The expression of the surfactant proteins SP-A and SP-B during postnatal alveolarization of the rat lung.

OBJECTIVE: Surfactant-specific proteins (SP) are responsible for the functional and structural integrity as well as for the stabilization of the intra-alveolar surfactant. Morphological lung maturation starts in rat lungs after birth. The aim of this study was to investigate whether the expression of the hydrophilic SP-A and the hydrophobic SP-B is associated with characteristic postnatal changes characterizing morphological lung maturation. METHODS: Stereological methods were performed on the light microscope. Using immunohistochemical and molecular biological methods (Western Blot, RT-qPCR), the SP-A and SP-B of adult rat lungs and of those with different postnatal developmental stages (3, 7, 14 and 21 days after birth) were characterized. RESULTS: As signs of alveolarization the total septal surface and volume increased and the septal thickness decreased. The significantly highest relative surface fraction of SP-A labeled alveolar epithelial cells type II (AEII) was found together with the highest relative SP-A gene expression before the alveolarization (3th postnatal day). With the downregulation of SP-A gene expression during and after alveolarization (between postnatal days 7 and 14), the surface fraction of the SP-A labeled AEII also decreased, so they are lowest in adult animals. The surface fraction of SP-B labeled AEII and the SP-B gene expression showed the significantly highest levels in adults, the protein expression increased also significantly at the end of morphological lung maturation. There were no alterations in the SP-B expression before and during alveolarization until postnatal day 14. The protein expression as well as the gene expression of SP-A and SP-B correlated very well with the total surface of alveolar septa independent of the postnatal age. CONCLUSION: The expression of SP-A and SP-B is differentially associated with morphological lung maturation and correlates with increased septation of alveoli as indirect clue for alveolarization.

Ultrastructural analysis of the intracellular surfactant in lungs of healthy and ovalbumin sensitized and challenged Brown Norway rats.

Introduction: In human and experimentally induced asthma, a dysfunction of the intra-alveolar-surface active agent (surfactant) has been demonstrated. Type II alveolar epithelial cells (AEII) synthesize, secrete and recycle surfactant. Prior to secretion, intracellular surfactant is stored in specific secretory organelles of AEII. The lamellar bodies (Lb) represent its ultrastructural correlate. The aim of this study was to investigate whether disturbances of the intra-alveolar surfactant are accompanied by alterations in the intracellular surfactant.Material and Methods: Brown-Norway rats were sensitized twice with ovalbumin (OVA) and heat killed Bordetella pertussis bacilli. During airway challenge, an aerosol of 5% ovalbumin/saline solution (0.25 l/min) was nebulized. 24 h after airway challenge, lungs were fixed by vascular perfusion. AEII and their Lb were characterized stereologically by light and electron microscopy.Results: In both groups, AEII were structurally intact. The number of AEII per lung and their number-weighted mean volume did not differ (controls: 49 × 106, 393 µm3; asthmatics: 44 × 106, 390 µm3). A mean of 90 Lb in AEII of asthmatics and of 93 Lb in AEII of controls were evaluated. The Lb mean total volume was 59 µm in asthmatics and 68 µm in controls. Values of both parameters did not reach significance. Also, the size distribution and mean volume of Lb was not influenced by asthma induction, because the volume weighted mean volume of Lb (2.18 µm in asthmatics compared to 1.87 µm in controls) and the numerical weighted mean volume (0.96 µm in asthmatics and 0.75 µm in controls) were comparable in both groups.Conclusion: The obtained results suggest that asthma-induced surfactant dysfunction is not related to disturbances in the intracellular surfactant´s ultrastructural correlates.

The chemicals between us-First results of the cluster analyses on anatomy embalming procedures in the German-speaking countries.

