The Dutch list of essential drugs for undergraduate medical education: A modified Delphi study.

AIMS: Prescribing errors among junior doctors are common in clinical practice because many lack prescribing competence after graduation. This is in part due to inadequate education in clinical pharmacology and therapeutics (CP&T) in the undergraduate medical curriculum. To support CP&T education, it is important to determine which drugs medical undergraduates should be able to prescribe safely and effectively without direct supervision by the time they graduate. Currently, there is no such list with broad-based consensus. Therefore, the aim was to reach consensus on a list of essential drugs for undergraduate medical education in the Netherlands. METHODS: A two-round modified Delphi study was conducted among pharmacists, medical specialists, junior doctors and pharmacotherapy teachers from all eight Dutch academic hospitals. Participants were asked to indicate whether it was essential that medical graduates could prescribe specific drugs included on a preliminary list. Drugs for which ≥80% of all respondents agreed or strongly agreed were included in the final list. RESULTS: In all, 42 (65%) participants completed the two Delphi rounds. A total of 132 drugs (39%) from the preliminary list and two (3%) newly proposed drugs were included. CONCLUSIONS: This is the first Delphi consensus study to identify the drugs that Dutch junior doctors should be able to prescribe safely and effectively without direct supervision. This list can be used to harmonize and support the teaching and assessment of CP&T. Moreover, this study shows that a Delphi method is suitable to reach consensus on such a list, and could be used for a European list.

The impact of a summative national prescribing assessment and curriculum type on the development of the prescribing competence of junior doctors.

PURPOSE: The primary aim of this study was to investigate the effect of including the Dutch National Pharmacotherapy Assessment (DNPA) in the medical curriculum on the level and development of prescribing knowledge and skills of junior doctors. The secondary aim was to evaluate the relationship between the curriculum type and the prescribing competence of junior doctors. METHODS: We re-analysed the data of a longitudinal study conducted in 2016 involving recently graduated junior doctors from 11 medical schools across the Netherlands and Belgium. Participants completed three assessments during the first year after graduation (around graduation (+ / - 4 weeks), and 6 months, and 1 year after graduation), each of which contained 35 multiple choice questions (MCQs) assessing knowledge and three clinical case scenarios assessing skills. Only one medical school used the DNPA in its medical curriculum; the other medical schools used conventional means to assess prescribing knowledge and skills. Five medical schools were classified as providing solely theoretical clinical pharmacology and therapeutics (CPT) education; the others provided both theoretical and practical CPT education (mixed curriculum). RESULTS: Of the 1584 invited junior doctors, 556 (35.1%) participated, 326 (58.6%) completed the MCQs and 325 (58.5%) the clinical case scenarios in all three assessments. Junior doctors whose medical curriculum included the DNPA had higher knowledge scores than other junior doctors (76.7% [SD 12.5] vs. 67.8% [SD 12.6], 81.8% [SD 11.1] vs. 76.1% [SD 11.1], 77.0% [12.1] vs. 70.6% [SD 14.0], p < 0.05 for all three assessments, respectively). There was no difference in skills scores at the moment of graduation (p = 0.110), but after 6 and 12 months junior doctors whose medical curriculum included the DNPA had higher skills scores (both p < 0.001). Junior doctors educated with a mixed curriculum had significantly higher scores for both knowledge and skills than did junior doctors educated with a theoretical curriculum (p < 0.05 in all assessments). CONCLUSION: Our findings suggest that the inclusion of the knowledge focused DNPA in the medical curriculum improves the prescribing knowledge, but not the skills, of junior doctors at the moment of graduation. However, after 6 and 12 months, both the knowledge and skills were higher in the junior doctors whose medical curriculum included the DNPA. A curriculum that provides both theoretical and practical education seems to improve both prescribing knowledge and skills relative to a solely theoretical curriculum.

Do we become better prescribers after graduation: A 1-year international follow-up study among junior doctors.

