More than an Amide Bioisostere: Discovery of 1,2,4-Triazole-containing Pyrazolo[1,5-a]pyrimidine Host CSNK2 Inhibitors for Combatting ß-Coronavirus Replication.

The pyrazolo[1,5-a]pyrimidine scaffold is a promising scaffold to develop potent and selective CSNK2 inhibitors with antiviral activity against ß-coronaviruses. Herein, we describe the discovery of a 1,2,4-triazole group to substitute a key amide group for CSNK2 binding present in many potent pyrazolo[1,5-a]pyrimidine inhibitors. Crystallographic evidence demonstrates that the 1,2,4-triazole replaces the amide in forming key hydrogen bonds with Lys68 and a water molecule buried in the ATP-binding pocket. This isosteric replacement improves potency and metabolic stability at a cost of solubility. Optimization for potency, solubility, and metabolic stability led to the discovery of the potent and selective CSNK2 inhibitor 53. Despite excellent in vitro metabolic stability, rapid decline in plasma concentration of 53 in vivo was observed and may be attributed to lung accumulation, although in vivo pharmacological effect was not observed. Further optimization of this novel chemotype may validate CSNK2 as an antiviral target in vivo.

Low-energy electronic structure in the unconventional charge-ordered state of ScV6Sn6.

Kagome vanadates AV3Sb5 display unusual low-temperature electronic properties including charge density waves (CDW), whose microscopic origin remains unsettled. Recently, CDW order has been discovered in a new material ScV6Sn6, providing an opportunity to explore whether the onset of CDW leads to unusual electronic properties. Here, we study this question using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM). The ARPES measurements show minimal changes to the electronic structure after the onset of CDW. However, STM quasiparticle interference (QPI) measurements show strong dispersing features related to the CDW ordering vectors. A plausible explanation is the presence of a strong momentum-dependent scattering potential peaked at the CDW wavevector, associated with the existence of competing CDW instabilities. Our STM results further indicate that the bands most affected by the CDW are near vHS, analogous to the case of AV3Sb5 despite very different CDW wavevectors.

Candida parapsilosis: heterogeneous and strain-specific expression of secreted aspartic proteases (Sapp1 and Sapp2).

The increasing prevalence of Candida parapsilosis as a causative agent of fungal infections underscores the need to comprehensively understand its virulence factors. Secreted aspartic proteases (Saps) play a significant role in adhesion events, promoting biofilm formation, causing tissue damage and evading the host immune response. The present study investigates the production dynamics of Sapp1 and Sapp2 across 10 clinical isolates of C. parapsilosis using various approaches. Each fungal isolate demonstrated the capability to utilize bovine serum albumin (BSA) as the sole nitrogen source, as evidenced by its degradation in cell-free culture medium, forming low molecular mass polypeptides. Interestingly, the degradation of different proteinaceous substrates, such as BSA, human serum albumin (HSA), gelatin and hemoglobin, was typically isolate-dependent. Notably, higher proteolysis of HSA compared to BSA, gelatin and hemoglobin was observed. A quantitative assay revealed that the cleavage of a peptide fluorogenic substrate (cathepsin D) was isolate-specific, ranging from 44.15 to 270.61 FAU, with a mean proteolysis of 150.7 FAU. The presence of both Sapp1 and Sapp2 antigens on the cell surface of these fungal isolates was confirmed through immunological detection employing specific anti-Sapp1 and anti-Sapp2 antibodies. The surface levels of Sapp1 were consistently higher, up to fourfold, compared to Sapp2. Similarly, higher levels of Sapp1 than Sapp2 were detected in fungal secretions. This study provides insights into the dynamic expression and regulation of Sapps in C. parapsilosis, highlighting a known virulence factor that is considered a potential target for drug development against this increasingly prominent pathogen.

The fungal pathogen Candida parapsilosis can secrete aspartic proteases (Sapps) as part of its arsenal of virulence factors. We demonstrated that Sapps were able to cleave key host proteins, and the production of Sapp1 and Sapp2 antigens was typically dependent on the fungal isolate when grown in both planktonic- and biofilm-forming cells.

Protein Tyrosine Phosphatase Receptors N and N2 Control Pituitary Melanotroph Development and POMC Expression.

