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Hong Kong Medical Journal = Xianggang... Apr 2023Postgraduate medical education (PGME) faces many challenges and must evolve. Three principles can guide this evolution. First, PGME apprenticeship, a form of situated...
Postgraduate medical education (PGME) faces many challenges and must evolve. Three principles can guide this evolution. First, PGME apprenticeship, a form of situated learning, is guided by the four dimensions of the Cognitive Apprenticeship Model: content, method, sequence, and sociology. Second, situated learning involves experiential learning and inquiry processes; it is most effective for learners practicing self-directed learning. The promotion of self-directed learning requires consideration of its three dimensions: process, person, and context. Finally, the need for competency-based PGME can be accomplished through holistic models, such as situated learning. The implementation of this evolution should be informed by the characteristics of the new paradigm, inner and outer settings of the organisations, and individuals involved. Implementation encompasses communication to engage stakeholders, training process redesign in accordance with the new paradigm, faculty development to empower and engage involved individuals, and research to enhance the understanding of PGME.
Topics: Humans; Education, Medical; Learning
PubMed: 37055193
DOI: 10.12809/hkmj235145 -
Materials (Basel, Switzerland) May 2023Research on the use of biomass resources for the generation of energy and chemical compounds is of great interest worldwide. The development and growth of the biodiesel... (Review)
Review
Research on the use of biomass resources for the generation of energy and chemical compounds is of great interest worldwide. The development and growth of the biodiesel industry has led to a parallel market for the supply of glycerol, its main by-product. Its wide availability and relatively low cost as a raw material make glycerol a basic component for obtaining various chemical products and allows for the development of a biorefinery around biodiesel plants, through the technological integration of different production processes. This work proposes a review of one of the reactions of interest in the biorefinery environment: the hydrogenolysis of glycerol to 1,2-propylene glycol. The article reviews more than 300 references, covering literature from about 20 years, focusing on the heterogeneous catalysts used for the production of glycol. In this sense, from about 175 catalysts, between bulk and supported ones, were revised and discussed critically, based on noble metals, such as Ru, Pt, Pd, and non-noble metals as Cu, Ni, Co, both in liquid (2-10 MPa, 120-260 °C) and vapor phase (0.1 MPa, 200-300 °C). Then, the effect of the main operational and decision variables, such as temperature, pressure, catalyst/glycerol mass ratio, space velocity, and H flow, are discussed, depending on the reactors employed. Finally, the formulation of several kinetic models and stability studies are presented, discussing the main deactivation mechanisms of the catalytic systems such as coking, leaching, and sintering, and the presence of impurities in the glycerol feed. It is expected that this work will serve as a tool for the development of more efficient catalytic materials and processes towards the future projection of glycerol biorefineries.
PubMed: 37176434
DOI: 10.3390/ma16093551 -
Scientific Reports Jan 2024Despite concerns over their safety, e-cigarettes (e-cigs) remain a popular tobacco product. Although nicotine and flavors found in e-cig liquids (e-liquids) can cause...
Despite concerns over their safety, e-cigarettes (e-cigs) remain a popular tobacco product. Although nicotine and flavors found in e-cig liquids (e-liquids) can cause harm in the airways, whether the delivery vehicles propylene glycol (PG) and vegetable glycerin (VG) are innocuous when inhaled remains unclear. Here, we investigated the effects of e-cig aerosols generated from e-liquid containing only PG/VG on airway inflammation and mucociliary function in primary human bronchial epithelial cells (HBEC) and sheep. Primary HBEC were cultured at the air-liquid interface (ALI) and exposed to e-cig aerosols of 50%/50% v/v PG/VG. Ion channel conductance, ciliary beat frequency, and the expression of inflammatory markers, cell type-specific markers, and the major mucins MUC5AC and MUC5B were evaluated after seven days of exposure. Sheep were exposed to e-cig aerosols of PG/VG for five days and mucus concentration and matrix metalloproteinase-9 (MMP-9) activity were measured from airway secretions. Seven-day exposure of HBEC to e-cig aerosols of PG/VG caused a significant reduction in the activities of apical ion channels important for mucus hydration, including the cystic fibrosis transmembrane conductance regulator (CFTR) and large conductance, Ca-activated, and voltage-dependent K (BK) channels. PG/VG aerosols significantly increased the mRNA expression of the inflammatory markers interleukin-6 (IL6), IL8, and MMP9, as well as MUC5AC. The increase in MUC5AC mRNA expression correlated with increased immunostaining of MUC5AC protein in PG/VG-exposed HBEC. On the other hand, PG/VG aerosols reduced MUC5B expression leading overall to higher MUC5AC/MUC5B ratios in exposed HBEC. Other cell type-specific markers, including forkhead box protein J1 (FOXJ1), keratin 5 (KRT5), and secretoglobin family 1A member 1 (SCGB1A1) mRNAs, as well as overall ciliation, were significantly reduced by PG/VG exposure. Finally, PG/VG aerosols increased MMP-9 activity and caused mucus hyperconcentration in sheep in vivo. E-cig aerosols of PG/VG induce airway inflammation, increase MUC5AC expression, and cause dysfunction of ion channels important for mucus hydration in HBEC in vitro. Furthermore, PG/VG aerosols increase MMP-9 activity and mucus concentration in sheep in vivo. Collectively, these data show that e-cig aerosols containing PG/VG are likely to be harmful in the airways.