AIM: The aim of this study was to investigate how the prescribing knowledge and skills of junior doctors in the Netherlands and Belgium develop in the year after graduation. We also analysed differences in knowledge and skills between surgical and nonsurgical junior doctors. METHODS: This international, multicentre (n = 11), longitudinal study analysed the learning curves of junior doctors working in various specialties via three validated assessments at about the time of graduation, and 6 months and 1 year after graduation. Each assessment contained 35 multiple choice questions (MCQs) on medication safety (passing grade ≥85%) and three clinical scenarios. RESULTS: In total, 556 junior doctors participated, 326 (58.6%) of whom completed the MCQs and 325 (58.5%) the clinical case scenarios of all three assessments. Mean prescribing knowledge was stable in the year after graduation, with 69% (SD 13) correctly answering questions at assessment 1 and 71% (SD 14) at assessment 3, whereas prescribing skills decreased: 63% of treatment plans were considered adequate at assessment 1 but only 40% at assessment 3 (P < .001). While nonsurgical doctors had similar learning curves for knowledge and skills as surgical doctors (P = .53 and P = .56 respectively), their overall level was higher at all three assessments (all P < .05). CONCLUSION: These results show that junior doctors' prescribing knowledge and skills did not improve while they were working in clinical practice. Moreover, their level was under the predefined passing grade. As this might adversely affect patient safety, educational interventions should be introduced to improve the prescribing competence of junior doctors.

Students' guide to documentation in clinical trials.

PURPOSE: In the wake of the coronavirus disease 2019 (COVID-19) pandemic, support in clinical trials by students of human medicine and related disciplines has become of even greater importance than in pre-pandemic times. Documentation in clinical trials adheres to the principles of Good Clinical Practice (GCP), and healthcare professionals involved in the conduct of clinical trials-including students-are obliged to perform documentation in accordance with GCP principles. Unprecedented challenges have arisen with regard to the appropriate training of students as training courses in presence had largely to be suspended due to social-distancing regulations during the heyday of the COVID-19 pandemic. Therefore, novel training formats and self-study training materials for students working in clinical trials are urgently warranted. METHODS: To overcome this shortcoming and to define a common quality standard, an interdisciplinary, multiprofessional (physicians, study nurses, medical students), and binational (Germany, The Netherlands) expert panel convened and devised the Students' guide to documentation in clinical trials. RESULTS: Following a brief description of the different roles in clinical trials (e.g., sponsor, (principal) investigator, monitor) and an introduction into the principles of GCP, the documentation of adverse events, concomitant medication, medical history, and quality control are comprehensively discussed. The Guide concludes with a trilingual medical dictionary (English, German, Dutch) and with recommendations of pertinent literature for further reading. CONCLUSION: Serving both as textbook for self-training and as (quick-) reference work for the daily routine, the Guide has specifically been designed to complement, but not to replace practical training courses for students. While primarily addressed at students of human medicine and related disciplines, the Guide can also be of high relevance and utility to other healthcare professionals involved in the conduct of clinical trials.

Skin barrier lipid enzyme activity in Netherton patients is associated with protease activity and ceramide abnormalities.

Individuals with Netherton syndrome (NTS) have increased serine protease activity, which strongly impacts the barrier function of the skin epidermis and leads to skin inflammation. Here, we investigated how serine protease activity in NTS correlates with changes in the stratum corneum (SC) ceramides, which are crucial components of the skin barrier. We examined two key enzymes involved in epidermal ceramide biosynthesis, ß-glucocerebrosidase (GBA) and acid-sphingomyelinase (ASM). We compared in situ expression levels and activities of GBA and ASM between NTS patients and controls and correlated the expression and activities with i) SC ceramide profiles, ii) in situ serine protease activity, and iii) clinical presentation of patients. Using activity-based probe labeling, we visualized and localized active epidermal GBA, and a newly developed in situ zymography method enabled us to visualize and localize active ASM. Reduction in active GBA in NTS patients coincided with increased ASM activity, particularly in areas with increased serine protease activity. NTS patients with scaly erythroderma exhibited more pronounced anomalies in GBA and ASM activities than patients with ichthyosis linearis circumflexa. They also displayed a stronger increase in SC ceramides processed via ASM. We conclude that changes in the localization of active GBA and ASM correlate with i) altered SC ceramide composition in NTS patients, ii) local serine protease activity, and iii) the clinical manifestation of NTS.

Applying a vernix caseosa based formulation accelerates skin barrier repair by modulating lipid biosynthesis.

