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.

Comparing the accuracy of ultrasound-based measurements of the cervical vagus nerve.

Vagus nerve stimulation (VNS) has become a promising therapy especially for drug resistant epilepsy and other pathologies. Side effects or missing therapeutic success are observed due to cuff electrodes that are too narrow or too wide. Preoperative high-resolution ultrasound is used to evaluate the size of the cervical vagus nerve (CVN) to estimate the size of cuff electrodes for VNS. It remains unclear how precise ultrasound reflects the CVN dimensions, which has been the objective of this study. CVN cross-sections and diameters were investigated in 23 sides from 12 bodies, using ultrasound, histology, and CVN casting in situ as a reference. Morphometric data were obtained including fascicle count and nerve composition in histology. CVN yielded significant side-, age-, and BMI-related differences. CVN cross-sections were smaller in ultrasound when compared to casting and histology (1.5 ± 0.4 vs. 3.1 ± 0.9 vs. 2.3 ± 0.7 mm2). With the given setting in ultrasound, CVN cross-sections were consistently underestimated when compared to casting. Ultrasound-based cross-section measurements are related to a biased estimation of CVN size. A factor to correct for method related differences may help to adjust for accurate cuff electrode sizes for patient needs and to reduce undesired effects and potentially material consumption.

Incidental finding of Clostridium perfringens on human corpses used for the anatomy course.

Post-mortem specimens used for anatomy teaching are commonly embalmed using compositions of chemicals, with the objective to maintain tissue quality and to avoid putrefaction. Monitoring for bacterial or fungal contamination is becoming increasingly important especially when measures are taken to minimize exposure by chemicals such as formaldehyde. In this case, random swabs were taken from six corpses embalmed with ethanol-glycerin and Thiel embalming. Cultures and MALDI-TOF analyses yielded four cases of Clostridium perfringens contamination. C. perfringens is of special interest as a human pathogen. A potential source was identified in the containers filled with the moistening solution. Cross contamination with Clostridium species has likely occurred between corpses sharing the moistening solution and soaking the cover linen directly within the containers. To minimize any risk for those exposed, the moistening solutions were discarded and all equipment thoroughly disinfected. The specimens had to be cremated as they formed a potential source of Clostridium spores. Deviating from previous routines it was formalized that the cover linen must not be submerged in the moistening contains rather than moistening the specimens directly with dedicated vessels. Follow-up analyses yielded no further contamination with C. perfringens.

Expect the unexpected: The course of the inferior alveolar artery - Preliminary results and clinical implications.

INTRODUCTION: The anatomical position of the inferior alveolar artery (IAA) within the mandibular canal and in relation to the substructures of the neurovascular mandibular bundle has been sparsely described to date. More detailed information on the exact IAA position would be beneficial for both dental and maxillofacial surgical procedures to minimize complications such as bleeding, nerve compression hematoma, and sensory deficiency. MATERIAL AND METHODS: In 31 Thiel-preserved and fresh-frozen cadaver hemimandibles the position of the IAA in relation to the structures of the inferior alveolar neurovascular bundle and the mandible borders was analyzed anatomically and histologically. RESULTS: In 77.4% of the cases, rotation of the IAA around the mental nerve was apparent, resulting in a typical site-dependent IAA position. While the IAA was situated buccally within the pterygomandibular space, buccal-inferior in the mandibular foramen, superior in the molar region, and lingually in the premolar region. In 12.9% of the cases, a persistent lingual position of the IAA was observed for the entire mandibular canal. In one case, an additional mandibular canal and an accessory IAA were identified. DISCUSSION: This study provides new and encompassing information on the complete course and position of the IAA. This course is of practical use for oral implantology and various surgical procedures in dental- and maxillofacial surgery. Variations in the typical IAA course and site-dependent positional changes may be referred to as mandible growth and functional adaption to occlusion anomalies. This report helps enhance the morphological and functional understanding of IAA relationship during mandible development.

Surgical Drill Guide for Insertion of an Infra-Acetabular Screw Based on an Anatomically Precontoured Plate System: A Cadaveric Study.

