Reliability and validity study of the Thai adaptation of the Maslach Burnout Inventory-Student Survey among preclinical medical students at a medical school in Thailand

Burnout syndrome is characterized by emotional exhaustion, cynicism, and lack of professional efficacy. A considerable proportion of medical students experience burnout syndrome during their educational training. Therefore, this issue has become a major concern in the medical education community. The Maslach Burnout Inventory-Student Survey (MBI-SS) is the most widely used assessment of burnout syndrome among college students, including preclinical medical students. Therefore, our objective was to culturally modify and validate the MBI-SS in a Thai context for use with preclinical medical students. The MBI-SS comprises 16 items, including five items for emotional exhaustion, five items for cynicism, and six items for academic efficacy. Four hundred and twenty-six preclinical medical students participated in this study. We randomly divided the samples into two equivalent subsamples of 213 participants. The first subsample was used to calculate McDonald’s omega coefficients to assess internal consistency and to perform exploratory factor analysis. McDonald’s omega coefficients for exhaustion, cynicism, and academic efficacy were 0.877, 0.844, and 0.846, respectively. The scree plot from the unweighted least squares estimation and a direct oblimin rotation, supplemented with Horn’s parallel analysis and the Hull method, revealed three major factors of the Thai MBI-SS. Due to the violation of the multivariate normality assumption in the second subsample, we performed a confirmatory factor analysis with the unweighted least squares with a mean and variance adjusted estimation approach. The results of the confirmatory factor analysis showed favorable goodness-of-fit indices. Data from 187 out of 426 participants (43.9%), who completed a second questionnaire, were utilized to evaluate test–retest reliability. The correlation coefficients for test–retest reliability with a three-week period between tests were 0.724, 0.760, and 0.769 for the exhaustion, cynicism, and academic efficacy domains, respectively (all p < 0.05). This indicates that the Thai MBI-SS is a valid and reliable instrument to assess burnout syndrome in our Thai preclinical medical student population

Insights into the salivary<i>N</i>-glycome of<i>Lutzomyia longipalpis</i>, vector of visceral leishmaniasis

AbstractDuringLeishmaniatransmission sand flies inoculate parasites and saliva into the skin of vertebrates. Saliva has anti-haemostatic and anti-inflammatory activities that evolved to facilitate bloodfeeding, but also modulate the host’s immune responses. Sand fly salivary proteins have been extensively studied, but the nature and biological roles of protein-linked glycans remain overlooked. Here, we characterised the profile ofN-glycans from the salivary glycoproteins ofLutzomyia longipalpis, vector of visceral leishmaniasis in the Americas.In silicopredictions suggest half ofLu. longipalpissalivary proteins may beN-glycosylated. SDS-PAGE coupled to LC-MS analysis of sand fly saliva, before and after enzymatic deglycosylation, revealed several candidate glycoproteins. To determine the diversity ofN-glycan structures in sand fly saliva, enzymatically released sugars were fluorescently tagged and analysed by HPLC, combined with highly sensitive LC-MS/MS, MALDI-TOF-MS, and exoglycosidase treatments. We found that theN-glycan composition ofLu. longipalpissaliva mostly consists of oligomannose sugars, with Man5GlcNAc2being the most abundant, and a few hybrid-type species. Interestingly, some glycans appear modified with a group of 144 Da, whose identity has yet to be confirmed. Our work presents the first detailed structural analysis of sand fly salivary glycans.</jats:p

A Simple Colorimetric Assay for Specific Detection of Glutathione-S Transferase Activity Associated with DDT Resistance in Mosquitoes

Aedes mosquitoes transmit many human viral pathogens including dengue, yellow fever and chikungunya. Most of these pathogens have no specific treatment or vaccine and hence their control is reliant on controlling the mosquito vectors, which usually involves the use of insecticides. In order to prevent the alarming prospect of mosquito control failure due to the rapid selection and spread of insecticide resistance in several mosquito populations worldwide, it is essential that effective resistance management strategies are implemented and adhered to. The development of simple diagnostic tests for the early identification and monitoring of resistance is an important prerequisite for this task. Here, we describe the development of a simple colorimetric test for the detection of GSTE2-2/DDTase-based resistance in individual mosquitoes. The novel assay combines the most desirable features of specificity and sensitivity with the low cost and ease of use required for a routine test in endemic countries. It can have direct application in routine vector monitoring as a resistance indicator and help improve the sustainability of insecticide based control strategies

Insights into the salivary N-glycome of Lutzomyia longipalpis, vector of visceral leishmaniasis.

