Effects of brief glucocorticoid exposure on growth of vascular smooth muscle cells in culture

While prolonged exposure of vascular smooth muscle cells (VSMC) to glucocorticoid has been shown to inhibit cell proliferation, the effect of a brief pulse exposure is not known. We studied the short-term effects of pulse exposure to dexamethasone (DEX) on DNA synthesis in cultured VSMC. VSMC were pulsed with DEx for varying time intervals and [3H]thymidine incorporation into cells after 24 h was measured. Exposure to DEX for 24 h decreased [3H]thymidine incorporation, while pulse treatments with DEX from 2 min to 6 h significantly increased [3H]thymidine incorporation. Maximal proliferative effect was observed with a 20-min exposure. The effect of a 20-min pulse was dose-dependent, with the half-maximal dose of DEX being approximately 10(-7) M. A selective glucocorticoid receptor antagonist, RU486, inhibited the proliferative effect of DEx. Concentrated conditioned medium from cells exposed to 10(-6) M DEX increased [3H]thymidine incorporation by other VSMC in a dose-dependent manner. These results suggest that short-term pulse DEX exposure is capable of producing one or more autocrine growth factors in VSMC via a glucocorticoid receptor action. This effect of glucocorticoid pulses may contribute to the pathogenesis of arteriosclerosis and hypertension.     

Synthesis of polysilane-acrylamide copolymers by photopolymerization and their application to polysilane-silica hybrid thin films

Various polysilane-acrylamide block copolymers have been prepared from photopolymerization of acrylamide-type monomers using poly(methylphenylsilane) (PMPS) as a macro-photo-radical initiator. The acrylamide block in the copolymers improved the hydrophilic property of PMPS. These PMPS-acrylamide block copolymers have been applied to formation of PMPS-silica hybrid thin films via sol-gel reaction. Homogeneous and transparent PMPS-silica hybrid thin films were obtained from a few PMPS-acrylamide block copolymers. It was found for these hybrid thin films based on hydrogen bonding formation between amide group and silanol group. The surface properties of hybrid thin films were evaluated by water contact angle measurement, scanning electron microscope (SEM), and atomic force microscope (AFM) images.     

Dynamic observation of dislocation-free plastic deformation in gold thin foils

Ductile fracture of metals produces a thin foil portion, which is observable by transmission electron microscopy, at the fractured edge. The thin foil portion shows unusual deformation microstructure, which contains no dislocations, but contains vacancy-type point defect clusters at extraordinarily high density. Dynamic observation of the deformation process revealed that these defect clusters are produced in the portion of local heavy deformation; however, no dislocation motion was observed during the course of the heavy plastic deformation, constituting direct evidence that the unusual deformation microstructure is produced by plastic deformation without dislocations. Also, the deformation was found to involve 14% elastic deformation, indicating that the dislocation-free plastic deformation occurs under an extraordinarily high internal stress level of more than 10 GPa, which is comparable to the ideal strength of metals. Furthermore, during the dislocation-free plastic deformation, equal-thickness fringes were found to disappear temporarily, suggesting that instability of crystalline state under extraordinarily high internal stress level is a key factor for the mechanism of dislocation-free plastic deformation.     

Effects of structural anisotropy of cancellous bone on speed of ultrasonic fast waves in the bovine femur

Ultrasonic waves in cancellous bone change dramatically depending on its structural complexity. One good example is the separation of an ultrasonic longitudinal wave into fast and slow waves during propagation. In this study, we examined fast wave propagation in cancellous bone obtained from the head of the bovine femur, taking the bone structure into consideration. We investigated the wave propagation perpendicular to the bone axis and found the two-wave phenomenon. By rotating the cylindrical cancellous bone specimen, changes in the fast wave speed due to the rotation angle then were observed. In addition to the ultrasonic evaluation, the structural anisotropy of each specimen was measured by X-ray micro-computed tomography (CT). From the CT images, we obtained the mean intercept length (MIL), degree of anisotropy (DA), and angle of insonification relative to the trabecular orientation. The ultrasonic and CT results showed that the fast wave speed was dependent on the structural anisotropy, especially on the trabecular orientation and length. The fast wave speeds always were higher for propagation parallel to the trabecular orientation. In addition, there was a strong correlation between the DA and the ratio between maximum and minimum speeds (V(max)/V(min)) (R(2) = 0.63).     

Novel reworkable resins: thermo‐ and photo‐curable di(meth)acrylates

The aim of the study reported in this paper was to develop new di(meth)acrylates having aromatic units and thermally degradable units in their molecules. It was also the aim to clarify the photo‐curing and degradation properties of the new monomers. Di(meth)acrylates having aromatic units and thermally degradable units were synthesized. As thermally cleavable linkages, tertiary ester moieties were incorporated into the di(meth)acrylates. Three types of processes for curing and degradation of the cured resins were studied: thermal curing and thermal degradation; thermal curing and photodegradation; and photo‐curing and thermal degradation. In the thermal curing and photodegradation process, di(meth)acrylate films containing a thermally induced radical initiator and a photoacid generator (PAG) became insoluble in solvents on heating. The cured films became soluble in solvents after ultraviolet irradiation followed by baking. The re‐dissolution behaviors were strongly affected by the structures of the PAGs. A mechanism for the photo‐ or thermo‐curing and photoassisted thermal degradation was studied using Fourier transform infrared, ¹H NMR, thermogravimetric, mass spectrometric and size exclusion chromatographic analyses. Copyright © 2009 Society of Chemical Industry     