Hands-on courses utilizing preserved human tissues for educational training offer an important pathway to acquire basic anatomical knowledge. Owing to the reevaluation of formaldehyde limits by the European Commission, a joint approach was chosen by the German-speaking anatomies in Europe (Germany, Austria, Switzerland) to find commonalities among embalming protocols and infrastructure. A survey comprising 537 items was circulated to all anatomies in German-speaking Europe. Clusters were established for "ethanol"-, formaldehyde-based ("FA"), and "other" embalming procedures, depending on the chemicals considered the most relevant for each protocol. The logistical framework, volumes of chemicals, and infrastructure were found to be highly diverse between the groups and protocols. Formaldehyde quantities deployed per annum were three-fold higher in the "FA" (223 L/a) compared to the "ethanol" (71.0 L/a) group, but not for "other" (97.8 L/a), though the volumes injected per body were similar. "FA" was strongly related to table-borne air ventilation and total fixative volumes ≤1000 L. "Ethanol" was strongly related to total fixative volumes >1000 L, ceiling- and floor-borne air ventilation, and explosion-proof facilities. Air ventilation was found to be installed symmetrically in the mortuary and dissection facilities. Certain predictors exist for the interplay between the embalming used in a given infrastructure and technical measures. The here-established cluster analysis may serve as decision supportive tool when considering altering embalming protocols or establishing joint protocols between institutions, following a best practice approach to cater toward best-suited tissue characteristics for educational purposes, while simultaneously addressing future demands on exposure limits.

The Use of Plantaris Muscle Flap for Facial Reanimation: A Comprehensive Anatomical Study.

Background: Functional facial reanimation remains challenging and the quest for optimization continues. Objective: To characterize the anatomical conditions of the plantaris muscle for facial reanimation. Study Design and Methods: Forty-two plantaris muscle specimens were obtained from 23 post-mortem chemically fixed cadavers. The muscles were dissected, evaluated, and measured. Mock facial reanimation was performed on three cadaver heads. Results: The plantaris muscle was a consistently available muscle. Mean muscle belly length was 10.1 cm (standard deviation [SD] 1.4), and mean width was 1.7 cm (SD 0.4). The mean tendon length of 30.1 cm (SD 2.8) is unique in the human body. The main artery supplying the muscle had a mean length of 1.4 cm (SD 0.4). The mean nerve length was 2.2 cm (SD 0.7). Sixteen variations of vascular supply were identified. Mock facial reanimations demonstrated a good size match, and great versatility of the long tendon for oral fixation. Conclusions: The plantaris muscle as a free flap for facial reanimation could offer new possibilities in terms of oral fixation and volumetric aesthetic conditions.

Bacterial species-specific antimicrobial efficacies of three different body embalming solutions for anatomical studies.

While body decompensation is mainly facilitated by bacteria, investigating the antimicrobial properties of body preservation methods is still a neglected research area. We performed microbiological sampling for potentially pathogenic bacteria species of brain, lung, liver, colon, and subcutis samples obtained from bodies perfused with embalming solutions of variable composition with emphasis on variable formaldehyde concentrations. We, thereby, identified spore-forming aerobic and anaerobic bacteria mainly in the samples obtained from the colon of ethanol- and lower-concentrated formaldehyde formulation embalmed bodies. Moreover, we could identify Enterococcus species in bodies preserved with the latter method. Tissue samples of the subcutis remained sterile. Long-term incubation of special mycobacteria growth indicator tubes revealed no growth of mycobacteria in all 60 samples analyzed. Overall, we show survival of bacterial genera known to be especially environmentally resistant but also include potentially pathogenic members. Knowledge of bactericidal capacities of embalming solutions are therefore critical to assess risk and apply appropriate disinfection routines while working with human bodies. Moreover, new formulations to reduce potentially toxic substances for embalming needs to be evaluated regarding their bactericidal capacities.

The relationship between the subclavian vessels and brachial plexus and the overlying clavicle: Anatomical study with application to plate osteosynthesis.

A subclavian artery aneurysm after clavicle fracture and plate osteosynthesis in a suspected case of a screw that was too long led us to investigate body donor cadavers. The aim was to verify clavicle variability, and the course of the neurovascular bundle in relation to the clavicle and to the osteosynthesis plate, in order to clarify safe zones for plate and screw fixation. We used one fresh frozen and 25 embalmed donors for in situ measurements: (1) length and craniocaudal thickness of the clavicle, (2) distances between the sternal end of the clavicle and the center of parts of the neurovascular bundle. The clavicle was 15.15 cm long. The mean distances from the sternal end of the clavicle were 5.62 cm to the subclavian vein, 6.75 cm to the subclavian artery and 8.42 cm to the cords of the brachial plexus. The subclavius muscle was 1 cm thick. Because of sex differences in length and distances, we recorded the distances between the sternal end and parts of the neurovascular bundle as ratios of clavicle length (at-risk area) to provide sex-independent parameters: 0.379 for the vein, 0.449 for the artery and 0.554 for the nerve. The neurovascular bundle runs below the clavicle between the medial fourth and three fifths of clavicle length. To avoid iatrogenic neurovascular injuries, special caution is necessary during drilling and screwing the osteosynthesis. We also recommend using screws shorter than 1.4 cm.