The neuroendocrine marker genes Ptprn and Ptprn2 encode protein tyrosine phosphatase receptors N and N2, 2 members of protein tyrosine phosphatase receptors void of enzymatic activity, and whose function and mechanism of action have not been elucidated. To explore the role(s) of Ptprn and Ptprn2 on the hypothalamic-pituitary-adrenal axis, we used mice in which both genes were knocked out (DKO). The focus in this study was on corticotrophs and melanotrophs from the anterior and intermediate lobes of the pituitary gland, respectively. In both sexes, DKO caused an increase in the expression of the corticotroph/melanotroph genes Pomc and Tbx19 and the melanotroph-specific gene Pax7. We also found in vivo and in vitro increased synthesis and release of beta-endorphin, alpha-melanocyte-stimulating hormone, and ACTH in DKO mice, which was associated with increased serum corticosterone levels and adrenal mass. DKO also increased the expression of other melanotroph-specific genes, but not corticotroph-specific genes. The dopaminergic pathway in the hypothalamus and dopaminergic receptors in melanotrophs were not affected in DKO mice. However, hyperplasia of the intermediate lobe was observed in DKO females and males, accompanied by increased proopiomelanocortin immunoreactivity per cell. These results indicate that protein tyrosine phosphatase receptor type N contributes to hypothalamic-pituitary-adrenal function by being involved in processes governing postnatal melanotroph development and Pomc expression.

(S)-ML-SA1 ACTIVATES AUTOPHAGY VIA TRPML1-TFEB PATHWAY.

Autophagic flux plays a crucial role in various diseases. Recently, the lysosomal ion channel TRPML1 has emerged as a promising target in lysosomal storage diseases, such as mucolipidosis. The discovery of mucolipin synthetic agonist-1 (ML-SA1) has expanded our understanding of TRPML1's function and its potential therapeutic uses. However, ML-SA1 is a racemate with limited cellular potency and poor water solubility. In this study, we synthetized rac-ML-SA1, separated the enantiomers by chiral liquid chromatography and determined their absolute configuration by vibrational circular dichroism (VCD). In addition, we focused on investigating the impact of each enantiomer of ML-SA1 on the TRPML1-TFEB axis. Our findings revealed that (S)-ML-SA1 acts as an agonist for TRPML1 at the lysosomal membrane. This activation prompts transcription factor EB (TFEB) to translocate from the cytosol to the nucleus in a dose-dependent manner within live cells. Consequently, this signaling pathway enhances the expression of coordinated lysosomal expression and regulation (CLEAR) genes and activates autophagic flux. Our study presents evidence for the potential use of (S)-ML-SA1 in the development of new therapies for lysosomal storage diseases that target TRPML1.

Chemical and Bioactive Evaluation of Essential Oils from Edible and Aromatic Mediterranean Lamiaceae Plants.

The Lamiaceae family, which includes several well-known aromatic plants, is scientifically relevant due to its essential oils (EOs). In this work, four EOs from Mediterranean species, namely Origanum vulgare L., Rosmarinus officinalis L., Salvia officinalis L., and Thymus vulgaris L., were evaluated for their volatile profiles and the biological activity in vitro to assess their potential use in the food and cosmetic sector. GC/MS analysis revealed dominant compounds, such as carvacrol, thymol, and eucalyptol. Regarding biological action, the samples exhibited antioxidant, cytotoxic, anti-inflammatory, antimicrobial, and antifungal activities, with O. vulgare and T. officinalis standing out. T. vulgaris showed the lowest EC50 in the reducing power assay, and O. vulgare had the lowest EC50 in the DPPH assay. Most EOs also displayed excellent anti-inflammatory responses and antifungal properties, with O. vulgare and T. vulgaris also demonstrating antibacterial activity. All EOs from Mediterranean species showed cytotoxicity against tumoral cell lines. Overall, the selected EOs stood out for their interesting bioactivities, with the obtained results underscoring their potential as natural preservatives and bioactive agents in various industrial applications, including food, pharmaceuticals, and cosmetics.

Enhancing Histopathological Image Classification Performance through Synthetic Data Generation with Generative Adversarial Networks.