During Leishmania transmission sand flies inoculate parasites and saliva into the skin of vertebrates. Saliva has anti-haemostatic and anti-inflammatory activities that evolved to facilitate bloodfeeding, but also modulate the host's immune responses. Sand fly salivary proteins have been extensively studied, but the nature and biological roles of protein-linked glycans remain overlooked. Here, we characterised the profile of N-glycans from the salivary glycoproteins of Lutzomyia longipalpis, vector of visceral leishmaniasis in the Americas. In silico predictions suggest half of Lu. longipalpis salivary proteins may be N-glycosylated. SDS-PAGE coupled to LC-MS analysis of sand fly saliva, before and after enzymatic deglycosylation, revealed several candidate glycoproteins. To determine the diversity of N-glycan structures in sand fly saliva, enzymatically released sugars were fluorescently tagged and analysed by HPLC, combined with highly sensitive LC-MS/MS, MALDI-TOF-MS, and exoglycosidase treatments. We found that the N-glycan composition of Lu. longipalpis saliva mostly consists of oligomannose sugars, with Man5GlcNAc2 being the most abundant, and a few hybrid-type species. Interestingly, some glycans appear modified with a group of 144 Da, whose identity has yet to be confirmed. Our work presents the first detailed structural analysis of sand fly salivary glycans

Tsetse salivary glycoproteins are modified with paucimannosidic N-glycans, are recognised by C-type lectins and bind to trypanosomes

African sleeping sickness is caused by Trypanosoma brucei, a parasite transmitted by the bite of a tsetse fly. Trypanosome infection induces a severe transcriptional downregulation of tsetse genes encoding for salivary proteins, which reduces its anti-hemostatic and anticlotting properties. To better understand trypanosome transmission and the possible role of glycans in insect bloodfeeding, we characterized the N-glycome of tsetse saliva glycoproteins. Tsetse salivary N-glycans were enzymatically released, tagged with either 2-aminobenzamide (2-AB) or procainamide, and analyzed by HILIC-UHPLC-FLR coupled online with positive-ion ESI-LC-MS/MS. We found that the N-glycan profiles of T. brucei-infected and naïve tsetse salivary glycoproteins are almost identical, consisting mainly (>50%) of highly processed Man3GlcNAc2 in addition to several other paucimannose, high mannose, and few hybrid-type N-glycans. In overlay assays, these sugars were differentially recognized by the mannose receptor and DC-SIGN C-type lectins. We also show that salivary glycoproteins bind strongly to the surface of transmissible metacyclic trypanosomes. We suggest that although the repertoire of tsetse salivary N-glycans does not change during a trypanosome infection, the interactions with mannosylated glycoproteins may influence parasite transmission into the vertebrate host