Restoring the lipid homeostasis of the stratum corneum (SC) is a common strategy to enhance skin barrier function. Here, we used a ceramide containing vernix caseosa (VC)-based formulation and were able to accelerate barrier recovery in healthy volunteers. The recovery was examined over 16 days by monitoring trans-epidermal water loss (TEWL) after barrier disruption by tape-stripping. Four skin sites were used to examine the effects of both treatment and barrier recovery. After 16 days, samples were harvested at these sites to examine the SC ceramide composition and lipid organization. Changes in ceramide profiles were identified using principal component analysis. After barrier recovery, the untreated sites showed increased levels of ceramide subclass AS and ceramides with a 34 total carbon-atom chain length, while the mean ceramide chain length was reduced. These changes were diminished by treatment with the studied formulation, which concurrently increased the formulated ceramides. Correlations were observed between SC lipid composition, lipid organization, and TEWL, and changes in the ceramide subclass composition suggest changes in the ceramide biosynthesis. These results suggest that VC-based formulations enhance skin barrier recovery and are attractive candidates to treat skin disorders with impaired barrier properties.

In situ visualization of glucocerebrosidase in human skin tissue: zymography versus activity-based probe labeling.

Epidermal ß-glucocerebrosidase (GBA1), an acid ß-glucosidase normally located in lysosomes, converts (glucosyl)ceramides into ceramides, which is crucial to generate an optimal barrier function of the outermost skin layer, the stratum corneum (SC). Here we report on two developed in situ methods to localize active GBA in human epidermis: i) an optimized zymography method that is less labor intensive and visualizes enzymatic activity with higher resolution than currently reported methods using either substrate 4-methylumbelliferyl-ß-D-glucopyranoside or resorufin-ß-D-glucopyranoside; and ii) a novel technique to visualize active GBA1 molecules by their specific labeling with a fluorescent activity-based probe (ABP), MDW941. The latter method pro-ved to be more robust and sensitive, provided higher resolution microscopic images, and was less prone to sample preparation effects. Moreover, in contrast to the zymography substrates that react with various ß-glucosidases, MDW941 specifically labeled GBA1. We demonstrate that active GBA1 in the epidermis is primarily located in the extracellular lipid matrix at the interface of the viable epidermis and the lower layers of the SC. With ABP-labeling, we observed reduced GBA1 activity in 3D-cultured skin models when supplemented with the reversible inhibitor, isofagomine, irrespective of GBA expression. This inhibition affected the SC ceramide composition: MS analysis revealed an inhibitor-dependent increase in the glucosylceramide:ceramide ratio.

Quantitative analysis of ceramides using a novel lipidomics approach with three dimensional response modelling.

In the outermost layer of the skin, the stratum corneum (SC), ceramides form a diverse and essential pool of lipids. Due to their diversity and the limited availability of synthetic standards it is challenging to quantitatively analyse all SC ceramides independently. We aim to perform a detailed analysis of ceramides on SC harvested from in vivo and ex vivo skin, therefore, a LC/MS method was developed in which all steps from sample acquisition until data analysis were examined and optimized. Improving extraction efficiency of ceramides resulted in an increase in efficiency from 71.5% to 99.3%. It was shown that sample harvesting by tape-stripping in vivo was accurate and precise. A full scan MS method was developed, compatible with all sample types, enabling simultaneously qualitative and quantitative data analysis. A novel three dimensional response model was constructed to quantify all detected ceramides from full scan data using a limited amount of synthetic ceramides. The application is demonstrated on various SC sample types. When ex vivo SC was regenerated during human skin culture, increases are observed in the amount of the ceramide sphingosine subclasses, in mono unsaturated ceramides (which have an cis-double bond in the acyl chain), and ceramides with a short C34 carbon chain (ceramides with a total carbon chain of 34 carbon atoms), compared with native human skin. These changes in ceramide levels are also often encountered in diseased skin.

Topically applied fatty acids are elongated before incorporation in the stratum corneum lipid matrix in compromised skin.