Breast cancer is the second most common cancer worldwide, primarily affecting women, while histopathological image analysis is one of the possibile methods used to determine tumor malignancy. Regarding image analysis, the application of deep learning has become increasingly prevalent in recent years. However, a significant issue is the unbalanced nature of available datasets, with some classes having more images than others, which may impact the performance of the models due to poorer generalizability. A possible strategy to avoid this problem is downsampling the class with the most images to create a balanced dataset. Nevertheless, this approach is not recommended for small datasets as it can lead to poor model performance. Instead, techniques such as data augmentation are traditionally used to address this issue. These techniques apply simple transformations such as translation or rotation to the images to increase variability in the dataset. Another possibility is using generative adversarial networks (GANs), which can generate images from a relatively small training set. This work aims to enhance model performance in classifying histopathological images by applying data augmentation using GANs instead of traditional techniques.

Clustering of 24H movement behaviors associated with clinic blood pressure in older adults: a cross-sectional study.

Physical activity (PA), sedentary behavior (SB), and sleep duration are known to have an individual effect on clinic blood pressure (BP) of older adults. However, whether different patterns of these so-called movement behaviors over the 24h-cycle on BP remains poorly investigated. The study aimed to identify movement behavior patterns associated with clinic BP among older adults with chronic diseases. Cross-sectional study with 238 older adults (80.3% female; mean age 68.8 ± 6.6) with at least one chronic disease. PA, SB, and sleep duration were measured by a triaxial accelerometer. Clinic systolic BP (SBP) and diastolic BP (DBP) were obtained through an automated method following standard procedures. Non-hierarchical K-means cluster and linear regression modeling were employed to identify the clusters of movement behaviors and to examine the associations. Two clusters were identified [active and non-sedentary, n = 103 (i.e., sufficient sleep duration, higher LPA and MVPA, and lower SB) and sedentary and inactive, n = 135 (i.e., sufficient sleep duration, lower LPA and MVPA, and higher SB). Active and non-sedentary older adults presented lower systolic BP compared to sedentary and inactive ones, even after adjustments for sociodemographic and clinical characteristics (ß = 6.356; CI 95% from 0.932 to 11.779; P = 0.022). No associations were found for diastolic BP. In conclusion, higher PA and lower SB were associated with lower systolic BP in older adults with chronic diseases. However, sleep duration did not modify this association. Therefore, interventions focusing on concomitantly increasing PA levels and reducing SB should be the priority for controlling blood pressure.

Dietary protein modulates intestinal dendritic cells to establish mucosal homeostasis.

Dietary proteins are taken up by intestinal dendritic cells (DCs), cleaved into peptides, loaded to major histocompatibility complexes, and presented to T cells to generate an immune response. Amino acid (AA)-diets do not have the same effects because AAs cannot bind to major histocompatibility complex to activate T cells. Here, we show that impairment in regulatory T cell generation and loss of tolerance in mice fed a diet lacking whole protein is associated with major transcriptional changes in intestinal DCs including downregulation of genes related to DC maturation, activation and decreased gene expression of immune checkpoint molecules. Moreover, the AA-diet had a profound effect on microbiome composition, including an increase in Akkermansia muciniphilia and Oscillibacter and a decrease in Lactococcus lactis and Bifidobacterium. Although microbiome transfer experiments showed that AA-driven microbiome modulates intestinal DC gene expression, most of the unique transcriptional change in DC was linked to the absence of whole protein in the diet. Our findings highlight the importance of dietary proteins for intestinal DC function and mucosal tolerance.

Optical manipulation of the charge-density-wave state in RbV3Sb5.

Broken time-reversal symmetry in the absence of spin order indicates the presence of unusual phases such as orbital magnetism and loop currents1-4. The recently discovered kagome superconductors AV3Sb5 (where A is K, Rb or Cs)5,6 display an exotic charge-density-wave (CDW) state and have emerged as a strong candidate for materials hosting a loop current phase. The idea that the CDW breaks time-reversal symmetry7-14 is, however, being intensely debated due to conflicting experimental data15-17. Here we use laser-coupled scanning tunnelling microscopy to study RbV3Sb5. By applying linearly polarized light along high-symmetry directions, we show that the relative intensities of the CDW peaks can be reversibly switched, implying a substantial electro-striction response, indicative of strong nonlinear electron-phonon coupling. A similar CDW intensity switching is observed with perpendicular magnetic fields, which implies an unusual piezo-magnetic response that, in turn, requires time-reversal symmetry breaking. We show that the simplest CDW that satisfies these constraints is an out-of-phase combination of bond charge order and loop currents that we dub a congruent CDW flux phase. Our laser scanning tunnelling microscopy data open the door to the possibility of dynamic optical control of complex quantum phenomenon in correlated materials.

