A spheroid-based 3-D culture model for pancreatic cancer drug testing, using the acid phosphatase assay

Current therapy for pancreatic cancer is multimodal, involving surgery and chemotherapy. However, development of pancreatic cancer therapies requires a thorough evaluation of drug efficacy in vitro before animal testing and subsequent clinical trials. Compared to two-dimensional culture of cell monolayer, three-dimensional (3-D) models more closely mimic native tissues, since the tumor microenvironment established in 3-D models often plays a significant role in cancer progression and cellular responses to the drugs. Accumulating evidence has highlighted the benefits of 3-D in vitro models of various cancers. In the present study, we have developed a spheroid-based, 3-D culture of pancreatic cancer cell lines MIAPaCa-2 and PANC-1 for pancreatic drug testing, using the acid phosphatase assay. Drug efficacy testing showed that spheroids had much higher drug resistance than monolayers. This model, which is characteristically reproducible and easy and offers rapid handling, is the preferred choice for filling the gap between monolayer cell cultures and in vivo models in the process of drug development and testing for pancreatic cancer.

Affordable nutrient solutions for improved food security as evidenced by crop trials

The continuing depletion of nutrients from agricultural soils in Sub-Saharan African is accompanied by a lack of substantial progress in crop yield improvement. In this paper we investigate yield gaps for corn under two scenarios: a micro-dosing scenario with marginal increases in nitrogen (N) and phosphorus (P) of 10 kg ha⁻¹ and a larger yet still conservative scenario with proposed N and P applications of 80 and 20 kg ha⁻¹ respectively. The yield gaps are calculated from a database of historical FAO crop fertilizer trials at 1358 locations for Sub-Saharan Africa and South America. Our approach allows connecting experimental field scale data with continental policy recommendations. Two critical findings emerged from the analysis. The first is the degree to which P limits increases in corn yields. For example, under a micro-dosing scenario, in Africa, the addition of small amounts of N alone resulted in mean yield increases of 8% while the addition of only P increased mean yields by 26%, with implications for designing better balanced fertilizer distribution schemes. The second finding was the relatively large amount of yield increase possible for a small, yet affordable amount of fertilizer application. Using African and South American fertilizer prices we show that the level of investment needed to achieve these results is considerably less than 1% of Agricultural GDP for both a micro-dosing scenario and for the scenario involving higher yet still conservative fertilizer application rates. In the latter scenario realistic mean yield increases ranged between 28 to 85% in South America and 71 to 190% in Africa (mean plus one standard deviation). External investment in this low technology solution has the potential to kick start development and could complement other interventions such as better crop varieties and improved economic instruments to support farmers.

A hybrid wetland map for China: a synergistic approach using census and spatially explicit datasets

Wetlands play important ecological, economic, and cultural roles in societies around the world. However, wetland degradation has become a serious ecological issue, raising the global sustainability concern. An accurate wetland map is essential for wetland management. Here we used a fuzzy method to create a hybrid wetland map for China through the combination of five existing wetlands datasets, including four spatially explicit wetland distribution data and one wetland census. Our results show the total wetland area is 384,864 km², 4.08% of China’s national surface area. The hybrid wetland map also shows spatial distribution of wetlands with a spatial resolution of 1 km. The reliability of the map is demonstrated by comparing it with spatially explicit datasets on lakes and reservoirs. The hybrid wetland map is by far the first wetland mapping that is consistent with the statistical data at the national and provincial levels in China. It provides a benchmark map for research on wetland protection and management. The method presented here is applicable for not only wetland mapping but also for other thematic mapping in China and beyond.

