Effect of Combined Sympathetic and Vagal Stimulation on Heart Rate in the Dog

journal articleBiomedical Informatic

Spreading and Enhanced Motility of Human Keratinocytes on Fibronectin

Soluble human plasma fibronectin or collagen types I or IV, when preincubated with tissue culture plastic dishes, were effective spreading agents for cultured human keratinocytes and increased spreading in a time and concentration-dependent manner. Spreading on fibronectin, but not on type IV collagen, was inhibited by antifibroneetin; therefore, the contribution of fibronectin to the spreading activity of the natural matrix produced by keratinocytes could not be determined using antifibronectin. Fibroneetin mediated spreading at both high (1.1 mM) and low (0.1 mM) Ca++ concentrations, and spreading was not altered by cycloheximide. Insoluble fibronectin deposited by keratinocytes correlated with phagokinetic tracks on particulate gold salts, and added fibronectin, as well as type I collagen and type IV collagen, enhanced motility of keratinocytes. These studies show that production of fibronectin and responsiveness to it are similar in fibroblasts and keratinocytes and demonstrate that fibronectin can act as a matrix factor for keratinocytes

Optical Fiber Strain Sensors for Cable Nondestructive Evaluation

Optical fiber strain sensors embedded within load-bearing cables may pose an effective and inexpensive approach to extending the service life and load capacity of such cables. Currently cables must be replaced according to a conservative schedule based on mean-time-before-failure statistics in order to prevent failure of the cable. Real-time, in-service measurement of cable mechanical parameters by optical fiber sensors may prevent premature and expensive retirement of cables, and will minimize exposure of personnel to catastrophic cable failure. Also, the cable may be rated for greater load capacities, since active monitoring means that conservative rating is not necessary

Production of Soluble and Cell-Associated Fibronectin by Cultured Keratinocytes

Fibronectin has been demonstrated in epithelial cell types in culture, but published studies of keratinocytes have shown patterns of fibronectin produced by cells grown in medium with serum, which contains fibronectin. Since plasma fibronectin can bind to cells in vitro, cells grown in serum-supplemented media could show artifactual patterns of cell-associated fibronectin. To study insoluble fibronectin produced by keratinocytes, we plated cells in the absence of feeder layers in medium lacking fibronectin. Medium conditioned by metabolically labeled keratinocytes was studied by immunoprecipitation and by extraction with gelatin-Sepharose. Cells grown in fibronectin-free medium were labeled using affinity-purified anti-fibronectin antibody and fluorescein-conjugated antirabbit IgG. Keratinocytes produced soluble fibronectin, since both immunoprecipitation and adsorption to gelatin-Sepharose detected 35S-methionine-labeled material which comigrated with human plasma fibronectin on sodium dodecyl sulfate polyacrylamide gels. Demonstration of insoluble, cell-associated fibronectin was enhanced in Triton X-100-extracted cells and was seen in subcellular fibrillar arrays at both physiologic and reduced Ca++ concentrations, but in intracellular locations only at physiologic Ca++ concentrations. When cells grown in 1.1 mM Ca++ were removed with Triton X-100, diffusely distributed fibrillar fibronectin remained on the surface of the coverslip. Asymmetric "tracks" of fibronectin left by sparsely plated cells suggested movement. Fibronectin is deposited by keratinocytes on the culture surface and may be modulated by culture conditions

Lipid Thermotropic Transitions in Human Stratum Corneum

The techniques of differential scanning calorimetry (DSC) and thermal perturbation infrared (IR) spectrometry were used to investigate thermal transitions in intact, fractionated, and lipid-extracted human stratum corneum. The DSC results show 3 major and one minor thermal transition in the range of 30-120°C. Of particular interest to this study are 2 transitions seen near 65° and 75°C in intact stratum corneum and a stratum corneum membrane preparation, but absent from lipid-extracted samples. Results of IR spectrometry show that thermally induced spectral changes related to enhanced motion of the lipid acyl chains also occur in the region of about 60-80°C. The combined DSC and IR results show that the thermal transitions near 65° and 75°C depend on water concentration in a manner identical to that seen for a variety of lipid-water systems. Taken together, these results suggest that thermal transitions occurring near 65° and 85°C involve increased acyl chain motion of stratum corneum lipids

Motion of the MMS Spacecraft Relative to the Magnetic Reconnection Structure Observed on 16 Oct 2015 at 1307 UT

We analyze a magnetopause crossing by the Magnetospheric Multiscale (MMS) spacecraft at 1307 UT on 16 Oct 2016 that showed features of electron scale reconnection. For this event, we find orthonormal LMN coordinates from the magnetic field, with N and L varying respectively along the maximum gradient and maximum variance directions. We find the motion along N from the Spatio-Temporal Difference analysis and motion along L from measured particle velocities. We locate the position of the magnetic X point, finding that MMS-4 passed within about 1.4 km from the X point and that MMS-3 and MMS-2 passed within about 1.7 km and 2.4 km, respectively, from the position of maximum out of plane current

Origin of two-band chorus in the radiation belt of Earth.

Naturally occurring chorus emissions are a class of electromagnetic waves found in the space environments of the Earth and other magnetized planets. They play an essential role in accelerating high-energy electrons forming the hazardous radiation belt environment. Chorus typically occurs in two distinct frequency bands separated by a gap. The origin of this two-band structure remains a 50-year old question. Here we report, using NASA's Van Allen Probe measurements, that banded chorus waves are commonly accompanied by two separate anisotropic electron components. Using numerical simulations, we show that the initially excited single-band chorus waves alter the electron distribution immediately via Landau resonance, and suppress the electron anisotropy at medium energies. This naturally divides the electron anisotropy into a low and a high energy components which excite the upper-band and lower-band chorus waves, respectively. This mechanism may also apply to the generation of chorus waves in other magnetized planetary magnetospheres

Transdermal flux predictions for selected selective oestrogen receptor modulators (SERMs):Comparison with experimental results

The aim of this work was to evaluate the feasibility of delivering transdermally a series of highly lipophilic compounds (log P similar to 4-7), comprising several selective oestrogen receptor modulators and a modified testosterone (danazol). The maximum fluxes of the drugs were predicted theoretically using the modified Potts & Guy algorithm (to determine the permeability coefficient (k(p)) from water) and the calculated aqueous solubilities. The correction provided by Cleek & Bunge took into account the contribution of the viable epidermal barrier to the skin permeation of highly lipophilic compounds. Experimental measurements of drug fluxes from saturated hydroalcoholic solutions were determined in vitro through excised pig skin. Overall, the predicted fluxes were in good general agreement (within a factor of 10) with the experimental results. Most of the experimental fluxes were greater than those predicted theoretically suggesting that the 70:30 v/v ethanol-water vehicle employed may have had a modest skin penetration enhancement effect. This investigation shows that the transdermal fluxes of highly lipophilic compounds can be reasonably predicted from first principles provided that the viable epidermis, underlying the stratum corneum, is included as a potentially important contributor to the skin's overall barrier function. Furthermore, the absolute values of the measured fluxes, when considered in parallel with previous clinical studies, indicate that it might be feasible to topically deliver a therapeutically useful amount of some of the compounds considered to treat cancerous breast tissue. (C) 2013 Elsevier B.V. All rights reserved

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.