Estimating the therapeutic potential of NSAIDs and linoleic acid-isomers supplementation against neuroinflammation.

Nonsteroidal anti-inflammatory drugs (NSAIDs) regulate inflammation, which is associated with their role in preventing neurodegenerative diseases in epidemiological studies. It has sparked interest in their unconventional application for reducing neuroinflammation, opening up new avenues in biomedical research. However, given the pharmacological drawbacks of NSAIDs, the development of formulations with naturally antioxidant/anti-inflammatory dietary fatty acids has been demonstrated to be advantageous for the clinical translation of anti-inflammatory-based therapies. It includes improved blood-brain barrier (BBB) permeability and reduced toxicity. It permits us to speculate about the value of linoleic acid (LA)-isomers in preventing and treating neuroinflammatory diseases compared to NSAIDs. Our research delved into the impact of various factors, such as administration route, dosage, timing of intervention, and BBB permeability, on the efficacy of NSAIDs and LA-isomers in preclinical and clinical settings. We conducted a systematic comparison between NSAIDs and LA-isomers regarding their therapeutic effectiveness, BBB compatibility, and side effects. Additionally, we explored their underlying mechanisms in addressing neuroinflammation. Through our analysis, we've identified challenges and drawn conclusions that could propel advancements in treating neurodegenerative diseases and inform the development of future alternative therapeutic strategies.

Superconductivity due to fluctuating loop currents.

Orbital magnetism and the loop currents (LCs) that accompany it have been proposed to emerge in many systems, including cuprates, iridates, and kagome superconductors. In the case of cuprates, LCs have been put forward as the driving force behind the pseudogap, strange-metal behavior, and dx2-y2-wave superconductivity. Here, we investigate whether fluctuating intra-unit-cell LCs can cause unconventional superconductivity. For odd-parity LCs, we find that they are repulsive in all pairing channels near the underlying quantum-critical point (QCP). For even-parity LCs, their fluctuations give rise to unconventional pairing, which is not amplified in the vicinity of the QCP, in sharp contrast to pairing mediated by spin-magnetic, nematic, or ferroelectric fluctuations. Applying our formalism to the cuprates, we conclude that fluctuating intra-unit-cell LCs are unlikely to yield dx2-y2-wave superconductivity. If LCs are to be relevant for the cuprates, they must break translation symmetry.

Binary and Ternary Deep Eutectic Solvents for Methylene Green Electropolymerization on Multiwalled Carbon Nanotubes: Optimization, Characterization and Application.

Choline chloride (ChCl) based binary and ternary deep eutectic solvents (DES) were evaluated for methylene green electropolymerization with oxalic acid (OA) and ethylene glycol (EG) as hydrogen bond donors. Binary DES ChCl:OA in molar ratios 1:1 and 2:1 and ChCl:EG 1:2 and ternary DES (tDES) in different molar ratios and percentages of water were evaluated. The highest polymer growth was in ChCl:OA:EG-tDES with added water, that had a lower viscosity and higher ionic conductivity when associated with HCl as dopant. This enhanced the formation of more cation radicals and, consequently, more polymer formation. The PMG/MWCNT/GCE-tDES sensor was successfully applied to the simultaneous determination of 5-aminosalicylic acid (5-ASA) and acetaminophen (APAP) by differential pulse voltammetry in the concentration range 2 µM - 200 µM, with detection limits of 0.37 µM and 0.49 µM for 5-ASA and APAP, respectively. The sensor demonstrated good repeatability, reproducibility and stability, and was successfully applied in pharmaceutical formulations.

Novel Dihydropteridinone Derivatives As Potent Inhibitors of the Understudied Human Kinases Vaccinia-Related Kinase 1 and Casein Kinase 1δ/ε.

Vaccinia-related kinase 1 (VRK1) and the δ and ε isoforms of casein kinase 1 (CK1) are linked to various disease-relevant pathways. However, the lack of tool compounds for these kinases has significantly hampered our understanding of their cellular functions and therapeutic potential. Here, we describe the structure-based development of potent inhibitors of VRK1, a kinase highly expressed in various tumor types and crucial for cell proliferation and genome integrity. Kinome-wide profiling revealed that our compounds also inhibit CK1δ and CK1ε. We demonstrate that dihydropteridinones 35 and 36 mimic the cellular outcomes of VRK1 depletion. Complementary studies with existing CK1δ and CK1ε inhibitors suggest that these kinases may play overlapping roles in cell proliferation and genome instability. Together, our findings highlight the potential of VRK1 inhibition in treating p53-deficient tumors and possibly enhancing the efficacy of existing cancer therapies that target DNA stability or cell division.

