Editorial for the Special Issue "Hydrogels for 3D Printing".

Hydrogels, which are three-dimensional networks of hydrophilic polymers capable of absorbing and retaining large amounts of water, have emerged as versatile materials with vast potential in various fields [...

[Superficial siderosis of the central nervous system. Report of one case].

Superficial siderosis of the central nervous system is produced by the deposit of hemosiderin within the subpial layers of the central nervous system and central parts of the cranial nerves, leading to progressive degeneration. We report a 55-year-old male who consulted for hearing loss and long-standing progressive decrease in visual acuity, associated with sudden onset of left hemiparesis. A brain CAT scan showed subacute ischemic lesions in the territory of the right posterior cerebral artery (thalamus and right subcortical temporal regions), old ischemic lesions in the right subcortical occipital regions and cerebellar atrophy.

Pellets and gummies: Seeking a 3D printed gastro-resistant omeprazole dosage for paediatric administration.

The production of 3D printed pharmaceuticals has thrived in recent years, as it allows the generation of customised medications in small batches. This is particularly helpful for patients who need specific doses or formulations, such as children. Compounding pharmacies seek alternatives to conventional solid oral doses, opting for oral liquid formulations.

Essential Guide to Hydrogel Rheology in Extrusion 3D Printing: How to Measure It and Why It Matters?

Rheology plays a crucial role in the field of extrusion-based three-dimensional (3D) printing, particularly in the context of hydrogels. Hydrogels have gained popularity in 3D printing due to their potential applications in tissue engineering, regenerative medicine, and drug delivery. The rheological properties of the printing material have a significant impact on its behaviour throughout the 3D printing process, including its extrudability, shape retention, and response to stress and strain.

Gold-catalyzed -selective cyclization of alkynylcyclobutanecarboxamides: synthesis of cyclobutane-fused dihydropyridones.

Cyclobutane-fused dihydropyridones can be efficiently synthesized by a completely -selective gold-catalyzed cyclization of alkynylcyclobutanes bearing an appended amide, which proceeds under mild conditions. The observed selectivity, which is reversed from that previously observed for the cyclization of related alcohols and acids, is supported by DFT calculations.

Effect on Rheological Properties and 3D Printability of Biphasic Calcium Phosphate Microporous Particles in Hydrocolloid-Based Hydrogels.

The production of patient-specific bone substitutes with an exact fit through 3D printing is emerging as an alternative to autologous bone grafting. To the success of tissue regeneration, the material characteristics such as porosity, stiffness, and surface topography have a strong influence on the cell-material interaction and require significant attention. Printing a soft hydrocolloid-based hydrogel reinforced with irregularly-shaped microporous biphasic calcium phosphate (BCP) particles (150-500 µm) is an alternative strategy for the acquisition of a complex network with good mechanical properties that could fulfill the needs of cell proliferation and regeneration.

Three-dimensional bioprinted cancer models: A powerful platform for investigating tunneling nanotube-like cell structures in complex microenvironments.

Bioprinting technology offers layer-by-layer positioning of cells within 3D space with complexity and a defined architecture. Cancer models based in this biofabrication technique are important tools to achieve representative and realistic in vivo conditions of the tumor microenvironment. Here, we show the development of a proof-of-concept three-dimensional bioprinted cancer model that successfully recapitulates the intercellular communication via the assembly of functional tunneling nanotube (TNT)-like cell projections.

3D printed gummies: Personalized drug dosage in a safe and appealing way.

Obtention of customized dosage forms is one of the main attractions of 3D printing in pharmaceuticals. In this sense, children are one of the groups within the population with a greater need for drug doses adapted to their requirements (age, weight, pathological state…), but most 3D printed oral dosages are solid forms and, therefore, not suitable for them. This work developed patient-tailored medicinal gummies, an alternative oral dosage form with eye-catching appearance and appropriate organoleptic characteristics.

Regiodivergent Electrophilic Cyclizations of Alkynylcyclobutanes for the Synthesis of Cyclobutane-Fused O-Heterocycles.