Topics: Humans; Animals; Sheep; Electronic Nicotine Delivery Systems; Glycerol; Matrix Metalloproteinase 9; Vegetables; Mucus; Aerosols; Tobacco Products; RNA, Messenger; Propylene Glycols
PubMed: 38253598
DOI: 10.1038/s41598-024-52317-8 -
Molecules (Basel, Switzerland) May 2023Refill liquids for electronic cigarettes are an important area of research due to the health safety and quality control of such products. A method was developed for the...
Refill liquids for electronic cigarettes are an important area of research due to the health safety and quality control of such products. A method was developed for the determination of glycerol, propylene glycol, and nicotine in refill liquids using liquid chromatography, coupled with tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring (MRM) mode with electrospray ionisation (ESI). Sample preparation was based on a simple dilute-and-shoot approach, with recoveries ranging from 96 to 112% with coefficients of variation < 6.4%. Linearity, limits of detection and quantification (LOD, LOQ), repeatability, and accuracy were determined for the proposed method. The proposed sample preparation and the developed chromatographic method using hydrophilic interaction liquid chromatography (HILIC) were successfully applied for the determination of glycerol, propylene glycol, and nicotine in refill liquid samples. For the first time, the developed method using HILIC-MS/MS has been applied for the determination of the main components of refill liquids in a single analysis. The proposed procedure is rapid and straightforward and is suitable for quick determination of glycerol, propylene glycol, and nicotine. The nicotine concentrations corresponded to the labelling of samples (it varied from
propylene glycol to glycerol were also determined. Topics: Nicotine; Glycerol; Chromatography, Liquid; Electronic Nicotine Delivery Systems; Tandem Mass Spectrometry; Propylene Glycol
PubMed: 37298901
DOI: 10.3390/molecules28114425 -
Epigenetics 2022Increasing use of non-combusted forms of nicotine such as e-cigarettes poses important public health questions regarding their specific risks relative to combusted...
Increasing use of non-combusted forms of nicotine such as e-cigarettes poses important public health questions regarding their specific risks relative to combusted tobacco products such as cigarettes. To fully delineate these risks, improved biomarkers that can distinguish between these forms of nicotine use are needed. Prior work has suggested that methylation status at cg05575921 may serve as a specific biomarker of combusted tobacco smoke exposure. We hypothesized combining this epigenetic biomarker with conventional metabolite assays could classify the type of nicotine product consumption. Therefore, we determined DNA methylation and serum cotinine values in samples from 112 smokers, 35 e-cigarette users, 19 smokeless tobacco users, and 269 controls, and performed mass spectroscopy analyses of urine samples from all nicotine users and 22 verified controls to determine urinary levels of putatively nicotine product-specific substances; propylene glycol, 2-cyanoethylmercapturic acid (CEMA), and anabasine. 1) Cigarette smoking was associated with a dose dependent demethylation of cg05575921 and increased urinary CEMA and anabasine levels, 2) e-cigarette use did not demethylate cg05575921, 3) smokeless tobacco use also did not demethylate cg05575921 but was positively associated with anabasine levels 4) CEMA and cg05575921 levels were highly correlated and 5) propylene glycol levels did not reliably distinguish use groups. Cg05575921 assessments distinguish exposure to tobacco smoke from smokeless sources of nicotine including e-cigarettes and smokeless tobacco, neither of which are associated with cg05575921 demethylation. A combination of methylomic and metabolite profiling may allow for accurate classification use status of a variety of nicotine containing products.