The plasma level of soluble receptor for advanced glycation end products is decreased in patients with systemic lupus erythematosus

In recent years, the role of high mobility group box-1 (HMGB1) protein and its receptors in autoimmune diseases has received increasing attention. It has been documented that HMGB1 is associated with disease activity in patients with systemic lupus erythematosus (SLE). This study was undertaken to determine the potential role of receptor for advanced glycation end products (RAGE), one receptor for HMGB1, in the pathogenesis of SLE. Plasma levels of soluble RAGE (sRAGE) from 105 patients with clinical diagnosis of SLE and 43 healthy controls were determined by ELISA. Associations between sRAGE levels and clinical, laboratory characteristics were assessed. The data showed that plasma levels of sRAGE in patients with SLE were significantly lower than those in healthy controls (HC) (P = 0.003). Plasma sRAGE in patients receiving short-period treatment showed an immediate decrease compared with the untreated patients (P = 0.023). In contrast, plasma sRAGE in patients receiving long-period treatment were significantly increased compared to those with short-period treatment (P = 0.000) and comparable with those in HC (P = 0.305). The significant decreased levels of sRAGE in patients with SLE suggest the potential association of RAGE signalling and SLE clinical pathology, whereas, long-period antilupus treatment may counteract the decreased sRAGE levels in patients with SLE.

Interface control of bulk ferroelectric polarization

The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.

The safety and efficacy of early-stage bi-weekly alendronate to improve bone mineral density and bone turnover in chinese post-menopausal women at risk of osteoporosis

The efficacy and safety of early, low frequency antiresorptive drug intervention for osteopaenia on bone mineral density (BMD) and bone turnover in Chinese post-menopausal women at risk of developing osteoporosis were investigated. A total of 180 women aged 40 - 70 years were enrolled and equally randomized to receive either 70 mg alendronate once every 2 weeks plus 0.5 μg alfacalcidol daily (treatment group) or alfacalcidol 0.5 μg daily alone (control group) for 12 months. In the treatment group, lumbar spine and total hip BMD at 12 months had increased significantly from baseline and compared with the control group. There were also significant reductions in serum levels of the bone turnover biomarkers, bone-specific alkaline phosphatase and C-terminal telopeptide of type I collagen, compared with the control. No serious adverse events were observed in either group and safety profiles were similar. It was concluded that early intervention with 70 mg alendronate once every 2 weeks was safe, well tolerated and more effective than alfacalcidol alone (control) in increasing BMD and reducing bone turnover, and might prevent serious outcomes, such as fragility fractures, reduce rates of adverse effects and improve patient compliance.

Microscopic origin of the giant ferroelectric polarization in tetragonal-like BiFeO(3)

We report direct experimental evidence for a room-temperature, ∼130  μC/cm(2) ferroelectric polarization from the tetragonal-like BiFeO(3) phase. The physical origin of this remarkable enhancement of ferroelectric polarization has been investigated by a combination of x-ray absorption spectroscopy, scanning transmission electron microscopy, and first principles calculations. A large strain-induced Fe-ion displacement relative to the oxygen octahedra, combined with the contribution of Bi 6s lone pair electrons, is the mechanism driving the large ferroelectric polarization in this tetragonal-like phase.

Spin squeezing: transforming one-axis twisting into two-axis twisting

Squeezed spin states possess unique quantum correlation or entanglement and are significantly promising for advancing quantum information processing and quantum metrology. In recent back-to-back publications [C. Gross et al., Nature (London) 464, 1165 (2010) and Max F. Riedel et al., Nature (London) 464, 1170 (2010)], reduced spin fluctuations are observed leading to spin squeezing at -8.2 and -2.5 dB, respectively, in two-component atomic condensates exhibiting one-axis-twisting interactions. The noise reduction limit for the one-axis twisting scales as ∝1/N(2/3), which for a condensate with N∼10(3) atoms is about 100 times below the standard quantum limit. We present a scheme using repeated Rabi pulses capable of transforming the one-axis-twisting spin squeezing into the two-axis-twisting type, leading to Heisenberg limited noise reduction ∝1/N or an extra tenfold improvement for N∼10(3).

