Pushing the envelope in tissue engineering: Ex vivo production of thick vascularized cardiac extracellular matrix constructs

Functional vascularization is a prerequisite for cardiac tissue engineering of constructs with physiological thicknesses. We previously reported the successful preservation of main vascular conduits in isolated thick acellular porcine cardiac ventricular ECM (pcECM). We now unveil this scaffold's potential in supporting human cardiomyocytes and promoting new blood vessel development ex vivo, providing long-term cell support in the construct bulk. A custom-designed perfusion bioreactor was developed to remodel such vascularization ex vivo, demonstrating, for the first time, functional angiogenesis in vitro with various stages of vessel maturation supporting up to 1.7 mm thick constructs. A robust methodology was developed to assess the pcECM maximal cell capacity, which resembled the human heart cell density. Taken together these results demonstrate feasibility of producing physiological-like constructs such as the thick pcECM suggested here as a prospective treatment for end-stage heart failure. Methodologies reported herein may also benefit other tissues, offering a valuable in vitro setting for "thick-tissue" engineering strategies toward large animal in vivo studies.Israeli Science Foundation/1563/10Singapore National Research Foundatio

Predictors for positive response to home kinematic training in chronic neck pain

Objectives: There is strong evidence for exercise therapy in neck pain, but a wide variety of protocols. Predictors for outcome are unknown and current practice is based on trial and error. The objective of this study was to identify predictors for response to home kinematic training (KT) considering improvement in both self-reported and kinematic measures. Methods: A continuing analysis of data from the second phase of a randomized controlled trial, which included 4 weeks of KT using laser or virtual reality, with baseline, postintervention, and 3-month follow-up measures. Positive self-reported response was defined as a ≥50% pain reduction, ≥7% reduction in neck disability index (NDI), or a global perceived effect of 3 to 5 of 5. A second model defined improvement by ≥40% increase in cervical velocity. Results: Data were retrieved from 79 participants with chronic neck pain who completed the postintervention evaluation and 52 who completed the 3-month follow-up. Self-reported response was 71% to 73% and kinematic response was 41% to 46%. Prediction models indicated an immediate increase in self-reported measures in men with NDI ≥ 20% slower (≤65°/s), and less accurate (≥16° error) cervical motion at baseline. In the longer term, older patients with higher NDI seemed to benefit more. In the second model, no factors significantly predicted improvement in kinematic measures at either time point. Conclusion: A high positive response rate to home KT was found by self-reported criteria. Males with poorer clinical and kinematic presentation at baseline, that is greater disability and slower neck motion, were more likely to respond

High-vs. low-tech cervical movement sense measurement in individuals with neck pain

Objectives: To compare diagnostic ability of the clinical cervical movement sense (CCMS) test to the neck virtual reality (VR) system accuracy module. Background: Altered cervical proprioception is common in patients with persistent neck pain (NP). Recently a simple CCMS has been found to be feasible and reliable. However, it is not known how this compares to a valid method. Methods: Twenty participants with persistent NP and 20 healthy controls were videoed while performing the CCMS using a laser pointer and traced a zigzag pattern and then assessed using the VR accuracy module which consisted of following 8 segments in four directions. Diagnostic ability using a model from potential variables from the video analysis of number of errors and task performance time was compared to a model provided from VR data. Results: Subjects with NP had significantly greater horizontal errors in the CCMS and VR accuracy. Both CCMS and VR measurement models utilising measurements of horizontal movement error demonstrated good diagnostic ability (AUC = 0.88, 0.91 respectively) and there was no statistical difference between the models’ AUC (p = 0.7). Conclusion: The simple clinical testing tool appears to provide a measure of cervical movement sense, similar to the established Neck VR accuracy measure. Both tools differentiated individuals with NP from controls with similar sensitivity and specificity, with some advantage to the VR. The rotational motion measures seem most suitable in the assessment of motion accuracy. CCMS has potential to be used as a simple clinical measure and warrants further research

Antibacterial Properties and Mode of Action of a Short Acyl-Lysyl Oligomer▿

We investigated the potency, selectivity, and mode of action of the oligo-acyl-lysine (OAK) NC12-2β12, which was recently suggested to represent the shortest OAK sequence that retains nonhemolytic antibacterial properties. A growth inhibition assay against a panel of 48 bacterial strains confirmed that NC12-2β12 exerted potent activity against gram-positive bacteria while exhibiting negligible hemolysis up to at least 100 times the MIC. Interestingly, NC12-2β12 demonstrated a bacteriostatic mode of action, unlike previously described OAKs that were bactericidal and essentially active against gram-negative bacteria only. The results of various experiments with binding to model phospholipid membranes correlated well with those of the cytotoxicity experiments and provided a plausible explanation for the observed activity profile. Thus, surface plasmon resonance experiments performed with model bilayers revealed high binding affinity to a membrane composition that mimicked the plasma membrane of staphylococci (global affinity constant [Kapp], 3.7 × 106 M−1) and significantly lower affinities to mimics of Escherichia coli or red blood cell cytoplasmic membranes. Additional insertion isotherms and epifluorescence microscopy experiments performed with model Langmuir monolayers mimicking the outer leaflet of plasma membranes demonstrated the preferential insertion of NC12-2β12 into highly anionic membranes. Finally, we provide mechanistic studies in support of the view that the bacteriostatic effect resulted from a relatively slow process of plasma membrane permeabilization involving discrete leakage of small solutes, such as intracellular ATP. Collectively, the data point to short OAKs as a potential source for new antibacterial compounds that can selectively affect the growth of gram-positive bacteria while circumventing potential adverse effects linked to lytic compounds

Monthly surveys of water properties along the Alexander micro-estuary

Monthly surveys of water properties along the estuary. These surveys include water column CTD profiles of temperature, salinity, dissolved oxygen, chlorophyll fluorescence, and turbidity (OBS). Profile data are accompanied by Secchi depth measurements and discrete water samples collected by a horizontal Niskin bottle near the surface and near the bottom. Water samples are analyzed for the concentrations of Phosphate, Nitrate, Nitrite, Ammonium, Total and particulate nitrogen and phosphorus, total suspended solids, particulate organic matter, biological oxygen demand, chlorophyll-a, cell counts of nano and pico planktonic algae and non-photosynthetic bacteria

Bi-weekly surveys of water properties at two marine stations at Alexander micro-estuary

Bi-weekly surveys of water properties at two marine stations ~1 and 6.6 Km from the estuary mouth at bottom depths of 8 and 48 meters. These surveys include water column CTD profiles of temperature, salinity, dissolved oxygen, chlorophyll fluorescence, and Turbidity (OBS). Profile data are accompanied by discrete water samples collected by a Niskin bottle at 10 m depth, these samples are analyzed for the concentrations of chlorophyll-a and pico and nano planktonic algae and non-photosynthetic bacteria