Publications by authors named "James Dennis"

Objectives: Hoarding difficulties (HD) affect many people and cause upset and danger for the person, as well as friends and family. Previous research found that people with HD feel less adequately socially supported compared with individuals with obsessive compulsive disorder (OCD). This study used the perspective of those offering support to infer whether people with HD view their support differently, or if there is a gap in support quality compared with those with OCD.

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Recent interest in the biology and function of peritoneal tissue resident macrophages (pMΦ) has led to a better understanding of their cellular origin, programming, and renewal. The programming of pMΦ is dependent on microenvironmental cues and tissue-specific transcription factors, including GATA6. However, the contribution of microRNAs remains poorly defined.

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Background: Antimicrobial resistance is a growing public health concern. There is a global need to estimate the population-level value of developing new antimicrobials and to ensure the effective use of existing antimicrobials as strategies to counteract antimicrobial resistance. To this aim, population-level value criteria need to be considered alongside conventional value measures.

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Proteostasis requires oxidative metabolism (ATP) and mitigation of the associated damage by glutathione, in an increasingly dysfunctional relationship with aging. SLC3A2 (4F2hc, CD98) plays a role as a disulfide-linked adaptor to the SLC7A5 and SLC7A11 exchangers which import essential amino acids and cystine while exporting Gln and Glu, respectively. The positions of N-glycosylation sites on SLC3A2 have evolved with the emergence of primates, presumably in synchrony with metabolism.

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Maintenance of the proteasome requires oxidative phosphorylation (ATP) and mitigation of oxidative damage, in an increasingly dysfunctional relationship with aging. SLC3A2 plays a role on both sides of this dichotomy as an adaptor to SLC7A5, a transporter of branched-chain amino acids (BCAA: Leu, Ile, Val), and to SLC7A11, a cystine importer supplying cysteine to the synthesis of the antioxidant glutathione. Endurance in mammalian muscle depends in part on oxidation of BCAA; however, elevated serum levels are associated with insulin resistance and shortened lifespans.

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Background: In the demyelinating disease multiple sclerosis (MS), chronic-active brain inflammation, remyelination failure and neurodegeneration remain major issues despite immunotherapy. While B cell depletion and blockade/sequestration of T and B cells potently reduces episodic relapses, they act peripherally to allow persistence of chronic-active brain inflammation and progressive neurological dysfunction. N-acetyglucosamine (GlcNAc) is a triple modulator of inflammation, myelination and neurodegeneration.

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Introduction: Antimicrobial resistance remains a serious and growing threat to public health, both globally and in the UK, leading to diminishing effectiveness of antimicrobials. Despite a clear need for new antimicrobials, the clinical pipeline is insufficient, driven by high research and development costs and limited expected returns on investment. To counteract this, National Institute for Health and Care Excellence (NICE) and National Health Service (NHS) England have launched a reimbursement mechanism, de-linked from volume of sales, that aims to reduce economic risk by recognising the broader population-level value of antimicrobials.

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Introduction: Antimicrobial resistance (AMR) is a major public health threat worldwide. Greece has the highest burden of infections due to antibiotic-resistant bacteria among European Union/European Economic Area (EU/EEA) countries. One of the most serious AMR threats in Greece is hospital-acquired infections (HAIs) with limited treatment options (LTO) caused by resistant gram-negative pathogens.

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Tissue Engineering of cartilage has been hampered by the inability of engineered tissue to express native levels of type II collagen . Inadequate levels of type II collagen are, in part, due to a failure to recapitulate the physiological environment in culture. In this study, we engineered primary rabbit chondrocytes to express a secreted reporter, Luciferase, driven by the type II collagen promoter, and applied a Design of Experiments approach to assess chondrogenic differentiation in micronutrient-supplemented medium.

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Introduction: Antimicrobial resistance (AMR) is a global public health challenge requiring a global response to which Australia has issued a National Antimicrobial Resistance Strategy. The necessity for continued-development of new effective antimicrobials is required to tackle this immediate health threat is clear, but current market conditions may undervalue antimicrobials. We aimed to estimate the health-economic benefits of reducing AMR levels for drug-resistant gram-negative pathogens in Australia, to inform health policy decision-making.

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Introduction: Hospital-acquired infections (HAIs) and growing antimicrobial resistance (AMR) represent a significant healthcare burden globally. Especially in Greece, HAIs with limited treatment options (LTO) pose a serious threat due to increased morbidity and mortality. This study aimed to estimate the clinical and economic value of introducing a new antibacterial for HAIs with LTO in Greece.