QSAR studies on the depuration rates of polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers and polychlorinated biphenyls in mussels (Elliptio complanata)

Based on the mechanism of action, a quantitative structure-activity relationship (QSAR) model for the depuration rate constants (k(d)) of 28 PAHs, 8 PBDEs and 28 PCBs in mussels (Elliptio complanata) was constructed by partial least squares (PLS) regression, following the guidelines for development and validation of QSAR models. For the training set of the QSAR model, r² = 0.953, the cross-validated regression coefficient (Q²(CUM)) was 0.947. The predicted log k(d) values for the validation set were consistent with the observed values, with a standard error (SE) of 0.160 log units and a squared correlation coefficient (Q²(EXT)) of 0.892. Comparatively, the developed QSAR model had good robustness, predictive ability and extended applicability domain. The electrophilicity index (ω), molecular polarizability (α), the averages of the negative potentials on the molecular surface (V(s⁻)) and the balance parameter of surface potential (τ) were the key parameters governing the log k(d) values in the QSAR model, which indicated that the log k(d) value was mainly related to the partition ability, electrostatic interactions, and van der Waals interactions of compounds.

Low Temperature Processing for Multilevel Interconnection and Packaging

The future high density multilevel interconnection and packaging requires that the combination of the insulator and conductor layers has a low RC value. Thermal stress and diffusion during processing are issues of great concern in the high density multilevel structures. The problem can be alleviated by a proper choice of materials and processes that do not require high temperature. In this paper we propose to use parylene and its derivatives (dielectric constant 2.3–2.6) as the possible interlayer dielectrics and Cu (bulk resistivity ∼1.7 μ Ω-cm) as the conductor. Parylene can be vapor-deposited and cured at room temperature. The metallization of Cu has been achieved at room temperature using the newly developed partially ionized beam deposition technique. This technique has been shown to grow high quality metal films with low resistivity at low substrate temperatures. The interaction between Cu and parylene, including adhesion and diffusion, is also discussed.

Vapor Deposition of Parylene Films from Precursors

Parylene films, depending on the type, are thermally stable up to 530°C and have low dielectric constants ranging from 2.35 to 3.15. One of the most interesting properties of this material is its vapor depositability. Conventional vapor deposition involves cracking the parylene dimers at temperatures from 600 to 730 °C and polymerizingthe monomers at - 35 °C to RT. We have developed a simpler and less expensive technique that directly uses the precursors from which the dimers are made. This method requires the use of metal catalysts to produce parylene films. We have used the precursors α,α'-dibromo-p-xylene and dibromotetrafluoro-p-xylene to produce N-type and F-type parylene films. FTIR, XPS, thermal stability, and electrical studies show that the F-type parylene films grown from the precursors are comparable to, or sometimes better than, the films grown from dimer, and have potential microelectronics applications.

A pilot study of the clinical relevance of the relationship between the serum level of pregnancy-associated plasma protein A and the degree of acute coronary syndrome

Serum levels of pregnancy-associated plasma protein-A (PAPP-A), high-sensitivity C-reactive protein (hs-CRP) and tumour necrosis factor-alpha (TNF-alpha) were measured in 70 patients with acute coronary syndrome (ACS), comprising 18 with unstable angina (UA), 37 with acute myocardial infarction (AMI) and 15 with stable angina (SA); 15 healthy controls were also included. Levels of PAPP-A were significantly higher in the UA and AMI groups than in the SA and control groups. Levels of PAPP-A were similar in the SA and control groups, and higher in the ACS patients who were cardiac troponin T-negative (comprising UA and AMI patients) than in the control and SA groups. Levels of hs-CRP and TNF-alpha were significantly higher in the SA group than in the control group, significantly higher in the UA group than in the SA and control groups, and significantly higher in the AMI group than in all other groups. Levels of PAPP-A in ACS patients were positively correlated with levels of hs-CRP and TNF-alpha. It would seem, therefore, that PAPP-A is associated with inflammation and might be used to detect plaque instability and rupture before an increase in cardiac troponin T is detectable.