In several skin diseases, both the lipid composition and organization in the stratum corneum (SC) are altered which contributes to the impaired skin barrier function in patients. One of the approaches for skin barrier repair is treatment with topical formulations to normalize SC lipid composition and organization. Vernix caseosa (VC), a white cheesy cream on the skin during gestational delivery, has shown to enhance skin barrier repair. In this study, we examined how a fatty acid (FA) containing formulation mimicking the lipid composition of VC interacts with the lipid matrix in the SC. The formulation was applied on ex vivo human skin after SC removal. Subsequently, the ex vivo human skin generated SC during culture. The effect of FA containing formulations on the lipid organization and composition in the regenerated SC was analysed by Fourier transform infrared (FTIR) spectroscopy and liquid chromatography mass spectroscopy (LC/MS), respectively. FTIR results demonstrate that the FAs are intercalated in the lipid matrix of the regenerated SC and partition in the same lattice with the endogenous SC lipids, thereby enhancing the fraction of lipids forming an orthorhombic (very dense) packing in the SC. LC/MS data show that the topically applied FAs are elongated before intercalation in the lipid matrix and are thus involved in the lipid biosynthesis in the skin.

Combined LC/MS-platform for analysis of all major stratum corneum lipids, and the profiling of skin substitutes.

Ceramides (CERs), cholesterol, and free fatty acids (FFAs) are the main lipid classes in human stratum corneum (SC, outermost skin layer), but no studies report on the detailed analysis of these classes in a single platform. The primary aims of this study were to 1) develop an LC/MS method for (semi-)quantitative analysis of all main lipid classes present in human SC; and 2) use this method to study in detail the lipid profiles of human skin substitutes and compare them to human SC lipids. By applying two injections of 10µl, the developed method detects all major SC lipids using RPLC and negative ion mode APCI-MS for detection of FFAs, and NPLC using positive ion mode APCI-MS to analyze CERs and cholesterol. Validation showed this lipid platform to be robust, reproducible, sensitive, and fast. The method was successfully applied on ex vivo human SC, human SC obtained from tape strips and human skin substitutes (porcine SC and human skin equivalents). In conjunction with FFA profiles, clear differences in CER profiles were observed between these different SC sources. Human skin equivalents more closely mimic the lipid composition of human stratum corneum than porcine skin does, although noticeable differences are still present. These differences gave biologically relevant information on some of the enzymes that are probably involved in SC lipid processing. For future research, this provides an excellent method for (semi-)quantitative, 'high-throughput' profiling of SC lipids and can be used to advance the understanding of skin lipids and the biological processes involved.

Modulation of stratum corneum lipid composition and organization of human skin equivalents by specific medium supplements.

Our in-house human skin equivalents contain all stratum corneum (SC) barrier lipid classes, but have a reduced level of free fatty acids (FAs), of which a part is mono-unsaturated. These differences lead to an altered SC lipid organization and thereby a reduced barrier function compared to human skin. In this study, we aimed to improve the SC FA composition and, consequently, the SC lipid organization of the Leiden epidermal model (LEM) by specific medium supplements. The standard FA mixture (consisting of palmitic, linoleic and arachidonic acids) supplemented to the medium was modified, by replacing protonated palmitic acid with deuterated palmitic acid or by the addition of deuterated arachidic acid to the mixture, to determine whether FAs are taken up from the medium and are incorporated into SC of LEM. Furthermore, supplementation of the total FA mixture or that of palmitic acid alone was increased four times to examine whether this improves the SC FA composition and lipid organization of LEM. The results demonstrate that the deuterated FAs are taken up into LEMs and are subsequently elongated and incorporated in their SC. However, a fourfold increase in palmitic acid supplementation does not change the SC FA composition or lipid organization of LEM. Increasing the concentration of the total FA mixture in the medium resulted in a decreased level of very long chain FAs and an increased level of mono-unsaturated FAs, which lead to deteriorated SC lipid properties. These results indicate that SC lipid properties can be modulated by specific medium supplements.

The importance of free fatty acid chain length for the skin barrier function in atopic eczema patients.

An important feature of atopic eczema (AE) is a decreased skin barrier function. The stratum corneum (SC) lipids - comprised of ceramides (CERs), free fatty acids (FFAs) and cholesterol - fulfil a predominant role in the skin barrier function. In this clinical study, the carbon chain length distribution of SC lipids (FFAs and CERs) and their importance for the lipid organization and skin barrier function were examined in AE patients and compared with control subjects. A reduction in FFA chain length and an increase in unsaturated FFAs are observed in non-lesional and lesional SC of AE patients. The reduction in FFA chain length associates with a reduced CER chain length, suggesting a common synthetic pathway. The lipid chain length reduction correlates with a less dense lipid organization and a decreased skin barrier function. All changes are more pronounced in lesional SC compared with non-lesional skin. No association was observed between lipid properties and filaggrin mutations, an important predisposing factor for developing AE. The results of this study demonstrate an altered SC lipid composition and signify the importance of these changes (specifically regarding the CER and FFA chain lengths) for the impaired skin barrier function in AE. This provides insights into epidermal lipid metabolism as well as new opportunities for skin barrier repair.

