The Effect of Fatalistic Tendency in Individuals on Attitudes Toward Epilepsy Patients.

Objective: This study was conducted to determine the effect of fatalistic tendency on attitudes toward epilepsy patients.

Methods: The study was conducted between August 17 and October 1, 2022 in a family health center in Sakarya province in western Türkiye. The sample consisted of 479 adults.

Infections among adults hospitalized in intensive care after the 2023 earthquake in the southeastern part of Türkiye: a multi-center observational study.

Background: Scarce evidence is available on the epidemiology of microbiologically proven clinical infections in patients admitted to the intensive care unit (ICU) after a great earthquake. The main aim of this study was to assess clinical infections and microbiological features in patients admitted to the ICU following the 2023 earthquake in the southeastern region of Türkiye with a focus on the timing of culture positivity during their ICU stay. The secondary objectives included determining antibiotic susceptibility patterns, identifying the types of antibiotics administered upon ICU admission, evaluating the appropriateness of antibiotic usage, assessing patient outcomes, and identifying factors that influence microbiologically confirmed clinical infections.

Time-resolved cryo-EM of G-protein activation by a GPCR.

G-protein-coupled receptors (GPCRs) activate heterotrimeric G proteins by stimulating guanine nucleotide exchange in the Gα subunit. To visualize this mechanism, we developed a time-resolved cryo-EM approach that examines the progression of ensembles of pre-steady-state intermediates of a GPCR-G-protein complex. By monitoring the transitions of the stimulatory G protein in complex with the β-adrenergic receptor at short sequential time points after GTP addition, we identified the conformational trajectory underlying G-protein activation and functional dissociation from the receptor.

Allosteric modulation and G-protein selectivity of the Ca-sensing receptor.

The calcium-sensing receptor (CaSR) is a family C G-protein-coupled receptor (GPCR) that has a central role in regulating systemic calcium homeostasis. Here we use cryo-electron microscopy and functional assays to investigate the activation of human CaSR embedded in lipid nanodiscs and its coupling to functional G versus G proteins in the presence and absence of the calcimimetic drug cinacalcet. High-resolution structures show that both G and G drive additional conformational changes in the activated CaSR dimer to stabilize a more extensive asymmetric interface of the seven-transmembrane domain (7TM) that involves key protein-lipid interactions.

Anxiety, Dyspnea Management, and Quality of Life in Palliative Care Patients: A Randomized Controlled Trial.

Aim: This study aimed to determine the influence of nursing care grounded on Watson's Human Care Model on anxiety, dyspnea control, and life quality in palliative care patients.

Method: A randomized controlled study was designed. It was conducted on 64 participants hospitalized in a training and research hospital and 2 state hospital palliative care services in Turkey.

Time-resolved cryo-EM of G protein activation by a GPCR.

G protein-coupled receptors (GPCRs) activate heterotrimeric G proteins by stimulating the exchange of guanine nucleotide in the Gα subunit. To visualize this mechanism, we developed a time-resolved cryo-EM approach that examines the progression of ensembles of pre-steady-state intermediates of a GPCR-G protein complex. Using variability analysis to monitor the transitions of the stimulatory Gs protein in complex with the β -adrenergic receptor (β AR) at short sequential time points after GTP addition, we identified the conformational trajectory underlying G protein activation and functional dissociation from the receptor.

Validity and Reliability of the Turkish Version of the Death Literacy Index.

Death literacy is defined as a set of knowledge and skills that make it possible to gain access to, understand, and act upon end-of-life and death care options. This study was conducted to test the validity and reliability of the 29-item original version of the Death Literacy Index (DLI) in Turkish society. The scale was applied on a sample of 436 Turkish adults determined using the snowball sampling method.

Insights into distinct signaling profiles of the µOR activated by diverse agonists.

Drugs targeting the μ-opioid receptor (μOR) are the most effective analgesics available but are also associated with fatal respiratory depression through a pathway that remains unclear. Here we investigated the mechanistic basis of action of lofentanil (LFT) and mitragynine pseudoindoxyl (MP), two μOR agonists with different safety profiles. LFT, one of the most lethal opioids, and MP, a kratom plant derivative with reduced respiratory depression in animal studies, exhibited markedly different efficacy profiles for G protein subtype activation and β-arrestin recruitment.

Structure determination of inactive-state GPCRs with a universal nanobody.

