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91.
Shiran Shapira Oded Ben-Amotz Osnat Sher Dina Kazanov Jacob Mashiah Sarah Kraus Eyal Gur Nadir Arber 《PloS one》2015,10(10)
Background
Healthy individuals rarely have problems with wound healing. Most skin lesions heal rapidly and efficiently within one to two weeks. However, many medical and surgical complications can be attributed to deficiencies in wound repair. Open wounds have lost the barrier that protects tissues from bacterial invasion and allows the escape of vital fluids. Without expeditious healing, infections become more frequent. The CD24 gene encodes a heavily-glycosylated cell surface protein anchored to the membrane by phosphatidylinositol. CD24 plays an important role in the adaptive immune response and controls an important genetic checkpoint for homeostasis and autoimmune diseases in both mice and humans. We have previously shown that overexpression of CD24 results in increased proliferation and migration rates.Aim
To examine the role of CD24 in the wound healing process.Methods
An excisional model of wound healing was used and delayed wound healing was studied in genetically modified heat stable antigen (HSA/CD24)-deficient mice (HSA -/-) compared to wild-type (WT) mice.Results
Large full-thickness skin wounds, excised on the back of mice, exhibited a significant delay in the formation of granulation tissue, and in wound closure when compared to their WTHSA +/+ littermates. Wounds were histologically analyzed and scored, based on the degree of cellular invasion, granulation tissue formation, vascularity, and re-epithelialization. Additionally, in stitched wounds, the HSA -/- mice failed to maintain their stitches; they did not hold and fell already 24 hours, revealing erythematous wound fields. Re-expression of HSA, delivered by lentivirus, restored the normal healing phenotype, within 24 hours post-injury, and even improved the healing in WT, and in BalbC mice.Conclusions
Delayed wound-healing in the absence of HSA/CD24 suggests that CD24 plays an important role in this process. Increased expression of CD24, even in the normal state, may be used to enhance wound repair. 相似文献92.
Dina Helmy El-Ghonemy Thanaa Hamed Ali Ahmed Mohamed El-Bondkly Maysa El-Sayed Moharam Fatma Nabeeh Talkhan 《Antonie van Leeuwenhoek》2014,106(5):853-864
Spore suspensions of Aspergillus oryzae NRRL 3484 were subjected to mutagenesis using ultraviolet-irradiation followed by chemical treatments to improve the biosynthesis of cellulase. Ten mutant strains namely UEAC7, UEAR5, UNAC4, UNAC16, UNAR19, UNBC7, UNBR3, UNBR10, UNBR23 and UNBR25 were selected and their extracellular cellulase activities were assayed. Mutant UNAC4 gave the highest cellulase production [2,455 ± 28 U/g-dry substrate (ds) for filter paper-ase (FP-ase)] in a yield 4-fold exceeding that of the wild type strain (578 ± 5.0 U/g-ds for FP-ase). Rice straw (RS) was used as a sole carbon source for the enzyme production at a concentration of 10 % (w/v). Maximum cellulase production was achieved at initial medium pH 5.5, initial moisture content 77 % and an incubation temperature 28 °C on the fifth day of growth. NH4Cl proved to be the suitable added nitrogen source for maximum enzyme production followed by peptone. These results clearly indicate the cost-effectiveness of solid state fermentation technology in the economic production of extracellular cellulase. The hyper-production of cellulase by mutant strain UNAC4 has potential for industrial processes that convert lignocellulosic material (e.g. RS) into products of commercial value such as glucose and biofuels. 相似文献
93.
Single-molecule fluorescence spectroscopy has become an important research tool in the life sciences but a number of limitations hinder the widespread use as a standard technique. The limited dynamic concentration range is one of the major hurdles. Recent developments in the nanophotonic field promise to alleviate these restrictions to an extent that even low affinity biomolecular interactions can be studied. After motivating the need for nanophotonics we introduce the basic concepts of nanophotonic devices such as zero mode waveguides and nanoantennas. We highlight current applications and the future potential of nanophotonic approaches when combined with biological systems and single-molecule spectroscopy. 相似文献
94.
95.
Indrikis Krams Dina Cirule Valerija Suraka Tatjana Krama Markus J. Rantala Gary Ramey 《Functional ecology》2010,24(1):172-177
1. In a seasonal environment, subcutaneous energy reserves of resident animals often increase in winter and decline again in summer reflecting gradual seasonal changes in their fattening strategies. We studied changes in body reserves of wintering great tits in relation to their dominance status under two contrasting temperature regimes to see whether individuals are capable of optimizing their body mass even under extreme environmental conditions.
2. We predicted that dominant individuals will carry a lesser amount of body reserves than subordinate great tits under mild conditions and that the body reserves of the same dominant individuals will increase and exceed the amount of reserves of subordinates under conditions of extremely low ambient temperatures, when ambient temperature dropped down to −37 °C.
3. The results confirmed the predictions showing that dominant great tits responded to the rising risk of starvation under low temperatures by increasing their body reserves and this was done at the expense of their safety.
4. Removal experiments revealed that lower body reserves of subordinate flock members are due to the increased intraspecific competition for food under low ambient temperatures.
5. Our results also showed that fattening strategies of great tits may change much quicker than previously considered, reflecting an adaptive role of winter fattening which is sensitive to changes in ambient temperatures. 相似文献
2. We predicted that dominant individuals will carry a lesser amount of body reserves than subordinate great tits under mild conditions and that the body reserves of the same dominant individuals will increase and exceed the amount of reserves of subordinates under conditions of extremely low ambient temperatures, when ambient temperature dropped down to −37 °C.
