Search Results (176)

This essay argues for the reciprocal benefits of joining the new theories of matter emerging out of critical posthumanism and the psychedelic drugs currently experiencing a so-called “renaissance” in global north societies. While the former’s twin emphasis on relationality and embodiment is perfectly suited to capture and ground the ontological, epistemological, and ethical implications of psychedelic experiences of interconnectedness and transformation, these substances are in turn powerful companions through which to enact a “posthuman phenomenology” that helps us with the urgent task to “access, amplify, and describe” our deep imbrication with our more-than-human environments. In other words, I argue that while the “new materialism” emerging out of posthumanism can help elaborate a psychedelic rationality, psychedelics can in turn operate as educators in materiality. It is from this materialist perspective that we can best make sense of psychedelics’ often touted potential for social transformation and the enduring suspicion that they are somehow at odds with the “ontoepistemological order” of modernity. From this point of view, I contend that a crucial critical move is to push against the common trope that this opposition is best expressed as a turn from the narrow scientific and “consumerist materialism” of modern Western societies to more expansive “spiritual” worldviews. Pushing against this science-–spirituality binary, which in fact reproduces modern “indivi/dualism” by confining psychedelic experience inside our heads, I argue instead that what is in fact needed to think through and actualize such potentials is an increased attention to our material transcorporeality. In a nutshell, if we want psychedelics to inform social change, we must be more, not less, materialist—albeit by redefining matter in a rather “weird”, non-reductive way and by redefining consciousness as embodied. By the end of the essay, attaching psychedelics to a new materialism will enable us to formulate a “material spirituality” that establishes psychedelics’ political value less in an idealistic or cognitive “politics of consciousness” and more in a “materialization of critique”. Full article

Retinal ischemia is implicated in ocular diseases involving aberrant neovessel proliferation that characterizes proliferative retinopathies. Their therapy still remains confined to the intravitreal administration of anti-vascular endothelial growth factor (VEGF) medication, which is limited by side effects and progressive reduction in efficacy. Mimicking neovascular diseases in rodents, although of great help for translating fundamental mechanistic findings and assessing therapeutic potential in humans, is limited by the rodent’s short life span, which prevents retinal vessel proliferation over time. However, the oxygen-induced retinopathy (OIR) model, which mimics retinopathy of prematurity, seems to meet some criteria that are common to proliferative retinopathies. The present review provides insight into preclinical models and their suitability to mimic proliferative retinopathies. Further considerations will be applied to emerging approaches and advanced methodologies for the management of proliferative retinopathies, leading to the identification of new therapeutic targets, including our contribution in the field. Major emphasis is given to the possibility of using systemic therapies either alone or in combination with intravitreal anti-VEGF administration to maximize clinical benefits by combining drugs with different modes of action. This review is concluded by an in-depth discussion on future advancements and a critical view of preclinical finding translatability. Despite the major effort of preclinical and clinical research to develop novel therapies, the blockade of VEGF activity still remains the only treatment for proliferative retinopathies for more than twenty years since its first therapeutic application. Full article

Diffusiophoresis of a weakly charged dielectric droplet in a cylindrical pore is investigated theoretically in this study. The governing fundamental electrokinetic equations are solved with a patched pseudo-spectral method based on Chebyshev polynomials, coupled with a geometric mapping scheme to take care of the irregular solution domain. The impact of the boundary confinement effect upon the droplet motion is explored in detail, which is most profound in narrow channels. We found, among other things, that the droplet moving direction may reverse with varying channel widths. Enhanced motion-inducing double-layer polarization due to the presence of a nearby channel wall is found to be responsible for it. In particular, an interesting and seemingly peculiar phenomenon referred to as the “solidification phenomenon” is observed here at some specific critical droplet sizes or electrolyte strengths in narrow channels, under which all the droplets move at identical speeds regardless of their viscosities. They move like a rigid particle without the surface spinning motions and the induced interior recirculating vortex flows. As the corresponding shear rate is zero at this point, the droplet is resilient to undesirable exterior shear stresses tending to damage the droplet in motion. This provides a helpful guideline in the fabrication of liposomes in drug delivery in terms of the optimal liposome size, as well as in the microfluidic and nanofluidic manipulations of cells, among other potential practical applications. The effects of other parameters of electrokinetic interest are also examined. Full article

