Endogent: Centre for Anatomy and Invasive Techniques

The invention of new endoscopical techniques for surgery and interventional radiology demand improved training at postgraduate level. The Endogent Centre for Anatomy and Invasive Techniques support these requirements by establishing hands-on practical training courses by using new procedures for cadaver embalming. Cadavers fixed by conventional procedures using formalin for conservation, are of limited use for practical surgical courses due to the profound changes of colour, strength and fragility of organs and tissues. The new Thiel embalming technique is based on the use of 4-chloro-3- methylenphenol, various salts for fixation, boric acid for disinfecting, and ethylene glycol for preservation of tissue plasticity, while the concentration of formalin is kept to the strict minimum (0.8%). This results in well preserved organs and tissues concerning colour, consistency, flexibility and plasticity. The articular joints remain freely movable and the peritoneal cavity can be inflated for laparoscopic procedures. Up to now this cadaver model was used in our institute for laparoscopic bariatric surgery, colon surgery, arthroscopy and thorax surgery. Another feature is that the lungs can be ventilated during surgical procedures. Preliminary findings seem to indicate that the corpses also serve as a suitable phantom for assessing thorax radiological equipment. Expert clinicians work as tutors and give intensive instructions before the participants start with hands-on surgery. We intend to expose also our undergraduate medical students to demonstrations of surgical approaches on Thiel embalmed corpses, in order to reveal the need for detailed anatomical knowledge in the clinic at an early stage in the medical curriculum

The calcium-sensing receptor as a regulator of cellular fate in normal and pathological conditions

The calcium-sensing receptor (CaSR) belongs to the evolutionarily conserved family of plasma membrane G protein-coupled receptors (GPCRs). Early studies identified an essential role for the CaSR in systemic calcium homeostasis through its ability to sense small changes in circulating calcium concentration and to couple this information to intracellular signaling pathways that influence parathyroid hormone secretion. However, the presence of CaSR protein in tissues is not directly involved in regulating mineral ion homeostasis points to a role for the CaSR in other cellular functions including the control of cellular proliferation, differentiation and apoptosis. This position at the crossroads of cellular fate designates the CaSR as an interesting study subject is likely to be involved in a variety of previously unconsidered human pathologies, including cancer, atherosclerosis and Alzheimer's disease. Here, we will review the recent discoveries regarding the relevance of CaSR signaling in development and disease. Furthermore, we will discuss the rational for developing and using CaSR-based therapeutics

3D computerized model for measuring strain and displacement of the brachial plexus following placement of reverse shoulder prosthesis

The aim of the present study was to develop a method for three-dimensional (3D) reconstruction of the brachial plexus to study its morphology and to calculate strain and displacement in relation to changed nerve position. The brachial plexus was finely dissected and injected with contrast medium and leaden markers were implanted into the nerves at predefined places. A reverse shoulder prosthesis was inserted in a cadaveric specimen what induced positional change in the upper limb nerves. Computed tomography (CT) was performed before and after this surgical intervention. The computer assisted image processing package Mimics (R) was used to reconstruct the pre- and postoperative brachial plexus in 3D. The results show that the current interactive model is a realistic and detailed representation of the specimen used, which allows 3D study of the brachial plexus in different configurations. The model estimated strains up to 15.3% and 19.3% for the lateral and the medial root of the median nerve as a consequence of placing a reverse shoulder prosthesis. Furthermore, the model succeeded in calculating the displacement of the brachial plexus by tracking each implanted lead marker. The presented brachial plexus 3D model currently can be used in vitro for cadaver biomechanical analyses of nerve movement to improve diagnosis and treatment of peripheral neuropathies. The model can also be applied to study the exact location of the plexus in unusual upper limb positions like during axillary radiation therapy and it is a potential tool to optimize the approaches of brachial plexus anesthetic blocks

Germination of Aspergillus fumigatus inside avian respiratory macrophages is associated with cytotoxicity