Glycobiology of adipose-derived stem cell differentiation

Theoretical thesis.Includes bibliographical references.1. Introduction -- 2.Evaluating adipose-derived stem cell differentiation in vitro -- 3. Characterisation and comparison of N- and O-linked glycosylation during in vivo and in vitro adipogenic differentiation -- 4.Characterisation and comparison of the plasma membrane proteome during in vivo and in vitro adipogenic differentiation -- 5. Adipose-derived stem cell differentiation: targeting the cell membrane protein glycosylation -- 6. General discussion.Human adipose tissue is a major source of mesenchymal stem cells, with numbers exceeding those in bone marrow and blood. These stem cells are referred to as adipose-derived stem cells (ADSCs) and have the ability to differentiate into different cell types. In vitro, ADSCs can be made to differentiate into the mesenchymal lineages of adipocytes, osteoblasts and chondrocytes, while in vivo, ADSCs become pre-adipocytes before further differentiating into mature adipocytes. Protein glycosylation has been shown to change in stem cell differentiation, and while ADSCs have been acknowledged for their therapeutic potential, the investigation of protein glycosylation changes during ADSC adipogenic differentiation has not been reported.First, adipogenic differentiation of ADSCs in vitro was optimised and evaluated by measuring the expression levels of established gene-markers and staining of the accumulated lipid in differentiated cells using Oil Red O. These results confirmed the cells had entered the adipogenic lineage and shared some characteristics with, but did not entirely mirror native, in vivo produced adipocytes.ADSCs, in vitro differentiated ADSCs and in vivo native mature adipocytes harvested from the same patients were used to investigate the membrane protein N- and O-linked glycosylation of adipogenesis. Using porous graphitised carbon LC coupled with negative ion ESI-MS/MS, a total of 138 glycan structures carried by the membrane proteins were characterised across the three cell types. Bisecting GlcNAc type N-linked structures were detected at a high level (32.1 % of total glycans) in mature adipocytes with some appearing in the differentiating ADSCs (1.9 %), while overall, ADSCs and their in vitro differentiated progeny showed similar glycosylation expression profiles. This finding was further correlated by increased mRNA expression of the MGAT3 gene responsible for the enzyme synthesis of this glycan structure type in both the in vivo and in vitro differentiated ADSCs.The same cell types (ADSCs, differentiated ADSCs and mature adipocytes) were characterised for their membrane proteome using label-free quantitative shotgun proteomics analysis. Many protein differences were identified between the three cell types, with, importantly, adipocyte-specific proteins found to be up-regulated in both mature adipocytes and differentiating ADSCs. Mitochondrial and lipid-related processes were also up-regulated in both adipogenic cell products, whereas epigenetic-related proteins and processes were found to be up-regulated in in vitro differentiated ADSCs alone.Analysis of the N-linked glycans from SDS-PAGE separated membrane proteins of the three cell types revealed that expression of bisecting GlcNAc structures was present on the majority of adipocyteglyco proteins. A more targeted methodology of carrying out proteomic analysis of de-N-glycosylated peptides of the gel-separated proteins unearthed new glycoproteins not detected previously in the shotgun proteomic analysis without de-glycosylation. This approach identified the adipogenic marker, CD36, as the dominant glycoprotein in the adipocyte membrane proteome that was also upregulated at the mRNA transcript level in both the in vitro differentiated ADSCs (7.1-fold increase) and mature adipocytes (102.9-fold increase). This work highlighted the importance of de-Nglycosylation of proteins in proteomics experiments for increased identification of glycoproteins.The systems glycobiology approach by the integration of glycomics, proteomics and transcriptomics analyses in this thesis extended the investigation of membrane protein glycosylation changes in adipose-derived stem cell differentiation. The work provides a framework for future glycoproteomics-based investigations into the differentiation of stem cells into adipocytes, and will allow their related pathologies and potential therapeutic applications to be discovered.Mode of access: World wide web1 online resource (238 pages) illustration

The Bioactivity Study of Active Compounds in Wolffia globosa Extract for an Alternative Source of Bioactive Substances

Wolffia globosa is a small plant found in the lagoons in tropical zones. The aim of our study was to examine the biological compounds found in W. globosa and their activities. The substances in W. globosa were extracted, isolated, and their chemical structures ascertained by Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The extract was tested for bioactivity, including antioxidant, anti-inflammatory, and cytotoxic activities. The results showed that the isolated compounds in fraction two were mainly β-sitosterol and stigmasterol. The sterols found in the extract were able to inhibit nitric oxide production in RAW 264.7 macrophage cells, which implied an anti-inflammatory activity. The extract was found to be non-toxic to human dermal fibroblast cells with an IC50 of 106.38 ± 37.0 µg/mL

Characterization of N- and O-linked glycosylation changes in milk of the tammar wallaby (Macropus eugenii) over lactation

As one of several biologically active compounds in milk, glycoproteins have been indicated to be involved in the protection of newborns from bacterial infection. As much of the physical and immune development of the tammar wallaby (Macropus eugenii) youn

Characterization of N- and O-linked glycosylation changes in milk of the tammar wallaby (Macropus eugenii) over lactation

As one of several biologically active compounds in milk, glycoproteins have been indicated to be involved in the protection of newborns from bacterial infection. As much of the physical and immune development of the tammar wallaby (Macropus eugenii) young occurs during the early phases of lactation and not in utero, the tammar is a model species for the characterization of potential developmental support agents provided by maternal milk. In the present study, the N- and O-linked glycans from tammar wallaby milk glycoproteins from six individuals at different lactation time points were subjected to glycomics analyses using porous graphitized carbon liquid chromatography electrospray ionization mass spectrometry. Structural characterization identified a diverse range of glycan structures on wallaby milk glycoproteins including sialylated, sulphated, core fucosylated and O-fucosylated structures. 30% of N-linked structures contained a core (α1-6) fucose. Several of these structures may play roles in development, and exhibit statistically significant temporal changes over the lactation period. The N-glycome was found to contain structures with NeuGc residues, while in contrast the O-glycome did not. O-fucosylated structures were identified in the early stages of lactation indicating a potential role in the early stages of development of the pouch young. Overall the results suggest that wallaby milk contains structures known to have developmental and immunological significance in human milk and reproduction in other animals, highlighting the importance of glycoproteins in milk.14 page(s