Metabolic enzymes and cancer-driving transcriptions factors are often overexpressed in neoplastic cells, and their exposed cysteine residues are amenable to chemical modification. This review explores cysteine alkylation as a cancer treatment strategy, focusing on Michael acceptors like curcumin and helenalin, which interact with transcription factors NF-κB, STAT3 and HIF-1α. Molecular docking studies using AutoDockFR revealed distinct binding affinities: curcumin showed strong interactions with STAT3 and NF-κB, while helenalin exhibited high affinity for STAT3 and HIF-1α. Synthetic compounds like STAT3-IN-1 and CDDO-Me demonstrated superior binding in most targets, except for CDDO-Me with HIF-1α, suggesting unique structural incompatibilities. Natural products such as zerumbone and umbelliferone displayed moderate activity, while palbociclib highlighted synthetic-drug advantages. These results underscore the importance of ligand−receptor structural complementarity, particularly for HIF-1α’s confined binding site, where helenalin’s terminal Michael acceptor system proved optimal. The findings advocate for integrating computational and experimental approaches to develop cysteine-targeted therapies, balancing synthetic precision with natural product versatility for context-dependent cancer treatment strategies. Full article

This study developed a novel water-soluble Cellulose Acetoacetate (CAA)-chitosan (CS) composite hydrogel drug delivery system. In this system, CAA and CS molecules are cross-linked via dynamic enamine bonds, forming a three-dimensional network structure suitable for drug encapsulation and controlled release. The primary objective was to address the challenges associated with the short half-life and significant fluctuations in therapeutic concentration of cytokine drugs, such as interleukin-2 (IL-2). A hydrogel system with a three-dimensional spatial network structure was successfully constructed via dynamic enamine bonds cross-linking between the acetoacetate groups in CAA molecules and the amino groups in CS. This system exhibits the following characteristics: (1) Dynamic covalent bonds impart adjustable mechanical properties to the hydrogel, enabling precise control over gelation time and mechanical performance; (2) A hierarchical pore structure (average pore size of 100–200 μm) provides a three-dimensional confined space for efficient drug encapsulation, achieving an IL-2 encapsulation efficiency of 83.3 ± 3.1%; (3) In vitro release studies demonstrated that the cumulative release of IL-2 within 72 h ranged from 18.4% to 34.7%, indicating sustained-release behavior. Cell viability assays confirmed that the hydrogel maintained the survival rate of L929 cells above 85% (as determined by the CCK-8 method), and live/dead staining revealed no apparent cytotoxicity. Overall, this three-dimensional network hydrogel based on dynamic covalent bonds represents a promising strategy for low-dose, long-lasting cytokine delivery. Full article

The aim of this paper is to review the literature on the environmental impacts of pasture-based dairy cattle systems, focusing on the factors affecting the main impact categories. This paper also aimed at comparing data of the literature on environmental impacts in pasture-based vs. confined systems. The environmental impact of pasture-based dairy cattle systems appears to be highly influenced by several input factors. Life cycle assessments have shown significant variability in methodological approaches, which complicates the comparison of results across studies. The different variables affecting environmental impacts make it challenging to draw universally valid conclusions regarding the comparison of pasture-based and confined dairy systems on a global scale. In addition, the analysis of the variables highlights the considerable potential to reduce the environmental impact of milk production in both systems by adopting productivity-enhancing activities, low inputs and best management practices. Further aspects such as geographical factors, carbon sequestration, animal health and welfare, toxicological aspects due to the use of drugs and antimicrobials in animals and the maintenance of local animal breeds should be incorporated into LCAs for a full comprehensive understanding of the environmental impacts of dairy farms. Full article

