Peroxisomes during postnatal development of mouse endocrine and exocrine pancreas display cell-type- and stage-specific protein composition.

Peroxisomal dysfunction unhinges cellular metabolism by causing the accumulation of toxic metabolic intermediates (e.g. reactive oxygen species, very -chain fatty acids, phytanic acid or eicosanoids) and the depletion of important lipid products (e.g. plasmalogens, polyunsaturated fatty acids), leading to various proinflammatory and devastating pathophysiological conditions like metabolic syndrome and age-related diseases including diabetes. Because the peroxisomal antioxidative marker enzyme catalase is low abundant in Langerhans islet cells, peroxisomes were considered scarcely present in the endocrine pancreas. Recently, studies demonstrated that the peroxisomal metabolism is relevant for pancreatic cell functionality. During the postnatal period, significant changes occur in the cell structure and the metabolism to trigger the final maturation of the pancreas, including cell proliferation, regulation of energy metabolism, and activation of signalling pathways. Our aim in this study was to (i) morphometrically analyse the density of peroxisomes in mouse endocrine versus exocrine pancreas and (ii) investigate how the distribution and the abundance of peroxisomal proteins involved in biogenesis, antioxidative defence and fatty acid metabolism change during pancreatic maturation in the postnatal period. Our results prove that endocrine and exocrine pancreatic cells contain high amounts of peroxisomes with heterogeneous protein content indicating that distinct endocrine and exocrine cell types require a specific set of peroxisomal proteins depending on their individual physiological functions. We further show that significant postnatal changes occur in the peroxisomal compartment of different pancreatic cells that are most probably relevant for the metabolic maturation and differentiation of the pancreas during the development from birth to adulthood.

The biogenesis protein PEX14 is an optimal marker for the identification and localization of peroxisomes in different cell types, tissues, and species in morphological studies.

Catalase and ABCD3 are frequently used as markers for the localization of peroxisomes in morphological experiments. Their abundance, however, is highly dependent on metabolic demands, reducing the validity of analyses of peroxisomal abundance and distribution based solely on these proteins. We therefore attempted to find a protein which can be used as an optimal marker for peroxisomes in a variety of species, tissues, cell types and also experimental designs, independently of peroxisomal metabolism. We found that the biogenesis protein peroxin 14 (PEX14) is present in comparable amounts in the membranes of every peroxisome and is optimally suited for immunoblotting, immunohistochemistry, immunofluorescence, and immunoelectron microscopy. Using antibodies against PEX14, we could visualize peroxisomes with almost undetectable catalase content in various mammalian tissue sections (submandibular and adrenal gland, kidney, testis, ovary, brain, and pancreas from mouse, cat, baboon, and human) and cell cultures (primary cells and cell lines). Peroxisome labeling with catalase often showed a similar tissue distribution to the mitochondrial enzyme mitochondrial superoxide dismutase (both responsible for the degradation of reactive oxygen species), whereas ABCD3 exhibited a distinct labeling only in cells involved in lipid metabolism. We increased the sensitivity of our methods by using QuantumDots™, which have higher emission yields compared to classic fluorochromes and are unsusceptible to photobleaching, thereby allowing more exact quantification without artificial mistakes due to heterogeneity of individual peroxisomes. We conclude that PEX14 is indeed the best marker for labeling of peroxisomes in a variety of tissues and cell types in a consistent fashion for comparative morphometry.

Knowledge, attitude and behavior towards vaccinations among nursing- and health care students in Hesse. An observational study.

Objective: Work-related vaccinations are recommended for employees in nursing and health care professions due to their elevated risk of infection because of job-related exposure. These vaccinations prevent work-related infections, protect patients and help to maintain the medical infrastructure. Thorough training and imparting of knowledge about vaccinations and work-related infections are essential pillars of the vaccination decision and thus for achieving a protective immune status. The present study examines the knowledge, attitudes and behavior of nursing- and health care students in Hesse regarding work-related infections and vaccinations. Methods: In spring 2018, seven nursing schools in Hesse took part in an anonymous survey study. A total of 690 surveys from students of various health care professions were included in the study. The content of the survey was based on the recommendations of the Standing Committee on Vaccination (STIKO), a literature review and sample questions from the World Health Organization (WHO) regarding "vaccine hesitancy". Vaccination cards were also evaluated based on the STIKO recommendations concerning standard vaccinations and occupational vaccinations for health care workers. Results: The risk of acquiring a work-related infection was estimated to be quite high over all years of training. Gaps in knowledge were particularly evident in the area of vaccinations. Only three quarter of those surveyed believed that the effectiveness of vaccinations has been proven, and nearly 30% believed that the doses of the drugs used in vaccines were dangerous. Over 80% of the students had never had an influenza vaccination documented in their vaccination card. Conclusions: The knowledge about vaccinations imparted in the course of the education should be expanded. A special course on the subject of vaccinations and the immune system with practical elements could contribute to a better understanding of how vaccinations work and misunderstandings could be eliminated in early stages of the training through the dialog between the students and the teacher in the classroom and the occupational physician as part of preventive occupational health check-ups.