In vivo evaluation of bioprinted prevascularized bone tissue

Bioprinting can be considered as a progression of the classical tissue engineering approach, in which cells are randomly seeded into scaffolds. Bioprinting offers the advantage that cells can be placed with high spatial fidelity within three-dimensional tissue constructs. A decisive factor to be addressed for bioprinting approaches of artificial tissues is that almost all tissues of the human body depend on a functioning vascular system for the supply of oxygen and nutrients. In this study, we have generated cuboid prevascularized bone tissue constructs by bioprinting human adipose-derived mesenchymal stem cells (ASCs) and human umbilical vein endothelial cells (HUVECs) by extrusion-based bioprinting and drop-on-demand (DoD) bioprinting, respectively. The computer-generated print design could be verified in vitro after printing. After subcutaneous implantation of bioprinted constructs in immunodeficient mice, blood vessel formation with human microvessels of different calibers could be detected arising from bioprinted HUVECs and stabilization of human blood vessels by mouse pericytes was observed. In addition, bioprinted ASCs were able to synthesize a calcified bone matrix as an indicator of ectopic bone formation. These results indicate that the combined bioprinting of ASCs and HUVECs represents a promising strategy to produce prevascularized artificial bone tissue for prospective applications in the treatment of critical-sized bone defects.     

Control of human eye movements: II. a model for the extraocular plant mechanism

Control of eye movements is essential in accomplishing visual or perceptive tasks. The brain and central nervous system process retinal information and send nervous signals to the extraocular muscles, which exert forces that cause the eye to move. A model for the human extraocular plant, which consists of the nervous input signals, the extraocular muscles, the orbit and the globe, is proposed. The derivation is based on anatomical and physiological data as well as experiments concerned with a variety of eye movements under normal and abnormal conditions. The nervous activity controlling eye movements was estimated from electromyography and single unit studies of the extraocular nuclei. The equations describing muscle properties were discussed in a previous paper by the authors; these results were incorporated into the present model. The characteristics of the isolated globe and its visco-elastic interaction with the orbit were computed from length- tension curves and isotonic experiments. Simulations using the resulting representation accurately depicted the isotonic experiments on the isolated globe and on the total extraocular plant, the isometric forces during three different types of eye movements, and the weighted globe experiment. A future paper will show that the model accurately simulates normal eye movements of different types and amplitudes.     

Molecular Mechanisms of Glutamine Synthetase Mutations that Lead to Clinically Relevant Pathologies

Glutamine synthetase (GS) catalyzes ATP-dependent ligation of ammonia and glutamate to glutamine. Two mutations of human GS (R324C and R341C) were connected to congenital glutamine deficiency with severe brain malformations resulting in neonatal death. Another GS mutation (R324S) was identified in a neurologically compromised patient. However, the molecular mechanisms underlying the impairment of GS activity by these mutations have remained elusive. Molecular dynamics simulations, free energy calculations, and rigidity analyses suggest that all three mutations influence the first step of GS catalytic cycle. The R324S and R324C mutations deteriorate GS catalytic activity due to loss of direct interactions with ATP. As to R324S, indirect, water-mediated interactions reduce this effect, which may explain the suggested higher GS residual activity. The R341C mutation weakens ATP binding by destabilizing the interacting residue R340 in the apo state of GS. Additionally, the mutation is predicted to result in a significant destabilization of helix H8, which should negatively affect glutamate binding. This prediction was tested in HEK293 cells overexpressing GS by dot-blot analysis: Structural stability of H8 was impaired through mutation of amino acids interacting with R341, as indicated by a loss of masking of an epitope in the glutamate binding pocket for a monoclonal anti-GS antibody by L-methionine-S-sulfoximine; in contrast, cells transfected with wild type GS showed the masking. Our analyses reveal complex molecular effects underlying impaired GS catalytic activity in three clinically relevant mutants. Our findings could stimulate the development of ATP binding-enhancing molecules by which the R324S mutant can be repaired extrinsically.     

Histamine H3 and H4 receptor affinity of branched 3-(1H-imidazol-4-yl)propyl N-alkylcarbamates

A series of imidazole-containing (non-)chiral carbamates were tested at human histamine H₃ receptor (H₃R). All compounds displayed K_i values below 100 nM. A trend for a stereoselectivity at human H₃R was observed for the chiral α-branched ligands. Selected compounds were also tested at human histamine H₄ receptor and showed moderate to weak affinities (118–1460 nM).     

Long-term ACTH induced diminished responsiveness of prolactin secretion to morphine

The effect of morphine on plasma prolactin level and on dopamine turnover in the median eminence was studied using adult male rats chronically treated with ACTH. It was found that the ACTH pretreatment caused a decrease in the effect of morphine on prolactin secretion and prevented the inhibitory effect of morphine on dopamine turnover measured in the median eminence. The prolonged ACTH administration did not influence the prolactin content of the pituitaries and the in vitro dopamine sensitivity of lactotroph cells. Acute dexamethasone injection did not change the morphine-caused prolactin release. These results suggest that chronic ACTH treatment (possibly via corticosterone hyperproduction) elicits an opiate-tolerance like state of tuberoinfundibular dopaminergic neurons.     

Yoga for Multiple Sclerosis: A Systematic Review and Meta-Analysis

While yoga seems to be effective in a number of neuropsychiatric disorders, the evidence of efficacy in multiple sclerosis remains unclear. The aim of this review was to systematically assess and meta-analyze the available data on efficacy and safety of yoga in patients with multiple sclerosis. Medline/PubMed, Scopus, the Cochrane Central Register of Controlled Trials, PsycINFO, CAM-Quest, CAMbase, and IndMED were searched through March 2014. Randomized controlled trials (RCTs) of yoga for patients with multiple sclerosis were included if they assessed health-related quality of life, fatigue, and/or mobility. Mood, cognitive function, and safety were defined as secondary outcome measures. Risk of bias was assessed using the Cochrane tool. Seven RCTs with a total of 670 patients were included. Evidence for short-term effects of yoga compared to usual care were found for fatigue (standardized mean difference [SMD] = −0.52; 95% confidence intervals (CI) = −1.02 to −0.02; p = 0.04; heterogeneity: I² = 60%; Chi² = 7.43; p = 0.06) and mood (SMD = −0.55; 95%CI = −0.96 to −0.13; p = 0.01; heterogeneity: I² = 0%; Chi² = 1.25; p = 0.53), but not for health-related quality of life, muscle function, or cognitive function. The effects on fatigue and mood were not robust against bias. No short-term or longer term effects of yoga compared to exercise were found. Yoga was not associated with serious adverse events. In conclusion, since no methodological sound evidence was found, no recommendation can be made regarding yoga as a routine intervention for patients with multiple sclerosis. Yoga might be considered a treatment option for patients who are not adherent to recommended exercise regimens.