Numb regulates meiotic spindle organisation in mouse oocytes

Numb is an adaptor protein that controls the fate of cells in different species through asymmetrical inheritance by sibling cells during division. It has been investigated extensively in mitosis, mostly in neural progenitor cells, but its function in meiosis remains unknown. The present study was designed to investigate the expression, subcellular localisation and functional roles of Numb during mouse oocyte meiotic maturation. Using real-time polymerase chain reaction and western blotting, we found that the expression of Numb increased from the germinal vesicle (GV) to MII stages. Immunofluorescent staining revealed that Numb was mainly concentrated in the GV before meiosis resumption, aggregated in the vicinity of the chromosomes after GV breakdown and then localised to the spindle poles from prometaphase I to MII. Nocodazole treatment resulted in spindle destruction and Numb diffusion into the cytoplasm. However, Numb appeared at the spindle poles again once the spindles had formed when nocodazole-treated oocytes were washed and cultured for spindle recovery. Depletion of Numb by RNA interference resulted in chromosome misalignment, spindle deformation and even doubled spindle formation. Our results suggest that Numb is critical for spindle organisation during mouse oocytes meiosis. The present study provides evidence of a new function for Numb in addition to its action as a cell fate-determining factor.

Observing the Einstein-de Haas effect with atoms in an optical lattice

The conservation of magnetization, or atomic spin angular momentum, is broken for anisotropic dipolar interactions. As a result, the Einstein-de Haas effect, or the transfer of spin to spatial angular momentum, arises because the total angular momentum is conserved. We identify the regime for observing this with two 87Rb atoms in a single well, stimulated by the recent result for a condensate. The two-atom system is found to be more easily observed and confirmed with the addition of a periodically modulated magnetic field. Our result of utilizing a feeble dipolar interaction may find potential applications in precision measurements.

Number fluctuation dynamics of atomic spin mixing inside a condensate

We investigate the quantum dynamics of number fluctuations inside an atomic condensate during coherent spin mixing among internal states of the ground state hyperfine manifold, by quantizing the semiclassical nonrigid pendulum model in terms of the conjugate variable pair: the relative phase and the atom number. Our result provides a theoretical basis that resolves the resolution limit, or the effective "shot-noise" level, for counting atoms that is needed to clearly detect quantum correlation effects in spin mixing.

Angular momentum of a magnetically trapped atomic condensate

For an atomic condensate in an axially symmetric magnetic trap, the sum of the axial components of the orbital angular momentum and the hyperfine spin is conserved. Inside an Ioffe-Pritchard trap (IPT) whose magnetic field (B field) is not axially symmetric, the difference of the two becomes surprisingly conserved. In this Letter we investigate the relationship between the values of the sum or difference angular momentums for an atomic condensate inside a magnetic trap and the associated gauge potential induced by the adiabatic approximation. Our result provides significant new insight into the vorticity of magnetically trapped atomic quantum gases.

Evolutionary design on a budget: robustness and optimality of bacteriophage T7

Exploring how biological systems have been 'designed' by evolution to achieve robust behaviours is now a subject of increasing research effort. Yet, it still remains unclear how environmental factors may contribute to this process. This issue is addressed by employing a detailed computer model for the intracellular growth of phage T7. More than 150 000 in silico T7 mutants were generated and the rates and efficiencies of their growth in two host environments, namely, a realistic environment that offered finite host resources for the synthesis of phage functions and a hypothetical environment where the phage was supplied infinite host resources, were evaluated. Results revealed two key properties of phage T7. First, T7 growth was overall robust with respect to perturbations in its parameters, but fragile with respect to changes in the ordering of its genetic elements. Secondly, the wild-type T7 had close to optimal fitness in the finite environment. Furthermore, a strong correlation was found between fitness and growth efficiency in the finite environment. The results underscore the potential importance of the environment in shaping robust design of a biological system. In particular, the strong correlation between fitness and growth efficiency suggests that T7 may have evolved to maximise its growth rate by minimising waste of finite resources.

Dipolar effect in coherent spin mixing of two atoms in a single optical lattice site

We show that atomic dipolar effects are detectable in the system that recently demonstrated two-atom coherent spin dynamics within individual lattice sites of a Mott state. Based on a two-state approximation for the two-atom internal states and relying on a variational approach, we have estimated the spin dipolar effect. Despite the absolute weakness of the dipole-dipole interaction, it is shown that it leads to experimentally observable effects in the spin mixing dynamics.

Controlled splitting of an atomic wave packet

We propose a simple scheme capable of adiabatically splitting an atomic wave packet using two independent translating traps. Implemented with optical dipole traps, our scheme allows a high degree of flexibility for atom interferometry arrangements and highlights its potential as an efficient and high fidelity atom optical beam splitter.

