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During medical school, students in Germany acquire knowledge, abilities, competencies, and skills in social medicine. The aim of this study was to investigate how human medicine students perceive the relevance of selected social medical issues and their knowledge gain depending on different teaching formats. The study was designed as a retrospective trend study. Included were four semester cohorts (n = 597 students). Five topics were selected as seminar subjects: work incapacity, rehabilitation, (long-term) care level, graded return to work, and assistive technology for activities of daily living. A new teaching format based on problem-based learning (PBL) and peer teaching (PT) was implemented. In the seminars, each student worked on one topic by him/herself (PBL; for this topic, the student is counted within group PBL in the statistical analysis). Through the presentations of fellow students, a student received information regarding other topics (PT; for these topics, the student is counted within group PT in the statistical comparison with group PBL). 550 students completed a standardized questionnaire at the end of the seminar, rating (a) their perceived relevance of these social medical topics with regard to clinical practice and (b) the personal knowledge gain regarding all topics. The results in group PBL tended to be better than those in group PT, indicating that active engagement with socio-medical topics increases the perception of their relevance. The students benefit more from working on topics themselves than from oral presentations or lectures: the probability of stating a notable knowledge gain regarding the respective topic was significantly higher for all topics in group PBL compared with in group PT (Work incapacity: OR: 1.3 (95%-CI: 1.07; 1.58), Rehabilitation: OR 1.8 (95%-CI: 1.41; 2.20), (Long-term) care level: OR: 1.6 (95%-CI: 1.25; 1.94); Graded return to work: OR: 1.95 (95%-CI: 1.57; 2.42), Assistive technology for activities of daily living: OR: 1.8 (95%-CI: 1.45; 2.31)). Medical students can be sensitized to the clinical relevance of social medicine, particularly when they experience its practical implications via appropriate activating teaching formats. The results suggest that PBL formats are preferable for increasing awareness of socio-medical issues.

Wilson disease is caused by accumulation of Cu 2+ in cells, which results in liver cirrhosis and, occasionally, anemia. Here, we show that Cu 2+ triggers hepatocyte apoptosis through activation of acid sphingomyelinase (Asm) and release of ceramide. Genetic deficiency or pharmacological inhibition of Asm prevented Cu 2+ -induced hepatocyte apoptosis and protected rats, genetically prone to develop Wilson disease, from acute hepatocyte death, liver failure and early death. Cu 2+ induced the secretion of activated Asm from leukocytes, leading to ceramide release in and phosphatidylserine exposure on erythrocytes, events also prevented by inhibition of Asm. Phosphatidylserine exposure resulted in immediate clearance of affected erythrocytes from the blood in mice. Accordingly, individuals with Wilson disease showed elevated plasma levels of Asm, and displayed a constitutive increase of ceramide- and phosphatidylserine-positive erythrocytes. Our data suggest a previously unidentified mechanism for liver cirrhosis and anemia in Wilson disease.

In the current paper, we compare the inter-day variability of the metabolite concentration of di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) in 247 morning urine samples obtained from 19 probands of different age and sex with the metabolite concentration in morning urine obtained from 215 probands of the “Tübingen Survey” cross-sectional study. In the first longitudinal study the morning urine of seven volunteers was collected four times a year for seven consecutive days (course of the year study). In a second study the morning urine of 12 students of a boarding school was collected on five consecutive days (course of a week study). For participants of the two different longitudinal studies we obtained mean concentrations in first void morning urine for mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP) in the range from 21.3 to 110 µg/L, 10.5 to 35.6 µg/L for mono(2-ethyl-5-oxohexyl) phthalate (5oxo-MEHP), and 45.5 to 143 µg/L for mono(2-ethyl-5-carboxypentyl) phthalate (5cx-MEPP). The corresponding relative standard deviations (rel. Std.D in %) for these DEHP-metabolites vary between 45.2% and 262%. The 50th percentiles vary for 5OH-MEHP between 17.5 and 65.6 µg/L, for 5oxo-MEHP between 9.0 and 20.3 µg/L and for 5cx-MEPP between 42.5 and 82.0 µg/L. For participants of the “Tübingen Survey” cross-sectional study the means vary for 5OH-MEHP between 58.2 and 85.0 µg/L, between 33.6 and 38.7 µg/L for 5oxo-MEHP and between 110 and 158 µg/L for 5cx-MEPP with rel. standard deviations in a range between 86.5 to 175%. The corresponding 50th percentiles vary for 5OH-MEHP between 26.5 and 42.3 µg/L, for 5oxo-MEHP between 18.0 and 26.3 µg/L, and for 5cx-MEPP between 57.2 and 77.6 µg/L. In order to compare the data from the longitudinal studies with the data from the cross-sectional study, the frequency distribution of the results of both types of studies was compared first. In a second step, the results of a t-test (p-values) was used to check whether the results of the long-term studies differ statistically significantly from the results of the cross-sectional study (p < 0.05). The present data show that the frequency distributions of DEHP-metabolites are comparable. For most of the participants respectively subject groups t-test results prove that no statistical significant difference between results obtained from longitudinal studies compared to the results of the cross-sectional study are apparent. The available data on the exposure of individual subjects mirror the data obtained from cross-sectional studies of the general population and give hints to the risk of individual increased DEHP exposure. Results also highlight the importance of living conditions on the risk of increased DEHP exposure.

