Emergentism and complexity in Michael Polanyi’s thought

Starting from a relatively brief --but hopefully understandable-- description of Michael Polanyi's ideas about emergentism and complexity, we will present a perspective of scientific knowledge under the aegis of two of his most relevant maxims: i) we know more than we can talk about, ii) in general, we employ more ideas than we define concepts. We will propose a conception of science from his views on the inexact, tacit knowledge, the self-regulation of science, the network, and the society of explorers in order to show that complexity and emergentism (almost always synonymous with novelty) are guiding threads, rarely visible, that organize such a conception. Complexity and emergentism are theses that express some of the most relevant features of Polanyian thought, since they help to understand the relations between scientific knowledge and the way the society of explorers carries out its actions based on an intertwining between knowledge network and tradition.info:eu-repo/semantics/publishedVersio

Dendritic Cells: A Spot on Sialic Acid

This work was supported by the Portuguese Foundation for Science and Technology (FCT) - PTDC/SAU-MII/67561/2006 and CEDOC (Paula A. Videira) and SFRH/BD/61204/2009 (He lio J. Crespo). FCT is co-financed by European Social Fund (ESF) under Human Potential Operation Program (POPH) from National Strategic Reference Framework (NSRF).Glycans decorating cell surface and secreted proteins and lipids occupy the juncture where critical host-host and host-pathogen interactions occur. The role of glycan epitopes in cell-cell and cell-pathogen adhesive events is already well-established, and cell surface glycan structures change rapidly in response to stimulus and inflammatory cues. Despite the wide acceptance that glycans are centrally implicated in immunity, exactly how glycans and their changes contribute to the overall immune response remains poorly defined. Sialic acids are unique sugars that usually occupy the terminal position of the glycan chains and may be modified by external factors, such as pathogens, or upon specific physiological cellular events. At cell surface, sialic acid-modified structures form the key fundamental determinants for a number of receptors with known involvement in cellular adhesiveness and cell trafficking, such as the Selectins and the Siglec families of carbohydrate recognizing receptors. Dendritic cells (DCs) preside over the transition from innate to the adaptive immune repertoires, and no other cell has such relevant role in antigen screening, uptake, and its presentation to lymphocytes, ultimately triggering the adaptive immune response. Interestingly, sialic acid-modified structures are involved in all DC functions, such as antigen uptake, DC migration, and capacity to prime T cell responses. Sialic acid content changes along DC differentiation and activation and, while, not yet fully understood, these changes have important implications in DC functions. This review focuses on the developmental regulation of DC surface sialic acids and how manipulation of DC surface sialic acids can affect immune-critical DC functions by altering antigen endocytosis, pathogen and tumor cell recognition, cell recruitment, and capacity for T cell priming. The existing evidence points to a potential of DC surface sialylation as a therapeutic target to improve and diversify DC-based therapies.publishersversionpublishe

Dendritic Cells: A Spot on Sialic Acid

Glycans decorating cell surface and secreted proteins and lipids occupy the juncture where critical host–host and host-pathogen interactions occur. The role of glycan epitopes in cell–cell and cell-pathogen adhesive events is already well-established, and cell surface glycan structures change rapidly in response to stimulus and inflammatory cues. Despite the wide acceptance that glycans are centrally implicated in immunity, exactly how glycans and their changes contribute to the overall immune response remains poorly defined. Sialic acids are unique sugars that usually occupy the terminal position of the glycan chains and may be modified by external factors, such as pathogens, or upon specific physiological cellular events. At cell surface, sialic acid-modified structures form the key fundamental determinants for a number of receptors with known involvement in cellular adhesiveness and cell trafficking, such as the Selectins and the Siglec families of carbohydrate recognizing receptors. Dendritic cells (DCs) preside over the transition from innate to the adaptive immune repertoires, and no other cell has such relevant role in antigen screening, uptake, and its presentation to lymphocytes, ultimately triggering the adaptive immune response. Interestingly, sialic acid-modified structures are involved in all DC functions, such as antigen uptake, DC migration, and capacity to prime T cell responses. Sialic acid content changes along DC differentiation and activation and, while, not yet fully understood, these changes have important implications in DC functions. This review focuses on the developmental regulation of DC surface sialic acids and how manipulation of DC surface sialic acids can affect immune-critical DC functions by altering antigen endocytosis, pathogen and tumor cell recognition, cell recruitment, and capacity for T cell priming. The existing evidence points to a potential of DC surface sialylation as a therapeutic target to improve and diversify DC-based therapies