Dynamical instability and domain formation in a spin-1 Bose-Einstein condensate

We interpret the recently observed spatial domain formation in spin-1 atomic condensates as a result of dynamical instability. Within the mean field theory, a homogeneous condensate is dynamically unstable (stable) for ferromagnetic (antiferromagnetic) atomic interactions. We find that this dynamical instability naturally leads to spontaneous domain formation as observed in several recent experiments for condensates with rather small numbers of atoms. For trapped condensates, our numerical simulations compare quantitatively to the experimental results, thus largely confirming the physical insight from our analysis of the homogeneous case.

Measuring the parity of an N-qubit state

We present a scheme for a projective measurement of the parity operator Pz = Product(N)i=1 sigma(i)z of N qubits. Our protocol uses a single ancillary qubit, or a probe qubit, and involves manipulations of the total spin of the N qubits without requiring individual addressing. We illustrate our protocol in terms of an experimental implementation with atomic ions in a two-zone linear Paul trap, and further discuss its extensions to several more general cases.

Quantum phases of dipolar spinor condensates

We study the zero-temperature ground state structure of a spin-1 condensate with magnetic dipole-dipole interactions. We show that the dipolar interactions break the rotational symmetry of the Hamiltonian and induce new quantum phases. Different phases can be reached by tuning the effective strength of the dipolar interactions via modifying the trapping geometry. The experimental feasibility of detecting these phases is investigated. The spin-mixing dynamics is also studied.

Calibrating dipolar interaction in an atomic condensate

We reexamine the topic of a dipolar condensate with the recently derived more rigorous pseudopotential for dipole-dipole interaction [Phys. Rev. A 67, 033607 (2003)]]. Based on the highly successful variational technique, we find that all dipolar effects estimated before (using the bare dipole-dipole interaction) become significantly larger, i.e., are amplified by the new velocity-dependent pseudopotential, especially in the limit of large or small trap aspect ratios. This result points to a promising prospect for detecting dipolar effects inside an atomic condensate.

Observation of spinor dynamics in optically trapped 87Rb Bose-Einstein condensates

We measure spin mixing of F=1 and F=2 spinor condensates of 87Rb atoms confined in an optical trap. We determine the spin mixing time to be typically less than 600 ms and observe spin population oscillations. The equilibrium spin configuration in the F=1 manifold is measured for different magnetic fields and found to show ferromagnetic behavior for low field gradients. An F=2 condensate is created by microwave excitation from the F=1 manifold, and this spin-2 condensate is observed to decay exponentially with time constant 250 ms. Despite the short lifetime in the F=2 manifold, spin mixing of the condensate is observed within 50 ms.

Quantum Zeno subspace and entangled Bose-Einstein condensates

We discuss a proposal for the efficient generation of the maximally entangled atomic N-GHZ state in a spinor-1 condensate by driving internal state atomic Raman transitions using (classical) laser fields. We illustrate the dynamics in terms of a quantum Zeno subspace and identify the resultant atomic elastic collision in facilitating the deterministic entanglement creation. Our proposal can be readily implemented in several laboratories where ferromagnetic spinor condensates (of 87Rb atoms) are investigated.

Quantum phase diffusions of a spinor condensate

We discuss the quantum phases and their diffusion in a spinor-1 atomic Bose-Einstein condensate. For ferromagnetic interactions, we obtain the exact ground state distribution of the phase fluctuations corresponding to the total atom number (N), the magnetization (M), and the alignment (or hypercharge) (Y) of the system. The mean-field ground state is shown to be stable against these fluctuations, which dynamically recover the two continuous symmetries associated with the conservation of N and M as in current experiments.

Conditional quantum phase gate between two 3-state atoms

We propose a scheme for conditional quantum logic between two 3-state atoms that share a quantum data bus such as a single mode optical field in cavity QED systems, or a collective vibrational state of trapped ions. Making use of quantum interference, our scheme achieves successful conditional phase evolution without any real transitions of atomic internal states or populating the quantum data bus. In addition, it requires only common addressing of the two atoms by external laser fields.

