Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been shown that glucocorticoids accelerate lung development by limiting alveolar formation resulting from a premature maturation of the alveolar septa. Based on these data, the aim of the present work was to analyze the influence of dexamethasone on cell cycle control mechanisms during postnatal lung development. Cell proliferation is regulated by a network of signaling pathways that converge to the key regulator of cell cycle machinery: the cyclin-dependent kinase (CDK) system. The activity of the various cyclin/CDK complexes can be modulated by the levels of the cyclins and their CDKs, and by expression of specific CDK inhibitors (CKIs). In the present study, newborn rats were given a 4-d treatment with dexamethasone (0.1-0.01 microg/g body weight dexamethasone sodium phosphate daily on d 1-4), or saline. Morphologically, the treatment caused a significant thinning of the septa and an acceleration of lung maturation on d 4. Study of cyclin/CDK system at d 1-36 documented a transient down-regulation of cyclin/CDK complex activities at d 4 in the dexamethasone-treated animals. Analysis of the mechanisms involved suggested a role for the CKIs p21CIP1 and p27KIP1. Indeed, we observed an increase in p21CIP1 and p27KIP1 protein levels on d 4 in the dexamethasone-treated animals. By contrast, no variations in either cyclin and CDK expression, or cyclin/CDK complex formation could be documented. We conclude that glucocorticoids may accelerate lung maturation by influencing cell cycle control mechanisms, mainly through impairment of G1 cyclin/CDK complex activation.
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PMID:Impairment of rat postnatal lung alveolar development by glucocorticoids: involvement of the p21CIP1 and p27KIP1 cyclin-dependent kinase inhibitors. 1180 10

Formation of calcium phosphate on alkali- and heat-treated titanium surfaces was investigated using transmission electron microscopy (TEM). The samples were prepared by immersing the alkali- and heat-treated titanium in a revised simulated body fluid (R-SBF) with the same HCO(3)(-) concentration level as in human blood plasma. The deposition and precipitation on treated titanium surfaces were extracted for TEM examination without thinning process. Electron diffraction of the precipitates revealed that octacalcium phosphate (OCP), instead of hydroxyapatite (HA), directly nucleates from amorphous calcium phosphate. The OCP crystals continuously grew on the titanium surfaces rather than transforming into apatite. Calcium titanate was also identified by electron diffraction. Its role in the formation bioactive calcium phosphate, however, is not clear from this experiment.
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PMID:TEM study of calcium phosphate precipitation on bioactive titanium surfaces. 1473 41

Small micellar casein particles, so-called submicelles, were obtained by removing colloidal calcium phosphate from native casein by adding sodium polyphosphate. Aqueous submicelle suspensions were characterized using light scattering and rheology as a function of concentration and temperature. The casein submicelles behave like soft spheres that jam at a critical concentration (C(c)) of about 100 g L(-1). The viscosity does not diverge at C(c), but increases sharply, similarly to that of multiarm star polymers. C(c) increases weakly with increasing temperature, which leads to a strong decrease of the viscosity close to and above C(c). Concentrated submicelle suspensions show strong shear-thinning above a critical shear rate and the shear stress becomes independent of the shear rate. The critical shear rates at different temperatures and concentrations are inversely proportional to the zero-shear viscosity. At much higher shear rates, the shear stress fluctuates strongly in time indicating inhomogeneous flow. The frequency dependence of casein submicelle suspensions is characterized by elastic behavior at high frequencies (concentrations) and viscous behavior at low frequencies (concentrations).
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PMID:Dynamic mechanical properties of suspensions of micellar casein particles. 1592 12