Secondary fracture prevention in Spanish primary care: results of the PREFRAOS Study.

This study demonstrated a large treatment gap in elderly subjects experiencing fragility fracture in Spanish primary care, a low treatment persistence among subjects who do receive treatment, and more than one-quarter having no follow-up visits post-fracture. These data highlight the need to improve secondary fracture prevention in primary care. PURPOSE: To describe osteoporosis (OP) treatment patterns and follow-up in subjects with fragility fracture seen in Spanish primary care (PC). METHODS: This observational, retrospective chart review included subjects aged ≥ 70 years listed in the centers' records (November 2018 to March 2020), with ≥ 1 fragility fracture and prior consultation for any reason; subjects who had participated in another study were excluded. Outcomes included OP treatments and follow-up visits post-fragility fracture. RESULTS: Of 665 subjects included, most (87%) were women; overall mean (SD) age, 82 years. Fewer than two thirds (61%) had received any prior OP treatment (women, 65%; men, 38%); of these, 38% had received > 1 treatment (women, 25%; men, 13%). Among treated subjects, the most frequent first-line treatments were alendronate (43%) and RANKL inhibitor denosumab (22%), with a higher discontinuation rate and shorter treatment duration observed for alendronate (discontinuation, 42% vs 16%; median treatment duration, 2.5 vs 2.1 years). Over one-quarter (26%) of subjects had no follow-up visits post-fragility fracture, with this gap higher in women than men (35% versus 25%). The most common schedule of follow-up visits was yearly (43% of subjects with a fragility fracture), followed by half-yearly (17%) and biennial (10%), with a similar trend in men and women. Most OP treatments were prescribed by PC physicians, other than teriparatide and zoledronate. CONCLUSIONS: Across Spanish PC, we observed a large gap in the treatment and follow-up of elderly subjects experiencing a fragility fracture. Our data highlights the urgent need to improve secondary fracture prevention in PC.

NADPH oxidase 4-derived hydrogen peroxide counterbalances testosterone-induced endothelial dysfunction and migration.

High levels of testosterone (Testo) are associated with cardiovascular risk by increasing reactive oxygen species (ROS) formation. NADPH oxidases (NOX) are the major source of ROS in the vasculature of cardiovascular diseases. NOX4 is a unique isotype, which produces hydrogen peroxide (H2O2), and its participation in cardiovascular biology is controversial. So far, it is unclear whether NOX4 protects from Testo-induced endothelial injury. Thus, we hypothesized that supraphysiological levels of Testo induce endothelial NOX4 expression to attenuate endothelial injury. Human mesenteric vascular endothelial cells (HMECs) and human umbilical vein endothelial cells (HUVEC) were treated with Testo (10-7 M) with or without a NOX4 inhibitor [GLX351322 (10-4 M)] or NOX4 siRNA. In vivo, 10-wk-old C57Bl/6J male mice were treated with Testo (10 mg/kg) for 30 days to study endothelial function. Testo increased mRNA and protein levels of NOX4 in HMECs and HUVECs. Testo increased superoxide anion (O2-) and H2O2 production, which were abolished by NOX1 and NOX4 inhibition, respectively. Testo also attenuated bradykinin-induced NO production, which was further impaired by NOX4 inhibition. In vivo, Testo decreased H2O2 production in aortic segments and triggered endothelial dysfunction [decreased relaxation to acetylcholine (ACh)], which was further impaired by GLX351322 and by a superoxide dismutase and catalase mimetic (EUK134). Finally, Testo led to a dysregulated endothelial cell migration, which was exacerbated by GLX351322. These data indicate that supraphysiological levels of Testo increase the endothelial expression and activity of NOX4 to counterbalance the deleterious effects caused by Testo in endothelial function.NEW & NOTEWORTHY By inducing ROS formation, high levels of testosterone play a major role in the pathogenesis of cardiovascular disease. NOXs are the major sources of ROS in the vasculature of cardiovascular diseases. Herein, we describe a novel compensatory mechanism by showing that NOX4 is a protective oxidant enzyme and counterbalances the deleterious effects of testosterone in endothelial cells by modulating hydrogen peroxide formation.

