Effects of compressive residual stress on the morphologic changes of fibroblasts

Recently, the term tensotaxis was proposed to describe the phenomenon that tensile stress or strain affects cell migration. Even so, less attention has been paid to the effects of compressive stress on cell behavior. In this study, by using an injection-molded method combined with photoelastic technology, we developed residual stress gradient-controlled poly-L-lactide discs. After culturing NIH-3T3 fibroblasts on the stress gradient substrate, the cell distributions for high- and low-stress regions were measured and compared. Our results showed that there were significantly more cells in the low-compressive stress region relative to their high-stress analogs (p < 0.05). In addition, NIH-3T3 fibroblasts in the low-compressive stress region expressed more abundant extensive filopodia. These findings provide greater insight into the interaction between cells and substrates, and could serve as a useful reference for connective tissue development and repair.

Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process

Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141)  keV, respectively. The deduced proton separation energy of -90(85)  keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point.

In vivo graft performance of an improved bone substitute composed of poor crystalline hydroxyapatite based biphasic calcium phosphate

The ability to promote new bone formation of poor crystalline hydroxyapatite (PC-HA) based biphasic calcium phosphate (BCP) bone substitutes were investigated. Various ratios of porous PC-HA/β-TCP (70/30, 60/40, and 0/100) grafts were fabricated. SEM and XRD measurements were performed to study the morphology and crystalline structure. Cylindrical artificial bone defects (3 × 6 mm(2)) were produced in alveolar bone at premolars extraction site and then filled with sterilized bone grafts. Commercial MBCP and unfilled empty defect served as control groups. At 8 weeks postoperation, samples were harvested from each artificial defect site for histological analysis. New bone formation of all the PC-HA/β-TCP groups was significantly greater than that of the empty control group (p<0.05), but without statistical difference from that of MBCP group. The degree of uniformity of new bone formation within defect region for PC-HA/β-TCP (60/40) was higher than that for MBCP. The PC-HA/β-TCP grafts showed enhanced bone regenerations with a more even dispersion of new bone formation than the other materials without causing inflammation, suggesting that these materials may be an alternative choice for bone void fillers in dental applications.

Assessment of soil contamination with Cd, Pb and Zn and source identification in the area around the Huludao Zinc Plant

The distribution characteristics of heavy metals (cadmium (Cd), lead (Pb) and zinc (Zn)) in the natural soil profiles around the Huludao Zinc Plant (HZP), an old industrial base in Northeast China, were analyzed. The pollutant source was identified using (210)Pb isotope technique to evaluate the geochemical characteristics of Pb and the historical production records of HZP. The results indicated: dust precipitation from HZP was the primary source of the pollutants. The average deposition rates of Cd, Pb and Zn were 0.33, 1.75, and 30.97 g/m(2)year, respectively at 1 km away after HZP, and 0.0048, 0.035, and 0.20 g/m(2) year, respectively at 10 km away after HZP. There is a risk of secondary pollution to the environment as well as the food chain in seriously polluted areas used for cultivation.

The role of the calmodulin-dependent pathway in static magnetic field-induced mechanotransduction

While the effects of static magnetic fields (SMFs) on osteoblastic differentiation are well demonstrated, the mechanotransduction pathways of SMFs are still unclear. The aim of this study was to explore the role of calmodulin in the biophysical effects of SMFs on osteoblastic cells. MG63 cells were exposed to a 0.4 T SMF. The expression of phosphodiesterase RNA in the cytoplasm was tested using real-time polymerase chain reaction. The differentiation of the cells was assessed by detecting changes in alkaline phosphatase activity. The role of calmodulin antagonist W-7 was used to evaluate alterations in osteoblastic proliferation and differentiation after the SMF simulations. Our results showed that SMF exposure increased alkaline phosphatase activity and phosphodiesterase 1C gene expression in MG63 cells. Addition of W-7 significantly inhibited the SMF-induced cellular response. We suggest that one possible mechanism by which SMFs affects osteoblastic maturation is through a calmodulin-dependent mechanotransduction pathway.