Topics: DNA Methylation; Electronic Nicotine Delivery Systems; Nicotine; Nicotiana; Tobacco Products; Vaping
PubMed: 33588690
DOI: 10.1080/15592294.2021.1890875 -
Current Allergy and Asthma Reports Mar 2021This article aims to summarize some recent trends in occupational allergic contact dermatitis (ACD), including dermatitis related to pandemic-level personal protective... (Review)
Review
PURPOSE OF REVIEW
This article aims to summarize some recent trends in occupational allergic contact dermatitis (ACD), including dermatitis related to pandemic-level personal protective equipment in healthcare workers, hazards patients may experience when working from home, and occupational perspectives on the recent American Contact Dermatitis Society (ACDS) allergens of the year and ACDS Core Allergen Series updates.
RECENT FINDINGS
Recent ACDS Allergens of the Year may be particularly relevant to healthcare workers, including isobornyl acrylate, which is present in glucose sensors and propylene glycol present in hand cleansers and disinfectants. Lavender, limonene, and linalool, all of which are new additions to the ACDS Core Allergen Series, have been reported as causes for occupational ACD in massage therapists and aromatherapists. Isothiazolinone allergy continues to rise in both consumer and occupational settings. Finally, the COVID-19 pandemic has resulted in a wave of occupational ACD in healthcare workers to personal protective equipment, and revealed new potential allergens for individuals working from home. Occupational allergic contact dermatitis continues to exert a significant occupational disease burden. Remaining aware of the current trends in allergens may allow for earlier recognition, diagnosis, and treatment, subsequently helping our patients to work in healthier and safer environments.
Topics: Acrylates; Acyclic Monoterpenes; Allergens; Allergy and Immunology; COVID-19; Camphanes; Dermatitis, Allergic Contact; Dermatitis, Occupational; Dermatology; Health Personnel; Humans; Lavandula; Limonene; Pandemics; Patch Tests; Propylene Glycol; Societies, Medical; United States
PubMed: 33779825
DOI: 10.1007/s11882-021-01000-3 -
Molecules (Basel, Switzerland) Dec 2023Binary ethosome vesicles have been developed as flexible lipid vesicles for the enhanced physicochemical stability and skin delivery of drugs. This work aimed to prepare...
Binary ethosome vesicles have been developed as flexible lipid vesicles for the enhanced physicochemical stability and skin delivery of drugs. This work aimed to prepare phloretin-loaded propylene glycol ethosomes (PHL-PGEs) to improve their stability, skin permeability and antioxidant activity. PHL-PGEs were prepared via the ethanol injection method and optimized using different weight ratios of ethanol to propylene glycol (PG). When the ethanol/PG mass ratio changed from 10:0 to 0:10, the encapsulation efficiency and stability of ethosomes increased. At a PHL concentration of 1mg/mL, the EE% was 89.42 ± 2.42 and the DL% was 4.21 ± 0.04, which exhibited their highest values. The encapsulation of the PHL in the PHL-PGEs was strengthened via XRD analysis and FTIR analysis. The results of the in vitro percutaneous permeability test demonstrated that the combined use of ethanol and PG exhibited a notable enhancement in skin permeability, and the skin retention of PHL-PGEs was 1.06 times that of PHL-ethosomes (PHL-Es) and 2.24 times that of the PHL solution. An in vitro antioxidant activity study indicated that solubility and antioxidant activity was potentiated via the nanoencapsulation of phloretin. Therefore, these results confirm the potential of this nanocarrier to enhance physicochemical stability, skin permeability and antioxidant activity.
Topics: Antioxidants; Ethanol; Permeability; Phloretin; Propylene Glycol
PubMed: 38202649
DOI: 10.3390/molecules29010066 -
Acta Otorhinolaryngologica Italica :... Oct 2021The aim of this study was to investigate the inhibitory effect of different doses of sodium-2-mercaptoethanesulphonate (MESNA) and 5-fluorouracil on cholesteatoma...
OBJECTIVE
The aim of this study was to investigate the inhibitory effect of different doses of sodium-2-mercaptoethanesulphonate (MESNA) and 5-fluorouracil on cholesteatoma formation.
METHODS
Fifty-six Wistar albino male rats were divided into seven groups with eight rats in each. On the first, eighth and fifteenth days, 0.2 ml of saline was administered to the group 1 (control group), and propylene glycol to induce cholesteatoma the other groups. On the 22 day of the study, 0.2 ml saline was given to Group 1 and Group 2. Groups 3 to 7 were treated with 0.2 ml 100% MESNA, 0.2 ml 50% MESNA, 0.2 ml 20% MESNA, 0.2 ml 5-fluorouracil and 0.1 ml 100% MESNA plus 0.1 ml 5-fluorouracil, respectively, with all applications performed by intratympanic injection.
