Transformation-mediated ductility in CuZr-based bulk metallic glasses

Bulk metallic glasses (BMGs) generally fail in a brittle manner under uniaxial, quasistatic loading at room temperature. The lack of plastic strain is a consequence of shear softening, a phenomenon that originates from shear-induced dilation that causes plastic strain to be highly localized in shear bands. So far, significant tensile ductility has been reported only for microscopic samples of around 100 nm (ref. 4) as well as for high strain rates, and so far no mechanisms are known, which could lead to work hardening and ductility in quasistatic tension in macroscopic BMG samples. In the present work we developed CuZr-based BMGs, which polymorphically precipitate nanocrystals during tensile deformation and subsequently these nanocrystals undergo twinning. The formation of such structural heterogeneities hampers shear band generation and results in macroscopically detectable plastic strain and work hardening. The precipitation of nanocrystals and their subsequent twinning can be understood in terms of a deformation-induced softening of the instantaneous shear modulus. This unique deformation mechanism is believed to be not just limited to CuZr-based BMGs but also to promote ductility in other BMGs.

Prenatal alcohol exposure triggers ceramide-induced apoptosis in neural crest-derived tissues concurrent with defective cranial development

Fetal alcohol syndrome (FAS) is caused by maternal alcohol consumption during pregnancy. The reason why specific embryonic tissues are sensitive toward ethanol is not understood. We found that in neural crest-derived cell (NCC) cultures from the first branchial arch of E10 mouse embryos, incubation with ethanol increases the number of apoptotic cells by fivefold. Apoptotic cells stain intensely for ceramide, suggesting that ceramide-induced apoptosis mediates ethanol damage to NCCs. Apoptosis is reduced by incubation with CDP-choline (citicoline), a precursor for the conversion of ceramide to sphingomyelin. Consistent with NCC cultures, ethanol intubation of pregnant mice results in ceramide elevation and increased apoptosis of NCCs in vivo. Ethanol also increases the protein level of prostate apoptosis response 4 (PAR-4), a sensitizer to ceramide-induced apoptosis. Prenatal ethanol exposure is concurrent with malformation of parietal bones in 20% of embryos at day E18. Meninges, a tissue complex derived from NCCs, is disrupted and generates reduced levels of TGF-β1, a growth factor critical for bone and brain development. Ethanol-induced apoptosis of NCCs leading to defects in the meninges may explain the simultaneous presence of cranial bone malformation and cognitive retardation in FAS. In addition, our data suggest that treatment with CDP-choline may alleviate the tissue damage caused by alcohol.

Persistent expression of biologically active anti-HER2 antibody by AAVrh.10-mediated gene transfer

Trastuzumab (Herceptin) is a recombinant humanized monoclonal antibody directed against an extracellular region of the HER2 protein. We hypothesized that a single adeno-associated virus mediated genetic delivery of an anti-HER2 antibody should be effective in mediating long term production of anti-HER2 and in suppressing the growth of human tumors in a xenograft model in nude mice. The adeno-associated virus gene transfer vector AAVrh.10αHER2 was constructed based on non-human primate AAV serotype rh.10 to express the cDNAs for the heavy and light chains of monoclonal antibody 4D5, the murine precursor to trastuzumab. The data demonstrates that genetically transferred anti-HER2 selectively bound human HER2 protein and suppressed proliferation of HER2 positive tumor cell lines. A single administration of AAVrh.10αHER2 provided long term therapeutic levels of anti-HER2 antibody expression without inducing anti-idiotype response, suppressed the growth of HER2 positive tumors and increased survival of the tumor-bearing mice. In the context that trastuzumab therapy requires frequent, repeated administration, this strategy might be developed as an alternate platform for delivery anti-HER2 therapy.

