External post-mortem examination in virtual reality-scalability of a monocentric application

Conducting external post-mortem examinations is an essential skill required of physicians in various countries, regardless of their specialization. However, the quality of these examinations has been a subject of continuous debates, and notable errors were reviled. In response to these shortcomings, a virtual reality (VR) application was developed at Halle's medical department in Germany, focusing on the scene of discovery and the completion of death certificates. The initial trial of this VR application in 2020 involved 39 students and 15 early-career professionals. Based on the feedback, the application underwent improvements and was subsequently introduced to the medical department in Dresden, Germany, in 2022. Its primary objective was to showcase the VR training's adaptability and scalability across various educational structures and levels of medical expertise. Out of 73 students who participated, 63 completed the evaluation process. 93.1% (n = 58) of the evaluators reported increased confidence in conducting external post-mortem examinations, and 96.8% (n = 61) felt more assured in filling out death certificates, crediting this progress to the VR training. Additionally, 98.4% (n = 62) believed that repeating forensic medical aspects in their coursework was crucial, and 96.8% (n = 61) viewed the VR examination as a valuable addition to their academic program. Despite these positive responses, 91.6% (n = 55) of participants maintained that training with real corpses remains irreplaceable due to the insufficiency of haptic feedback in VR. Nevertheless, the potential for enhancing the VR content and expanding the training to additional locations or related disciplines warrants further exploration.

External bleeding from femoro-crural vein bypass with aneurysmal dilation

Deaths due to external bleeding outside the hospital setting are often suspected to involve violence. However, some disease-related causes, can also lead to fatal external bleeding. While bleeding from natural body orifices is a common end stage of non-curable gastrointestinal bleeding, fatal bleeding via newly formed skin defects is quite rare and highly suspicious in light of external impact. Reliable clarification of the source and cause of bleeding is only possible in the context of an autopsy. The reported case involves the death of a man early 60 s who bled to death as a result of rupture of a femoro-crural bypass. The rupture originated from a rare true aneurysm of an autologous femoro-crural vein bypass implanted 8 years before due to peripheral arterial occlusive disease (PAD) with gangrene. The aneurysm rupture passed all subcutaneous and skin layers leading to fatal external bleeding.

Lithium carbonate: Updated reproductive and developmental toxicity assessment using scientific literature and guideline compliant studies

The current publication describes most recent so far unpublished (key) guideline and GLP compliant reproductive and developmental toxicity studies of lithium carbonate in rats, including their interpretation and conclusions in terms of human hazard assessment when compared to existing literature. Particular attention was paid to the target organs and dose response of lithium ion related effects to differentiate between a primary (pharmacokinetic/pharmacodynamic) action and secondary effects as a result of systemic and target organ toxicity. In the key two-generation reproduction toxicity (OECD TG 416) study in rats, doses of 5, 15 and 45 mg/kg bw/d (0.95, 2.9 and 8.6 mg Li⁺/kg bw/d) were given by oral gavage, resulting in clear NOAELs of 15 mg/kg bw/d (2.9 mg Li⁺/kg bw/d) for systemic parental toxicity and 45 mg/kg bw/d (8.6 mg Li⁺/kg bw/d) for reproductive toxicity and fetal toxicity. Target organ changes were consistently observed in liver (cytoplasmic rarefaction) and kidney (dilated tubuli). In the key developmental toxicity (OECD TG 414) study in rats, doses given by oral gavage were 10, 30 and 90 mg/kg bw/d (1.9, 5.7 and 17.1 mg Li⁺/kg bw/d) was investigated resulting in NO(A)ELs of 30 mg/kg bw/d (5.7 mg Li⁺/kg bw/d) (maternal toxicity) and 90 mg/kg bw/d (17 mg Li⁺/kg bw/d) (fetal toxicity and teratogenicity). The highest dose of 90 mg/kg bw/day resulted in clear signs of toxicity and peak plasma concentrations at the toxic range (>1.0 mEq lithium/L). Toxic effects of lithium carbonate were not seen in the reproductive and developmental organs. No adverse effects on sperm (total motility, progressive motility and morphology of testicular and cauda epididymal sperm) were observed in the two-generation rat reproduction toxicity study. There was also no impact on fertility indices or on litter sizes in this study, nor were there any fetal effects in the two-generation reproduction toxicity and developmental toxicity study at doses causing already systemic toxicity in the dams. Secondary effects such as decreased weight (gain) and food consumption were reported in the developmental toxicity study. The absence of any reproductive/developmental findings at dose levels causing clear systemic toxicity in the test animals in these key mammalian studies, does not suggest an immediate concern for possible human reproductive or developmental toxicity effects from exposure to lithium during drug use.