Diffusion of probe polymer in gellan gum solutions during gelation process studied by gradient NMR

The diffusion coefficients of pullulan added in gellan gum solutions as a probe polymer were measured using pulsed-field-gradient stimulated-spin-echo (PFG-Ste) ¹H NMR in order to investigate the gelation mechanism and gel structure. The echo intensity of gellan was steeply decreased at around the gelling temperature T_gel indicating stiffening of the gellan chains upon aggregation and formation of the network. The diffusion coefficient of pullulan D_pull increased with decreasing temperature below T_gel. This result suggests that the decrease in concentration of solute gellan in the interspaces of the network below T_gel, as evidenced by the decrease in its echo intensity, leads to an overall decrease of hydrodynamic interactions between gellan and pullulan. The characteristic hydrodynamic shielding length ξ was calculated from the relation D_pull/D_pull,0 = exp(−R_h/ξ), where D_pull,0 is D_pull in dilute solution and R_h is the hydrodynamic radius of pullulan. The temperature dependence of ξ, which was investigated for varying concentrations of several cations, was found to follow closely the gelling temperature, and in particular, showing a very similar thermal hysteresis.     

Chronic pulmonary thromboendarterectomy complicated by antithrombin III deficiency and antiphospholipid syndrome

Pulmonary thromboendarterectomy was performed on two patients with chronic pulmonary thromboembolism showing thrombotic tendency. Patient 1 was a 25-year-old male with the disease complicated by congenital antithrombin III deficiency. Patient 2 was a 21-year-old male with the disease complicated by antiphospholipid syndrome. Both patients were admitted to the center upon showing dyspnea. Lung perfusion scintigraphy revealed multiple defects in the right and left lungs. Pulmonary arteriography showed occlusion and stenosis from lobar to segmental arteries. Cardiac catheterization showed marked pulmonary hypertension. Pulmonary angioscopy confirmed the presence of organized thrombi while an intravascular ultrasound revealed a thickening of the pulmonary arterial walls in both lungs. After the insertion of an inferior vena cava filter in each patient, surgery was performed. Following a median sternotomy, a cardiopulmonary bypass was utilized to induce deep hypothermia at a pharyngeal temperature of 16 degrees C, after which a thromboendarterectomy of the bilateral pulmonary arteries was performed under intermittent circulatory arrest. A large amount of organized thrombi was extracted from these arteries. After surgery, both patients showed good postoperative outcome with improved blood flow in both lungs, reduced pulmonary arterial pressure and increased cardiac output.     

In vitro and in vivo calcification of vascular bioprostheses

Efficacy of different chemical treatments on calcification of vascular graft in vitro and in vivo was studied. Culture medium-filled rat aortas were separately treated in 0.2% glutaraldehyde and epoxy compound, and photooxidized in 0.01% methylene blue for a shorter period (group 1). Another group of rat aortas were separately treated in the same chemicals for a longer period (group 2). All fresh and treated aortas of both groups were cultured for 21 days in an organ culture medium and implanted (except for group 1) in weanling rats for five months. Histology and immunohistochemistry revealed that differently treated aortas of group 1 grow and calcify, and the smooth muscle cells between elastin fibers are the primary site of calcium deposition. In contrast, differently treated aortas of group 2 neither grew, nor did calcify in the medium except the epoxy compound cross-linked aorta of group 2 which did not grow but did calcify. Untreated aorta did not calcify. All fresh and differently treated aortic homografts calcified severely in rats. Our whole arterial segment-calcification system would be useful for analyzing the molecular and cellular mechanisms of both bioprosthetic and atherosclerotic calcification of vascular graft. New anticalcification technique is the only hope for better outcome of future vascular bioprostheses.     

The efficacy of postural drainage in a case of pulmonary edema following cholecystectomy

An 81-year-old man underwent percutaneous transluminal gallbladder drainage. As the drain was accidentally removed six days later, he received cholecystectomy. After the operation, he developed hypotension, hypoxemia and ST level depression on ECG. He received artificial ventilation and cathecholamines. His chest CT showed marked pulmonary edema, and total protein of the edema-fluid was 3.3 g.dl-1. These findings suggested permeability pulmonary edema. He received postural drainage of the edema-fluid, and the pulmonary oxygenation was gradually improved. He was weaned from artificial ventilation on the 6th ICU day and discharged the next day.     

In‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to miniemulsion polymerization

We present in‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to prepare hybrid latex particles by miniemulsion polymerization. On the surface of a silver nanoparticle/silica nanoparticle/acrylic polymer hybrid layer formed in‐situ on a polyethylene terephthalate (PET) substrate, a copper film is deposited using electroless copper deposition. Silver nanoparticles, which are formed in‐situ via the reduction of silver ion by radical species and subsequent annealing, work as a catalyst for the electroless deposition. Miniemulsion polymerization via the in‐situ formation of nanoparticles affords nanoparticle/acrylic polymer hybrid latex particles and polymer particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42675.