Knock-down of filaggrin does not affect lipid organization and composition in stratum corneum of reconstructed human skin equivalents.

Human skin mainly functions as an effective barrier against unwanted environmental influences. The barrier function strongly relies on the outermost layer of the skin, the stratum corneum (SC), which is composed of corneocytes embedded in an extracellular lipid matrix. The importance of a proper barrier function is shown in various skin disorders such as atopic dermatitis (AD), a complex human skin disorder strongly associated with filaggrin (FLG) null mutations, but their role in barrier function is yet unclear. To study the role of FLG in SC barrier properties in terms of SC lipid organization and lipid composition, we generated an N/TERT-based 3D-skin equivalent (NSE) after knock-down of FLG with shRNA. In these NSEs, we examined epidermal morphogenesis by evaluating the expression of differentiation markers keratin 10, FLG, loricrin and the proliferation marker ki67. Furthermore, the SC was extensively analysed for lipid organization, lipid composition and SC permeability. Our results demonstrate that FLG knock-down (FLG-KD) did not affect epidermal morphogenesis, SC lipid organization, lipid composition and SC permeability for a lipophilic compound in NSEs. Therefore, our findings indicate that FLG-KD alone does not necessarily affect the functionality of a proper barrier function.

A Clinical Pharmacology and Therapeutics Teacher's Guide to Race-Based Medicine, Inclusivity, and Diversity.

The relationship between race and biology is complex. In contemporary medical science, race is a social construct that is measured via self-identification of study participants. But even though race has no biological essence, it is often used as variable in medical guidelines (e.g., treatment recommendations specific for Black people with hypertension). Such recommendations are based on clinical trials in which there was a significant correlation between self-identified race and actual, but often unmeasured, health-related factors such as (pharmaco)genetics, diet, sun exposure, etc. Many teachers are insufficiently aware of this complexity. In their classes, they (unintentionally) portray self-reported race as having a biological essence. This may cause students to see people of shared race as biologically or genetically homogeneous, and believe that race-based recommendations are true for all individuals (rather than reflecting the average of a heterogeneous group). This medicalizes race and reinforces already existing healthcare disparities. Moreover, students may fail to learn that the relation between race and health is easily biased by factors such as socioeconomic status, racism, ancestry, and environment and that this limits the generalizability of race-based recommendations. We observed that the clinical case vignettes that we use in our teaching contain many stereotypes and biases, and do not generally reflect the diversity of actual patients. This guide, written by clinical pharmacology and therapeutics teachers, aims to help our colleagues and teachers in other health professions to reflect on and improve our teaching on race-based medical guidelines and to make our clinical case vignettes more inclusive and diverse.

Increase in short-chain ceramides correlates with an altered lipid organization and decreased barrier function in atopic eczema patients.

A hallmark of atopic eczema (AE) is skin barrier dysfunction. Lipids in the stratum corneum (SC), primarily ceramides, fatty acids, and cholesterol, are crucial for the barrier function, but their role in relation to AE is indistinct. Filaggrin is an epithelial barrier protein with a central role in the pathogenesis of AE. Nevertheless, the precise causes of AE-associated barrier dysfunction are largely unknown. In this study, a comprehensive analysis of ceramide composition and lipid organization in nonlesional SC of AE patients and control subjects was performed by means of mass spectrometry, infrared spectroscopy, and X-ray diffraction. In addition, the skin barrier and clinical state of the disease were examined. The level of ceramides with an extreme short chain length is drastically increased in SC of AE patients, which leads to an aberrant lipid organization and a decreased skin barrier function. Changes in SC lipid properties correlate with disease severity but are independent of filaggrin mutations. We demonstrate for the first time that changes in ceramide chain length and lipid organization are directly correlated with the skin barrier defects in nonlesional skin of AE patients. We envisage that these insights will provide a new therapeutic entry in therapy and prevention of AE.