Current in vitro models fail to recapitulate specific physiological properties of the human blood–brain barrier (BBB); hence the need for a reliable platform to study central nervous system diseases and drug permeability. To mimic the normally tight blood–brain interface, primary human endothelial cells (HAECs) and primary human astrocytes (A) were grown in a confined space of the physical scaffold created by gelatin methacrylate (GelMA) hydrogel to allow optimal astrocyte–endothelial cell direct/indirect interaction. Evidence for a physiologically relevant BBB was established by assessing the expression of tight junction markers conferring the barrier function, and by measuring biophysical attributes using the trans-endothelial electrical resistance (TEER) and the Evans blue albumin (EBA) permeability assay. An HAEC+A three-dimensional (3D) co-culture was associated with 12-fold higher claudin-5 (CLDN5) and cadherin-1 (CDH1 or Epithelial [E]-cadherin) transcriptional levels than two-dimensional (2D) models. This model conferred the highest TEER (45 Ω·cm²) in 3D HAEC+A, which value was 30 Ω·cm² in 2D (p < 0.01) and 25 Ω·cm² in 3D HAEC cultures (p < 0.001). Functionally, in 3D HAEC+A co-cultures, higher TEER resulted in 10-fold and 7-fold lower EBA permeability at 120 min, in HAECs alone or in to 2D co-cultures (p < 0.01). The established human primary cell model has acquired features mimicking the human BBB in vitro, and is now poised to be tested for the permeability of the BBB to pharmacological agents, parasites, cells (such as brain-tropic cancer cell metastasis) and any mechanisms that might involve traversing the BBB. Full article

Nanotechnology, particularly quantum dots (QDs), has ushered in a transformative era in the pharmaceutical and medical industries, offering notable opportunities for nanoscale advancements. These nanoscale particles, known for their exceptional optical properties and quantum confinement, have emerged as indispensable tools in cancer drug delivery and bioimaging. This review delves into various drug conjugation techniques with QDs, including covalent linking, non-covalent conjugation, click chemistry, disulfide linkage, and pH-sensitive linkage. Each method provides distinct advantages, such as enhanced stability, reversibility, specificity, and controlled drug release. Moreover, QDs have demonstrated significant promise in oncology by efficiently delivering drugs to cancerous tissues while minimising systemic toxicity. Investigations into their applications in different cancers, such as blood, brain, cervical, breast cancers, etc., reveal their efficacy in targeted drug delivery, real-time imaging, and improved therapeutic outcomes. However, challenges such as potential toxicity, stability, pharmacokinetics, and targeting specificity must be addressed to fully harness the benefits of QDs in cancer therapy. Future research should focus on developing biocompatible QDs, optimising conjugation techniques, and elucidating their safety profiles and long-term effects in biological systems. Overall, QDs represent a promising frontier in cancer treatment, offering multifaceted capabilities that hold the potential for enhanced therapeutic outcomes and reduced side effects across various cancers. Full article

There is relatively little research on cyclic amphiphilic block polymers, having both hydrophilic and hydrophobic segments placed in the ring and thus resulting in a higher degree of topological restriction, as drug vehicles. Cyclic amphiphilic binary block polymer is synthesized by the click coupling reaction of bimolecular homodifunctional precursors. The results indicate that cyclization between linear polymer precursors is successful if the trace linear by-products generated are ignored, which also suggests that the small molecule bifunctional terminating agent applied in traditional bimolecular homodifunctional ring-closure process can be extended to large molecule. Moreover, the study on the self-assembly behavior of polymers shows that, compared with linear counterparts, the stability and drug loading capacity of micelles based on the resultant cyclic polymer are not significantly improved due to the influence of topological structure and linear impurities. Nevertheless, drug loaded micelles formed by the obtained cyclic polymers still exhibit superior cellular uptake ability. It can be seen that topological effects do play an irreplaceable role in the application performance of polymers. Therefore, the construction and synthesis of cyclic and its derivative polymers with moderate topological confinement and high purity may be a key direction for future exploration of polymer drug delivery carriers. Full article

