodenum, and the colorectal region, revealing a fairly uniform and low complexity community made up primarily of proteobacteria at the top of the gut and much more diversity in the colon. We used deep short read sequencing to further interrogate this colorectal community. The two sequencing approaches were concordant with respect to community structure but substantially more detail was available in the short read data, in spite of high levels of host DNA contamination. Using both approaches we were able to show that the colorectal community is a potential reservoir for antibiotic resistance, human pathogens such as Clostridiodes difficile and a possible source of novel antimicrobials or other useful secondary metabolites.


Assuntos
Jacarés e Crocodilos , Neoplasias Colorretais , Microbiota , Jacarés e Crocodilos/genética , Animais , Resistência Microbiana a Medicamentos , Humanos , Metagenômica/métodos , Microbiota/genética , Boca/microbiologia
17.
Medicina (Kaunas) ; 58(7)2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35888692

RESUMO

Background and Objectives: Previous studies demonstrated a huge variability among surgeons when it comes to reproducing the position of an acetabular cup in total hip arthroplasty. Our main objective is to determine if orthopedic surgeons can replicate a given orientation on a pelvic model better than untrained individuals. Our secondary objective is to determine if experience has any influence on their ability for this task. Materials and Methods: A group of specialist orthopedic hip surgeons and a group of volunteers with no medical training were asked to reproduce three given (randomly generated) acetabular cup orientations (inclination and anteversion) on a pelvic model. Error was measured by means of a hip navigation system and comparisons between groups were made using the appropriate statistical methods. Results: The study included 107 individuals, 36 orthopedic surgeons and 71 untrained volunteers. The mean error among surgeons was slightly greater as regards both inclination (7.84 ± 5.53 vs. 6.70 ± 4.03) and anteversion (5.85 ± 4.52 vs. 5.48 ± 3.44), although statistical significance was not reached (p = 0.226 and p = 0.639, respectively). Similarly, although surgeons with more than 100 procedures a year obtained better results than those with less surgical experience (8.01 vs. 7.67 degrees of error in inclination and 5.83 vs. 5.87 in anteversion), this difference was not statistically significant, either (p = 0.852 and p = 0.981). Conclusions: No differences were found in the average error made by orthopedic surgeons and untrained individuals. Furthermore, the surgeons' cup orientation accuracy was not seen to improve significantly with experience.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Cirurgiões Ortopédicos , Cirurgiões , Acetábulo/cirurgia , Humanos
18.
Neurobiol Stress ; 19: 100460, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35734023

RESUMO

This manuscript is dedicated to the memory of Bruce S. McEwen, to commemorate the impact he had on how we understand stress and neuronal plasticity, and the profound influence he exerted on our scientific careers. The focus of this review is the impact of stressors on inhibitory circuits, particularly those of the limbic system, but we also consider other regions affected by these adverse experiences. We revise the effects of acute and chronic stress during different stages of development and lifespan, taking into account the influence of the sex of the animals. We review first the influence of stress on the physiology of inhibitory neurons and on the expression of molecules related directly to GABAergic neurotransmission, and then focus on specific interneuron subpopulations, particularly on parvalbumin and somatostatin expressing cells. Then we analyze the effects of stress on molecules and structures related to the plasticity of inhibitory neurons: the polysialylated form of the neural cell adhesion molecule and perineuronal nets. Finally, we review the potential of antidepressants or environmental manipulations to revert the effects of stress on inhibitory circuits.

19.
J Cell Physiol ; 237(5): 2503-2515, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35224740

RESUMO

Epithelial-mesenchymal transition (EMT) is a physiological process that is essential during embryogenesis and wound healing and also contributes to pathologies including fibrosis and cancer. EMT is characterized by marked gene expression changes, loss of cell-cell contacts, remodeling of the cytoskeleton, and acquisition of enhanced motility. In the late stages of EMT, cells can exhibit myofibroblast-like properties with enhanced expression of the mesenchymal protein marker α-smooth muscle actin and contractile activity. Transforming growth factor (TGF)-ß1 is a well-known inducer of EMT and it activates a plethora of signaling cascades including extracellular signal-regulated kinase (ERK). Previous reports have demonstrated a role for ERK signaling in the early stages of EMT, but the molecular impacts of ERK signaling on the late stages of EMT are still unknown. Here, we found that inhibition of the phosphorylation of ERK enhances focal adhesions, stress fiber formation, cell contractility, and gene expression changes associated with TGFß1-induced EMT in mammary epithelial cells. These effects are mediated in part by the phosphorylation state and subcellular localization of myocardin-related transcription factor-A. These findings indicate that the intricate crosstalk between signaling cascades plays an important role in regulating the progression of EMT and suggests new approaches to control EMT processes.


Assuntos
Transição Epitelial-Mesenquimal , MAP Quinases Reguladas por Sinal Extracelular , Transativadores/metabolismo , Células Epiteliais/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Miofibroblastos/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta1/metabolismo , Fator de Crescimento Transformador beta1/farmacologia
20.
Microsc Res Tech ; 85(5): 1990-2015, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35040538

RESUMO

Cellulose obtained from plants is a bio-polysaccharide and the most abundant organic polymer on earth that has immense household and industrial applications. Hence, the characterization of cellulose is important for determining its appropriate applications. In this article, we review the characterization of cellulose morphology, surface topography using microscopic techniques including optical microscopy, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Other physicochemical characteristics like crystallinity, chemical composition, and thermal properties are studied using techniques including X-ray diffraction, Fourier transform infrared, Raman spectroscopy, nuclear magnetic resonance, differential scanning calorimetry, and thermogravimetric analysis. This review may contribute to the development of using cellulose as a low-cost raw material with anticipated physicochemical properties. HIGHLIGHTS: Morphology and surface topography of cellulose structure is characterized using microscopy techniques including optical microscopy, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Analytical techniques used for physicochemical characterization of cellulose include X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and thermogravimetric analysis.


Assuntos
Celulose , Varredura Diferencial de Calorimetria , Celulose/química , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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