Oncogenic E17K mutation in the pleckstrin homology domain of AKT1 promotes v-Abl-mediated pre-B-cell transformation and survival of Pim-deficient cells

Abl-mediated transformation requires the activation of multiple pathways involved in the cellular proliferation and survival, including PI3K/AKT and JAK/STAT-dependent Pim kinases. Recently, the E17K mutation in the AKT1 has been associated with multiple human malignancies and leukemia in mice. However, this mutation has not been identified in Abl-transformed cells. We investigated the presence of the AKT1(E17K) mutation in v-Abl-transformed cell clones. AKT1(E17K) was detected in 3 (2.6%) of 116 specimens examined. To show the involvement of AKT1(E17K) directly in v-Abl-mediated tumorigenesis, we infected bone marrow cells from mice with bicistronic retroviruses encoding v-Abl and either wild-type or the mutant AKT1. Interestingly, we found that E17K mutant greatly increased the v-Abl transformation efficiency as compared with wild-type AKT1. Ectopic expression of E17K mutant increased the expression levels of antiapoptotic protein BCL2 and phosphorylation levels of proapoptotic protein BAD. This correlated with an increased protection from imatinib-induced apoptosis in Abl transformants. Furthermore, AKT1(E17K) promotes survival of the Pim-deficient cells, indicating a functional link between AKT and Pim in v-Abl transformation. In addition, AKT1(E17K) delays loss of Pim-1 and Pim-2 protein levels on v-Abl inactivation, which suggests that there exists reciprocal signaling between AKT and Pim in v-Abl transformants.

Plasma oxidized polyhydroxymethylsiloxane--a new smooth surface for supported lipid bilayer formation

A novel substrate for preparation of supported lipid bilayers (SLBs), smooth at the subnanometer scale and of variable thickness from ten to several hundred nanometers, was developed by surface oxidation of spin-coated poly(hydroxymethylsiloxane) (PHMS) films. The deposited polymeric thin films were modified by a combination of oxygen plasma and thermal treatment (PHMS(ox)), in order to convert the outermost surface layer of the polymer film to a stable SiO(2) film, suitable for SLB formation. The hydrophilic, SiO(2)-like surfaces were characterized by XPS, wetting angle, ellipsometry, and AFM. Lipid bilayers were formed on this surface using the well-known vesicle adsorption-rupture-fusion process, usually performed on glass or vapor-deposited SiO(2). Reproducible formation of homogeneous SLBs of different compositions (POPC, DOEPC, and POPC/DOPS) was demonstrated on the new SiO(2) surface by quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), and optical reflectometry measurements. The SLB formation kinetics on the PHMS(ox)-coated sensors showed very similar characteristics, for all investigated PHMS thicknesses, as on reference sensors coated with vapor-deposited SiO(2). The good adhesive properties of the PHMS to gold allows for the preparation of thin PHMS(ox) layers compatible with SPR. The much smaller roughness at the nanometer scale of the PHMS(ox) surfaces, compared to standard vapor-deposited SiO(2)-coated sensors, makes them advantageous for AFM and optical experiments and promising for patterning. To benefit optical experiments with the PHMS(ox) surfaces, it was also investigated how the PHMS film thickness influences the SPR and reflectometry responses upon SLB formation.

Venlafaxine monotherapy in bipolar type II depressed patients unresponsive to prior lithium monotherapy

OBJECTIVE

We examine the safety and efficacy of venlafaxine monotherapy in bipolar type II (BP II) patients with major depressive episode (MDE) who were unresponsive to prior lithium monotherapy. We hypothesized that venlafaxine would be superior to lithium with a low hypomanic conversion rate.

METHOD

Seventeen patients who were unresponsive to prior lithium monotherapy were crossed to venlafaxine monotherapy for 12 weeks. The primary outcome was within-subject change in total Hamilton Depression Rating (HAM-D) score over time. Secondary outcomes included the change in Young Mania Rating (YMRS) and clinical global impressions severity (CGI/S) and change (CGI/C) scores.

RESULTS

Venlafaxine produced significantly greater reductions in HAM-D (P < 0.0005), CGI/S (P < 0.0005), and CGI/C (P < 0.0005) scores vs. prior lithium. There was no difference in mean YMRS scores between treatment conditions (P = 0.179).

CONCLUSION

Venlafaxine monotherapy may be a safe and effective monotherapy of BP II MDE with a low hypomanic conversion rate in lithium non-responders.