A single nucleotide polymorphism and sequence analysis of CSN1S1 gene promoter region in Chinese Bos grunniens (yak)

The aim of this study was to investigate the polymorphism of the CSN1S1 gene promoter region in 4 Chinese yak breeds, and compare the yak CSN1S1 gene promoter region sequences with other ruminants. A Polymerase Chain Reaction-Single Strand Conformation Polymorphism protocol was developed for rapid genotyping of the yak CSN1S1 gene. One hundred fifty-eight animals from 4 Chinese yak breeds were genotyped at the CSN1S1 locus using the protocol developed. A single nucleotide polymorphism of the CSN1S1 gene promoter region has been identified in all yak breeds investigated. The polymorphism consists of a single nucleotide substitution G-->A at position 386 of the CSN1S1 gene promoter region, resulting in two alleles named, respectively, G(386) and A(386), based on the nucleotide at position 386. The allele G(386) was found to be more common in the animals investigated. The corresponding nucleotide sequences in GenBank of yak (having the same nucleotides as allele G(386) in this study), bovine, water buffalo, sheep, and goat had similarity of 99.68%, 99.35%, 97.42%, 95.14%, and 94.19%, respectively, with the yak allele A(386.).

Spray-dried microparticles containing polymeric micelles encapsulating hematoporphyrin

The purpose of this study was to examine the properties of a new pulmonary delivery platform of microparticles containing micelles in which a therapeutic photosensitizing drug, hematoporphyrin (Hp), was encapsulated. Different poloxamers were used to form micellar Hp, and one of these, Pluronic L122-Hp, was subsequently incorporated into lactose microparticles by spray-drying. Spectral and morphological analyses were performed on both micellar Hp, and lactose microparticles containing micellar Hp (lactose-micellar Hp) before and after dissolution of the microparticles in water. Photodynamic activity of the various Hp samples were evaluated in human lung epithelial carcinoma A549 cells using a light-emitting diode (LED) device at a wavelength of 630 +/- 5 nm. No significant difference was observed between micellar Hp and lactose-micellar Hp regarding the generation of singlet oxygen. The mean particle size of the microparticles was 2.3 +/- 0.7 microm which is within the size range for potential lung delivery. The cellular uptake of micellar Hp and lactose-micellar Hp measured on A549 cells was at least twofold higher than those obtained with the Hp at equivalent concentrations. Micellar Hp exhibited higher cytotoxicity than Hp due to reduced formation of Hp aggregates and increased cellar uptake. The spectral properties as well as the photodynamic activity of the micellar Hp was retained when formulated into microparticles by spray-drying. Microparticles containing micelles have the potential for delivering micelle-encapsulated hydrophobic drugs in targeted therapy of pulmonary diseases.

The influence of liposomal adjuvant on intranasal vaccination of chickens against Newcastle disease

The adjuvant effect of liposomes formulated with three phospholipids including phosphatidylcholine-liposomes (PC-Lip), phosphatidylserine-liposomes (PS-Lip), and stearylamine-liposomes (SA-Lip) was compared with virus alone using inactivated Newcastle disease virus (NDV) as a model antigen. The difference in adjuvanticity was evaluated using the haemagglutination-inhibition (HI) test, enzyme-linked immunosorbent assay, and a challenge study following intranasal inoculation of specific pathogen-free chickens. After two inoculations, a liposomal vaccine consisting of NDV in PC-Lip resulted in a significant increase in HI titre, up to 32-fold higher than a vaccine containing virus alone and 320-fold higher than a vaccine containing NDV in SA-Lip. PC-Lip also elicited a significant mucosal secretary immunoglobulin A response (P<0.05) in tracheal lavages and a serum IgG response (P<0.05). In response to viral challenge, all control animals died, whereas 90% of animals which received PC-Lip survived. The results suggest that PC-Lip may be suitable as an adjuvant for mucosal vaccination against NDV in chickens.

Rapid detection of bovine milk in yak milk using a polymerase chain reaction technique

Yak milk contains a greater percentage of protein and has better quality than bovine milk. There has been an increasing focus on yak milk and milk products during the last few years. In the present study, a PCR-based assay was developed for the specific identification of bovine milk in yak milk by designing 3 primers targeting the mitochondrial ND1 gene. The use of 3 primers in a single PCR reaction set yielded 2 amplification fragments of 293 and 190 bp from bovine milk DNA, whereas only 1 amplification fragment of 293 bp was obtained in yak milk DNA. The technique was applied to raw and heat-treated binary mixtures of yak and bovine milks and enabled the specific detection of bovine milk with a detection limit of 0.1%. The assay developed is sensitive, fast, and straightforward, and it might be useful in the quality control of yak milk and milk products.