Electro-mechanical and mechano-electrical interactions in healthy and drug-induced LQTS rabbit hearts

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): German Research Foundation

Background

Electrical and mechanical heterogeneities and their interactions (electro-mechanical and mechano-electrical coupling; EMC / MEC) are essential for normal cardiac function. Alterations in these can result in increased arrhythmia formation.

Purpose

With this study, we aim to investigate EMC and MEC under physiological and pathological conditions to better understand their roles in arrhythmia development.

Methods

Multi-channel ECG and TPM-MRI were used to measure regional differences in EMC in healthy ("control") and IKr-blocker E-4031 induced acute LQTS ("E-4031") rabbit hearts in vivo. MEC was studied in both groups by acutely changing mechanical function (increased preload by 6 ml/kg BW bolus of NaCl).

Results

In acute LQTS hearts (E-4031 10µg/kg bolus + 1µg/(kg*min) iv), cardiac repolarization was markedly prolonged compared to healthy controls, (p < 0.0001; n = 13), with increased QT-dispersion (Max-Min), a marker for regional heterogeneity of repolarization (p < 0.01; n = 13).

Changing electrical function by E-4031 resulted in changes of mechanical features (EMC): in acute LQTS hearts, diastolic longitudinal velocity (Vz) was reduced in all basal (p = 0.003; n = 19) and 4/6 mid segments (p = 0.006; n = 19). Longitudinal diastolic TTP was prolonged significantly in 5/6 basal and 4/6 mid segments by E-4031. These alterations led to an increased apicobasal heterogeneity of longitudinal contraction duration (basal-apical Vz_dia_TTP [ms] 2.9 ± 10.6 vs. 21.1 ± 21.3; p = 0.01; n = 9).

Increased preload acutely prolonged QTc in both "control" and "E-4031" hearts (‘control’ 156.6 ± 11.6 to 198.3 ± 20.3; p < 0.0001 vs. ‘E-4031’ 193.9 ± 19.6 to 256.0 ± 37.5; p < 0.0001; n = 13) (MEC). This effect was more pronounced in "E-4031" acute LQTS hearts than in healthy hearts (Figure 1; delta QTc [ms] ‘control’ 41.6 ± 14.9 vs. ‘E4031’ 62.1 ± 32.1; p < 0.006, n = 13). QT-dispersion (Max-Min) was increased significantly upon mechanical change only in "E-4031" (‘E-4031’ 25.8 ± 5.5 to 32.7 ± 12.3; p < 0.03, n = 13).

Conclusion

E-4031-induced changes in electrical function resulted in marked alterations in mechanical features via EMC. Similarly, acute changes in mechanical function (increased preload) resulted in electrical changes via MEC. Importantly, QT-prolonging effects of acutely increased preload, as well as its effects on regional heterogeneity of repolarization, were more pronounced in E-4031-induced acute LQTS hearts, indicating that cardiac repolarization in LQTS may be more susceptible to acute MEC effects than in healthy hearts. Acute MEC effects may thus play an additional role in LQT-related arrhythmogenesis. Abstract Figure.

Stabilized rice bran improves weaning pig performance via a prebiotic mechanism

Stabilized rice bran (SRB) is classified as a "functional food" because of its prebiotic characteristics. With increasing grain prices and the pressure to remove antibiotics from swine diets because of concern over antibiotic resistance, SRB was investigated as a nursery diet ingredient with and without the addition of antibiotics (ANT). Two hundred pigs were weaned at 21 d of age, blocked by BW, and allotted to diets containing 0 or 10% SRB ± ANT according to a 2 × 2 factorial arrangement of treatments. Five animals were housed per pen throughout a 28-d growth period. At the end of the trial, 1 pig from each pen was euthanized for measurement of intestinal morphology. Antibiotic supplementation improved ADG by 6.4% during Phase 2 (d 14 to 28; P = 0.02), but other production variables were unaffected by ANT. During Phase 2 and cumulatively (d 0 to 28), the supplementation of SRB improved G:F by 10% in ANT-free pigs but not in pigs fed ANT (ANT × SRB, P < 0.03). Ileal histology revealed an increase in crypt depth of pigs fed the diet containing ANT plus SRB and corresponding decreases in villi:crypt associated with both ANT and SRB supplementation (P < 0.05). Intraepithelial lymphocytes were increased by 15% in pigs fed SRB without ANT, but were unaffected by SRB in pigs fed ANT (ANT x SRB, P = 0.003). Colonic bifidobacteria tended to increase with SRB supplementation (P < 0.10). Differences in ileal and cecal digesta short-chain fatty acid concentrations were not detected. In summary, SRB improved the efficiency of nutrient utilization in nursery diets lacking antibiotics and tended to increase intestinal bifidobacteria concentrations, indicating that SRB may exert beneficial prebiotic effects in weanling pigs.