Teaching resources for the European Open Platform for Prescribing Education (EurOP2E)-a nominal group technique study.

The European Open Platform for Prescribing Education (EurOP2E) seeks to improve and harmonize European clinical pharmacology and therapeutics (CPT) education by facilitating international collaboration and sharing problem-based, online, open educational resources. The COVID-19 pandemic forced teachers to switch to virtual modalities, highlighting the need for high-quality online teaching materials. The goal of this study was to establish the online problem-based teaching resources needed to sustain prescribing education during the pandemic and thereafter. A nominal group technique study was conducted with prescribing teachers from 15 European countries. Results were analyzed through thematic analysis. In four meetings, 20 teachers from 15 countries proposed and ranked 35 teaching materials. According to the participants, the most necessary problem-based-online teaching materials related to three overarching themes. Related to learning outcomes for CPT, participants proposed creating prescription scenarios, including materials focusing on background knowledge and resources on personalized medicine and topical/ethical issues such as the prescription's impact on planetary health. Second, related to teaching, they proposed online case discussions, gamification and decision support systems. Finally, in relation to faculty development, they recommend teacher courses, a repository of reusable exam questions and harmonized formularies. Future work will aim to collaboratively produce such materials.

LC/MS analysis of stratum corneum lipids: ceramide profiling and discovery.

Ceramides (CERs) in the upper layer of the skin, the stratum corneum (SC), play a key role in the skin barrier function. In human SC, the literature currently reports 11 CER subclasses that have been identified. In this paper, a novel quick and robust LC/MS method is presented that allows the separation and analysis of all known human SC CER subclasses using only limited sample preparation. Besides all 11 known and identified subclasses, a 3D multi-mass chromatogram shows the presence of other lipid subclasses. Using LC/MS/MS with an ion trap (IT) system, a Fourier transform-ion cyclotron resonance system, and a triple quadrupole system, we were able to identify one of these lipid subclasses as a new CER subclass: the ester-linked ω-hydroxy fatty acid with a dihydrosphingosine base (CER [EOdS]). Besides the identification of a new CER subclass, this paper also describes the applicability and robustness of the developed LC/MS method by analyzing three (biological) SC samples: SC from human dermatomed skin, human SC obtained by tape stripping, and SC from full-thickness skin explants. All three biological samples showed all known CER subclasses and slight differences were observed in CER profile.

Glucocerebrosidase: Functions in and Beyond the Lysosome.

Glucocerebrosidase (GCase) is a retaining ß-glucosidase with acid pH optimum metabolizing the glycosphingolipid glucosylceramide (GlcCer) to ceramide and glucose. Inherited deficiency of GCase causes the lysosomal storage disorder named Gaucher disease (GD). In GCase-deficient GD patients the accumulation of GlcCer in lysosomes of tissue macrophages is prominent. Based on the above, the key function of GCase as lysosomal hydrolase is well recognized, however it has become apparent that GCase fulfills in the human body at least one other key function beyond lysosomes. Crucially, GCase generates ceramides from GlcCer molecules in the outer part of the skin, a process essential for optimal skin barrier property and survival. This review covers the functions of GCase in and beyond lysosomes and also pays attention to the increasing insight in hitherto unexpected catalytic versatility of the enzyme.

Glucosylated cholesterol in skin: Synthetic role of extracellular glucocerebrosidase.

The existence of glucosylated cholesterol (GlcChol) in tissue has recently been recognized. GlcChol is generated from glucosylceramide (GlcCer) and cholesterol through transglucosylation by two retaining ß-glucosidases, GBA and GBA2. Given the abundance of GBA, GlcCer and cholesterol in the skin's stratum corneum (SC), we studied the occurrence of GlcChol. A significant amount of GlcChol was detected in SC (6 pmol/mg weight). The ratio GlcChol/GlcCer is higher in SC than epidermis, 0.083 and 0.011, respectively. Examination of GlcChol in patients with Netherton syndrome revealed comparable levels (11 pmol/mg). Concluding, GlcChol was identified as a novel component in SC and is likely locally metabolized by GBA. The physiological function of GlcChol in the SC warrants future investigation.