A new Meckel’s cartilage from the Devonian Hangenberg black shale in Morocco and its position in chondrichthyan jaw morphospace

Fossil chondrichthyan remains are mostly known from their teeth, scales or fin spines only, whereas their cartilaginous endoskeletons require exceptional preservational conditions to become fossilized. While most cartilaginous remains of Famennian (Late Devonian) chondrichthyans were found in older layers of the eastern Anti-Atlas, such fossils were unknown from the Hangenberg black shale (HBS) and only a few chondrichthyan teeth had been found therein previously. Here, we describe a Meckel’s cartilage from the Hangenberg black shale in Morocco, which is the first fossil cartilage from these strata. Since no teeth or other skeletal elements have been found in articulation, we used elliptical Fourier (EFA), principal component (PCA), and hierarchical cluster (HCA) analyses to morphologically compare it with 41 chondrichthyan taxa of different size and age and to evaluate its possible systematic affiliation. PCA and HCA position the new specimen closest to some acanthodian and elasmobranch jaws. Accordingly, a holocephalan origin was excluded. The jaw shape as well as the presence of a polygonal pattern, typical for tessellated calcified cartilage, suggest a ctenacanth origin and we assigned the new HBS Meckel’s cartilage to the order Ctenacanthiformes with reservations

A new Meckel's cartilage from the Devonian Hangenberg black shale in Morocco and its position in chondrichthyan jaw morphospace

Fossil chondrichthyan remains are mostly known from their teeth, scales or fin spines only, whereas their cartilaginous endoskeletons require exceptional preservational conditions to become fossilized. While most cartilaginous remains of Famennian (Late Devonian) chondrichthyans were found in older layers of the eastern Anti-Atlas, such fossils were unknown from the Hangenberg black shale (HBS) and only a few chondrichthyan teeth had been found therein previously. Here, we describe a Meckel's cartilage from the Hangenberg black shale in Morocco, which is the first fossil cartilage from these strata. Since no teeth or other skeletal elements have been found in articulation, we used elliptical Fourier (EFA), principal component (PCA), and hierarchical cluster (HCA) analyses to morphologically compare it with 41 chondrichthyan taxa of different size and age and to evaluate its possible systematic affiliation. PCA and HCA position the new specimen closest to some acanthodian and elasmobranch jaws. Accordingly, a holocephalan origin was excluded. The jaw shape as well as the presence of a polygonal pattern, typical for tessellated calcified cartilage, suggest a ctenacanth origin and we assigned the new HBS Meckel's cartilage to the order Ctenacanthiformes with reservations

NcGRA2 as a molecular target to assess the parasiticidal activity of toltrazuril against Neospora caninum

The treatment of Neospora caninum infection in the bovine host is still at an experimental stage. In contrast to the in vivo situation, a wide range of compounds have been intensively investigated in cell-culture-based assays. Tools to demonstrate efficacy of treatment have remained conventional including morphological and cell biological criteria. In this work, we present a molecular assay that allows the distinction between live and dead parasites. Live parasites can be detected by measuring the mRNA level of specific genes, making use of the specific mRNA available in live cells. The NcGra2 gene of N. caninum, which is known to be expressed in both tachyzoites and bradyzoites, was used to establish a quantitative real-time RT-PCR, for monitoring parasite viability. Validation of the system in vitro was achieved using Neospora-infected cells that had been treated for 2-20 days with 30μg/ml toltrazuril. NcGRA2-RT-real time PCR demonstrated that a 10-day toltrazuril-treatment exerted parasitostatic activity, as assessed by the presence of NcGRA2-transcripts, whereas after a 14-day treatment period no NcGRA2-transcripts were detected, showing that the parasites were no longer viable. Concurrently, extended culture for a period of 4 weeks in the absence of the drug following the 14-day toltrazuril treatment did not lead to further parasite proliferation, confirming the parasiticidal effect of the treatment. This assay has the potential to be widely used in the development of novel drugs against N. caninum, with a view to distinguishing between parasiticidal and parasitostatic efficacy of given compound

Equation of state sensitivities when inferring neutron star and dense matter properties

Understanding the dense matter equation of state at extreme conditions is an important open problem. Astrophysical observations of neutron stars promise to solve this, with NICER poised to make precision measurements of mass and radius for several stars using the waveform modelling technique. What has been less clear, however, is how these mass-radius measurements might translate into equation of state constraints and what are the associated equation of state sensitivities. We use Bayesian inference to explore and contrast the constraints that would result from different choices for the equation of state parametrization; comparing the well-established piecewise polytropic parametrization to one based on physically motivated assumptions for the speed of sound in dense matter. We also compare the constraints resulting from Bayesian inference to those from simple compatibility cuts. We find that the choice of equation of state parametrization and particularly its prior assumptions can have a significant effect on the inferred global mass-radius relation and the equation of state constraints. Our results point to important sensitivities when inferring neutron star and dense matter properties. This applies also to inferences from gravitational wave observations

Ultrasound-guided spermatic cord block for scrotal surgery

Background Performing spermatic cord block for scrotal surgery avoids the potential risks of neuraxial and general anaesthesia and provides long-lasting postoperative analgesia. A blindly performed block is often inefficient and bears its own potential risks (intravascular injection of local anaesthetics, haematoma formation and perforation of the deferent duct). The use of ultrasound may help to overcome these disadvantages. The aim of this study was to test the feasibility and monitor the success rate of a new ultrasound-guided spermatic cord block. Methods Twenty consecutive patients undergoing urologic surgery (subcapsular orchiectomy or vaso-vasostomy) were included in this prospective study. Using a linear ultrasound probe, the spermatic cord was identified by locating the spermatic artery and the deferent duct. A 23 G Microlance needle was advanced close to the deferent duct by avoiding vessel perforation, and local anaesthetic was deposited around the deferent duct under direct visualization. The primary outcome was the success rate of the block which was defined as surgery without any substitution of opioids, additional local anaesthetics, or sedatives. Results In 20 patients, 40 blocks were performed with a success rate of 95% (n=38). The failure rate was 5% (n=2) and no conversion to general anaesthesia was needed. The mean duration of the block was 14.1 h (sd 6.9). Conclusions The use of ultrasound guidance to perform spermatic cord block is feasible and has a high success rate. Our new approach may become a suitable alternative to neuraxial or general anaesthesia especially in the ambulatory surgical setting. Registry: International Standard Randomised Controlled Trial Number Register; www.controlled-trials.com; Registry Nr.: ISRCTN4464781