Publications by authors named "Joao Carlos Sousa"

Article Synopsis
  • The study examines how social restrictions and different variants, specifically Alpha, Delta, and Omicron-BA.1, affected the spread of SARS-CoV-2 in Galicia, Spain.
  • Using genomic data and mobility statistics, the research found that initial variant introductions mostly came from other Spanish regions and France, later shifting to include imports from Portugal and the U.S.
  • Despite the number of introductions, most did not contribute significantly to the pandemic's evolution in Galicia, but major coastal cities were identified as key areas for viral transmission.
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Article Synopsis
  • The study investigates how social restrictions and different variants, specifically Alpha, Delta, and Omicron, affected SARS-CoV-2 transmission in Galicia, Spain.
  • Using genomic data and mobility information, the research shows that the Alpha variant initially spread from other Spanish regions and France, while later variants saw increased influences from Portugal and the USA.
  • Key coastal cities in Galicia were identified as significant hubs for the virus's dissemination, underscoring the importance of regional connectivity for public health strategies.
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Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that presents a largely unknown etiopathology. The presence of reactive astrocytes in MS lesions has been described for a long time; however, the role that these cells play in the pathophysiology of MS is still not fully understood. Recently, we used an MS animal model to perform high-throughput sequencing of astrocytes' transcriptome during disease progression.

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Aim: Experimental models are a powerful aid in visualizing molecular phenomena. This work reports how the worm () can be effectively explored for students to learn how molecular cues dramatically condition axonal guidance and define nervous system structure and behavior at the organism level. Summary of work: A loosely oriented observational activity preceded detailed discussions on molecules implied in axonal migration.

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Aging causes considerable changes in the nervous system, inducing progressive and long-lasting loss of physiological integrity and synaptic plasticity, leading to impaired brain functioning. These age-related changes quite often culminate in behavioral dysfunctions, such as impaired cognition, which can ultimately result in various forms of neurodegenerative disorders. Still, little is known regarding the effects of aging on behavior.

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Anemia and inflammation are common clinical conditions in emergency departments. This study explored a cohort of patients admitted to the emergency department with a particular interest in determining the frequency of anemia and inflammation and the association between hemoglobin (Hb) and C-reactive protein (CRP) concentrations. The study included 125 patients categorized according to their demographic (gender and age) and clinical condition (Hb and CRP concentrations, pathological background, and diagnostic).

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Exosomes are cell-derived vesicles that act as carriers for proteins and nucleic acids, with therapeutic potential and high biocompatibility. We propose a new concept of exosome-like liposomes for controlled delivery. The goal of this work was to develop a new type of liposomes with a unique mixture of phospholipids, similar to naturally occurring exosomes but overcoming their limitations of heterogeneity and low productivity, for therapeutic delivery of bioactive compounds.

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Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) that affects about 2.5 million people worldwide. In MS, the patients' immune system starts to attack the myelin sheath, leading to demyelination, neurodegeneration, and, ultimately, loss of vital neurological functions such as walking.

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Aging is associated with cognitive decline. Herein, we studied a large cohort of old age and young adult male rats and confirmed that, as a group, old  rats display poorer spatial learning and behavioral flexibility than younger adults. Surprisingly, when animals were clustered as good and bad performers, our data revealed that while in younger animals better cognitive performance was associated with longer dendritic trees and increased levels of synaptic markers in the hippocampus and prefrontal cortex, the opposite was found in the older group, in which better performance was associated with shorter dendrites and lower levels of synaptic markers.

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The continuous generation of new neurons in the adult mammalian hippocampus is a form of neural plasticity that modulates learning and memory functions, and also emotion (anxiety and depression). Among the factors known to modulate adult hippocampal neurogenesis and brain function, lipocalin-2 (LCN2) was recently described as a key regulator of neural stem cells (NSCs) proliferation and commitment, with impact on several dimensions of behaviour. Herein, we evaluated whether voluntary running, a well-known regulator of cell genesis, rescue the deficient adult hippocampal neurogenesis observed in mice lacking LCN2.

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Article Synopsis
  • - Neudesin (NENF) is a protein secreted by neurons that has neurotrophic effects during embryonic development, but its role in the adult brain is not well understood.
  • - In experiments with neudesin-null (Nenf) mice, it was found that there was no reduction in cell proliferation in the adult subventricular zone (SVZ), but a decrease in cell proliferation and newborn neurons in the hippocampus subgranular zone (SGZ) was observed.
  • - The study suggests that NENF plays a neurotrophic role in the adult brain through mechanisms involving progesterone metabolism and the modulation of neurosteroids in the dentate gyrus region.
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The process of generating new functional neurons in the adult mammalian brain occurs from the local neural stem and progenitor cells and requires tight control of the progenitor cell's activity. Several signaling pathways and intrinsic/extrinsic factors have been well studied over the last years, but recent attention has been given to the critical role of cellular metabolism in determining the functional properties of progenitor cells. Here, we review recent advances in the current understanding of when and how metabolism affects neural stem cell (NSC) behavior and subsequent neuronal differentiation and highlight the role of lipocalin-2 (LCN2), a protein involved in the control of oxidative stress, as a recently emerged regulator of NSC activity and neuronal differentiation.

