Polymer grafted chromatography media for direct capture and high-resolution purification of enveloped virus-like particles

Usually, the downstream processing of viruses and virus-like particles (VLP) does not include conventional chromatography media (beads) in the capture and/or purification steps. For large biomolecules, the binding capacity of conventional resins is limited to the outer surface of the beads. We developed a purification process based on polymer-grafted media, which allows a swift purification of HIV-1 VLP from CHO cell culture supernatant. The dynamic binding capacity is one order of magnitude lower than convective media but still in the range of 5-7x1011 particles/ml packed bed, which is unexpectedly high. For that reason, the binding mechanism was studied in detail. As expected, transmission electron micrographs showed that the VLPs only adsorb at the outer surface of the beads. This was corroborated by confocal microscopy using florescence labelled VLPs by incorporating cell membrane label. In batch update experiments, we observed a biphasic behavior with a fast uptake within minutes followed by a slow adsorption within hours. Desorption was also occurring very fast within minutes. Modeling linear gradient elutions with different gradient slopes showed that the number of effective charges involved in the adsorption is in the range of 30 and the adsorption is not really affected by salt. This explains why VLPs can be directly loaded from culture supernatant without further preconditioning. Scalability is not an issue, because these polymer grafted media can be packed in any scale from less than 0.5 ml to several hundred liters and in any column geometry

Media on-demand: continuous reconstitution of a chemically defined media directly from solids

Chemically defined media are reconstituted batchwise and stored in hold tanks until use. To avoid large hold tanks and batchwise production of media, we developed continuous on-demand reconstitutions directly from solids consisting of a hopper and a screw conveyor capable of feeding dry powdered media with the required precision +/- 5% at low dosing rates of 0.171 g min(-1). A commercially available dry powdered cell culture medium was continuously fed over a duration of 12 h into a mixer which was connected to a UV-cell for monitoring and the media were compared to a batchwise production. A comparable amino acid, carbohydrate, and osmolality profile to a batchwise reconstitution could be obtained. Cell cultivation showed comparable performance of batch and continuous reconstitution for two CHO cell lines producing the antibodies adalimumab and trastuzumab on a small and benchtop scale. In-depth analysis of the produced antibodies showed the same glycosylation pattern, other posttranslational profiles such as methionine oxidation and deamidation compared to batchwise reconstitution. Therefore, we conclude a continuous reconstitution of the medium results in the same quality of the product. A continuous on-demand media reconstitution will impact the supply chain and significantly reduce the floor space necessary for preparation and storage.Proteomic

Mucosal Melanoma In Situ of the Oral Cavity: A Case Report and Systematic Review of the Literature

Objective:Malignant mucosal melanomas of the head and neck comprise a very small portion of all melanomas, particularly in the oral cavity. These lesions are associated with high rates of local recurrence, distant metastasis, and a very poor 5-year survival rate; however, the clinical outcomes of mucosal melanoma in situ of the oral cavity are unclear. Therefore, we present a case report of mucosal melanoma in situ and a systematic review of the literature to shed light on this rare but important disease.Methods:PubMed, Scopus, and CINAHL were searched per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were only considered for inclusion if they described oral cavity melanoma in situ and documented specific data pertaining to treatment including modality, lesion size, or outcomes.Results:A total of 28 reported cases from the literature fulfilled the inclusion criteria, as well as one case from our own institution. Men comprised the majority (64.3%) of the cases, and the average age at presentation was 57.4 years. The hard palate was the most common location, and most cases were treated with surgical excision. Eight had no evidence of disease after a minimum of six months of follow-up, one reported spread to the cervical lymph nodes, and only one reported progression with distant metastasis.Conclusion:Oral mucosal melanoma in situ is a rare entity and most commonly treated with surgical excision. High rates of recurrence necessitate long term follow-up. Further studies may be useful to determine whether adjuvant therapy may play a role in reducing recurrence

The effect of Germany’s federalism on student success : The “Index of Commitment“ as comparative measure for study and examination regulations