Differential temporal development of alveoli and the alveolar capillary network in the postnatal rat lung.

Quantitative data about the internal lung structure are needed to better understand normal and pathological lung development. Aberrant lung development causes deficits in alveolar and microvascular development; however, the normal temporal relationship between these processes is still not fully understood. We hypothesized that alveolar and capillary development show a differential time pattern. Lungs of rats aged 3, 7, 14, 21 days (d) or 3 mo (n = 8-10 each) were fixed by vascular perfusion and processed for light microscopy. Using design-based stereology number, the surface area and volume of alveoli, septal capillaries, and alveolar septa were quantified. The total number and the total volume of alveoli increased progressively during postnatal development. Interestingly, the numerical density of capillary loops was significantly higher in 14- and 21-d-old rats than before or after this age, causing a duplication of the total number of capillary loops between 1 and 2 wk of age. The mean thickness of alveolar septa started to decline slightly at the age of 14d and more pronounced at later stages. Although the septal epithelial surface area increased in proportion to alveolar number during the first 3 wk, the capillary endothelial surface area grew only slightly compared with the number of capillaries. In conclusion, the number of elements composing the alveolar capillary network expands massively during the first two postnatal weeks and exceeds the formation of alveoli. The thinning of the alveolar septa during further development suggests a reduction of the capillary network during alveolarization.

Teaching gross anatomy during the Covid-19 pandemic: Effects on medical students' gain of knowledge, confidence levels and pandemic-related concerns.

For medical students the dissection course is the preferred method to learn gross anatomy. However, the added value of active cadaver dissection on knowledge gain in multimodal curricula offering a diversity of e-learning resources is unknown. The Covid-19-related lockdown forced educators to replace the dissection course by e-learning resources. At the end of the summer term 2020 loosening of pandemic-related regulations allowed offering a compact, voluntary active dissection course of the head-neck region to first-year medical students at Hannover Medical School. A study was conducted comparing a dissection group (G1, n = 115) and a non-dissection group (G2, n = 23). Knowledge gain and confidence level were measured with a multiple-choice (MC-)test. The use of e-learning resources was recorded. A questionnaire measured motivation, interest and level of concern regarding Covid-19 and anatomy teaching. No differences between groups were found regarding motivation and interest in anatomy of the head-neck region. G2, however, had significantly higher concerns regarding the Covid-19 pandemic than G1. Neither before nor after the educational intervention, differences in the scores of the MC-test were found. However, after the course G1 answered more MC-questions with highest confidence level than G2 (6.7 ± 6.0 vs. 3.6 ± 4.6, p < 0.05) and demonstrated by trend an increased improvement in the scores of image-based questions (30.8 ± 18.2 % vs. 17.1 ± 14.8 %, p = 0.06). In general, frequent users of online quizzes, a part of the e-learning resources, scored significantly better in the knowledge test. Active dissection improves self-assurance to identify anatomical structures and should be re-implemented in multimodal, blended-learning-based anatomical curricula in the post-pandemic era.

Lung development and immune status under chronic LPS exposure in rat pups with and without CD26/DPP4 deficiency.

Dipeptidyl-peptidase IV (CD26), a multifactorial integral type II protein, is expressed in the lungs during development and is involved in inflammation processes. We tested whether daily LPS administration influences the CD26-dependent retardation in morphological lung development and induces alterations in the immune status. Newborn Fischer rats with and without CD26 deficiency were nebulized with 1 µg LPS/2 ml NaCl for 10 min from days postpartum (dpp) 3 to 9. We used stereological methods and fluorescence activated cell sorting (FACS) to determine morphological lung maturation and alterations in the pulmonary leukocyte content on dpp 7, 10, and 14. Daily LPS application did not change the lung volume but resulted in a significant retardation of alveolarization in both substrains proved by significantly lower values of septal surface and volume as well as higher mean free distances in airspaces. Looking at the immune status after LPS exposure compared to controls, a significantly higher percentage of B lymphocytes and decrease of CD4+CD25+ T cells were found in both subtypes, on dpp7 a significantly higher percentage of CD4 T+ cells in CD26+ pups, and a significantly higher percentage of monocytes in CD26- pups. The percentage of T cells was significantly higher in the CD26-deficient group on each dpp. Thus, daily postnatal exposition to low doses of LPS for 1 week resulted in a delay in formation of secondary septa, which remained up to dpp 14 in CD26- pups. The retardation was accompanied by moderate parenchymal inflammation and CD26-dependent changes in the pulmonary immune cell composition.