Microstructure, bioactivity and osteoblast behavior of monoclinic zirconia coating with nanostructured surface

A monoclinic zirconia coating with a nanostructural surface was prepared on the Ti-6Al-4V substrate by an atmospheric plasma-spraying technique, and its microstructure and composition, as well as mechanical and biological properties, were investigated to explore potential application as a bioactive coating on bone implants. X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Raman spectroscopy revealed that the zirconia coating was composed of monoclinic zirconia which was stable at low temperature, and its surface consists of nano-size grains 30-50 nm in size. The bond strength between the coating and the Ti-6Al-4V substrate was 48.4 + or - 6.1 MPa, which is higher than that of plasma-sprayed HA coatings. Hydrothermal experiments indicated that the coating was stable in a water environment and the phase composition and Vickers hardness were independent of the hydrothermal treatment time. Bone-like apatite is observed to precipitate on the surface of the coating after soaking in simulated body fluid for 6 days, indicating excellent bioactivity in vitro. The nanostructured surface composed of monoclinic zirconia is believed to be crucial to its bioactivity. Morphological observation and the cell proliferation test demonstrated that osteoblast-like MG63 cells could attach to, adhere to and proliferate well on the surface of the monoclinic zirconia coating, suggesting possible applications in hard tissue replacements.

The use of silk fibroin/hydroxyapatite composite co-cultured with rabbit bone-marrow stromal cells in the healing of a segmental bone defect

In a rabbit model we investigated the efficacy of a silk fibroin/hydroxyapatite (SF/HA) composite on the repair of a segmental bone defect. Four types of porous SF/HA composites (SF/HA-1, SF/HA-2, SF/HA-3, SF/HA-4) with different material ratios, pore sizes, porosity and additives were implanted subcutaneously into Sprague-Dawley rats to observe biodegradation. SF/HA-3, which had characteristics more suitable for a bone substitite based on strength and resorption was selected as a scaffold and co-cultured with rabbit bone-marrow stromal cells (BMSCs). A segmental bone defect was created in the rabbit radius. The animals were randomised into group 1 (SF/HA-3 combined with BMSCs implanted into the bone defect), group 2 (SF/HA implanted alone) and group 3 (nothing implanted). They were killed at four, eight and 12 weeks for visual, radiological and histological study.

The bone defects had complete union for group 1 and partial union in group 2, 12 weeks after operation. There was no formation of new bone in group 3. We conclude that SF/HA-3 combined with BMSCs supports bone healing and offers potential as a bone-graft substitute.

Bioluminescence tomography based on the phase approximation model

A reconstruction method of bioluminescence sources is proposed based on a phase approximation model. Compared with the diffuse approximation, this phase approximation model more correctly predicts bioluminescence photon propagation in biological tissues, so that bioluminescence tomography can accurately locate and quantify the distribution of bioluminescence sources. The compressive sensing (CS) technique is applied to regularize the inverse source reconstruction to enhance numerical stability and efficiency. The numerical simulation and phantom experiments demonstrate the feasibility of the proposed approach.

A tetrahedron-based inhomogeneous Monte Carlo optical simulator

Optical imaging has been widely applied in preclinical and clinical applications. Fifteen years ago, an efficient Monte Carlo program 'MCML' was developed for use with multi-layered turbid media and has gained popularity in the field of biophotonics. Currently, there is an increasingly pressing need for simulating tools more powerful than MCML in order to study light propagation phenomena in complex inhomogeneous objects, such as the mouse. Here we report a tetrahedron-based inhomogeneous Monte Carlo optical simulator (TIM-OS) to address this issue. By modeling an object as a tetrahedron-based inhomogeneous finite-element mesh, TIM-OS can determine the photon-triangle interaction recursively and rapidly. In numerical simulation, we have demonstrated the correctness and efficiency of TIM-OS.