Cyclobutane-fused dihydropyrans and methylenetetrahydrofurans are highly interesting cores found in numerous natural products. Both these cores are selectively prepared from a common alkynylcyclobutane precursor bearing an appended hydroxyl group herein. Thus, cyclobutane-fused dihydropyrans can be obtained by a selective 6-endo-dig iodocyclization, whereas gold-catalyzed 5-exo-dig cycloisomerization provides a bicyclic core containing a methylenetetrahydrofuran moiety as major product.

Dramatic Reduction in 30-Day Readmissions Through High-Risk Screening and Two-Phase Interdisciplinary Care.

Objectives: Thirty-day readmissions are common, serious, and costly. Most important, often they are preventable. The purpose of this quality improvement study was to evaluate an interdisciplinary, two-phase intervention to reduce 30-day readmissions among high-risk medical patients.

1,3-Dien-5-ynes: Versatile Building Blocks for the Synthesis of Carbo- and Heterocycles.

1,3-Dien-5-ynes have been extensively used as starting materials for the synthesis of a wide number of different carbo- and heterocycles. The aim of this review is to give an overview of their utility in organic synthesis, highlighting the variety of compounds that can be directly accessed from single reactions over these systems. Thus, cycloaromatization processes are initially commented, followed by reactions directed toward the syntheses of five-membered rings, other carbocycles and, finally, heterocycles.

Regioselective synthesis of oxepinones and azepinones by gold-catalyzed cycloisomerization of functionalyzed cyclopropyl alkynes.

A regioselective synthesis of oxepinones and azepinones in good to excellent yields from alkynylcyclopropanecarboxylic acid derivatives is described. This novel cycloisomerization cascade process consists of a nucleophilic addition followed by a cyclopropane ring-opening, where both donor and acceptor groups are required as substituents of the cyclopropane ring.

Characterization of the reproductive effects of the Vgf-derived peptide TLQP-21 in female rats: in vivo and in vitro studies.

Background: VGF (non-acronymic), a protein expressed in the hypothalamus and pituitary, is involved in the control of metabolism and body weight homeostasis. Different active peptide fragments are generated from VGF, including TLQP-21. Previous studies of our group reported that this molecule participates also in the regulation of reproductive function in male rats, with predominant stimulatory effects.

Differential modulation of gonadotropin responses to kisspeptin by aminoacidergic, peptidergic, and nitric oxide neurotransmission.

Kisspeptins (Kp), products of the Kiss1 gene, have emerged as essential elements in the control of GnRH neurons and gonadotropic secretion. However, despite considerable progress in the field, to date limited attention has been paid to elucidate the potential interactions of Kp with other neurotransmitters known to centrally regulate the gonadotropic axis. We characterize herein the impact of manipulations of key aminoacidergic (glutamate and GABA), peptidergic (NKB, Dyn, and MCH), and gaseous [nitric oxide (NO)] neurotransmission on gonadotropin responses to Kp-10 in male rats.

Kisspeptins and reproduction: physiological roles and regulatory mechanisms.

Procreation is essential for survival of species. Not surprisingly, complex neuronal networks have evolved to mediate the diverse internal and external environmental inputs that regulate reproduction in vertebrates. Ultimately, these regulatory factors impinge, directly or indirectly, on a final common pathway, the neurons producing the gonadotropin-releasing hormone (GnRH), which stimulates pituitary gonadotropin secretion and thereby gonadal function.

Catalytic intermolecular hetero-dehydro-Diels-Alder cycloadditions: regio- and diasteroselective synthesis of 5,6-dihydropyridin-2-ones.

A novel catalyzed intermolecular heterodehydro-Diels-Alder reaction between push-pull 1,3-dien-5-ynes and aldimines or silylaldimines is reported. The sequence is promoted both by gold(I) or silver(I) catalysts and leads to the diastereo- and regioselective formation of 5,6-dihydropyridin-2-ones.

Early metabolic programming of puberty onset: impact of changes in postnatal feeding and rearing conditions on the timing of puberty and development of the hypothalamic kisspeptin system.