Does an Audiovisual Dissection Manual Improve Medical Students' Learning in the Gross Anatomy Dissection Course?

The gross anatomy dissection course is considered to be one of the most important subjects in medical school. Advancing technology facilitates the production of e-learning material that can improve the learning of topographic anatomy during the course. The purpose of this study was to examine a locally produced audiovisual dissection manual's effects on performance in dissection, formal knowledge gained, motivation, emotions, learning behavior, and learning efficiency of the medical students. The results, combined with the total effort put into the production of the manual, should support decisions on further implementation of this kind of audiovisual e-learning resource into the university's curriculum. First-year medical students (n = 279) were randomly divided into three groups for two weeks within the regular dissection course hours during the dissection of the anterior and posterior triangles of the neck. Two groups received an audiovisual dissection manual (n = 96) or an improved written manual (n = 94) as an intervention, the control group (n = 89) received the standard dissection manual. After dissection, each student filled out tests and surveys and their dissections were evaluated. The audiovisual dissection manual did not have any significant positive effects on the examined parameters. The effects of the audiovisual dissection manual on the medical students' learning experience, as observed in this study, did not support further curriculum implementation of this kind of e-learning resource. This study can serve as an orientation for further evaluation and design of e-learning resources for the gross anatomy dissection course.

Bone Tunnel Orientation in Suspension Arthroplasty of the Thumb Carpometacarpal Joint: An Anatomical Cadaver Study.

Background: Ligament suspension after trapeziectomy is a common technique in patients with osteoarthrosis. In this study, we set out to determine whether the orientation of the bone tunnel in the first metacarpal base affects the intraoperative position of the first metacarpal after surgery. Methods: Trapeziectomy and Epping procedure were performed in 32 cadaver hands. A drill hole was placed in the base of the first metacarpal, leaving a radial to ulnar tunnel parallel to the joint surface or a diagonal bone tunnel from the radiodorsal surface to the ulnar joint surface of the first metacarpal. Positioning of the first metacarpal was studied via radiography. Results: The distance between the first metacarpal and the scaphoid after suspension arthroplasty was 9.5 ± 2.6 mm when using the parallel radioulnar bone tunnel and 10.9 ± 2.3 mm when using the diagonal bone tunnel. Suspension of the first metacarpal was 33% higher with the diagonal bone tunnel compared with when using the parallel bone tunnel (displacement of 2.8 ± 2.0 mm vs 4.2 ± 2.0 mm). Conclusions: Higher suspension of the first metacarpal after trapeziectomy can be significantly achieved in our cadaveric model when using ligament suspension of the flexor carpi radialis tendon passed from the ulnar joint surface to the dorsum of the metacarpal. Our results have to be determined via clinical examination. To date, we prefer the diagonal bone tunnel when performing ligament suspension arthroplasty.

Aging impairs alveolar epithelial type II cell function in acute lung injury.

Morbidity and mortality rates in acute lung injury (ALI) increase with age. As alveolar epithelial type II cells (AE2) are crucial for lung function and repair, we hypothesized that aging promotes senescence in AE2 and contributes to the severity and impaired regeneration in ALI. ALI was induced with 2.5 µg lipopolysaccharide/g body weight in young (3 mo) and old (18 mo) mice that were euthanized 24 h, 72 h, and 10 days later. Lung function, pulmonary surfactant activity, stereology, cell senescence, and single-cell RNA sequencing analyses were performed to investigate AE2 function in aging and ALI. In old mice, surfactant activity was severely impaired. A 60% mortality rate and lung function decline were observed in old, but not in young, mice with ALI. AE2 of young mice adapted to injury by increasing intracellular surfactant volume and proliferation rate. In old mice, however, this adaptive response was compromised, and AE2 of old mice showed signs of cell senescence, increased inflammatory signaling, and impaired surfactant metabolism in ALI. These findings provide evidence that ALI promotes a limited proliferation rate, increased inflammatory response, and surfactant dysfunction in old, but not in young, mice, supporting an impaired regenerative capacity and reduced survival rate in ALI with advancing age.