Cryogenic electron microscopy (cryo-EM) has widened the field of structure-based drug discovery by allowing for routine determination of membrane protein structures previously intractable. Despite representing one of the largest classes of therapeutic targets, most inactive-state G protein-coupled receptors (GPCRs) have remained inaccessible for cryo-EM because their small size and membrane-embedded nature impedes projection alignment for high-resolution map reconstructions. Here we demonstrate that the same single-chain camelid antibody (nanobody) recognizing a grafted intracellular loop can be used to obtain cryo-EM structures of inactive-state GPCRs at resolutions comparable or better than those obtained by X-ray crystallography.

Bespoke library docking for 5-HT receptor agonists with antidepressant activity.

There is considerable interest in screening ultralarge chemical libraries for ligand discovery, both empirically and computationally. Efforts have focused on readily synthesizable molecules, inevitably leaving many chemotypes unexplored. Here we investigate structure-based docking of a bespoke virtual library of tetrahydropyridines-a scaffold that is poorly sampled by a general billion-molecule virtual library but is well suited to many aminergic G-protein-coupled receptors.

Signaling snapshots of a serotonin receptor activated by the prototypical psychedelic LSD.

Serotonin (5-hydroxytryptamine [5-HT]) 5-HT2-family receptors represent essential targets for lysergic acid diethylamide (LSD) and all other psychedelic drugs. Although the primary psychedelic drug effects are mediated by the 5-HT serotonin receptor (HTR2A), the 5-HT serotonin receptor (HTR2B) has been used as a model receptor to study the activation mechanisms of psychedelic drugs due to its high expression and similarity to HTR2A. In this study, we determined the cryo-EM structures of LSD-bound HTR2B in the transducer-free, Gq-protein-coupled, and β-arrestin-1-coupled states.

The tethered peptide activation mechanism of adhesion GPCRs.

Adhesion G-protein-coupled receptors (aGPCRs) are characterized by the presence of auto-proteolysing extracellular regions that are involved in cell-cell and cell-extracellular matrix interactions. Self cleavage within the aGPCR auto-proteolysis-inducing (GAIN) domain produces two protomers-N-terminal and C-terminal fragments-that remain non-covalently attached after receptors reach the cell surface. Upon dissociation of the N-terminal fragment, the C-terminus of the GAIN domain acts as a tethered agonist (TA) peptide to activate the seven-transmembrane domain with a mechanism that has been poorly understood.

Asymmetric activation of the calcium-sensing receptor homodimer.

The calcium-sensing receptor (CaSR), a cell-surface sensor for Ca, is the master regulator of calcium homeostasis in humans and is the target of calcimimetic drugs for the treatment of parathyroid disorders. CaSR is a family C G-protein-coupled receptor that functions as an obligate homodimer, with each protomer composed of a Ca-binding extracellular domain and a seven-transmembrane-helix domain (7TM) that activates heterotrimeric G proteins. Here we present cryo-electron microscopy structures of near-full-length human CaSR in inactive or active states bound to Ca and various calcilytic or calcimimetic drug molecules.

G-protein activation by a metabotropic glutamate receptor.

Family C G-protein-coupled receptors (GPCRs) operate as obligate dimers with extracellular domains that recognize small ligands, leading to G-protein activation on the transmembrane (TM) domains of these receptors by an unknown mechanism. Here we show structures of homodimers of the family C metabotropic glutamate receptor 2 (mGlu2) in distinct functional states and in complex with heterotrimeric G. Upon activation of the extracellular domain, the two transmembrane domains undergo extensive rearrangement in relative orientation to establish an asymmetric TM6-TM6 interface that promotes conformational changes in the cytoplasmic domain of one protomer.

Structural and functional dissection of reovirus capsid folding and assembly by the prefoldin-TRiC/CCT chaperone network.

Intracellular protein homeostasis is maintained by a network of chaperones that function to fold proteins into their native conformation. The eukaryotic TRiC chaperonin (TCP1-ring complex, also called CCT for cytosolic chaperonin containing TCP1) facilitates folding of a subset of proteins with folding constraints such as complex topologies. To better understand the mechanism of TRiC folding, we investigated the biogenesis of an obligate TRiC substrate, the reovirus σ3 capsid protein.

Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6.

Heterotrimeric G proteins communicate signals from activated G protein-coupled receptors to downstream effector proteins. In the phototransduction pathway responsible for vertebrate vision, the G protein-effector complex is composed of the GTP-bound transducin α subunit (Gα·GTP) and the cyclic GMP (cGMP) phosphodiesterase 6 (PDE6), which stimulates cGMP hydrolysis, leading to hyperpolarization of the photoreceptor cell. Here we report a cryo-electron microscopy (cryoEM) structure of PDE6 complexed to GTP-bound Gα.