56 EFFECTS OF PHYLOGENIC GENERA OF RECIPIENT CYTOPLASTS ON DEVELOPMENT AND VIABILITY OF CANADA LYNX (LYNX CANADENSIS) CLONED EMBRYOS

Canada lynx (Lynx canadensis; CL) once occupied 16 states in the Unites States of America, but small populations remain in only 3 states. Interspecies-somatic cell nuclear transfer (Is-SCNT) offers the possibility of preventing their extinction; however, developmental constraints on Is-SCNT embryos are proportional to the phylogenetic distance between the donor cell and the recipient oocyte. Mitochondrial DNA (mtDNA) heteroplasmy may be involved in nuclear-cytoplasmic incompatibilities, thus inhibiting development of cloned embryos at the time of genomic activation. Minimizing the phylogenetic distance between the donor cell and recipient oocyte may enhance development of clone embryos. Caracal (Caracal caracal) may be suitable as an oocyte donor for SCNT and a recipient of CL cloned embryos because caracals hybridize with other felid species and share physical characteristics with the lynx family, marked by being previously classified in the lynx genera and having similar gestational length. To ensure compatibilities between the donor nuclei of the CL and the mitochondria of recipient oocytes, we (1) compared in vitro development of CL cloned embryos reconstructed with domestic cat (Felis catus; DSH) or caracal cytoplasts, (2) examined the mtDNA genotypes in CL cloned embryos, and (3) evaluated in vivo developmental competence of CL cloned embryos after transfer into caracal recipients. A total of 160 and 217 preovulatory oocytes were collected by laparoscopy from gonadotropin-treated caracals (n = 8) and DSH (n = 10) and used as recipient cytoplasts for reconstructing CL embryos. Results indicated that the phylogenetic genera of recipient cytoplasts did not affect embryo cleavage at Day 2 (caracal 50/55, 91% v. DSH 63/65, 97%), but development of CL cloned embryos to the blastocyst stage was higher when caracal oocytes were used as recipient cytoplasts (15/50; 30%) than with DSH cytoplasts (9/63, 14%; P < 0.05). The extent of mtDNA homoplasmy or heteroplasmy in CL cloned embryos was calculated by the number of single nucleotide polymorphisms (SNP) derived from the DSH or caracal oocyte donors and from the somatic cell donor CL. DNA was isolated from 25 and 35 CL cloned embryos reconstructed with caracal or DSH cytoplasts, respectively. All amplified products after PCR were sequenced and SNP analyzed. All CL embryos reconstructed with DSH cytoplasts were homoplasmic, carrying mtDNA only from the DSH oocyte donor (n = 35; SNP DSH = 2-6). Embryos reconstructed with caracal cytoplasts were homoplasmic for CL mtDNA (n = 9; SNPCL = 10-12) or heteroplasmic (caracal × CL, n = 17; SNPCL = 7-9; SNP caracal = 2-3). A total of 69 (mean = 34.5 ± 4.9 per caracal) and 70 (mean = 35.0 ± 9.8 per caracal) CL cloned embryos reconstructed with caracal and DSH cytoplasts, respectively, were transferred into 4 caracal recipients; however, no pregnancies were established. In summary, Is-SCNT between 2 phylogenetically closer species favors retention of the donor’s mitochondria, which might lead to a better nucleo-cytoplasmic interaction for reprogramming of donor nucleus.

Azimuthal charged-particle correlations and possible local strong parity violation

Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system's orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au + Au and Cu + Cu collisions at square root of s(NN) = 200 GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation.

Breast-Conserving Surgery Is Preferred Though Not Commonly Performed in an Urban Region of China

