Technical delivery of myogenic cells through an endocardial injection catheter for myocardial cell implantation

BACKGROUND: The next clinical frontier in the therapeutics of ischemic heart disease may involve the development and delivery of specific molecules and cells into the myocardium. The aim of the present study was to evaluate the efficiency and safety of the MyoStar injection catheter (Biosense-Webster Inc.) that has recently been developed to deliver molecules and cells to the myocardium. The 8 Fr (110 cm length) catheter comprises a navigation sensor with a 27 gauge needle at the distal tip. METHODS: Mouse myogenic cells (C2) were delivered to a tissue culture dish through different modalities: a standard laboratory pipette, a syringe needle (27 gauge) and the injection catheter. The cells were counted and monitored for growth and differentiation in the tissue culture immediately after delivery and two, three and six days later. Cells that were injected through a regular syringe needle or through the injection catheter demonstrated the same capacity to proliferate in tissue culture up to six days. RESULTS: The behavior of the cells in culture (fusion) was identical for the cells delivered to the tissue culture by a pipette or by the injection catheter. CONCLUSION: The results of the present study indicate that delivery of cells through the MyoStar injection catheter is a method with no significant loss or adverse effects to the cells along the path of the catheter. The catheter, which possesses both injection and navigation capabilities, can be used to deliver cell therapy to patients with ischemic heart disease.     

Strong photosynthetic acclimation and enhanced water‐use efficiency in grassland functional groups persist over 21 years of CO2 enrichment,independent of nitrogen supply

Uncertainty about long‐term leaf‐level responses to atmospheric CO₂ rise is a major knowledge gap that exists because of limited empirical data. Thus, it remains unclear how responses of leaf gas exchange to elevated CO₂ (eCO₂) vary among plant species and functional groups, or across different levels of nutrient supply, and whether they persist over time for long‐lived perennials. Here, we report the effects of eCO₂ on rates of net photosynthesis and stomatal conductance in 14 perennial grassland species from four functional groups over two decades in a Minnesota Free‐Air CO₂ Enrichment experiment, BioCON. Monocultures of species belonging to C₃ grasses, C₄ grasses, forbs, and legumes were exposed to two levels of CO₂ and nitrogen supply in factorial combinations over 21 years. eCO₂ increased photosynthesis by 12.9% on average in C₃ species, substantially less than model predictions of instantaneous responses based on physiological theory and results of other studies, even those spanning multiple years. Acclimation of photosynthesis to eCO₂ was observed beginning in the first year and did not strengthen through time. Yet, contrary to expectations, the response of photosynthesis to eCO₂ was not enhanced by increased nitrogen supply. Differences in responses among herbaceous plant functional groups were modest, with legumes responding the most and C₄ grasses the least as expected, but did not further diverge over time. Leaf‐level water‐use efficiency increased by 50% under eCO₂ primarily because of reduced stomatal conductance. Our results imply that enhanced nitrogen supply will not necessarily diminish photosynthetic acclimation to eCO₂ in nitrogen‐limited systems, and that significant and consistent declines in stomatal conductance and increases in water‐use efficiency under eCO₂ may allow plants to better withstand drought.     

Advances, challenges and a developing synthesis of ecological community assembly theory

Ecological approaches to community assembly have emphasized the interplay between neutral processes, niche-based environmental filtering and niche-based species sorting in an interactive milieu. Recently, progress has been made in terms of aligning our vocabulary with conceptual advances, assessing how trait-based community functional parameters differ from neutral expectation and assessing how traits vary along environmental gradients. Experiments have confirmed the influence of these processes on assembly and have addressed the role of dispersal in shaping local assemblages. Community phylogenetics has forged common ground between ecologists and biogeographers, but it is not a proxy for trait-based approaches. Community assembly theory is in need of a comparative synthesis that addresses how the relative importance of niche and neutral processes varies among taxa, along environmental gradients, and across scales. Towards that goal, we suggest a set of traits that probably confer increasing community neutrality and regionality and review the influences of stress, disturbance and scale on the importance of niche assembly. We advocate increasing the complexity of experiments in order to assess the relative importance of multiple processes. As an example, we provide evidence that dispersal, niche processes and trait interdependencies have about equal influence on trait-based assembly in an experimental grassland.     

Eye movements predict recollective experience

Previously encountered stimuli can bring to mind a vivid memory of the episodic context in which the stimulus was first experienced ("remembered" stimuli), or can simply seem familiar ("known" stimuli). Past studies suggest that more attentional resources are required to encode stimuli that are subsequently remembered than known. However, it is unclear if the attentional resources are distributed differently during encoding and recognition of remembered and known stimuli. Here, we record eye movements while participants encode photos, and later while indicating whether the photos are remembered, known or new. Eye fixations were more clustered during both encoding and recognition of remembered photos relative to known photos. Thus, recognition of photos that bring to mind a vivid memory for the episodic context in which they were experienced is associated with less distributed overt attention during encoding and recognition. The results suggest that remembering is related to encoding of a few distinct details of a photo rather than the photo as a whole. In turn, during recognition remembering may be trigged by enhanced memory for the salient details of the photos.     