Background/Objectives: Helicobacter pylori infects approximately half of the global population, causing chronic gastritis, peptic ulcers, and gastric cancer, a leading cause of cancer mortality. While current therapies face challenges from rising antibiotic resistance, particularly to clarithromycin, alongside treatment complexity and costs, the World Health Organization has prioritized the development of new antibiotics to combat this high-risk pathogen. In this study, we employed computer-aided drug design (CADD) methodologies, including molecular docking, Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) analysis, molecular dynamics (MD) simulations, and Density Functional Theory (DFT) calculations, to explore the potential repurposing of FDA-approved agents as inhibitors of Helicobacter pylori shikimate kinase (HpSK). Methods: Using the Glide module, the HTVS method was initially applied to screen 1615 FDA-approved agents followed by extra-precision (XP) docking for the obtained 111 hits. The obtained XP scores were used to confine the results to those hits with a score above the reference ligand, shikimate, score. This yielded 31 final hits with an XP score above −5.867. MM-GBSA calculations were performed on these top candidates and the reference ligand to refine the analysis and compounds’ prioritization. Results: The 31 compounds displayed binding free energy (ΔG_bind) values ranging from 3.61 to −55.92 kcal/mol, with shikimate exhibiting a ΔG_bind of −34.24 kcal/mol and 10 hits having a lower ΔG_bind value. Out of these ten, three drugs—Dolutegravir, Cangrelor, and Isavuconazonium—were selected for further analysis based on their drug-like properties. Robust and stable binding profiles for both Isavuconazonium and Cangrelor were verified via molecular dynamics simulation. Additionally, Density Functional Theory (DFT) analysis was conducted, and the Highest Occupied Molecular Orbitals (HOMOs), Lowest Unoccupied Molecular Orbitals (LUMOs), and the energy gap (HLG) between them were calculated. All three drug candidates displayed lower HLG values than shikimate, suggesting higher reactivity and more efficient electronic transitions than the reference ligand. Conclusions: These findings suggest that the identified drugs, although not optimal for direct repurposing, would serve as promising leads against Helicobacter pylori shikimate kinase. These drugs could be valuable leads for experimental assessment and further optimization, particularly with no prototype yet identified. In terms of potential for clinical repurposing, the results point to diflunisal as a promising candidate for further testing. Full article

Small interfering RNAs (siRNAs) are short, double-stranded RNA molecules that play a crucial role in the regulation of gene expression, particularly through a natural process called RNA interference (RNAi). Their discovery, about 25 years ago, paved the way for a whole series of research leading to synthetic molecules. The gene silencing potential of these siRNAs was initially oriented towards diseases resulting from genetic dysfunctions. This led to the development of the first synthetic siRNAs approved for human use in hereditary transthyretin amyloidosis. Subsequently, the field of application expanded beyond the confines of genetic diseases. The refinement of pharmacological techniques has led to the synthesis of a variety of siRNAs capable of blocking the production of individual proteins responsible for various disease conditions, thus expanding their field of therapeutic application. The kidney has also been affected by this new therapeutic tool, largely indirectly but also, with some difficulty, directly. The structural complexity of the kidney has made the search for siRNAs targeting its individual components very challenging. Nevertheless, the first results of the application of this new therapeutic technology to the kidney are beginning to be seen in experimental animals and in humans. siRNAs have been approved for the treatment of amyloidosis with patisiran and oxalosis with lumasiran and nedosiran. Studies are ongoing for the use of siRNAs as anti-complement drugs in IgA nephropathy, as angiotensinogen inhibitors in hypertension, or against some mediators of acute kidney injury. In this review, the biological mechanisms underlying the use of siRNAs are briefly exposed. The results of the therapeutic application of RNA interference to the kidney and its diseases are also analyzed and discussed. Full article

In exploring adjuvant therapies for head and neck cancer, hyperthermia (40–45 °C) has shown efficacy in enhancing chemotherapy and radiation, as well as the delivery of liposomal drugs. Current hyperthermia treatments, however, struggle to reach large deep tumors uniformly and non-invasively. This study investigates the feasibility of delivering targeted uniform hyperthermia deep into the tissue using a non-invasive ultrasound spherical random phased array transducer. Simulations in 3D patient-specific models for thyroid and oropharyngeal cancers assessed the transducer’s proficiency. The transducer consisting of 256 elements randomly positioned on a spherical shell, operated at a frequency of 1 MHz with various phasing schemes and power modulations to analyze 40, 41, and 43 °C isothermal volumes and the penetration depth of the heating volume, along with temperature uniformity within the target area using T10, T50, and T90 temperatures, across different tumor models. Intensity distributions and volumetric temperature contours were calculated to define moderate hyperthermia boundaries. The results indicated the array’s ability to produce controlled heating volumes from 1 to 48 cm³ at 40 °C, 0.35 to 27 cm³ at 41 °C, and 0.1 to 8 cm³ at 43 °C. The heating depths ranged from 7 to 39 mm minimum and 52 to 59 mm maximum, measured from the skin’s inner surface. The transducer, with optimal phasing and water-cooled bolus, confined the heating to the targeted regions effectively. Multifocal sonications also improved the heating homogeneity, reducing the length-to-diameter ratio by 38% when using eight foci versus a single one. This approach shows potential for treating a range of tumors, notably deep-seated and challenging oropharyngeal cancers. Full article