Long-term studies and drop-outs are a major issue in higher education research, but explanatory factors have often been focusing on attitudinal and sociological characteristics using student surveys as methodology. Institutional rules regarding study and learning regulations have often been neglected, although recent research has shown that they incentivize student behaviour. We develop and Index of Commitment (IOC) to cover these rules over different types of study phases and different types of commitments of different actors. We distinguish between an early study phase, a main phase and a late study phase and commitments regarding consultation and examination rules by the state, a higher education institution (HEI) and students. This paper shows empirically that there is a considerable variance of these rules between the 16 German states, which are responsible for the legislation and financing of most of the higher education institutions in Germany. We find states with very soft regulation, where legislation sets almost no rules and student autonomy is held in high regard and states with very precise rules setting strong incentives and leaving only little room for implementation to the HEI. We can show that our index correlates with the percentage of students successfully finishing their degree in time in a state. By presenting our index, we provide a comprehensive understanding of the commitment of study and examination regulations. The findings and insights can contribute to the ongoing discourse on student autonomy and state control in higher education, as well as inform policy makers and educational institutions in developing effective strategies to address dropout and long-term study. It also shows again that “bringing the state back in” in higher education research is important

Global Health Education: a cross-sectional study among German medical students to identify needs, deficits and potential benefits (Part 1 of 2: Mobility patterns & educational needs and demands)

<p>Abstract</p> <p>Background</p> <p>In recent years, education and training in global health has been the subject of recurring debate in many countries. However, in Germany, there has been no analysis of the educational needs or demands of medical students, or the educational deficits or potential benefits involved in global health education. Our purpose is to analyse international health elective patterns of medical students enrolled at German universities and assess whether or how they prepare for their electives abroad. We examine the exposure of medical students enrolled at German universities to training courses in tropical medicine or global health and assess students' perceived needs and demands for education in global health.</p> <p>Methods</p> <p>Cross-sectional study among medical students in Germany including all 36 medical schools during the second half of the year 2007. All registered medical students were eligible to participate in the study. Recruitment occurred via electronic mailing-lists of students' unions. We developed a web-based, semi-structured questionnaire to capture students' international mobility patterns, preparation before electives, destination countries, exposure to and demand for global health learning opportunities.</p> <p>Results</p> <p>1126 online-replies were received and analysed from all registered medical students in Germany (N = 78.067). 33.0% of all respondents (370/1126) declared at least one international health elective and of these, 36.0% (133/370) completed their electives in developing countries. 36.0% (131/363) did not prepare specifically at all, 59.0% (214/363) prepared either by self-study or declared a participation in specific preparation programmes. 87.8% of 5^thand 6^thyear students had never participated in a global health course and 72.6% (209/288) had not completed a course in tropical medicine. 94.0% (861/916) endorsed the idea of introducing global health into medical education.</p> <p>Conclusion</p> <p>Students in our sample are highly mobile during their studies. International health electives are common, also in developing countries. Formal preparation beyond self-study is virtually non-existent amongst our sample and the participation rate in courses of tropical medicine or global health is appallingly low. We have identified unmet perceived needs and the demand for more learning opportunities in global health in our sample, urging for reforms to adjust curricula to a globalising world.</p

Inventory of the chemicals and the exposure of the workers’ skin to these at two leather factories in Indonesia

PURPOSE: Tannery workers are exposed to hazardous chemicals. Tannery work is outsourced to newly industrialized countries (NICs) where attention into occupational health hazards is limited. In this study, we investigated the skin exposure to hazardous chemicals in tannery workers and determined the prevalence of occupational skin diseases (OSDs) at tanneries in a NIC. METHODS: A cross-sectional study on the observation of the working process and an inventory and risk assessment of the chemicals used. Classification of chemicals as potential sensitizers/irritants and a qualitative assessment of exposure to these chemicals. Workers were examined and interviewed using Nordic Occupational Skin Questionnaire-2002/LONG. RESULTS: The risk of OSDs at the investigated tanneries was mainly related to the exposure of the workers' skin to chemicals in hot and humid environmental conditions. In 472 workers, 12% reported a current OSD and 9% reported a history of OSD. In 10% of all cases, an OSD was confirmed by a dermatologist and 7.4% had an occupational contact dermatitis (OCD). We observed that personal protective equipment (PPE) used was mainly because of skin problems in the past and not as a primary protection against OSD. CONCLUSION: We observed a high frequency and prolonged exposure to many skin hazardous factors in tannery work although PPE was relatively easily available and which was generally used as a secondary preventative measure. The observed point-prevalence in this study was at the same level as that reported for other high-risk OSDs in Western countries and other tanneries in NICs. However, the observed point-prevalence in this study was lower than that reported in India and Korea. The results of our study and those of other studies at tanneries from other NICs were probably influenced by Healthy Worker Survivor Effect (HWSE)