DMBT1 is upregulated in lung epithelial cells after hypoxia and changes surfactant ultrastructure.

BACKGROUND: Hypoxia and asphyxia are known to induce surfactant inactivation in newborns. Deleted in Malignant Brain Tumors 1 (DMBT1) is an innate immunity protein with functions in epithelial differentiation and angiogenesis. It was detected in hyaline membranes of infants with respiratory distress syndrome. Human recombinant DMBT1 is able to increase the surface tension of exogenous surfactant preparations in a dose-dependent manner. METHODS: Immunohistochemistry was performed on lung sections of infants who died due to pre-, peri- or postnatal hypoxia. The lung epithelial cell line A549 was stably transfected with a DMBT1 (DMBT1+ cells) expression plasmid or with an empty plasmid (DMBT1- cells). The cells were cultured in normoxic or hypoxic conditions, and then DMBT1 as well as HIF-1α RNA expression were analyzed by using real-time-polymerase chain reaction. Human recombinant DMBT1 was added to the modified porcine natural surfactant Curosurf to examine the effect of DMBT1 on surfactant ultrastructure with electron microscopy. RESULTS: DMBT1 expression was upregulated in human lung tissue after fetal/peri-/postnatal hypoxia. In addition, in vitro experiments showed increased DMBT1 RNA expression in A549 cells after hypoxia. HIF-1α was upregulated in both DMBT1+ and DMBT1- cells in response to hypoxia. The addition of human recombinant DMBT1 to Curosurf caused an impaired surfactant ultrastructure. CONCLUSIONS: DMBT1 is upregulated in response to hypoxia and there seems to be a link between hypoxia and surfactant inactivation.

Spermidine supplementation and voluntary activity differentially affect obesity-related structural changes in the mouse lung.

Obesity is associated with lung function impairment and respiratory diseases; however, the underlying pathophysiological mechanisms are still elusive, and therapeutic options are limited. This study examined the effects of prolonged excess fat intake on lung mechanics and microstructure and tested spermidine supplementation and physical activity as intervention strategies. C57BL/6N mice fed control diet (10% fat) or high-fat diet (HFD; 60% fat) were left untreated or were supplemented with 3 mM spermidine, had access to running wheels for voluntary activity, or a combination of both. After 30 wk, lung mechanics was assessed, and left lungs were analyzed by design-based stereology. HFD exerted minor effects on lung mechanics and resulted in higher body weight and elevated lung, air, and septal volumes. The number of alveoli was higher in HFD-fed animals. This was accompanied by an increase in epithelial, but not endothelial, surface area. Moreover, air-blood barrier and endothelium were significantly thicker. Neither treatment affected HFD-related body weights. Spermidine lowered lung volumes as well as endothelial and air-blood barrier thicknesses toward control levels and substantially increased the endothelial surface area under HFD. Activity resulted in decreased volumes of lung, septa, and septal compartments but did not affect vascular changes in HFD-fed mice. The combination treatment showed no additive effect. In conclusion, excess fat consumption induced alveolar capillary remodeling indicative of impaired perfusion and gas diffusion. Spermidine alleviated obesity-related endothelial alterations, indicating a beneficial effect, whereas physical activity reduced lung volumes apparently by other, possibly systemic effects.

Bone marrow stem cells accelerate lung maturation and prevent the LPS-induced delay of morphological and functional fetal lung development in the presence of ErbB4.

ErbB4 is a regulator in lung development and disease. Prenatal infection is an important risk factor for the delay of morphologic lung development, while promoting the maturation of the surfactant system. Bone marrow-derived mesenchymal stem cells (BMSCs) have the potential to prevent lung injury. We hypothesized that BMSCs in comparison with hematopoietic control stem cells (HPSCs) minimize the lipopolysaccharide (LPS)-induced lung injury only when functional ErbB4 receptor is present. We injected LPS and/or murine green fluorescent protein-labeled BMSCs or HPSCs into the amniotic cavity of transgenic ErbB4heart mothers at gestational day 17. Fetal lungs were analyzed 24 h later. BMSCs minimized significantly LPS-induced delay in morphological lung maturation consisting of a stereologically measured increase in mesenchyme and septal thickness and a decrease of future airspace and septal surface. This effect was more prominent and significant in the ErbB4heart+/- lungs, suggesting that the presence of functioning ErbB4 signaling is required. BMSC also diminished the LPS induced increase in surfactant protein (Sftp)a mRNA and decrease in Sftpc mRNA is only seen if ErbB4 is present. The reduction of morphological delay of lung development and of levels of immune-modulating Sftp was more pronounced in the presence of the ErbB4 receptor. Thus, ErbB4 may be required for the protective signaling of BMSCs.