3. The results confirmed the predictions showing that dominant great tits responded to the rising risk of starvation under low temperatures by increasing their body reserves and this was done at the expense of their safety.
4. Removal experiments revealed that lower body reserves of subordinate flock members are due to the increased intraspecific competition for food under low ambient temperatures.
5. Our results also showed that fattening strategies of great tits may change much quicker than previously considered, reflecting an adaptive role of winter fattening which is sensitive to changes in ambient temperatures. 相似文献
96.
Ilan Hammel Tanya Shoichetman Dina Amihai Stephen J. Galli Ehud Skutelsky 《Cell and tissue research》2010,339(3):561-570
We used the egg avidin gold complex as a polycationic probe for the localization of negatively charged sites in the secretory
granules of mouse mast cells. We compared the binding of this reagent to mast cell granules in wild-type mice and in congenic
brachymorphic mice in which mast cell secretory granules contained undersulfated proteoglycans. We localized anionic sites
by post-embedding labeling of thin sections of mouse skin and tongue tissues fixed in Karnovsky’s fixative and OsO4 and embedded in Araldite. Transmission electron microscopy revealed that the mast cell granules of bm/bm mice had a lower optical density than those of wild-type mice (P<0.001) and a lower avidin gold binding density (by approximately 50%, P<0.001). The latter result provided additional evidence that the contents of mast cell granules in bm/bm mice were less highly sulfated than in those of wild-type mice. In both wild-type and bm/bm mast cells, the distribution of granule equivalent volumes was multimodal, but the unit granule volume was approximately
19% lower in bm/bm cells than in wild-type cells (P<0.05). Thus, bm/bm mast cells develop secretory granules that differ from those of wild-type mice in exhibiting a lower optical density and
slightly smaller unit granules, however the processes that contribute to granule maturation and granule-granule fusion in
mast cells are operative in bm/bm cells. 相似文献
97.
98.
Maria E. Silva Serra Dina Murtinho Albertino Goth António M. D'A. Rocha Gonsalves Paulo E. Abreu Alberto A. C. C. Pais 《Chirality》2010,22(4):425-431
New chiral salen ligands were prepared by the ultrasound‐irradiated condensation of optically active (1R, 3S)‐1,2,2‐trimethyl‐1,3‐diaminocyclopentane with aromatic 1‐hydroxyaldehydes. The ultrasound‐mediated process is more convenient due to shorter reaction times, energy economy, and easier isolation of the products. The in situ formed Ti(IV)(salen) complexes, evaluated as catalysts in the enantioselective trimethylsilylcyanation of benzaldehyde, were found to be efficient for this process, originating the corresponding product in high yields (72–99%) and selectivities of up to 79%. The lowest energy transition states were determined by computational studies. These results were in qualitative agreement with the experimentally observed ones. Chirality, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
99.
Prospects of yeast systems biology for human health: integrating lipid, protein and energy metabolism 总被引:2,自引:0,他引:2
The yeast Saccharomyces cerevisiae is a widely used model organism for studying cell biology, metabolism, cell cycle and signal transduction. Many regulatory pathways are conserved between this yeast and humans, and it is therefore possible to study pathways that are involved in disease development in a model organism that is easy to manipulate and that allows for detailed molecular studies. Here, we briefly review pathways involved in lipid metabolism and its regulation, the regulatory network of general metabolic regulator Snf1 (and its human homologue AMPK) and the proteostasis network with its link to stress and cell death. All the mentioned pathways can be used as model systems for the study of homologous pathways in human cells and a failure in these pathways is directly linked to several human diseases such as the metabolic syndrome and neurodegeneration. We demonstrate how different yeast pathways are conserved in humans, and we discuss the possibilities of using the systems biology approach to study and compare the pathways of relevance with the objective to generate hypotheses and gain new insights. 相似文献
100.
The purpose of this study was to prepare sublingual tablets, containing the antiasthmatic drug ketotifen fumarate which suffers an extensive first-pass effect, using the fast-melt granulation technique. The powder mixtures containing the drug were agglomerated using a blend of polyethylene glycol 400 and 6000 as meltable hydrophilic binders. Granular mannitol or granular mannitol/sucrose mixture were used as fillers. A mechanical mixer was used to prepare the granules at 40°C. The method involved no water or organic solvents, which are used in conventional granulation, and hence no drying step was included, which saved time. Twelve formulations were prepared and characterized using official and non official tests. Three formulations showed the best results and were subjected to an ex vivo permeation study using excised chicken cheek pouches. The formulation F4I possessed the highest permeation coefficient due to the presence of the permeation enhancer (polyethylene glycol) in an amount which allowed maximum drug permeation, and was subjected to a pharmacokinetic study using rabbits as an animal model. The bioavailability of F4I was significantly higher than that of a commercially available dosage form (Zaditen® solution-Novartis Pharma-Egypt) (p > 0.05). Thus, fast-melt granulation allowed for rapid tablet disintegration and an enhanced permeation of the drug through the sublingual mucosa, resulting in increased bioavailabililty.Key words: chicken pouches, fast-melt granulation, ketotifen fumarate, permeation, sublingual tablet, Zaditen® 相似文献