Leprosy presenting as remitting seronegative symmetrical synovitis with pitting oedema syndrome - a case report

Background: Leprosy typically manifests with skin and peripheral nerve involvement. Musculoskeletal complaints are the third most common, and can be the sole presenting manifestation. They range from arthralgia/arthritis in reactional states to full mimics of systemic rheumatic diseases. Remitting Seronegative Symmetrical Synovitis with Pitting Oedema syndrome has only been described once in a patient with already diagnosed Leprosy. Case report: A 68-year-old male, from an endemic region of familial amyloid polyneuropathy, presented with an inaugural Remitting Seronegative Symmetrical Synovitis with Pitting Oedema like syndrome, more that 20 years after travelling to Leprosy endemic areas. Arthritis would resurface whenever oral prednisone was tapered, so methotrexate was started, controlling the complaints. Only one year later, after the appearance of peripheral neuropathy and skin lesions, it was possible to diagnose Leprosy, through the identification of Mycobacterium leprae bacilli in a peripheral nerve biopsy. Conclusion: This report is an example of the heterogeneity of manifestations of Leprosy, namely rheumatic, and the challenge of diagnosing it when typical complaints are absent. It is also a reminder that this disease should be considered whenever a patient with a combination of skin/neurologic/rheumatic complaints has travelled to endemic countries in the past.info:eu-repo/semantics/publishedVersio

Toxicity and structure-activity relationship (SAR) of α, β-dehydroamino acids against human cancer cell lines

A library of N-protected dehydroamino acids, namely dehydroalanine, dehydroaminobutyric acid and dehydrophenylalanine derivatives, was screened in three human cancer cell lines [(lung (A549), gastric (AGS) and neuroblastoma (SH-SY5Y)] in order to characterize their toxicological profile and identify new molecules with potential anticancer activity. Results showed N-protected dehydrophenylalanine and dehydroaminobutyric acid derivatives have no or low toxicity for all tested cell lines. The N-protected dehydroalanines exhibit significant toxic effects and the AGS and SH-SY5Y cells were significantly more vulnerable than A549 cells. Four α,β- dehydroalanine derivatives, with IC50 < 62.5 μM, were selected to investigate the pathways by which these compounds promote cell death. All compounds, at their IC50 concentrations, were able to induce apoptosis in both AGS and SH-SY5Y cell lines. In both cell lines, loss of mitochondrial membrane potential (ΔΨm) was found and caspase activity was increased, namely endoplasmic reticulum-resident caspase-4 in AGS cells and caspase-3/7 in SH-SY5Y cells. When evaluated in a non-cancer cell line, the molecules displayed no to low toxicity, thus suggesting some degree of selectivity for cancer cells. The results indicate that α,β-dehydroalanine derivatives can be considered a future resource of compounds able to work as anticancer drugs.This work received financial support from National Funds (FCT/MEC) through Project UID/QUI/50006/2013, co-financed by European Union (FEDER under the Partnership Agreement PT2020); and from Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) (project NORTE-01-0145-FEDER 000024).info:eu-repo/semantics/publishedVersio

Diet during early life defines testicular lipid content and sperm quality in adulthood