N-ethoxybenzylimidazoles: a novel acid-sensitive linker for controlled release of therapeutics from drug delivery systems

Abstract #2156

Background:&#x2028; Drug delivery systems (DDS) are useful for cancer therapies because they can target tumors and cancer cells more specifically than cancer therapeutics alone. An important component of a DDS is the triggering mechanism for drug release. This presentation will highlight a new class of N-linked imidazoles as potential acid-sensitive cleavable linkers for use in cancer DDSs. These acid-sensitive linkers are designed to exploit the lower extracellular pH of some tumors and the endosomes and lysosomes within cells to trigger the controlled release of therapeutic agents from drug delivery vessels. Cleavage of N-ethoxybenzylimidazoles (NEBIs) exhibit a 10-fold increase in the rate of hydrolysis in mild aqueous acidic solutions (at pH = 5.5) compared to solutions at normal, physiological pH. The rate of hydrolysis can be tuned to range from minutes to months through the addition of electron donating or withdrawing groups.&#x2028; The NEBI linker can be used to conjugate a cytotoxic agent to a carrier. Carriers for this DDS include molecules such as tumor specific antibodies, polymers/nanoparticles, peptides, and ligands, that can target cancer cells or accumulate around tumors. Cytotoxic agents include FDA approved small molecules and chemotherapeutics.&#x2028; Methods and Materials:&#x2028; The NEBI was developed into a bifunctional crosslinker containing a carboxylic acid and an azide for conjugation of cancer therapeutics to carriers. For simplicity, we used Human Serum Albumin (HSA) as our model carrier and doxorubicin as our model cytotoxic agent. The NEBI was conjugated to doxorubicin through a simple amide coupling. The NEBI was then conjugated to an alkyne containing HSA via “Click Chemistry.”&#x2028; Results:&#x2028; We were able to load approximately 1-2 doxorubicin molecules per HSA. Imaging studies have shown that our HSA conjugates to doxorubicin via a NEBI linker (HSA-NEBI-dox) localize in lysosomes. Cytotoxicity studies show HSA-NEBI-dox is cytotoxic while HSA conjugates to doxorubicin via a stable linkage is not.&#x2028; Discussion:&#x2028; We were able to develop methods for conjugating doxorubicin to HSA. The techniques used here can be applied to conjugate other carriers and other cancer therapeutics. We will continue to develop the NEBI linker and demonstrate how the linker can be used to conjugate trastuzumab to doxorubicin. We chose use trastuzumab, a monoclonal antibody, as a carrier because it is known to bind to the HER2 receptor. HER2 is over expressed in 25%-30% of breast cancers. Trastuzumab not only targets cancer cells that are over expressing the HER2 receptor, but binding of trastuzumab to the HER2 receptor can trigger receptor mediated endocytosis, which can lead to controlled release of doxorubicin within the cell.&#x2028; &#x2028;

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2156.

Effect of vinyl-modified silica and raw silica particles on the properties of as-prepared polymer-silica nanocomposite foams

In this study, the first comparative studies for the effect of vinyl-modified silica (VMS) and raw silica (RS) particles on the physical properties of as-prepared polymer-silica nanocomposite (PSN) foams are presented. First of all, the VMS particles were synthesized by performing conventional acid-catalyzed sol-gel reactions of TEOS in the presence/absence of MSMA molecules. The as-prepared VMS particles were then characterized through Fourier Transform Infrared (FTIR), solid-state 13C-nuclear magnetic resonance (13C-NMR) and 29Si-NMR spectroscopy. Subsequently, a series of PSN materials have been prepared through bulk polymerization of MMA monomers in the presence of VMS and RS particles with BPO as initiator. The dispersion capability of silica particles in polymer matrix was further observed by transmission electron microscopy (TEM) studies. The PSN foams can be further obtained by performing batch-foaming process on as-prepared bulky PSN materials with N2 as foaming agent. The cell structure analysis of the PSN foams was subsequently examined by the scanning electron microscopy (SEM) images. Gel permeation chromatography (GPC) was used to determine the molecular weights of as-prepared samples. It should be noted that the incorporated VMS and RS particles served as heterogeneous nucleation agent in polymer matrix under foaming process to reduce the cell size and increase the cell density of the PSN foams. Furthermore, the VMS particles exhibited a better dispersion capability of silica particles in PMMA matrix as compared to that of RS particles, leading to the PSN foams with smaller cell size and higher cell density. Effect of material composition on the thermal transport properties, thermal stability and mechanical strength of PSN foams were investigated by transient plane source (TPS) technique, thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA), respectively.