Postnatal morphological lung development of wild type and CD26/DPP4 deficient rat pups in dependency of LPS exposure.

BACKGROUND: Rodents are born with morphological immature lungs and an intact surfactant system. CD26/DPP4 is a multifactorial transmembrane integral type II protein, which is involved in physiological and pathophysiological processes and is already expressed during development. CD26/DPP4, called CD26 in the following, is able to enhance or dampen differently triggered inflammation. LPS exposure often used to simulate perinatal infection delays lung development. OBJECTIVE: A perinatal LPS rat model was used to test the hypothesis that CD26 deficiency modulates LPS-induced retardation in morphological lung development. METHODS: New born Fischer CD26 positive (CD26+) and deficient (CD26-) rats were exposed to LPS on postnatal day (day post partum, dpp) 3 and 5. Morphological parameters of lung development were determined stereologically. Lung development was analysed in 7, 10 14 and 21day old rats. RESULTS: Compared to controls LPS application resulted (1) in a mild inflammation independent of the strain, (2) in significantly lower total surface and volume of alveolar septa combined with significantly higher total volume of airspaces and alveolar size on dpp 7 in both substrains. However, compared to controls in LPS treated CD26- rats significant lower values of total septal surface and volume combined with higher values of total parenchymal airspaces and alveolar size were found until the end of classical alveolarization (dpp14). In LPS treated CD26+ rat pups the retardation was abolished already on dpp 10. CONCLUSION: In absence of CD26, LPS enhances the delay of morphological lung development. Morphological recovery was slower after the end of LPS exposure in CD26 deficient lungs.

Differential severity of LPS-induced lung injury in CD26/DPP4 positive and deficient F344 rats.

BACKGROUND: Lipopolysaccharide (LPS) induced inflammation often leads to lung injury, in which pulmonary recruitment of neutrophils plays a pivotal role. Inflammatory processes are influenced by CD26/DPP4, highly expressed in lungs. Asthma induced CD26/DPP4 deficient (CD26/DPP4⁻) Fischer (F) 344 rats suffering from a transport block in the rER caused by a point mutation showed reduced pulmonary inflammation and reduced expression of immunomodulating surfactant proteins (SP). The degree of LPS induced lung injury in CD26/DPP4 deficient rats has not been investigated so far. OBJECTIVE: We hypothesize that LPS induced lung injury leads not only to an attenuated inflammation but also to a reduced SP expression and decreased structural damage in CD26/DPP4⁻ rats. METHODS: Both genotypes were intratracheally instilled with 250 µl LPS or with 250 µl 0.9% NaCl. Nine hours later animals were killed and either bronchoalveolar lavage was carried out to determine inflammatory cells and surface tension or lung blocks were removed and processed for histology, immunohistochemistry, electron microscopy or qRt-PCR analyses and Western Blot analyses. RESULTS: Signs of acute lung injury, such as structural damage of the blood gas barrier occurred only sporadically in both genotypes. LPS-induced CD26/DPP4⁻ rats showed decreased gene expression of SP-A and SP-D and reduced signs of lung inflammation associated with a reduced alveolar influx of macrophages and neutrophils. CONCLUSIONS: Less pulmonary inflammation combined with less structural alterations and minor expression of immunomodulating SP may be an indication of the critical role of CD26/DPP4 in regulating lung inflammation.

Recommendations of the working group of the Anatomische Gesellschaft on reduction of formaldehyde exposure in anatomical curricula and institutes.