The hemocompatibility of artificial surfaces in extracorporeal blood circulation systems can be improved by coatings. According to the literature, heparin coatings should avoid the leaching of the plasticizer di(2-ethylhexyl) phthalate (DEHP) into the blood from components made from plasticized polyvinyl chloride (PVC). DEHP and its metabolites are known to impair the fertility of male rodents; effects on human fertility are assumed. Three different surface coatings with and without heparin were examined in a Chandler Loop model at 37°C using fresh human blood to evaluate their hemocompatibility and barrier property to plasticizer. The levels of toxic oxidation products of DEHP generated in the blood, particularly, were found as high as in the uncoated tubing. The coatings improved the hemocompatibility, but are not safe protection against the hazardous metabolites of DEHP. For pregnant women, neonates and children, we would recommend using the available surface-coated plasticized PVC tubing sets, but free of DEHP.

1. Di-(2-ethylhexyl)-phthalate (DEHP) possesses a great industrial value as a plasticizing agent and has become an ubiquitous environmental contaminant. In most species it is rapidly metabolized to mono-(2-ethylhexyl)-phthalate (MEHP) and 2-ethylhexanoic acid (2-EHA). Evaluation of toxicity of DEHP and its primary metabolites has been focussed on reproductive toxicity and hepatocarcinogenic properties. The aim of this study was to determine the nephrotoxic potential of both DEHP metabolites by use of cultured kidney epithelial cells (Opossum kidney cells; OK cells). 2. For this purpose, OK cells were exposed for 3 days to MEHP and 2-EHA at concentrations ranging from 0.1 -500 micromol/L and the toxicity as well as the effects on migratory activity and intracellular cytoskeleton were studied by cell biological, morphological and morphometric methods. 3. When compared with corresponding controls, treatment of OK cells with MEHP and 2-EHA, respectively, showed marked differences in cell viability between both DEHP metabolites. MEHP caused a dose-dependent decrease in cell viability (ED50 = 25 micromol/L) accompanied by a moderate swelling of the cells at concentrations up to 25 micromol/L. MEHP concentrations higher than 25 micromol/L caused a dose-dependent shrinkage of the cells and the occurrence of a high amount of cell debris as a result of cell lysis. 2-EHA did not cause a reduced viability or an altered cell volume. The migratory activity of OK cells was not significantly influenced by both metabolites. Moreover, MEHP toxicity resulted in a largely reduced and altered organization of F-actin (stress fibers), but not of myosin, microtubules and vimentin. 4. The study indicates that cultured epithelial cells can be used as a prescreening system to assess the nephrotoxicity of hazardous substances such as DEHP. As demonstrated in this study, only MEHP, but not 2-EHA, has a marked nephrotoxic effect in vitro.

1 Di-(2-ethylhexyl)-phthalate (DEHP) possesses a great industrial value as a plasticizing agent and has become an ubiquitous environmental contaminant. In most species it is rapidly metabolized to mono-(2-ethylhexyl)-phthalate (MEHP) and 2-ethylhexanoic acid (2- EHA). Evaluation of toxicity of DEHP and its primary metabolites has been focussed on reproductive toxicity and hepatocarcinogenic properties. The aim of this study was to determine the nephrotoxic potential of both DEHP metabolites by use of cultured kidney epithelial cells (Opossum kidney cells; OK cells). 2 For this purpose, OK cells were exposed for 3 days to MEHP and 2-EHA at concentrations ranging from 0.1 -500 mmol/L and the toxicity as well as the effects on migratory activity and intracellular cytoskeleton were studied by cell biological, morphological and morpho-metric methods. 3 When compared with corresponding controls, treatment of OK cells with MEHP and 2-EHA, respectively, showed marked differences in cell viability between both DEHP metabolites. MEHP caused a dose-depen-dent decrease in cell viability (ED50 =25 mmol/L) accompanied by a moderate swelling of the cells at concentrations up to 25 mmol/L. MEHP concentrations higher than 25 mmol/L caused a dose-dependent shrinkage of the cells and the occurrence of a high amount of cell debris as a result of cell lysis. 2-EHA did not cause a reduced viability or an altered cell volume. The migratory activity of OK cells was not significantly influenced by both metabolites. Moreover, MEHP toxicity resulted in a largely reduced and altered organization of F-actin (stress fibers), but not of myosin, microtubules and vimentin. 4 The study indicates that cultured epithelial cells can be used as a prescreening system to assess the nephrotoxicity of hazardous substances such as DEHP. As demonstrated in this study, only MEHP, but not 2-EHA, has a marked nephrotoxic effect in vitro.