Creating maximally entangled atomic states in a Bose-Einstein condensate

We propose a protocol to create maximally entangled pairs, triplets, quartiles, and other clusters of Bose-condensed atoms starting from a condensate in the Mott insulator state. The essential element is to drive single atom Raman transitions using laser pulses. Our scheme is simple, efficient, and can be readily applied to the recent experimental system as reported by M. Greiner 413, 44 (2002)].

Stochastic vs. deterministic modeling of intracellular viral kinetics

Within its host cell, a complex coupling of transcription, translation, genome replication, assembly, and virus release processes determines the growth rate of a virus. Mathematical models that account for these processes can provide insights into the understanding as to how the overall growth cycle depends on its constituent reactions. Deterministic models based on ordinary differential equations can capture essential relationships among virus constituents. However, an infection may be initiated by a single virus particle that delivers its genome, a single molecule of DNA or RNA, to its host cell. Under such conditions, a stochastic model that allows for inherent fluctuations in the levels of viral constituents may yield qualitatively different behavior. To compare modeling approaches, we developed a simple model of the intracellular kinetics of a generic virus, which could be implemented deterministically or stochastically. The model accounted for reactions that synthesized and depleted viral nucleic acids and structural proteins. Linear stability analysis of the deterministic model showed the existence of two nodes, one stable and one unstable. Individual stochastic simulation runs could access and remain at the unstable node. In addition, deterministic and averaged stochastic simulations yielded different transient kinetics and different steady-state levels of viral components, particularly for low multiplicities of infection (MOI), where few virus particles initiate the infection. Furthermore, a bimodal population distribution of viral components was observed for low MOI stochastic simulations. The existence of a low-level infected subpopulation of cells, which could act as a viral reservoir, suggested a potential mechanism of viral persistence.

Genistein and methoxychlor modulate the activity of natural killer cells and the expression of phenotypic markers by thymocytes and splenocytes in F0 and F1 generations of Sprague-Dawley rats

The isoflavone genistein (GE) and methoxychlor (MXC) have been shown to be estrogenic in both in vitro and in vivo experimental systems. The objective of the present study was to evaluate the effects of GE and MXC on the immune system in adult and developing rats and the potential interaction between these compounds in their immunomodulatory actions. Timely pregnant Sprague-Dawley rats were exposed to GE (300 or 800 ppm), MXC (800 ppm), or their combinations in feed starting on day 1 of gestation. The offspring were exposed to these chemicals gestationally and lactationally. Immunological evaluation was performed on postnatal day 22. In F0 females, exposure to GE had no effect on the percentages of thymocyte subsets, but caused a significant decrease in the absolute thymus weight at the 800-ppm dose level. In the spleen, GE did not affect the activity of natural killer cells but induced changes in the percentages of splenic T lymphocyte subsets. Exposure to MXC produced no effect on the immune parameters examined except for a decrease in the percentage of CD4+CD8- thymocytes. Additionally, minimal interaction between GE and MXC was observed. In F(1) males, both GE and MXC decreased the percentage of CD4+CD8- thymocytes, but only GE increased spleen natural killer cell activity. MXC in combination with 300 ppm-GE, but not separately, produced significant decreases in the absolute weights of thymus and spleen. In F1 females, GE decreased the percentage of CD4+CD8- thymocytes, increased the percentage of CD4+CD8+ thymocytes, and decreased the activity of spleen natural killer cells. In contrast, MXC increased the percentages of spleen natural killer cells and CD8+ T cells. Overall, the results demonstrate that both GE and MXC can modulate the immune system with greater effects observed in developing rats. Moreover, male and female rats have differential responses to these compounds. A lack of interaction between these two estrogenic chemicals in modulating these immune parameters indicates that their effects on the immune system might involve other mechanisms in addition to the estrogen receptors.