The objective was to improve the protocol that was used to obtain the first reported piglets from transferred vitrified and warmed zona-intact blastocysts. Blastocysts were collected from superovulated sows and gilts, centrifuged to polarize lipid, vitrified, warmed and cultured for 24h or transferred immediately. Removing the zona pellucida after warming increased the number of cells in the surviving blastocysts (zona-free 60.8+/-4.3, zona-intact 39.1+/-2.8; P<0.05). Thinning the zona pellucida produced similar results to zona removal. Changing the basal medium of the vitrification and warming solutions from modified PBS to phosphate buffered NCSU-23 increased the number of cells (44.7+/-2.2 versus 56.0+/-3.9, respectively; P<0.05). Reducing the plunge temperature of the liquid nitrogen from -196 degrees C to less than -204 degrees C improved the embryo survival rate (61.9% versus 82.9%, respectively; P<0.05). These modifications were incorporated into the vitrification protocol that was used to vitrify and warm 105 blastocysts (that were subsequently transferred into four recipients). Three recipients became pregnant, farrowing three litters (average litter size, 5.3; 18.8% embryo survival in farrowing sows). Changing the warming protocol to using sucrose rather than ethylene glycol resulted in a trend towards improved embryo survival (73.5% versus 91.2%) but this was not statistically significant. Incorporating this modification, 203 blastocysts were vitrified, warmed and transferred into seven recipients. Five became pregnant and 36 fetuses were recovered (average litter size 7.2; 24.8% embryo survival in pregnant sows) at Day 40 of pregnancy. In conclusion, changes made to the vitrification protocol improved pregnancy rate and in vivo embryo survival compared to an earlier study using the original protocol.
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PMID:Changes to porcine blastocyst vitrification methods and improved litter size after transfer. 1605 93

Polycaprolactone is susceptible to enzymatic biodegradation via ester bond cleavage. This study examined the susceptibility of Resilon, a polycaprolactone-based root filling material to enzymatic hydrolysis. Resilon, gutta-percha, and polycaprolactone disks, prepared by compression molding, were incubated in phosphate-buffered saline, lipase PS or cholesterol esterase at 37 degrees C for 96 h. They were retrieved at different time intervals for gravimetric analysis and scanning electron microscopy. The materials exhibited slight weight gains when incubated in phosphate-buffered saline that can be attributed to water sorption. Gutta-percha showed similar weight gains in the two enzymes. Conversely, Resilon and polycaprolactone exhibited extensive surface thinning and weight losses after incubation in lipase PS and cholesterol esterase. Glass filler particles in Resilon were exposed following surface dissolution of the polymer matrix, creating rough surface topography. Biodegradation of Resilon by bacterial and salivary enzymes warrants further investigation of their activities using cultures of endodontically relevant microbes and human saliva extracts.
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PMID:Susceptibility of a polycaprolactone-based root canal filling material to degradation. II. Gravimetric evaluation of enzymatic hydrolysis. 1618 53

Inhaled corticosteroids continue to be hallmark players in asthma control. In time, they induced fear, hope, and created numerous discussions in specialty literature. Usually, the studies focus more on their beneficial effects and less on adverse effects. Surprisingly, lately more was written about systemic effects. A detailed review of some recent studies demonstrates that the most feared systemic effects (risk for osteoporosis due to calcium and phosphate metabolic changes, adrenal suppression, skin thinning, cataract, growth problems in children and teenagers, glaucoma) are very rare. The local effects, if properly addressed by the physician and patient, can be largely diminished. The conclusion of this article is that there is a non-due fear for this class of medication with certain virtues in asthma and COPD therapy.
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PMID:[Inhaled corticosteroids and the local effects--a justified fear?]. 1619 32

In this paper, the steady and dynamic rheological properties of concentrated aqueous injectable calcium phosphate cement (CPC) slurry were investigated. The results indicate that the concentrated aqueous injectable CPC showed both plastic and thixotropic behavior. As the setting process progressed, the yield stress of CPC slurry was raised, the area of the thixotropic hysteresis loop was enlarged, indicating that the strength of the net structure of the slurry had increased. The results of dynamic rheological behavior indicate that the slurry presented the structure similar to viscoelastic body and the property of shear thinning at the beginning. During the setting process, the slurry was transformed from a flocculent structure to a net structure, and the strength increased. Different factors had diverse effects on the rheological properties of the CPC slurry in the setting process, a reflection of the flowing properties (or injection), and the microstructure development of this concentrated suspension. Raising the powder-to-liquid ratio decreased the distance among the particles, increased the initial strength, and shortened the setting time. In addition, raising the temperature improved the initial strength, increased the order of reaction, and shortened the setting time, which was favorable to the setting process. The particle size of the raw material had much to do with the strength of original structure and setting time. The storage module G' of CPC slurry during the setting process followed the rule of power law function G'=A exp(Bt), which could be applied to forecast the setting time, and the calculated results thereafter are in agreement with the experimental data.
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PMID:Rheological properties of concentrated aqueous injectable calcium phosphate cement slurry. 1678 61