PURPOSE: Due to the anatomic structure of the pelvis, free-hand placement of screws in the acetabular fracture management can be difficult. Infra-acetabular screw fixation increases acetabular stability by distal fixation of the cup. Aim of this cadaveric study is to investigate if a plate-referenced drill guide can provide save placement of an infra-acetabular screw over a precontoured suprapectineal quadrilateral buttress plate (SQBP). METHODS: We constructed a drill guide for an infra-acetabular screw based on the surface of an anatomically precontoured SQBP. A total of 12 adult cadaveric acetabular specimens were used for drill guide-assisted placement of the infra-acetabular screw. The drill guide contains a radiopaque spiral to allow longitudinal fine adjustment of the SQBP along the pelvic brim to assure correct position of the plate-drill-guide construct in relation to the Koehler's teardrop. After screw placement, we conducted a computed tomography (CT) scan of all specimens to assess the actual position of the screw in relation of the infra-acetabular corridor and the acetabular joint surface. RESULTS: The position of the screw was within the infra-acetabular corridor in all cases. We did not see any intra-articular or intrapelvic screw penetration. The mean distance of the centerline of the screw to the medial border of the infra-acetabular corridor was 3.35 mm. The secure distance to the virtual surface of the femoral head to was 7.3 mm. CONCLUSIONS: A plate-referenced drill guide can provide safe placement of an infra-acetabular screw for treatment of acetabular fractures. Radiographic fine adjustment is necessary to access the optimal entry point.

MALDI versus ESI: The Impact of the Ion Source on Peptide Identification.

For mass spectrometry-based proteomic analyses, electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) are the commonly used ionization techniques. To investigate the influence of the ion source on peptide detection in large-scale proteomics, an optimized GeLC/MS workflow was developed and applied either with ESI/MS or with MALDI/MS for the proteomic analysis of different human cell lines of pancreatic origin. Statistical analysis of the resulting data set with more than 72 000 peptides emphasized the complementary character of the two methods, as the percentage of peptides identified with both approaches was as low as 39%. Significant differences between the resulting peptide sets were observed with respect to amino acid composition, charge-related parameters, hydrophobicity, and modifications of the detected peptides and could be linked to factors governing the respective ion yields in ESI and MALDI.

Identification and Validation of Novel Subtype-Specific Protein Biomarkers in Pancreatic Ductal Adenocarcinoma.

OBJECTIVES: Pancreatic ductal adenocarcinoma (PDAC) has been subclassified into 3 molecular subtypes: classical, quasi-mesenchymal, and exocrine-like. These subtypes exhibit differences in patient survival and drug resistance to conventional therapies. The aim of the current study is to identify novel subtype-specific protein biomarkers facilitating subtype stratification of patients with PDAC and novel therapy development. METHODS: A set of 12 human patient-derived primary cell lines was used as a starting material for an advanced label-free proteomics approach leading to the identification of novel cell surface and secreted biomarkers. Cell surface protein identification was achieved by in vitro biotinylation, followed by mass spectrometric analysis of purified biotin-tagged proteins. Proteins secreted into a chemically defined serum-free cell culture medium were analyzed by shotgun proteomics. RESULTS: Of 3288 identified proteins, 2 pan-PDAC (protocadherin-1 and lipocalin-2) and 2 exocrine-like-specific (cadherin-17 and galectin-4) biomarker candidates have been validated. Proximity ligation assay analysis of the 2 exocrine-like biomarkers revealed their co-localization on the surface of exocrine-like cells. CONCLUSIONS: The study reports the identification and validation of novel PDAC biomarkers relevant for the development of patient stratification tools. In addition, cadherin-17 and galectin-4 may serve as targets for bispecific antibodies as novel therapeutics in PDAC.

The pivotal role of reactivity in the design of novel biotinylation reagents for the chemical-proteomics-based identification of vascular accessible biomarkers.