Although aspergillosis is one of the most common diseases in captive birds, the pathogenesis of avian aspergillosis is poorly known. We studied the role of avian respiratory macrophages as a first line of defense against avian aspergillosis. The phagocytic and killing capacities of avian respiratory macrophages were evaluated using pigeon respiratory macrophages that were inoculated with Aspergillus fumigatus conidia. On average, 25% of macrophage-associated conidia were phagocytosed after one hour. Sixteen percents of these cell-associated conidia were killed after 4 h and conidial germination was inhibited in more than 95% of the conidia. A. fumigatus conidia were shown to be cytotoxic to the macrophages. Intracellularly germinating conidia were located free in the cytoplasm of necrotic cells, as shown using transmission electron microscopy. These results suggest that avian respiratory macrophages may prevent early establishment of infection, unless the number of A. fumigatus conidia exceeds the macrophage killing capacity, leading to intracellular germination and colonization of the respiratory tract

Postmortem pump-driven reperfusion of the vascular system of porcine lungs: towards a new model for surgical training

PURPOSE: The objective of this experiment is to establish a continuous postmortem circulation in the vascular system of porcine lungs and to evaluate the pulmonary distribution of the perfusate. This research is performed in the bigger scope of a revascularization project of Thiel embalmed specimens. This technique enables teaching anatomy, practicing surgical procedures and doing research under lifelike circumstances. METHODS: After cannulation of the pulmonary trunk and the left atrium, the vascular system was flushed with paraffinum perliquidum (PP) through a heart-lung machine. A continuous circulation was then established using red PP, during which perfusion parameters were measured. The distribution of contrast-containing PP in the pulmonary circulation was visualized on computed tomography. Finally, the amount of leak from the vascular system was calculated. RESULTS: A reperfusion of the vascular system was initiated for 37 min. The flow rate ranged between 80 and 130 ml/min throughout the experiment with acceptable perfusion pressures (range: 37-78 mm Hg). Computed tomography imaging and 3D reconstruction revealed a diffuse vascular distribution of PP and a decreasing vascularization ratio in cranial direction. A self-limiting leak (i.e. 66.8% of the circulating volume) towards the tracheobronchial tree due to vessel rupture was also measured. CONCLUSIONS: PP enables circulation in an isolated porcine lung model with an acceptable pressure-flow relationship resulting in an excellent recruitment of the vascular system. Despite these promising results, rupture of vessel walls may cause leaks. Further exploration of the perfusion capacities of PP in other organs is necessary. Eventually, this could lead to the development of reperfused Thiel embalmed human bodies, which have several applications

Understanding Thiel embalming in pig kidneys to develop a new circulation model

The quality of tissue preservation in Thiel embalmed bodiesvaries. Research on the administered embalming volume and its vascular distribution may elucidate one of the mechanisms of tissue preservation and allow for new applications of Thiel embalming. Vascular embalming with (group 1, n = 15) or without (group 2, n = 20) contrast agent was initiated in pig kidneys. The distribution of Thiel embalming solution in group 1 was visualized using computed tomography. The kidneys in both groups were then immersed in concentrated salt solutions to reduce their weight and volume. Afterwards, to mimic a lifelike circulation in the vessels, group 2 underwent pump-driven reperfusion for 120 minutes with either paraffinum perliquidum or diluted polyethylene glycol. The circulation was imaged with computed tomography. All of the kidneys were adequately preserved. The embalming solution spread diffusely in the kidney, but fluid accumulation was present. Subsequent immersion in concentrated salt solutions reduced weight (P < 0.01) and volume (P < 0.01). Reperfusion for 120 minutes was established in group 2. Paraffinum perliquidum filled both major vessels and renal tissue, whereas diluted polyethylene glycol spread widely in the kidney. There were no increases in weight (P = 0.26) and volume (P = 0.79); and pressure further decreased (P = 0.032) after more than 60 minutes of reperfusion with paraffinum perliquidum, whereas there were increases in weight (P = 0.005), volume (P = 0.032) and pressure (P < 0.0001) after reperfusion with diluted polyethylene glycol. Arterial embalming of kidneys results in successful preservation due to complete parenchymatous spreading. More research is needed to determine whether other factors affect embalming quality. Dehydration is an effective method to regain the organs' initial status. Prolonged vascular reperfusion with paraffinum perliquidum can be established in this model without increases in weight, volume and pressure