The emission soot of biomass fuels combustion as a source of endocrine disrupters

Emissions of biomass fuel combustion in residential stove from Chinese countryside were analyzed to determine the endocrine disrupters by using recombinant yeast bioassay. The results showed that there were significant steroid modulating activities found in combustion soot of five kinds of biomass fuels, which were wood, crop residue, grass, bush and rice straw. The steroid activities in the different sub-fractions from chromatographic separation were also determined, and the results indicated that polar fraction extracted by methanol and aromatic fraction extracted by benzene had relatively high steroid activities, and aliphatic fraction almost had no activity. The GC/MS results showed that polycyclic aromatic compounds and their derivatives, substituted phenolic compounds and their derivatives, aromatic carbonyl compounds, and higher molecular weight alcohols and ketones may be the main steroid disrupters in these soots.

Genistein modulates immune responses and increases host resistance to B16F10 tumor in adult female B6C3F1 mice

The isoflavone genistein (4,7,4'-trihydroxyisoflavone) is a phytoestrogen found in high levels in soy products that has been associated with decreased incidences of breast and prostate cancers. The potential effects of genistein on the immune system were evaluated in adult female B6C3F1 mice. Groups of mice were exposed to vehicle or genistein by gavage for 28 d. The doses of genistein used were 2, 6 and 20 mg/kg body. Consistent with the chemopreventive effect of genistein, exposure to this compound significantly increased host resistance to B16F10 tumor as reflected by a decrease in the number of lung tumor nodules after tumor cell injection at the middle and high dose levels. Inhibition of B16F10 tumor formation was not due to a direct effect of serum genistein and/or its metabolites on the proliferation of B16F10 tumor cells. When innate and acquired immune responses were evaluated, a dose-related increase of cytotoxic T-cell activity was observed in genistein-treated mice with significant changes observed at the middle and high dose levels. Furthermore, in vitro interleukin (IL)-2-stimulated natural killer (NK) cell activity was significantly enhanced in the high genistein dose group, although the basal NK cell activity was not affected. Although no affect on the mixed lymphocyte responses and anti-CD3 antibody-mediated splenocyte proliferation was observed, exposure to genistein significantly increased basal splenocyte proliferation. Exposure to genistein did not alter the activity of the mononuclear phagocyte system and the cytotoxic/cytostatic function of thioglycollate-recruited peritoneal cells on B16F10 tumor cells. Finally, exposure to genistein did not produce biologically meaningful changes in spleen immunoglobulin (Ig)M and IgG antibody-forming cell responses. In conclusion, genistein enhanced host resistance as evaluated in the B16F10 tumor model, which may be related to the increases in the activities of cytotoxic T cells and NK cells.

[Construction of Ag85B DNA vaccine for Mycobacterium tuberculosis and its immunogenicities]

OBJECTIVE

To construct pcDNA3-Ag85B recombinant and evaluate its immunogenicity and types of immune response induced by recombinant pcDNA3-Ag85B.

METHODS

Ag85B gene of Mycobacterium tuberculosis was inserted into pcDNA3 to construct DNA vaccine pcDNA3-Ag85B. BALB/c mice were intramuscularly immunized with DNA vaccine, saline and pcDNA3, respectively. The levels of anti-Ag85B antibody were examined with ELISA and the transcripts of IL-2, IL-4, IL-10 and IFN-gamma of spleen lymphocytes stimulated with recombinant Ag85B were tested with RT-PCR at the end of 6th week of inoculation.

RESULTS

Compared with control group, the specific antibody levels against Ag85B were much higher and the IL-2 and IFN-gamma transcripts were up regulated in the pcDNA3-Ag85B group. There was no change of IL-4 and IL-10 expressions in three groups.

CONCLUSION

The pcDNA3-Ag85B stimulated the specific antibody products and induced the Th1 type cell immunity.