The effects of melatonin and magnesium in a novel supplement delivery system on sleep scores, body composition and metabolism in otherwise healthy individuals with sleep disturbances.

The purpose of this study was to investigate the effects of a novel dietary supplement, including melatonin and magnesium, delivered via coffee pods on sleep quality, resting metabolic rate (RMR), and body composition in individuals with poor sleep quality disturbances. Using a double-blinded, randomized, crossover trial, we recruited 35 participants to a 4-week intervention with both supplements (1.9 mg melatonin + 200 mg elemental magnesium before sleep) and placebo conditions, considering a 7d washout period between treatments. The Pittsburgh Sleep Quality Index (PSQI) questionnaire was applied, RMR (kcal) was measured using indirect calorimetry (canopy ventilated open-circuit system) and body composition was assessed using dual-energy X-ray absorptiometry. Decreases in PSQI and anger - hostility scores, as well as in energy intake and fat mass, were observed (p < 0.05) for both conditions, from baseline to the end of each 4-week intervention. Differences between conditions were also observed for these parameters along with energy spent in activity, number of sedentary breaks, sleep efficiency, latency time, time in bed, total sleep time, awakening time, and movement index (p < 0.05) favouring the supplement condition. However, the final PSQI questionnaire scores still indicated poor sleep quality on average (PSQI > 5), in both conditions, with no changes regarding RMR. A melatonin-magnesium supplement, in a coffee pod format, showed improvements in sleep quality in otherwise healthy individuals with sleep disturbances, however PSQI questionnaire scores still indicated poor quality on average (PSQI > 5).

Preliminary evaluation of the toxicological, antioxidant and antitumor activities promoted by the compounds 2,4-dihydroxy-benzylidene-thiosemicarbazones an in silico, in vitro and in vivo study.

Thiosemicarbazones are promising classes of compounds with antitumor activity. For this study, six 2,4-dihydroxy-benzylidene-thiosemicarbazones compounds were synthesized. These compounds were submitted to different assays in silico, in vitro and in vivo to evaluate the toxicological, antioxidant and antitumor effects. The in silico results were evaluated by the SwissADME and pkCSM platforms and showed that all compounds had good oral bioavailability profiles. The in vitro and in vivo toxicity assays showed that the compounds showed low cytotoxicity against different normal cells and did not promote hemolytic effects. The single dose acute toxicity test (2000 mg/kg) showed that none of the compounds were toxic to mice. In in vitro antioxidant activity assays, the compounds showed moderate to low activity, with PB17 standing out for the ABTS radical capture assay. The in vivo antioxidant activity highlighted the compounds 1, 6 and 8 that promoted a significant increase in the concentration of liver antioxidant enzymes. Finally, all compounds showed promising antitumor activity against different cell lines, especially MCF-7 and DU145 lines, in addition, they inhibited the growth of sarcoma 180 at concentrations lower than 50 mg/kg. These results showed that the evaluated compounds can be considered as potential antitumor agents.

Trends in preoperative carbohydrate load practice: A systematic review.

BACKGROUND: The preoperative carbohydrate load (PCL) is intended to improve surgical outcomes by reducing the catabolic state induced by overnight fasting. However, there is disagreement on the optimal PCL prescription, leaving local institutions without a standardized PCL recommendation. Results from studies that do not prescribe PCL in identical ways cannot be pooled to draw larger conclusions on outcomes affected by the PCL. The aim of this systematic review is to catalog prescribed PCL characteristics, including timing of ingestion, percentage of carbohydrate contribution, and volume, to ultimately standardize PCL practice. METHODS: A comprehensive search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials were included if they studied at least one group of patients who were prescribed a PCL and the PCL was described with respect to timing of ingestion, carbohydrate contribution, and total volume. RESULTS: A total of 67 studies with 6551 patients were included in this systematic review. Of the studies, 49.3% were prescribed PCL on the night before surgery and morning of surgery, whereas 47.8% were prescribed PCL on the morning of surgery alone. The mean prescribed carbohydrate concentration was 13.5% (±3.4). The total volume prescribed was 648.2 ml (±377). CONCLUSION: Variation in PCL practices prevent meaningful data pooling and outcome analysis, highlighting the need for standardized PCL prescription. Efforts dedicated to the establishment of a gold standard PCL prescription are necessary so that studies can be pooled and analyzed with respect to meaningful clinical end points that impact surgical outcomes and patient satisfaction.