Helicobacter heilmannii sp. nov., isolated from feline gastric mucosa

Three Gram-negative, microaerophilic bacteria, strains ASB1(T), ASB2 and ASB3, with a corkscrew-like morphology isolated from the gastric mucosa of cats were studied using a polyphasic taxonomic approach. The isolates grew on biphasic culture plates under microaerobic conditions at 37 degrees C and exhibited urease, oxidase and catalase activities. They were also able to grow in colonies on dry agar plates. Based on 16S rRNA gene sequence analysis, ASB1(T), ASB2 and ASB3 were identified as members of the genus Helicobacter and showed 98 to 99% sequence similarity to strains of Helicobacter felis, Helicobacter bizzozeronii, 'Candidatus Helicobacter heilmannii', Helicobacter cynogastricus, Helicobacter baculiformis and Helicobacter salomonis, six related Helicobacter species previously detected in feline or canine gastric mucosa. Sequencing of the partial hsp60 gene demonstrated that ASB1(T), ASB2 and ASB3 constitute a separate taxon among the feline and canine Helicobacter species. The urease gene sequences of ASB1(T), ASB2 and ASB3 showed approximately 91% similarity to those of 'Candidatus Helicobacter heilmannii'. Protein profiling, the absence of alkaline phosphatase activity and several other biochemical characteristics also allowed strains ASB1(T), ASB2 and ASB3 to be differentiated from other Helicobacter species of feline or canine gastric origin. The results of this polyphasic taxonomic study show that the cultured isolates constitute a new taxon corresponding to 'Candidatus Helicobacter heilmannii', which was previously demonstrated in the stomach of humans, wild felidae, cats and dogs. The name Helicobacter heilmannii sp. nov. is proposed for these isolates; the type strain is ASB1(T) (=DSM 23983(T)=LMG 26292(T))

Isolation and characterization of a new Helicobacter sp. belonging to the 'Helicobacter heilmannii' type 2 group from feline stomachs

Three Gram-negative, microaerophillic bacteria with a corkscrew-like morphology isolated from the gastric mucosa of cats and designated ASB1, ABS2 and ASB3, were subjected to a polyphasic taxonomic study. The isolates grew on biphasic culture plates in microaerobic conditions at 37°C and exhibited urease, oxidase and catalase activity. They were also able to grow in colonies on dry agar plates. Based on 16S rRNA gene sequence analysis, ASB1, ABS2 and ASB3 were identified as a member of the genus Helicobacter and showed 98 to 99% sequence similarity to H. felis, H. bizzozeronii, Candidatus H. heilmannii, H. cynogastricus and H. salomonis, five related Helicobacter species belonging to the “Helicobacter heilmannii” type 2 group and previously detected in the feline or canine gastric mucosa. Sequencing of the partial hsp60 gene demostrated that ASB1, ASB2 and ASB3 constitute a separate taxon in the “Helicobacter heilmannii” type 2 group. The urease gene sequences of ASB1, ASB2 and ASB3 showed approximately 92% homology to the urease gene sequences of “Candidatus Helicobacter heilmannii” described by O’Rourke et al. (2004). Protein profiling of the strains ASB1, ASB2 and ASB3 using SDS-PAGE also allowed to differentiate them from other Helicobacter species of feline or canine gastric origin. The results of this polyphasic taxonomic study indicate that the cultured isolates constitute a new taxon corresponding to “Candidatus Helicobacter heilmannii” from cats but further investigations are still needed

Phagocytosis of necrotic cells by macrophages is phosphatidylserine dependent and does not induce inflammatory cytokine production

Apoptotic cells are cleared by phagocytosis during development, homeostasis, and pathology. However, it is still unclear how necrotic cells are removed. We compared the phagocytic uptake by macrophages of variants of L929sA murine fibrosarcoma cells induced to die by tumor necrosis factor-induced necrosis or by Fas-mediated apoptosis. We show that apoptotic and necrotic cells are recognized and phagocytosed by macrophages, whereas living cells are not. In both cases, phagocytosis occurred through a phosphatidylserine-dependent mechanism, suggesting that externalization of phosphatidylserine is a general trigger for clearance by macrophages. However, uptake of apoptotic cells was more efficient both quantitatively and kinetically than phagocytosis of necrotic cells. Electron microscopy showed clear morphological differences in the mechanisms used by macrophages to engulf necrotic and apoptotic cells. Apoptotic cells were taken up as condensed membrane-bound particles of various sizes rather than as whole cells, whereas necrotic cells were internalized only as small cellular particles after loss of membrane integrity. Uptake of neither apoptotic nor necrotic L929 cells by macrophages modulated the expression of proinflammatory cytokines by the phagocytes