RESULTS
Significant differences were found between Group 1 and all other groups except Group 3. Significant differences were also found between Group 3 and Groups 2, 5 and 6 (P < 0.05).
CONCLUSIONS
According to the results of this study, experimental cholesteatoma induced with propylene glycol may be inhibited by MESNA at 100% concentration.
Topics: Animals; Cholesteatoma, Middle Ear; Fluorouracil; Humans; Mesna; Propylene Glycols; Rats; Rats, Wistar
PubMed: 34734585
DOI: 10.14639/0392-100X-N1392 -
Nicotine & Tobacco Research : Official... Nov 2023Although the greater popularity of electronic cigarettes (EC) among asthmatics is alarming, there is limited knowledge of the long-term consequences of EC exposure in...
INTRODUCTION
Although the greater popularity of electronic cigarettes (EC) among asthmatics is alarming, there is limited knowledge of the long-term consequences of EC exposure in asthmatics.
AIMS AND METHODS
Mild asthmatic C57/BL6J adult male and female mice were established by intranasal insufflation with three combined allergens. The asthmatic and age and sex-matched' naïve mice were exposed to air, nicotine-free (propylene glycol [PG]/vegetable glycerin [VG]-only), or PG/VG+Nicotine, 4 hours daily for 3 months. The effects of EC exposure were accessed by measuring cytokines in bronchoalveolar lavage, periodic acid-schiff (PAS) staining, mitochondrial DNA copy numbers (mtCN), and the transcriptome in the lung. Significance was false discovery rate <0.2 for transcriptome and 0.05 for the others.
RESULTS
In asthmatic mice, PG/VG+Nicotine increased PAS-positive cells and IL-13 compared to mice exposed to air and PG/VG-only. In naïve mice exposed to PG/VG+Nicotine and PG/VG-only, higher INF-γ was observed compared to mice exposed only to air. PG/VG-only and PG/VG+Nicotine had significantly higher mtCN compared to air exposure in asthmatic mice, while the opposite pattern was observed in non-asthmatic naïve mice. Different gene expression patterns were profoundly found for asthmatic mice exposed to PG/VG+Nicotine compared to PG/VG-only, including genes involved in mitochondrial dysfunction, oxidative phosphorylation, and p21-activated kinase (PAK) signaling.
CONCLUSIONS
This study provides experimental evidence of the potential impact of nicotine enhancement on the long-term effects of EC in asthmatics compared to non-asthmatics.
IMPLICATIONS
The findings from this study indicate the potential impact of EC in asthmatics by addressing multiple biological markers. The long-term health outcomes of EC in the susceptible group can be instrumental in supporting policymaking and educational campaigns and informing the public, healthcare providers, and EC users about the underlying risks of EC use.
Topics: Male; Mice; Female; Animals; Nicotine; Electronic Nicotine Delivery Systems; Asthma; Lung; Propylene Glycol; Glycerol; Vegetables
PubMed: 37349133
DOI: 10.1093/ntr/ntad100 -
Pharmaceutics Aug 2023Ischemic stroke is the second-leading cause of death. Hyperglycemia, which is characteristic of diabetes mellitus, contributes to the development of endothelial...
Ischemic stroke is the second-leading cause of death. Hyperglycemia, which is characteristic of diabetes mellitus, contributes to the development of endothelial dysfunction and increases the risk of stroke. Isoxsuprine is an efficient beta-adrenergic agonist that improves blood flow to the ischemic aria and stops the infarct core from growing. However, low bioavailability, a short biological half-life, and first-pass hepatic metabolism reduce the therapeutic efficacy of oral isoxsuprine. Therefore, the authors focused on developing isoxsuprine-loaded liposomes containing ethanol and propylene glycol (ILEP) formulation as nasal drops for the treatment of ischemic stroke in diabetic patients. Different ILEP formulations were optimized using Design Expert software, and the selected formulation was examined in vivo for its anti-stroke effect using a rat model of diabetes and stroke. The optimized ILEP, composed of 15% propylene glycol, 0.16% cholesterol, 10% ethanol, and 3.29% phospholipid, improved the sustainability, permeation, and targeting of isoxsuprine. Furthermore, the in vivo studies verified the improved neurological behavior and decreased dead shrunken neurons and vascular congestion of the rats treated with the optimized ILEP formulation, demonstrating its anti-stroke activity. In conclusion, our study found that treatment with an optimized ILEP formulation prevented the initiation and severity of stroke, especially in diabetic patients.
PubMed: 37765211
DOI: 10.3390/pharmaceutics15092242