A promising approach for the development of novel therapeutics with fewer side effects in healthy tissues is the targeted delivery of bioactive molecules directly to the site of disease. Thus, one prerequisite is the identification of a robust, disease-specific, vascular accessible biomarker localized on the surface of diseased cells, in the surrounding extracellular matrix or on newly formed blood vessels. One avenue towards the identification of such biomarkers consists in the enrichment of the vascular accessible surface proteome fraction prior to analysis. This can be achieved by covalent modification of the target proteins with membrane-impermeable ester derivatives of biotin, followed by streptavidin-based affinity capturing. The properties of the respective reagents are determined by the linker between the biotin moiety and the reactive group for protein coupling. In the frame of this study, novel, reactivity-improved peptide-based biotinylation reagents as well as reagents based on highly hydrophilic heparin linkers were synthesized and validated. The comprehensive evaluation of different biotinylation reagent classes with aliphatic, PEGylated, peptide-based and heparin-based linkers on single model protein BSA, HeLa cells as well as perfused kidney tissue revealed that the linker-dependent chemical reactivity is the crucial factor for the design of novel biotinylation reagents for vascular targeting approaches. Significance To obtain a reliable identification and stable quantification of vascular accessible protein targets by means of mass spectrometry, covalent modification with a membrane-impermeable ester derivative of biotin, followed by streptavidin-based affinity capturing, is frequently applied for in vivo or ex vivo biomarker identification studies. Nevertheless, no comprehensive evaluation of different biotinylation reagent classes has been performed so far. Within this study, we systematically evaluated novel peptide- and heparin-based biotinylation reagents as well as established compounds based on aliphatic and PEGylated linkers. We identified the linker-dependant chemical reactivity of biotinylation reagents to be the critical factor for the design of novel reagents with high efficiency. The novel, site-specifically activated peptide-based reagents were found to be efficient compounds for application in mass spectrometry-based discovery of novel vascular-accessible biomarkers.

Ion source-dependent performance of 4-vinylpyridine, iodoacetamide, and N-maleoyl derivatives for the detection of cysteine-containing peptides in complex proteomics.

Cysteine is unique among the proteinogenic amino acids due to its ability to form disulfide bonds. While this property is of vital importance for protein structures and biological processes, it causes difficulties for the mass spectrometric identification of cysteine-containing peptides. A common approach to overcome these problems in bottom-up proteomics is the reduction and covalent modification of sulfhydryl groups prior to enzymatic digestion. In this study, established alkylating agents and N-maleoyl amino acids with variable hydrophobicity were characterized with respect to a variety of relevant parameters and subsequently evaluated in a large-scale analysis using different ion sources. Depending on the compound, the ion source had a profound impact on the relative and absolute identification of cysteine-containing peptides. The best results were obtained by derivatization of the cysteine residues with 4-vinylpyridine and subsequent matrix-assisted laser desorption ionization (MALDI). Modification with 4-vinylpyridine increased the number of cysteine-containing peptides identified with any other compound using LC-MALDI/MS at least by a factor of 2. This experimental observation is mirrored by differences in the gas-phase basicities, which were computed for methyl thiolate derivatives of the compounds using density functional theory. With electrospray ionization (ESI), complementary use of reagents from three different compound classes, e.g., iodoacetamide, 4-vinylpyridine, and N-maleoyl beta-alanine, was beneficial compared to the application of a single reagent.

Detection of Puumala and Rift Valley Fever virus by quantitative RT-PCR and virus viability tests in samples of blood dried and stored on filter paper.

Haemorrhagic fever viruses cause emerging infections worldwide, and blood or serum is the main sample used for diagnosis. However, storage and transportation of such samples from remote areas to regional laboratories may be complicated and expensive. In this study, a novel approach was evaluated for the detection of Puumala hantavirus (PUUV) RNA and Rift Valley fever virus (RVFV) RNA. Whole-blood samples spiked with viable virus particles were tested in parallel with clinical samples from patients with acute haemorrhagic fever with renal syndrome (nephropathia epidemica). Individual blood samples were spotted on filter paper, dried, and used for RNA extraction at later time points. PUUV RNA was detected by RT-PCR after storage at room temperature for up to six weeks. In contrast, only low copy numbers of RVFV RNA were detected after 1-2 days even though viable RVFV was eluted from the dried filter papers after the same time. The use of filter paper to collect and store blood samples for PUUV RNA detection is therefore a simple and reliable procedure. This approach might facilitate sampling and analysis of other RNA viruses from human or animal sources and could be used for field studies in remote areas or in developing countries.