Families of membranous proteins can be characterized by the amino acid composition of their transmembrane domains

SUMMARY: In eukaryotes, membranous proteins account for 20-30% of the proteome. Most of these proteins contain one or more transmembrane (TM) domains. These are short segments that transverse the bilayer lipid membrane. Various properties of the TM domains, such as their number, their topology and their arrangement within the membrane, are closely related to the protein's cellular functions. The properties of the TM domains also determine the cellular targeting and localization of these proteins. It is not known, however, whether the information encoded by TM domains suffices for the purpose of classifying proteins into their functional families. This is the question we address here. We introduce an algorithm that creates a profile of each functional family of membranous proteins based only on the amino acid composition of their TM domains. This is complemented by a classifier program for each such family (to determine whether a given protein belongs to it or not). We find that in most instances TM domains contain enough information to allow an accurate discrimination of approximately 80% sensitivity and approximately 90% specificity among unrelated polytopic functional families with the same number of TM domains. SUPPLEMENTARY INFORMATION: Available at www.protonet.cs.huji.ac.il/TM/     

Placental mesenchymal stromal cells induced into neurotrophic factor-producing cells protect neuronal cells from hypoxia and oxidative stress

Background aimsMesenchymal stromal cells (MSC) may be useful in a range of clinical applications. The placenta has been suggested as an abundant, ethically acceptable, less immunogenic and easily accessible source of MSC. The aim of this study was to evaluate the capacity of induced placental MSC to differentiate into neurotrophic factor-producing cells (NTF) and their protective effect on neuronal cells.MethodsMSC were isolated from placentas and characterized by fluorescence-activated cell sorting (FACS). The cells underwent an induction protocol to differentiate them into NTF. Analysis of the cellular differentiation was done using polymerase chain reactions (PCR), immunocytochemical staining and enzyme-linked immunosorbent assays (ELISA). Conditioned media from placental MSC (PL-MSC) and differentiated MSC (PL-DIFF) were collected and examined for their ability to protect neural cells.ResultsThe immunocytochemical studies showed that the cells displayed typical MSC membrane markers. The cells differentiated into osteoblasts and adipocytes. PCR and immunohistology staining demonstrated that the induced cells expressed typical astrocytes markers and neurotrophic factors. Vascular endothelial growth factor (VEGF) levels were higher in the conditioned media from PL-DIFF compared with PL-MSC, as indicated by ELISA. Both PL-DIFF and PL-MSC conditioned media markedly protected neural cells from oxidative stress induced by H₂O₂ and 6-hydroxydopamine. PL-DIFF conditioned medium had a superior effect on neuronal cell survival. Anti-VEGF antibodies (Bevacizumab) reduced the protective effect of the conditioned media from differentiated and undifferentiated MSC.ConclusionsThis study has demonstrated a neuroprotective effect of MSC of placental origin subjected to an induction differentiation protocol. These data offer the prospect of using placenta as a source for stem cell-based therapies.     

Management affects the pollinator abundance but not the reproductive success of butterfly orchids

Management of semi-natural grasslands should be based on the requirements of plants as well as their pollinators since conditions beneficial for plants are not necessarily beneficial for their pollinators and vice versa. The factors affecting the reproductive success (fruit set) of Platanthera bifolia and Platanthera chlorantha and their pollinators in agricultural landscape and woodlands were studied. In the years 2014–2016, we observed and caught moths during the flowering period of Platanthera species (late June–mid July) in four pure P. bifolia, five pure P. chlorantha and nine mixed populations under management or no management in Estonia. We determined pollinator species richness, pollinator abundance, fruit set and visibility of Platanthera plants in each population. We found that pollinator assemblages of P. bifolia and P. chlorantha did not differ between managed and unmanaged sites. Pollinator abundance had an effect on the fruit set of P. bifolia but not on that of P. chlorantha. Presence or absence of management, visibility of plants and rarefied pollinator species richness did not affect the fruit set of either plant species. Pollinator abundance was significantly higher in unmanaged populations of both plant species but rarefied pollinator species richness was higher only in unmanaged populations of P. chlorantha. Based on our findings the recommendations for management of semi-natural grasslands are to promote larger landscape diversity for the benefit of moth abundance by leaving unmanaged patches in different parts of a grassland in different years and rotational and post-fruiting management for higher reproductive success of orchids.     

Expression of a plant expansin is involved in the establishment of root knot nematode parasitism in tomato

A group of plant proteins, expansins, have been identified as wall-loosening factors and as facilitators of cell expansion in vivo. The root knot nematode Meloidogyne javanica establishes a permanent feeding site composed of giant cells surrounded by gall tissue. We used quantitative PCR and in situ localization to demonstrate the induction of a tomato (Lycopersicon esculentum cv. VF36) expansin (LeEXPA5) expression in gall cells adjacent to the nematode feeding cells. To further characterize the biological role of LeEXPA5 we have generated LeEXPA5-antisense transgenic roots. The ability of the nematode to establish a feeding site and complete its life cycle, the average root cell size and the rate of root elongation were determined for the transgenic roots, as well as the level of LeEXPA5 expression in non-infected and nematode-infected roots. Our results demonstrated that a decrease of LeEXPA5 expression reduces the ability of the nematode to complete its life cycle in transgenic roots. We suggest that a plant-originated expansin is necessary for a successful parasitic nematode–plant interaction.