The high‐affinity D2/D3 agonist D512 protects PC12 cells from 6‐OHDA‐induced apoptotic cell death and rescues dopaminergic neurons in the MPTP mouse model of Parkinson's disease

In this study, in vitro and in vivo experiments were carried out with the high‐affinity multifunctional D2/D3 agonist D‐512 to explore its potential neuroprotective effects in models of Parkinson's disease and the potential mechanism(s) underlying such properties. Pre‐treatment with D‐512 in vitro was found to rescue rat adrenal Pheochromocytoma PC12 cells from toxicity induced by 6‐hydroxydopamine administration in a dose‐dependent manner. Neuroprotection was found to coincide with reductions in intracellular reactive oxygen species, lipid peroxidation, and DNA damage. In vivo, pre‐treatment with 0.5 mg/kg D‐512 was protective against neurodegenerative phenotypes associated with systemic administration of MPTP, including losses in striatal dopamine, reductions in numbers of DAergic neurons in the substantia nigra (SN), and locomotor dysfunction. These observations strongly suggest that the multifunctional drug D‐512 may constitute a novel viable therapy for Parkinson's disease.

     

COX-1 and COX-2 contribute differentially to the LPS-induced release of PGE2 and TxA2 in liver macrophages

LPS induces an immediate release of thromboxane TxA2 and a delayed release of PGE2. Dexamethasone suppresses the LPS-induced release of TxA2 and PGE2. In the first 8 h after LPS addition, the specific COX-2 inhibitor SC236 inhibits the PGE2 and TxA2 release by about 80% and 20%, whereas the release of PGE2 and TxA2 between 8 and 24 h is inhibited by about 40% and 35%, respectively. Resident liver macrophages express substantial amounts of COX-1, TxAS, cPGES and mPGES-2, small amounts of COX-2 but almost no detectable amounts of mPGES-1. LPS induces an increase of COX-2 and mPGES-1, but does not change COX-1, cPGES, mPGES-2 and TxAS at protein level. Dexamethasone suppresses almost completely the LPS-induced effects on COX-2 and mPGES-1. It is concluded that (1) COX-1 and COX-2 are involved in the LPS-induced synthesis of TxA2 and PGE2; (2) TxA2 release is catalyzed at early time-points by the combined action of COX-1 and TxAs, whereas at later time points the newly expressed COX-2 couples to TxAS and contributes to the TxA2 release; (3) PGE2 release within the first 8 h is predominantly catalyzed by COX-2, whereas at later time-points COX-1 couples to the newly expressed mPGES-1 and contributes to the PGE2 release.     

Automated Blood Sampling in a Canine Telemetry Cardiovascular Model

Successful implementation of automated blood sampling (ABS) into a telemetry instrumented canine cardiovascular model provides simultaneous cardiovascular assessment of novel compounds while collecting multiple blood samples for analysis of drug level, cytokines, and biomarkers. Purpose-bred male Beagle dogs (n = 36) were instrumented with a dual-pressure telemetry transmitter and vascular access port. Modifications to acclimation practices, surgical procedures, and housing were required for implementation of ABS in our established cardiovascular canine telemetry colony. These modifications have increased the use and reproducibility of the model by combining early pharmacokinetic and cardiovascular studies, thus achieving both refinement and reduction from a 3R perspective. In addition, the modified model can shorten timelines and reduce the compound requirement in early stages of drug development. This telemetry–ABS model provides an efficient means to quickly identify potential effects on key cardiovascular parameters in a large animal species and to obtain a more complete pharmacokinetic–pharmacodynamic profile for discovery compounds.

Safety pharmacology is an important facet of drug discovery and development. Prior to the first in-human studies, safety pharmacology outcomes are used to predict clinical risk profiles of potential new drugs. Dogs that are chronically instrumented for telemetry are a well-characterized in vivo model for safety pharmacology studies and for screening new compounds for cardiovascular physiologic effects.² Relatively few blood collections are performed during conscious telemetry studies due to the potential disturbance of cardiovascular data.¹⁰ Personnel entering the room cause excitement in dogs, which can mask drug-induced changes in physiologic parameters, such as heart rate and blood pressure.¹⁰ The ‘work around’ for the excitation artifact involves obtaining blood samples from a different group of dogs (known as a satellite group) while recording physiologic changes in the first group or repeating the pharmacokinetic study in the telemetry-instrumented dogs. Pharmacokinetic properties of drugs vary due to individual dog variability and can vary across dosing events (for example, batch-to-batch variability). If adverse effects are noted on either study, determining a correlation of occurrences can be difficult especially when involving a single animal. These approaches do not compensate for individual variability, dosing variations between animals, or changing environmental conditions.⁹Heart rate and circulating cortisol concentration increase during manual blood sampling as compared with automated blood sampling in macaques¹⁷ and swine.¹² Automated blood sampling (ABS) is designed to collect blood painlessly from awake and freely moving animals.¹⁶ The use of ABS reduces stress from handling and eliminates the repeated venipunctures that are required for manual blood sampling.⁶ The implementation of ABS allowed us to achieve a complete pharmacokinetic–pharmacodynamic drug assessment in cardiovascular safety telemetry dog studies with no collection-related disturbance of physiologic parameters. Combining the pharmacokinetic and cardiovascular studies by using this method also reduces the need to synthesize more compound and shortens drug development timelines. Another advantage of this approach is the reduction of animal use by eliminating satellite animal groups.¹⁹Our incorporation of ABS into cardiovascular safety telemetry dog studies required changes to the dog acclimation procedure, addition of vascular access ports (VAP) to the surgical protocol, and modifications to the canine housing. This report is an overview of how we successfully incorporated ABS into a colony of telemetry-implanted dogs and the modifications necessary for continued success.     

Pathogenic Huntingtin Repeat Expansions in Patients with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis

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Cell-extracellular matrix interactions regulate neural differentiation of human embryonic stem cells

Background  

Interactions of cells with the extracellular matrix (ECM) are critical for the establishment and maintenance of stem cell self-renewal and differentiation. However, the ECM is a complex mixture of matrix molecules; little is known about the role of ECM components in human embryonic stem cell (hESC) differentiation into neural progenitors and neurons.     

Empirical mode decomposition method for investigating the structure of large-scale MHD instabilities in a tokamak

A new approach to the processing of experimental data from MHD diagnostics is developed for the purpose of investigating the spatial structure of large-scale MHD instabilities in a tokamak. The empirical mode decomposition method is applied to expand a multimode MHD perturbation in individual modes, which are then identified by constructing a spatial analytic signal with the help of the Hilbert transform. The method can be used to analyze the structure of the tearing instability and of the resistive wall modes.     

Different modes of swimming of the carp, Cyprinus carpio L.

An electromyographical study has been made of carp swimming muscles at various points along the body length during sustained and burst locomotion. During sustained swimming, red muscles show a constant time lag between activation of anterior and posterior segments which is practically independent of the speed of locomotion. In contrast, anterior and posterior homolateral segments are activated simultaneously during bursts of rapid movement. This pattern of co-ordination between body segments differs from that reported for other species.     

Hilbert-Huang transform in MHD plasma diagnostics

A new method for processing experimental data from MHD diagnostics is discussed that provides a more detailed study of the dynamics of large-scale MHD instabilities. The method is based on the Hilbert-Huang transform method and includes an empirical mode decomposition algorithm, which is used to decompose the experimental MHD diagnostic signals into a set of frequency-and amplitude-modulated harmonics in order to construct the time evolutions of the amplitudes and frequencies of these harmonics with the help of the Hilbert transform. The method can also be applied to analyze data from other diagnostics that measure unsteady oscillating signals.