The practice of human and veterinary medicine is based on the science of anatomy and dissection courses are still irreplaceable in the teaching of anatomy. Embalming is required to preserve body donors, for which process formaldehyde (FA) is the most frequently used and well characterized biocidal substance. Since January 2016, a new occupational exposure limit (OEL) for FA of 0.37mg/m3 issued by the European Committee on Hazardous Substances is obligatory since FA has been classified as a human 1B carcinogen. The anatomical institutes in the German-speaking region are called upon to consolidate efforts to reduce use of FA in anatomical curricula and body donations. As a result, the Anatomische Gesellschaft (AG) has formed a "Working Group for Reduction of Formaldehyde Exposure in Dissection Courses" tasked with discussion and recommendation of measures to reduce FA. Based on the assessment of the Working Group, the AG has issued an official opinion to the effect that, at this point in time, embalming of body donors without FA completely is not feasible. Therefore, a combination of approaches are to be used to reduce FA exposure, including technical and structural (architectural) adaptations, modification of protocols for fixation and preservation as well as organizational measures. One structural measure considered unavoidable is the integration of air supply and exhaust of individual dissecting tables into the ventilation system of the anatomy building. To embalm human body donors, intra-arterial perfusion fixation with up to 4% FA and a total fluid volume of 150mL/kg body weight will suffice. For animals where body weights and biology of bodies vary widely (i.e. special needs of fixation for ruminants, large animals as horses) perfusion fixation with up to 4% FA and a quantity of fixative solution of 10-15% of the body weight may be required. Preservation of body donors in storage (immersion) can be done with 40% ethanol or in a full bath preservation containing up to 2% FA. Corpse humidification in the dissecting room is possible with 2% phenoxyethanol, in each case without FA. In veterinary anatomy, microbiological burden is often higher and therefore might lead to a need of FA in long-time storage. Compliance with the current OEL in all institutes would appear to be feasible in combination with various organizational measures.

Hands-on or no hands-on training in ultrasound imaging: A randomized trial to evaluate learning outcomes and speed of recall of topographic anatomy.

Medical students have difficulties in interpreting two-dimensional (2D) topographic anatomy on sectional images. Hands-on and no hands-on training in ultrasound imaging facilitate learning topographic anatomy. Hands-on training is linked with active search for patterns of anatomical structures and might train pattern recognition for image interpretation better although the added value on learning outcomes is unclear. This study explores first year medical students' knowledge in topographic anatomy of the upper abdomen after attending hands-on or no hands-on training in ultrasound in a randomized trial. While students in the hands-on ultrasound group (N = 21) generated and interpreted standardized planes of ultrasound imaging, students in the no hands-on seminar group (N = 22) interpreted provided ultrasound images by correlation to three-dimensional (3D) anatomical prosections. Afterwards knowledge in topographic anatomy was measured repetitively by text and ultrasound image-based multiple choice (MC) examinations. As surrogate for pattern recognition, students rated whether answers were known after reflection or instantly. While intrinsic motivation was higher in the ultrasound group, no differences in the MC-examination score were found between ultrasound and seminar group instantly (66.5 ±10.9% vs. 64.5% ±11.0%, P = 0.551) or six weeks (62.9% ±12.3% vs. 61.5% ±11.0%, P = 0.718) after training. In both groups scores in text-based questions declined (P < 0.001) while scores in image-based questions remained stable (P = 0.895) with time. After six weeks more image-based questions were instantly known in the hands-on ultrasound compared to seminar-group (28% ±17.3% vs. 16% ±13.5%, P = 0.047). Hands-on ultrasound-training is linked with faster interpreting of ultrasound images without loss in accuracy. The added value of hands-on training might be facilitation of pattern recognition.

Microbes and Viruses Are Bugging the Gut in Celiac Disease. Are They Friends or Foes?

The links between microorganisms/viruses and autoimmunity are complex and multidirectional. A huge number of studies demonstrated the triggering impact of microbes and viruses as the major environmental factors on the autoimmune and inflammatory diseases. However, growing evidences suggest that infectious agents can also play a protective role or even abrogate these processes. This protective crosstalk between microbes/viruses and us might represent a mutual beneficial equilibrium relationship between two cohabiting ecosystems. The protective pathways might involve post-translational modification of proteins, decreased intestinal permeability, Th1 to Th2 immune shift, induction of apoptosis, auto-aggressive cells relocation from the target organ, immunosuppressive extracellular vesicles and down regulation of auto-reactive cells by the microbial derived proteins. Our analysis demonstrates that the interaction of the microorganisms/viruses and celiac disease (CD) is always a set of multidirectional processes. A deeper inquiry into the CD interplay with Herpes viruses and Helicobacter pylori demonstrates that the role of these infections, suggested to be potential CD protectors, is not as controversial as for the other infectious agents. The outcome of these interactions might be due to a balance between these multidirectional processes.