A model for strain amplification in the actin cytoskeleton of osteocytes due to fluid drag on pericellular matrix

A model is presented that provides a resolution to a fundamental paradox in bone physiology, namely, that the strains applied to whole bone (i.e., tissue level strains) are much smaller (0.04-0.3 percent) than the strains (1-10 percent) that are necessary to cause bone signaling in deformed cell cultures (Rubin and Lanyon, J. Bone Joint Surg. 66A (1984) 397-410; Fritton et al., J. Biomech. 33 (2000) 317-325). The effect of fluid drag forces on the pericellular matrix (PM), its coupling to the intracellular actin cytoskeleton (IAC) and the strain amplification that results from this coupling are examined for the first time. The model leads to two predictions, which could fundamentally change existing views. First, for the loading range 1-20MPa and frequency range 1-20Hz, it is, indeed, possible to produce cellular level strains in bone that are up to 100 fold greater than normal tissue level strains (0.04-0.3 percent). Thus, the strain in the cell process membrane due to the loading can be of the same order as the in vitro strains measured in cell culture studies where intracellular biochemical responses are observed for cells on stretched elastic substrates. Second, it demonstrates that in any cellular system, where cells are subject to fluid flow and tethered to more rigid supporting structures, the tensile forces on the cell due to the drag forces on the tethering fibers may be many times greater than the fluid shear force on the cell membrane.

Creating massive entanglement of Bose-Einstein condensed atoms

We propose a direct, coherent coupling scheme that can create massively entangled states of Bose-Einstein condensed atoms. Our idea is based on an effective interaction between two atoms from coherent Raman processes through a (two atom) molecular intermediate state. We compare our scheme with other recent proposals for the generation of massive entanglement of Bose condensed atoms.

Glial cell-derived neurotrophic factor (GDNF)-induced migration and signal transduction in corneal epithelial cells

PURPOSE

To identify signal-transduction pathways induced by glial cell-derived neurotrophic factor (GDNF) in corneal epithelial cells and to characterize its effect on cell migration.

METHODS

Expression of GDNF receptor (GFR) alpha-1 in human corneal epithelium was detected by RT-PCR and Western blot analysis. Expression and phosphorylation of Ret, activation of focal adhesion kinase (FAK) and mitogen-associated protein kinase (MAPK) signaling pathways, and phosphorylation of paxillin by GDNF were investigated by immunoprecipitation and Western blot analysis in primary human corneal epithelial cells and a corneal epithelial cell line. The tyrosine kinase inhibitor herbimycin A and Ras farnesyltransferase inhibitor manumycin were used to specifically inhibit GDNF-induced signaling pathways. In vitro wound-healing assays and modified Boyden chamber analysis were performed to investigate the effect of GDNF on epithelial cell migration.

RESULTS

Expression of GFRalpha-1 was detected in normal and transformed human corneal epithelium. GDNF induced tyrosine phosphorylation of Ret. Furthermore, tyrosine phosphorylation of FAK and phosphotyrosine kinase (Pyk) 2; serine phosphorylation of c-Raf, MEK1, and Elk 1; and tyrosine-threonine phosphorylation of Erk-1 and -2 were time-dependently activated in the presence of GDNF. Tyrosine phosphorylation of paxillin was also induced by GDNF. Migration of corneal epithelial cells was significantly stimulated by GDNF. Herbimycin A strongly inhibited the activation of Ret, FAK, c-Raf, and Erk-1 and -2; the phosphorylation of paxillin; and corneal epithelial cell migration. More specifically, the Ras inhibitor manumycin inhibited phosphorylation of c-Raf, MEK 1, Erk-1 and -2, and Elk 1, but not that of FAK.

CONCLUSIONS

Corneal epithelial cells express receptors specific for GDNF that are used by GDNF to induce intracellular signaling. FAK and MAPK pathways seem to be activated by GDNF to modulate gene transcription and cell migration. FAK seems to be an upstream regulator of the MAPK cascade for GDNF signal transduction. As an inducer of FAK-dependent corneal epithelial migration, GDNF may play an important role in corneal regeneration and wound healing.

[Ectopic expression of human brain derived neurotrophic factor gene in fibroblasts]

The full-length sequence encoding hBDNF was inserted down into the enhancer-promotor regulatory element of Colia1 to construct minigene Colia1-BDNF. The recombinant eukaryotic expression plasmid pSCEPBFCAT was transfected into human fetal tendon fibroblasts in culture to realize ectopic expression of hBDNF gene in fibroblasts. The results of immuno-dot blot, Elisa and Western hybridization confirm that the expression protein with apparent molecular weight 27 kDa in pSCEPBFCAT transfected fibroblasts possesses antigen activity specific for the antibodies to BDNF.