Src family kinase oncogenic potential and pathways in prostate cancer as revealed by AZD0530

Prostate cancer is the most frequently diagnosed cancer in American men. We have previously demonstrated that Src mediates androgen-independent proliferation in prostate cancer. We sought to investigate the Src-mediated oncogenic pathways and tumor biology using AZD0530, a novel Src family kinase/Abl dual-kinase inhibitor that is entering phase II clinical trials. We show that while both Src and Abl are expressed in all prostate cancer cell lines, Src but not Abl is activated in the prostate. Furthermore, Src activation is inhibited by AZD0530 in a rapid and dose-dependent manner. We show that Src mediates cell proliferation in DU145 and PC3 cells at the G1 phase of cell cycle. Src inhibition resulted in decreased binding of beta-catenin to the promoters of G1 phase cell cycle regulators cyclin D1 and c-Myc. C-Myc may also be regulated at the protein level by extracellular signal-regulated kinase 1/2 and GSK3beta. Cell motility factors focal adhesion kinase, p130CAS and paxillin activation in DU145 and PC3 cells were also inhibited. Administration of AZD0530 in mice reduced orthotopic DU145 xenograft growth by 45%. We have further delineated the Src-mediated oncogenic growth and migration pathways in prostate cancer and established mechanistic rationale for Src inhibition as novel therapy in the treatment of prostate cancer.

Effect of amino-modified silica nanoparticles on the corrosion protection properties of epoxy resin-silica hybrid materials

In this paper, a series of organic-inorganic hybrid materials consisting of epoxy resin frameworks and dispersed nanoparticles of amino-modified silica (AMS) were successfully prepared. First of all, the AMS nanoparticles were synthesized by carrying out the conventional acid-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) in the presence of (3-aminopropyl)-trimethoxysilane (APTES) molecules. The as-prepared AMS nanoparticles were then characterized by FTIR, 13C-NMR and 29Si-NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in-situ thermal ring-opening polymerization reactions of epoxy resin in the presence of as-prepared AMS nanoparticles and raw silica (RS) particles. The as-prepared epoxy-silica hybrid materials with AMS nanoparticles were found to show better dispersion capability than that of RS particles existed in hybrid materials based on the morphological observation of transmission electron microscopy (TEM). The hybrid materials containing AMS nanoparticles in the form of coating on cold-rolled steel (CRS) were found to be much superior in corrosion protection over those of hybrid materials with RS particles when tested by a series of electrochemical measurements of potentiodynamic and impedance spectroscopy in 5 wt% aqueous NaCI electrolyte. The increase of corrosion protection effect of hybrid coatings may have probably resulted from the enhancement of the adhesion strength of the hybrid coatings on CRS coupons, which may be attributed to the formation of Fe-O-Si covalent bond at the interface of coating/CRS system based on the FTIR-RAS (reflection absorption spectroscopy) studies. The better dispersion capability of AMS nanoparticles in hybrid materials were found to lead more effectively enhanced molecular barrier property, mechanical strength, surface hydrophobicity and optical clarity as compared to that of RS particles, in the form of coating and membrane, based on the measurements of molecular permeability analysis, dynamic mechanical analysis, contact angle measurements and ultraviolet-visible transmission spectra, respectively.

Effects of external phosphorus on the cell ultrastructure and the chlorophyll content of maize under cadmium and zinc stress

Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis, it was found that the ultrastructure of chloroplasts were changed, the shape of the chloroplasts altered and the numbers of grana that were asymmetrical increased; the numbers of grana and thylakoids decreased under the stress of Cd and Zn. The results indicated that the complex pollution involving Cd and Zn resulted in the membrane system of chloroplasts being damaged. When external phosphorus was applied, the numbers of damaged chloroplasts were significantly reduced and the nucleoli were better formed than those that did not receive phosphorus treatment. Moreover, many phosphate deposits were found in the vacuoles and on the surface of the roots, which were formed by phosphorus complexing with Cd (K(sp)=2.53x10(-33)) and Zn (K(sp)=9.00x10(-33)), respectively. Treatment with phosphorus conduced an increased chlorophyll content in plants compared with those that did not receive external phosphorus.