Structure of a Hallucinogen-Activated Gq-Coupled 5-HT Serotonin Receptor.

Hallucinogens like lysergic acid diethylamide (LSD), psilocybin, and substituted N-benzyl phenylalkylamines are widely used recreationally with psilocybin being considered as a therapeutic for many neuropsychiatric disorders including depression, anxiety, and substance abuse. How psychedelics mediate their actions-both therapeutic and hallucinogenic-are not understood, although activation of the 5-HT serotonin receptor (HTR2A) is key. To gain molecular insights into psychedelic actions, we determined the active-state structure of HTR2A bound to 25-CN-NBOH-a prototypical hallucinogen-in complex with an engineered Gαq heterotrimer by cryoelectron microscopy (cryo-EM).

Structures of metabotropic GABA receptor.

Stimulation of the metabotropic GABA receptor by γ-aminobutyric acid (GABA) results in prolonged inhibition of neurotransmission, which is central to brain physiology. GABA belongs to family C of the G-protein-coupled receptors, which operate as dimers to transform synaptic neurotransmitter signals into a cellular response through the binding and activation of heterotrimeric G proteins. However, GABA is unique in its function as an obligate heterodimer in which agonist binding and G-protein activation take place on distinct subunits.

Structures of Gα Proteins in Complex with Their Chaperone Reveal Quality Control Mechanisms.

Many chaperones promote nascent polypeptide folding followed by substrate release through ATP-dependent conformational changes. Here we show cryoEM structures of Gα subunit folding intermediates in complex with full-length Ric-8A, a unique chaperone-client system in which substrate release is facilitated by guanine nucleotide binding to the client G protein. The structures of Ric-8A-Gα and Ric-8A-Gα complexes reveal that the chaperone employs its extended C-terminal region to cradle the Ras-like domain of Gα, positioning the Ras core in contact with the Ric-8A core while engaging its switch2 nucleotide binding region.

Comprehensive evaluation of irisin levels in fetomaternal circulation of pregnant women with obesity or gestational diabetes mellitus.

Aim: To evaluate maternal and cord blood irisin levels in pregnant women with gestational diabetes mellitus (GDM) and in obese pregnant women without GDM.

Methods: The study included 109 patients, with 34 patients in the GDM group, 40 in the obese non-GDM group, and 35 in the control group. Maternal serum irisin levels at the time of delivery were measured by an enzyme-linked immunosorbent assay kit.

Temperament and character differences of patients with polycystic ovary syndrome.

Aim: There is an unclear relationship between Polycystic Ovary Syndrome and psychiatric disorders including anxiety and depression. We aimed to evaluate temperamental and personal characteristics of patients with PCOS.

Methods: Fifty patients with PCOS and 41 healthy controls were included in the study.

Dendronic trimaltoside amphiphiles (DTMs) for membrane protein study.

The critical contribution of membrane proteins in normal cellular function makes their detailed structure and functional analysis essential. Detergents, amphipathic agents with the ability to maintain membrane proteins in a soluble state in aqueous solution, have key roles in membrane protein manipulation. Structural and functional stability is a prerequisite for biophysical characterization.

Vitamin E-based glycoside amphiphiles for membrane protein structural studies.

Membrane proteins play critical roles in a variety of cellular processes. For a detailed molecular level understanding of their biological functions and roles in disease, it is necessary to extract them from the native membranes. While the amphipathic nature of these bio-macromolecules presents technical challenges, amphiphilic assistants such as detergents serve as useful tools for membrane protein structural and functional studies.

Simultaneous lipid and content mixing assays for in vitro reconstitution studies of synaptic vesicle fusion.

This protocol describes reconstitution assays to study how the neurotransmitter release machinery triggers Ca-dependent synaptic vesicle fusion. The assays monitor fusion between proteoliposomes containing the synaptic vesicle SNARE synaptobrevin (with or without the Ca sensor synaptotagmin-1) and proteoliposomes initially containing the plasma membrane SNAREs syntaxin-1 and soluble NSF attachment protein (SNAP)-25. Lipid mixing (from fluorescence de-quenching of Marina-Blue-labeled lipids) and content mixing (from development of fluorescence resonance energy transfer (FRET) between phycoerythrin-biotin (PhycoE-Biotin) and Cy5-streptavidin trapped in the two proteoliposome populations) are measured simultaneously to ensure that true, nonleaky membrane fusion is monitored.