Introduction: Breast-conserving surgery (BCS) followed by radiation therapy has proven to be as effective as modified radical mastectomy, and has, therefore, been considered as the standard treatment for patients with localized breast cancer in Western societies. However, performance of BCS for the treatment of breast cancer in China is not as common as in Western countries. This study was to evaluate healthy women's attitudes towards BCS in an urban region of China.Method: Between February and March 2009, three hundred and fifty healthy women from three urban suburbs of Taiyuan city in Northern China were invited to complete a self-administered questionnaire. Participants' characteristics, including age, education, occupation, and attitudes towards breast cancer treatment options and involvement of treatment decisions, were collected and analyzed.Results: Three hundred and fifteen women returned the questionnaire. The response rate was 90%. The median age of the participants was 31.2 years old (range: 16 – 69 years old). Among them, 49.2% were married, 27.9% had received high levels of education, and 87.3%, 95.2% and 71.4% would like to know the disease status, to involve making treatment decisions, and to accept BCS, respectively, if they were diagnosed with breast cancer. Women aged above 45 years were more likely to choose BCS compared with those less than 45 years old (73.4% vs 61.5%, P = 0.08). There was no association between choices of surgical approaches and levels of education or occupation. As for breast cancer treatment information sources, 76.8% of the participants mentioned oncologists, followed by the internet (12.1%), friends, and media (10.8%). Almost all responders (93.3%) would like to attend hospitals specialized in cancer treatment if breast lumps were detected.Conclusion: Although only 7.1% of breast cancer patients attending a specialized tumor hospital in Taiyuan city underwent BCS, the current study indicate that most women in Northern China would prefer BCS to mastectomy if they were diagnosed with breast cancer. Therefore, further occupational training is warranted for oncologists in China so that optimal treatments for patients with breast cancer can be carried out.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6077.

The Developing Nature of Menstrual and Reproductive Factors Associated with Breast Cancer Risk among Women in an Urban Region of China

Introduction: The incidence rate of female breast cancer has increased rapidly over the past 20 years in China. It has become the leading cause of newly diagnosed cancer and a major cause of mortality among women in some large Chinese cities with higher socio-economic status. This was partly explained by the change of lifestyle and reproductive risk factors. However, little data exists on the extent to which the menstrual and reproductive factors with breast cancer risk have changed in other less developed Chinese cities.Method: One cross sectional study was conducted in urban region of Taiyuan of China from September 2008 to March 2009. One thousand and five hundreds healthy women were invited to complete a self-administered questionnaire. Participants' characteristics, including age, education, occupation, weight, height, age at menarche, age at first birth, parity, duration of breastfeeding, and age at menopause were collected and analyzed. Study subjects were divided into six groups: younger than or equal to 20, 21 to 30, 31 to 40, 41 to 50, 51 to 60 and older than 60 years old.Results: One thousand four hundreds and twenty eight women returned the questionnaire. The response rate was 95.2%. Median age of women in this study was 39 years old (range: 16 – 86 years old). There was a 4.8cm difference in the mean height between women born in 1990s and 1940s. The average age at menarche dropped from 16 years for women aged above 60 to 14.3 years for those younger than 20 years old. The average birth rate markedly decreased from 4.4 births per woman in the 1960s to 1.1 births per woman in the 1990s. The mean age at first birth increased 5.6 years through the period from the 1940s to 1980s. The breastfeeding time significantly reduced from 20.3 months to 3.6 months over 40 years.Conclusion: This study indicates that there has been significant change in the menstrual and reproductive factors associated with breast cancer risk in the last 40 years. These changes will certainly influence the incidence rate of breast cancer in the local city. Therefore, measures are needed to enhance the awareness of breast cancer and its early-detection methods among the urban region women in China.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6068.

Clinical Applications and Acute Hepatotoxicity of Intravenous Amiodarone

This cross-sectional, retrospective study was designed to evaluate the current clinical applications and acute hepatotoxicity of intravenous amiodarone administration at a hospital in China. Clinical data were collected from 1214 patients receiving intravenous amiodarone treatment between October 2003 and September 2005. Baseline patient characteristics, drug indications, administration records and acute hepatotoxicity associated with the drug were examined. Amiodarone was used primarily in arrhythmic patients with obvious cardiac dysfunction. Atrial fibrillation and ventricular arrhythmia were the two most commonly treated dysfunctions. Incorrect indications and administration methods were also noted. Hepatotoxicity occurred in 12.6% of the patients, but was mild in most cases. Males showed a higher incidence of hepatotoxicity than females. The use of amiodarone was considered to be reasonable and standardized, but there was still considerable room for improvement, particularly in the standardization of administration guidelines. Intravenous amiodarone can cause hepatotoxicity and hepatic function tests should be performed soon after giving amiodarone intravenously.