A pilot study on the corneal curvatures and ocular dimensions of horses less than one year of age

Intraocular lenses (IOLs) have been implanted in adult equine eyes after cataract surgery. Foals and weanlings comprise a large proportion of those horses undergoing cataract surgery. Due to potential differences in the size and corneal curvature of the juvenile eye, it is not currently known whether implantation of adult IOLs is appropriate in foals and weanlings. The objective of the study was to measure the anterior chamber depth (ACD), central lens thickness (CLT), vitreous chamber depth (VCD), axial globe length (AGL) and corneal curvature of horses less than one year of age. The axial dimensions from one eye of 10 foals were measured using simultaneous A and B scan ultrasonography. The corneal curvature from one eye of 7 weanlings was determined using a modified photokeratometer. Ultrasonography revealed a mean ACD of 4.94 mm, mean CLT of 9.38 mm, mean VCD of 18.96 mm and mean AGL of 33.32 mm for the foals. The mean corneal curvature was 15.4 diopters (D). The mean ACD, CLT, VCD and AGL of the foals were less than the measurements reported in the literature for adult horses. The mean corneal curvature was similar to the values reported by some authors for adult horses. Due to the differences in axial dimensions between adult and juvenile eyes, an IOL that corrects vision in an adult horse might not adequately correct vision in a horse less than one year of age.

REPDOSE: A database on repeated dose toxicity studies of commercial chemicals—A multifunctional tool

A database for repeated dose toxicity data has been developed. Studies were selected by data quality. Review documents or risk assessments were used to get a pre-screened selection of available valid data. The structure of the chemicals should be rather simple for well defined chemical categories. The database consists of three core data sets for each chemical: (1) structural features and physico-chemical data, (2) data on study design, (3) study results. To allow consistent queries, a high degree of standardization categories and glossaries were developed for relevant parameters. At present, the database consists of 364 chemicals investigated in 1018 studies which resulted in a total of 6002 specific effects. Standard queries have been developed, which allow analyzing the influence of structural features or PC data on LOELs, target organs and effects. Furthermore, it can be used as an expert system. First queries have shown that the database is a very valuable tool.

Structure of a fusion peptide analogue at the air-water interface, determined from surface activity, infrared spectroscopy and scanning force microscopy

We have investigated a point mutant of the HIV-1 fusion peptide in a compressed monolayer at the air-water interface. A variety of surface sensitive techniques were applied to study structural features under conditions mimicking the hydrophobic/hydrophilic environment of a biomembrane. Possible partitioning into the aqueous bulk phase and molecular areas were examined by surface activity based mass conservation plots. This shows that the peptide is practically fully accumulated in the interface. Secondary structure and orientation was analyzed by means of polarized infrared reflectivity. Brewster angle microscopy and scanning force microscopy contributed nanostructural images. At low surface pressures the molecules form anti-parallel beta-sheets lying flat on the interface. Upon a moderate increase of the lateral pressure a flat beta-turn structure appears with inter- and intramolecular H-bonds. We also observed aggregates forming fingerprint-like structures with a diameter of approximately double the hydrophobic length of a beta-turn conformation. Beyond approximately 18 mN m(-1) the beta-turns straighten up. The lowest measured tilt angle was 45 degrees at 36 mN m(-1).