Kiss1 neurons have recently emerged as a putative conduit for the metabolic gating of reproduction, with leptin being a regulator of hypothalamic Kiss1 expression. Early perturbations of the nutritional status are known to predispose to different metabolic disorders later in life and to alter the timing of puberty; however, the potential underlying mechanisms remain poorly defined. Here we report how changes in the pattern of postnatal feeding affect the onset of puberty and evaluate key hormonal and neuropeptide [Kiss1/kisspeptin (Kp)] alterations linked to these early nutritional manipulations.

Characterization of the reproductive effects of the anorexigenic VGF-derived peptide TLQP-21: in vivo and in vitro studies in male rats.

VGF (nonacronymic) is a 68-kDa protein encoded by the homonymous gene, which is expressed abundantly at the hypothalamus and has been involved in the control of metabolism and body weight homeostasis. Different active peptide fragments are generated from VGF, including TLQP-21. Circumstantial evidence has suggested that VGF might also participate in the control of reproduction.

[Orthostatic tremor causing postural instability in Parkinson disease: report of one case].

Parkinson disease (PD) is a movement disorder characterized clinically by the variable combination of rigidity, bradykinesia, rest tremor and postural instability. Usually postural instability is a late-onset manifestation and is frequently associated with axial manifestations and with a poor prognosis. We report a 67-year-old female with orthostatic tremor as the etiology of her postural instability.

Competitive pathways in the reaction of lithium oxy-ortho-quinodimethanes and Fischer alkoxy alkynyl carbene complexes: synthesis of highly functionalised seven-membered benzocarbocycles.

Up to four different outcomes have been found for the reaction between 1-oxy-ortho-quinodimethanes (oQDMs) and alkoxy alkynyl Fischer carbene complexes (FCCs). The product formed depends on the structure of both reagents and on the reaction solvent. The pathways can be topologically classified as a [4C+2C], a [3(2C+O)+3C], and two different [4C+3C] processes and, in all these sequences, 1-oxy-oQDMs behave as enolates or as vinylogous enolates.

Multi-component reactions involving group 6 Fischer carbene complexes: a source of inspiration for future catalytic transformations.

The ability of heteroatom stabilized Fischer carbene complexes (FCCs) to participate in multicomponent reactions (MCRs) has become a characteristic of such organometallics, particularly of chromium carbenes. This feature article updates the main results in this field during the last lustrum, highlighting the ability of FCCs for the construction of densely functionalized frameworks, mainly through the successive incorporation of unsaturated moieties (alkynes, CO ligands,…) in a sequential manner. Examples where up to seven components are coupled will be presented.

Exemestane and chemotherapy as first-line treatment of metastatic breast cancer: results of a phase II study.

Background: Metastatic breast cancer remains largely incurable. Strategies involving the combination of the selective estrogen receptor modulator tamoxifen and chemotherapy have been abandoned in view of unacceptable toxicity because of thromboembolic events. The aim of this study was to investigate the safety and efficacy of the third-generation steroidal aromatase inhibitor exemestane plus chemotherapy.

The anorexigenic neuropeptide, nesfatin-1, is indispensable for normal puberty onset in the female rat.

The hypothalamic peptide, nesfatin-1, derived from the precursor NEFA/nucleobindin 2 (NUCB2), was recently identified as anorexigenic signal, acting in a leptin-independent manner. Yet its participation in the regulation of other biological functions gated by body energy status remains unexplored. We show herein that NUCB2/nesfatin-1 is involved in the control of female puberty.

Physiological roles of the kisspeptin/GPR54 system in the neuroendocrine control of reproduction.

Reproductive maturation and function are maintained by a complex neurohormonal network that integrates at the so-called hypothalamic-pituitary-gonadal (HPG) axis. This system is hierarchically controlled by the decapeptide, GnRH, which in turn is under the dynamic regulation of multiple stimulatory and inhibitory pathways, including peripheral signals (prominently, sex steroids) and different central modulators. Among the latter, considerable interest has been raised recently by the identification of the major roles and mechanisms of action of kisspeptins, a family of neuropeptides encoded by the Kiss1 gene, which acting via the G protein-coupled receptor, GPR54, have been shown to play essential functions as potent activators and major gatekeepers of the HPG axis.