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Article Synopsis
  • There is a lack of comprehensive head-to-head comparisons for advanced treatments of moderately to severely active ulcerative colitis (UC), prompting the need for further analysis.
  • A network meta-analysis was conducted to evaluate the effectiveness of various treatments, including filgotinib and several other biologics, analyzing patient populations and treatment phases.
  • The findings indicate that most targeted therapies outperform placebo, with filgotinib showing comparable efficacy to standard treatments, but it was found to be less effective than infliximab in certain scenarios while performing better than adalimumab and golimumab under specific conditions.
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  • Establishing causal links between genetic variants and cancer risk is complicated, but this study highlights the single-nucleotide polymorphism rs55705857, which significantly increases the risk of low-grade glioma (LGG).
  • The research identifies rs55705857 as the causal variant influencing molecular pathways related to LGG, specifically by disrupting OCT2/4 binding within a brain-specific enhancer, leading to greater gene expression.
  • Animal experiments show that altering the corresponding mouse gene accelerated tumor development, demonstrating the variant's role in hereditary susceptibility to severe gliomas in approximately 40% of LGG patients.
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  • The study focuses on improving the growth and differentiation of human chondrocytes, which is crucial for cartilage tissue engineering.
  • Chondrocytes were cultured under four different conditions, and all showed increased cell growth and production of important cartilage components compared to standard methods.
  • The combination of synoviocyte matrix (SCM) and basic fibroblast growth factor (bFGF) had the best results, boosting cell growth by about 36% compared to using only SCM.
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Impaired T cell immunity with aging increases mortality from infectious disease. The branching of Asparagine-linked glycans is a critical negative regulator of T cell immunity. Here we show that branching increases with age in females more than males, in naïve more than memory T cells, and in CD4 more than CD8 T cells.

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Background: Chronic inflammation plays a crucial role in the initiation, promotion, and invasion of tumors, and thus the antiproliferative effects of numerous anti-inflammatory drugs have been frequently reported in the literature. Upregulation of the pro-inflammatory enzyme cyclooxygenase-2 (COX-2) has been linked to various human cancers, including breast cancer.

Objectives: This research aims to investigate the antiproliferative activity of different Non-steroidal anti-inflammatory drugs (NSAIDs), including COX-2 selective and non-selective agents, against various breast cancer cell lines and to elucidate possible molecular pathways involved in their activity.

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Importance: N-glycan branching modulates cell surface receptor availability, and its deficiency in mice promotes inflammatory demyelination, reduced myelination, and neurodegeneration. N-acetylglucosamine (GlcNAc) is a rate-limiting substrate for N-glycan branching, but, to our knowledge, endogenous serum levels in patients with multiple sclerosis (MS) are unknown.

Objective: To investigate a marker of endogenous serum GlcNAc levels in patients with MS.

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Background: Glioblastomas stem-like cells (GSCs) by invading the brain parenchyma, remains after resection and radiotherapy and the tumoral microenvironment become stiffer. GSC invasion is reported as stiffness sensitive and associated with altered N-glycosylation pattern. Glycocalyx thickness modulates integrins mechanosensing, but details remain elusive and glycosylation enzymes involved are unknown.

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Aberrant -glycan Golgi remodeling and metabolism are associated with epithelial-mesenchymal transition (EMT) and metastasis in patients with breast cancer. Despite this association, the -glycosylation pathway has not been successfully targeted in cancer. Here, we show that inhibition of the mevalonate pathway with fluvastatin, a clinically approved drug, reduces both -glycosylation and -glycan-branching, essential components of the EMT program and tumor metastasis.

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Article Synopsis
  • * GlcNAc, a key metabolite, influences N-glycan branching which is important for cell growth and differentiation and can promote myelination from precursor cells.
  • * Administering oral GlcNAc in studies with mice shows it enhances myelination and protects against nerve damage in demyelinating conditions, and lower GlcNAc levels in MS patients are linked with worse damage.
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Cartilage tissue has been recalcitrant to tissue engineering approaches. In this study, human chondrocytes were formed into self-assembled cartilage sheets, cultured in physiologic (5%) and atmospheric (20%) oxygen conditions and underwent biochemical, histological and biomechanical analysis at 1- and 2-months. The results indicated that sheets formed at physiological oxygen tension were thicker, contained greater amounts of glycosaminoglycans (GAGs) and type II collagen, and had greater compressive and tensile properties than those cultured in atmospheric oxygen.

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The mechanistic target of rapamycin complex 1 (mTORC1) couples nutrient sufficiency to cell growth. mTORC1 is activated by exogenously acquired amino acids sensed through the GATOR-Rag guanosine triphosphatase (GTPase) pathway, or by amino acids derived through lysosomal degradation of protein by a poorly defined mechanism. Here, we revealed that amino acids derived from the degradation of protein (acquired through oncogenic Ras-driven macropinocytosis) activate mTORC1 by a Rag GTPase-independent mechanism.

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The de novo synthesis of fatty acids has emerged as a therapeutic target for various diseases, including cancer. Because cancer cells are intrinsically buffered to combat metabolic stress, it is important to understand how cells may adapt to the loss of de novo fatty acid biosynthesis. Here, we use pooled genome-wide CRISPR screens to systematically map genetic interactions (GIs) in human HAP1 cells carrying a loss-of-function mutation in fatty acid synthase (FASN), whose product catalyses the formation of long-chain fatty acids.

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