13-week drinking water toxicity study of hydrogen peroxide with 6-week recovery period in catalase-deficient mice

A GLP OECD guideline study was conducted to evaluate the subchronic toxicity of hydrogen peroxide (HP) when administered continuously in the drinking water of catalase-deficient (C57BL/6N) mice and reversibility of toxic effects. Groups of mice (15/sex/group) received solutions of 0, 100, 300, 1000 or 3000 ppm HP in distilled water for 13 weeks; five/sex/group continued on untreated distilled water for an additional 6 weeks. Animals drinking 3000 ppm HP exhibited depressed water and food consumption and body weight. Females drinking 1000 ppm HP had reduced water consumption with intermittent effects on food consumption, but no body weight effects. HP administration did not produce any mortality, clinical signs, hematological effects or organ weight effects on brain, liver, kidneys, adrenals, testes, heart or spleen. Total protein and globulin were depressed among high dose males. Mild to minimal duodenal mucosal hyperplasia was noted in animals receiving 1000 and 3000 ppm HP and one male receiving 300 ppm for 13 weeks. There were no other histopathological findings. All effects noted during the treatment period, including the duodenal hyperplasia, were reversible during the 6-week recovery period. Females dosed with 300-3000 ppm HP during the treatment period showed increased water consumption during the recovery period. The no-observed-effect level (NOEL), based on duodenal mucosal hyperplasia, is 100 ppm in drinking water or 26 and 37 mg/kg/day HP, respectively, for males and females.

Assessment of structurally related chemicals: toxicity and ecotoxicity of acrylic acid and acrylic acid alkyl esters (acrylates), methacrylic acid and methacrylic acid alkyl esters (methacrylates)

BUA compiled the available data on toxicity and ecotoxicity for several acrylic and methacrylic acid esters and their corresponding acids. A comparison of these data revealed a qualitative similarity in the toxicological and ecotoxicological properties of the compounds considered. The data indicate that methacrylates are less reactive than the corresponding acrylates.

Analysis of Epstein-Barr virus-binding sites on complement receptor 2 (CR2/CD21) using human-mouse chimeras and peptides. At least two distinct sites are necessary for ligand-receptor interaction

The predicted amino acid sequence of human complement receptor 2 (CR2, CD21, C3d,g/Epstein-Barr virus receptor) and its genetic murine homologue are approximately 70% identical. The sequence of each consists of a linear array of 60-70 amino acid repeats designated short consensus repeats (SCRs). Although they share significant sequence identity, a major difference in the activities of these two proteins has been believed to be the ability of human, but not mouse, CR2 to mediate Epstein-Barr virus (EBV) infection of B lymphocytes. In order to formally address this question and to directly compare the activities of the CR2 protein of each species, we have expressed recombinant mouse CR2 (rMCR2) in a human K562 erythroleukemia cell line background. We have found that rMCR2 reacts with two previously described rat anti-MCR2 monoclonal antibodies (mAbs), 7G6 and 7E9, but not mAb 8C12, which recognizes only mouse complement receptor 1. rMCR2 rosettes with erythrocytes bearing mouse and human C3d,g and binds glutaraldehyde cross-linked human C3d,g with a similar Kd as human CR2 (HCR2). rMCR2 does not bind EBV. By using this observation and constructing chimeras bearing portions of MCR2 on a HCR2 background, we have been able to define unique sequences in HCR2 SCRs 1 and 2 important in the interaction with both mAb OKB7, which blocks EBV binding and infection, and with EBV. In addition, by using blocking peptides derived from HCR2 sequence, we have identified a second distinct region in SCR2 important in EBV binding. Therefore, within the first two SCRs of HCR2 are multiple distinct sites of interaction with EBV and with mAb OKB7.

Hydrolysis and oxidation of 1H-benzotriazole-carboxylic acid esters by rat liver microsomes

The 1H-benzotriazole-carboxylic acid esters under investigation were almost - with the exception of the tert.-butylester - completely hydrolyzed by rat liver microsomes. Some substrates were metabolically oxidized to a very small extent (less than 1%) yielding small amounts of possibly toxic metabolites after inhibition of the esterases with paraoxone.

Metabolism of 1H-benzotriazolecarboxylic acids in vitro and in vivo

The 1H-benzotriazolecarboxylic acids 1 and 2 were stable towards oxidative metabolism as well in vitro as in vivo. In the in vivo studies 2.25% of the ester glucuronide of 1H-benzotriazole-5-carboxylic acid was found in urine.

[Hydrolysis of the antiemetic alizapride]

First order rate constants of the hydrolysis of N-[(1-allyl-2-pyrrolidinyl)-methyl]-6-methoxy-1H-benzotriazole-5-carboxa mide (alizapride, Vergentan) in acid and alkaline medium were determined. The activation energy observed in alkaline solution was 60.3 kJ X mol-1. The substance was not hydrolized in vitro by esterase, liver homogenate and plasma.