Childhood obesity is a serious concern associated with ill health later in life. Emerging data suggest that obesity has long-term adverse effects upon male sexual and reproductive health but few studies addressed this issue. We hypothesized that exposure to high-fat diet during early life alters testicular lipid content and metabolism leading to permanent damage to sperm parameters. After weaning (day 21 after birth), 36 male mice were randomly divided into 3 groups and fed with different diet regimen for 200 days: CTRL-standard chow; HFD-high-fat diet (Carbohydrate: 35.7%, Protein: 20.5%, Fat: 36.0%); HFDt-high-fat diet for 60 days then replaced by standard chow. Biometric and metabolic data were monitored. Animals were then sacrificed, and tissues collected. Epididymal sperm parameters and endocrine parameters were evaluated. Testicular metabolites were extracted and characterized by 1H-NMR and GC-MS. Testicular mitochondrial and antioxidant activity were evaluated. Our results show that mice fed with high-fat diet, even if only until early adulthood, had lower sperm viability and motility, and higher incidence of head and tail defects. Although diet reversion with weight loss during adulthood prevents the progression of metabolic syndrome, testicular content in fatty acids is irreversibly affected. Excessive fat intake promoted an over-accumulation of pro-inflammatory n-6 polyunsaturated fatty acids in testis, which are strongly correlated with negative effects upon sperm quality. Therefore, the adoption of high-fat diets during early life correlates to irreversible changes in testicular lipid content and metabolism, which are related to permanent damage to sperm quality later in life

The Portuguese Severe Asthma Registry: Development, Features, and Data Sharing Policies

The Portuguese Severe Asthma Registry (Registo de Asma Grave Portugal, RAG) was developed by an open collaborative network of asthma specialists. RAG collects data from adults and pediatric severe asthma patients that despite treatment optimization and adequate management of comorbidities require step 4/5 treatment according to GINA recommendations. In this paper, we describe the development and implementation of RAG, its features, and data sharing policies. The contents and structure of RAG were defined in a multistep consensus process. A pilot version was pretested and iteratively improved. The selection of data elements for RAG considered other severe asthma registries, aiming at characterizing the patient's clinical status whilst avoiding overloading the standard workflow of the clinical appointment. Features of RAG include automatic assessment of eligibility, easy data input, and exportable data in natural language that can be pasted directly in patients' electronic health record and security features to enable data sharing (among researchers and with other international databases) without compromising patients' confidentiality. RAG is a national web-based disease registry of severe asthma patients, available at asmagrave.pt. It allows prospective clinical data collection, promotes standardized care and collaborative clinical research, and may contribute to inform evidence-based healthcare policies for severe asthma.info:eu-repo/semantics/publishedVersio

ST3Gal.I sialyltransferase relevance in bladder cancer tissues and cell lines

<p>Abstract</p> <p>Background</p> <p>The T antigen is a tumor-associated structure whose sialylated form (the sialyl-T antigen) involves the altered expression of sialyltransferases and has been related with worse prognosis. Since little or no information is available on this subject, we investigated the regulation of the sialyltransferases, able to sialylate the T antigen, in bladder cancer progression.</p> <p>Methods</p> <p>Matched samples of urothelium and tumor tissue, and four bladder cancer cell lines were screened for: <it>ST3Gal.I</it>, <it>ST3Gal.II </it>and <it>ST3Gal.IV </it>mRNA level by real-time PCR. Sialyl-T antigen was detected by dot blot and flow cytometry using peanut lectin. Sialyltransferase activity was measured against the T antigen in the cell lines.</p> <p>Results</p> <p>In nonmuscle-invasive bladder cancers, <it>ST3Gal.I </it>mRNA levels were significantly higher than corresponding urothelium (p < 0.001) and this increase was twice more pronounced in cancers with tendency for recurrence. In muscle-invasive cancers and matching urothelium, <it>ST3Gal.I </it>mRNA levels were as elevated as nonmuscle-invasive cancers. Both non-malignant bladder tumors and corresponding urothelium showed <it>ST3Gal.I </it>mRNA levels lower than all the other specimen groups. A good correlation was observed in bladder cancer cell lines between the <it>ST3Gal.I </it>mRNA level, the ST activity (r = 0.99; p = 0.001) and sialyl-T antigen expression, demonstrating that sialylation of T antigen is attributable to ST3Gal.I. The expression of sialyl-T antigens was found in patients' bladder tumors and urothelium, although without a marked relationship with mRNA level. The two <it>ST3Gal.I </it>transcript variants were also equally expressed, independently of cell phenotype or malignancy.</p> <p>Conclusion</p> <p>ST3Gal.I plays the major role in the sialylation of the T antigen in bladder cancer. The overexpression of <it>ST3Gal.I </it>seems to be part of the initial oncogenic transformation of bladder and can be considered when predicting cancer progression and recurrence.</p