Enhanced In Vitro Refolding of Fibroblast Growth Factor 15 with the Assistance of SUMO Fusion Partner

Fibroblast growth factor 15 (Fgf15) is the mouse orthologue of human FGF19. Fgf15 is highly expressed in the ileum and functions as an endocrine signal to regulate liver function, including bile acid synthesis, hepatocyte proliferation and insulin sensitivity. In order to fully understand the function of Fgf15, methods are needed to produce pure Fgf15 protein in the prokaryotic system. However, when expressed in Escherichia coli (E. coli), the recombinant Fgf15 protein was insoluble and found only in inclusion bodies. In the current study, we report a method to produce recombinant Fgf15 protein in E. coli through the use of small ubiquitin-related modifier (SUMO) fusion tag. Even though the SUMO has been shown to strongly improve protein solubility and expression levels, our studies suggest that the SUMO does not improve Fgf15 protein solubility. Instead, proper refolding of Fgf15 protein was achieved when Fgf15 was expressed as a partner protein of the fusion tag SUMO, followed by in vitro dialysis refolding. After refolding, the N-terminal SUMO tag was cleaved from the recombinant Fgf15 fusion protein by ScUlp1 (Ubiquitin-Like Protein-Specific Protease 1 from S. cerevisiae). With or without the SUMO tag, the refolded Fgf15 protein was biologically active, as revealed by its ability to reduce hepatic Cyp7a1 mRNA levels in mice. In addition, recombinant Fgf15 protein suppressed Cyp7a1 mRNA levels in a dose-dependent manner. In summary, we have developed a successful method to express functional Fgf15 protein in prokaryotic cells

Global Health Education: a cross-sectional study among German medical students to identify needs, deficits and potential benefits (Part 2 of 2: Knowledge gaps and potential benefits)

<p>Abstract</p> <p>Background</p> <p>In Germany, educational deficits or potential benefits involved in global health education have not been analysed till now.</p> <p>Objective</p> <p>We assess the importance medical students place on learning about social determinants of health (SDH) and assess their knowledge of global health topics in relation to (i) mobility patterns, their education in (ii) tropical medicine or (iii) global health.</p> <p>Methods</p> <p>Cross-sectional study among medical students from all 36 medical schools in Germany using a web-based, semi-structured questionnaire. Participants were recruited via mailing-lists of students' unions, all medical students registered in 2007 were eligible to participate in the study. We captured international mobility patterns, exposure to global health learning opportunities and attitudes to learning about SDH. Both an objective and subjective knowledge assessment were performed.</p> <p>Results</p> <p>1126 online-replies were received and analysed. International health electives in developing countries correlated significantly with a higher importance placed on all provided SDH (p ≤ 0.006). Participation in tropical medicine (p < 0.03) and global health courses (p < 0.02) were significantly associated with a higher rating of 'culture, language and religion' and the 'economic system'. Global health trainings correlated with significantly higher ratings of the 'educational system' (p = 0.007) and the 'health system structure' (p = 0.007), while the item 'politics' was marginally significant (p = 0.053).</p> <p>In the knowledge assessment students achieved an average score of 3.6 (SD 1.5; Mdn 4.0), 75% achieved a score of 4.0 or less (Q₂₅= 3.0; Q₇₅= 4.0) from a maximum achievable score of 8.0. A better performance was associated with international health electives (p = 0.032), participation in tropical medicine (p = 0.038) and global health (p = 0.258) courses.</p> <p>Conclusion</p> <p>The importance medical students in our sample placed on learning about SDH strongly interacts with students' mobility, and participation in tropical medicine and global health courses. The knowledge assessment revealed deficits and outlined needs to further analyse education gaps in global health. Developing concerted educational interventions aimed at fostering students' engagement with SDH could make full use of synergy effects inherent in student mobility, tropical medicine and global health education.</p