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This article brings the choroid plexus into the context of health and disease. It is remarkable that the choroid plexus, composed by a monolayer of epithelial cells that lie in a highly vascularized stroma, floating within the brain ventricles, gets so little attention in major physiology and medicine text books and in the scientific literature in general. Consider that it is responsible for producing most of the about 150mL of cerebrospinal fluid that fills the brain ventricles and the subarachnoid space and surrounds the spinal cord in the adult human central nervous system, which is renewed approximately 2-3 times daily.

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Alzheimer's disease (AD) is the most common form of dementia, whose prevalence is growing along with the increased life expectancy. Although the accumulation and deposition of amyloid beta (Aβ) peptides in the brain is viewed as one of the pathological hallmarks of AD and underlies, at least in part, brain cell dysfunction and behavior alterations, the etiology of this neurodegenerative disease is still poorly understood. Noticeably, increased amyloid load is accompanied by marked inflammatory alterations, both at the level of the brain parenchyma and at the barriers of the brain.

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It is estimated that more than 2.5 million individuals worldwide have multiple sclerosis (MS). MS is an autoimmune neurodegenerative disease resulting from the destruction of the myelin sheath that enwraps axons driven by an immune cell attack to the central nervous system.

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A mild and simple method was developed to prepare a series of fifteen 5-aminoimidazole 4-carboxamidrazones, starting from the easily accessible 5-amino-4-cyanoformimidoyl imidazoles. The antimicrobial activity of these novel amidrazones was screened against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa) bacteria and Candida sp. (Candida albicans, Candida krusei, Candida parapsilosis).

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The aging process correlates with a progressive failure in the normal cellular and organ functioning; these alterations are aggravated in Alzheimer's disease (AD). In both aging and AD there is a general decrease in the capacity of the body to eliminate toxic compounds and, simultaneously, to supply the brain with relevant growth and nutritional factors. The barriers of the brain are targets of this age related dysfunction; both the endothelial cells of the blood-brain barrier and the choroid plexus epithelial cells of the blood-cerebrospinal fluid barrier decrease their secretory capacity towards the brain and their ability to remove toxic compounds from the brain.

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The subependymal zone (SEZ), frequently named as adult subventricular zone (SVZ), is a niche of adult neural stem and progenitor cells that lines a large extension of the lateral ventricles of the brain. The majority of the studies do not analyze the SEZ throughout its entire extension. Instead, studies of cell populations within the SEZ typically focus their analysis on a narrow space between specific bregma coordinates that provides a perspective of only a small portion of the SEZ.

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IN ADULT MAMMALS, UNDER PHYSIOLOGICAL CONDITIONS, NEUROGENESIS, THE PROCESS OF GENERATING NEW FUNCTIONAL NEURONS FROM PRECURSOR CELLS, OCCURS MAINLY IN TWO BRAIN AREAS: the subgranular zone in the dentate gyrus of the hippocampus, and the subventricular zone (SVZ) lining the walls of the brain lateral ventricles. Taking into account the location of the SVZ and the cytoarchitecture of this periventricular neural progenitor cell niche, namely the fact that the slow dividing primary progenitor cells (type B cells) of the SVZ extend an apical primary cilium toward the brain ventricular space which is filled with cerebrospinal fluid (CSF), it becomes likely that the composition of the CSF can modulate both self-renewal, proliferation and differentiation of SVZ neural stem cells. The major site of CSF synthesis is the choroid plexus (CP); quite surprisingly, however, it is still largely unknown the contribution of molecules specifically secreted by the adult CP as modulators of the SVZ adult neurogenesis.

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The emerging model for the adult subependymal zone (SEZ) cell population indicates that neuronal diversity is not generated from a uniform pool of stem cells but rather from diverse and spatially confined stem cell populations. Hence, when analysing SEZ proliferation, the topography along the anterior-posterior and dorsal-ventral axes must be taken into account. However, to date, no studies have assessed SEZ proliferation according to topographical specificities and, additionally, SEZ studies in animal models of neurological/psychiatric disorders often fail to clearly specify the SEZ coordinates.

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The biochemistry and molecular biology of the extracellular matrix (ECM) is difficult to convey to students in a classroom setting in ways that capture their interest. The understanding of the matrix's roles in physiological and pathological conditions study will presumably be hampered by insufficient knowledge of its molecular structure. Internet-available resources can bridge the division between the molecular details and ECM's biological properties and associated processes.

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Objectives: To investigate the diversity of integrons and extended-spectrum beta-lactamases (ESBLs) among Enterobacteriaceae from chickens and swine in Portugal and analyse the clonal relationships between Portuguese ESBL-producing isolates of animal and human origin.

Methods: We analysed samples from faeces of healthy swine (HSF, n = 35), from uncooked chicken carcasses (CM, n = 20) and from faeces of healthy chickens (HCF, n = 20). Samples were plated on MacConkey agar with and without ceftazidime (1 mg/L) or cefotaxime (1 mg/L).

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Objectives: To investigate the occurrence and the diversity of Ambler class A ESBLs among Enterobacteriaceae from different Portuguese clinical settings over a 2 year period (2002-04).

Methods: One hundred and nine extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolates from five geographically distant health institutions in Portugal were studied. ESBLs were characterized by isoelectric focussing, PCR and further sequencing.

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