As an appealing approach for discovering novel leads, the key advantage of de novo drug design lies in its ability to explore a much broader dimension of chemical space, without being confined to the knowledge of existing compounds. So far, many generative models have been described in the literature, which have completely redefined the concept of de novo drug design. However, many of them lack practical value for real-world drug discovery. In this work, we have developed a graph-based generative model within a reinforcement learning framework, namely, METEOR (Molecular Exploration Through multiplE-Objective Reinforcement). The backend agent of METEOR is based on the well-established GCPN model. To ensure the overall quality of the generated molecular graphs, we implemented a set of rules to identify and exclude undesired substructures. Importantly, METEOR is designed to conduct multi-objective optimization, i.e., simultaneously optimizing binding affinity, drug-likeness, and synthetic accessibility of the generated molecules under the guidance of a special reward function. We demonstrate in a specific test case that without prior knowledge of true binders to the chosen target protein, METEOR generated molecules with superior properties compared to those in the ZINC 250k data set. In conclusion, we have demonstrated the potential of METEOR as a practical tool for generating rational drug-like molecules in the early phase of drug discovery. Full article

Since its conceptualization, click chemistry in all its variants has proven to be a superior synthesis protocol, compared to conventional methods, for forming new covalent bonds under mild conditions, orthogonally, and with high yields. If a term like reactive resilience could be established, click reactions would be good examples, as they perform better under increasingly challenging conditions. Particularly, highly hindered couplings that perform poorly with conventional chemistry protocols—such as those used to conjugate biomacromolecules (e.g., proteins and aptamers) or multiple drugs onto macromolecular platforms—can be more easily achieved using click chemistry principles, while also promoting high stereoselectivity in the products. In this review, three molecular platforms relevant in the field of nanomedicine are considered: polymers/copolymers, cyclodextrins, and fullerenes, whose functionalization poses a challenge due to steric hindrance, either from the intrinsic bulk behavior (as in polymers) or from the proximity of confined reactive sites, as seen in cyclodextrins and fullerenes. Their functionalization with biologically active groups (drugs or biomolecules), primarily through copper-catalyzed azide–alkyne cycloaddition (CuAAC), strain-promoted azide–alkyne cycloaddition (SPAAC), inverse electron-demand Diels–Alder (IEDDA) and thiol–ene click reactions, has led to the development of increasingly sophisticated systems with enhanced specificity, multifunctionality, bioavailability, delayed clearance, multi-targeting, selective cytotoxicity, and tracking capabilities—all essential in the field of nanomedicine. Full article

An intracellular protozoan, the Apicomplexan parasite Toxoplasma gondii (T. gondii) infects nucleated cells, in which it triggers the formation of a specialized membrane-confined cytoplasmic vacuole, named the parasitophorous vacuole (PV). One of the most prominent events in the parasite’s intracellular life is the congregation of the host cell mitochondria around the PV. However, the significance of this event has remained largely unsolved since the parasite itself possesses a functional mitochondrion, which is essential for its replication. Here, we explore several fundamental aspects of the interaction between the PV and the host cell mitochondria. They include the detailed features of the congregation, the nature and mechanism of the mitochondrial travel to the PV, and the potential significance of the migration and congregation. Using a combination of biochemical assays, high-resolution imaging, and RNAi-mediated knockdown, we show that: (i) mitochondrial travel to the PV starts very early in parasite infection, as soon as the smallest PV takes shape; (ii) the travel utilizes the contractile microtubular network of the host cell; and (iii) near the end of the parasitic life cycle, when most PVs have reached their largest sustainable size and are about to lyse in order to release the progeny parasites, the associated mitochondria change their usual elongated shape to small spheres, apparently resulting from increased fission. Intriguingly, despite the well-known mitochondrial role as a major producer of cellular ATP, the parasite does not seem to use cellular mitochondrial ATP. Together, these findings may serve as foundations for future research in host–parasite interaction, particularly in the elucidation of its mechanisms, and the possible development of novel antiparasitic drug regimens. Full article