We use an in vitro motility assay to determine the biochemical basis for a hypermotile state of myosin-based actin sliding. It is widely assumed that the sole biochemical determinant of actin-sliding velocities, V, is actin-myosin detachment kinetics (1/tauon), yet we recently reported that, above a critical ATP concentration of approximately 100 microM, V exceeds the detachment limit by more than 2-fold. To determine the biochemical basis for this hypermotile state, we measure the effects of ATP and inorganic phosphate, Pi, on V and observe that at low [ATP] V decreases as ln [Pi], whereas above 100 microM ATP the hypermotile V is independent of Pi. The ln [Pi] dependence of V at low [ATP] is consistent with a macroscopic model of muscle shortening, similar to Hill's contractile component, which predicts that V varies linearly with an internal force (Hill's active state) that drives actin movement against the viscous drag of myosin heads strongly bound to actin (Hill's dashpot). At high [ATP], we suggest that the hypermotile V is caused by shear thinning of the resistive population of strongly bound myosin heads. Our data and analysis indicate that, in addition to contributions from tauon and myosin's step size, d, V is influenced by the biochemistry of myosin's working step as well as resistive properties of actin and myosin.
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PMID:An accelerated state of myosin-based actin motility. 1730 93

A recombinant ECTO-NOX (tNOX) and a recombinant plasma membrane associated AAA-ATPase (ATPase Associated with Different Cellular Activities) were combined in stoichiometric proportions into liposomes together with albumin as a source of protein thiols. Large lamellar vesicles were formed from phosphatidylcholine, cholesterol and dicetyl phosphate in a molar ratio of 50:45:5, where the phosphatidylcholine was a 2:1 mixture of synthetic dimyristoyl and dipalmitoyl phosphatidylcholines. The lipids were dried to a film and reconstituted into vesicles by resuspension in buffer containing the recombinant proteins in equimolar ratios of 0.04 nmoles/mg lipid. In the presence of ATP, these vesicles enlarged in an ATP-dependent manner based on light-scattering measurements. Because the drug-inhibited ECTO-NOX protein, tNOX was utilized, the enlargement was inhibited by capsaicin, a quinone site tNOX inhibitor specific for tNOX. With the lipid vesicle systems, the recombinant ECTO-NOX, the recombinant AAA-ATPase, a source of protein thiols and ATP all were required. In control experiments, no ATP-dependent vesicle enlargement was observed with the AAA-ATPase or the ECTO-NOX protein alone. Also addition of ATP was without any effect when only the single proteins were incorporated into the lipid vesicles. A model has been developed whereby the plasma membrane AAA-ATPase is linked via disulfide bonds, formed and broken by the ECTO-NOX protein, to membrane structural proteins. Binding of ATP and subsequent hydrolysis and release of ADP would advance the ATPase hexamer ratchet thereby both thinning the membrane and increasing the vesicle surface.
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PMID:ATP-dependent and drug-inhibited vesicle enlargement reconstituted using synthetic lipids and recombinant proteins. 1737 41

Identifying the mechanisms responsible for the interaction of peptides with cell membranes is critical to the design of new antimicrobial peptides and membrane transporters. We report here the results of a computational simulation of the interaction of the 13-residue peptide indolicidin with single-phase lipid bilayers of dioleoylphosphatidylcholine, distearoylphosphatidylcholine, dioleoylphosphatidylglycerol, and distearoylphosphatidylglycerol. Ensemble analysis of the membrane-bound peptide revealed that, in contrast to the extended, linear backbone structure reported for indolicidin in sodium dodecyl sulphate detergent micelles, the peptide adopts a boat-shaped conformation in both phosphatidylglycerol and phosphatidylcholine lipid bilayers, similar to that reported for dodecylphosphocholine micelles. In agreement with fluorescence and NMR experiments, simulations confirmed that the peptide localizes in the membrane interface, with the distance between phosphate headgroups of each leaflet being reduced in the presence of indolicidin. These data, along with a concomitant decrease in lipid order parameters for the upper-tail region, suggest that indolicidin binding results in membrane thinning, consistent with recent in situ atomic force microscopy studies.
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PMID:Molecular dynamics simulations of indolicidin association with model lipid bilayers. 1741 17


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