Superparamagnetic iron oxide nanoparticle-labeled cells as an effective vehicle for tracking the GFP gene marker using magnetic resonance imaging

BACKGROUND

Detection of a gene using magnetic resonance imaging (MRI) is hindered by the magnetic resonance (MR) targeting gene technique. Therefore it may be advantageous to image gene-expressing cells labeled with superparamagnetic iron oxide (SPIO) nanoparticles by MRI.

METHODS

The GFP-R3230Ac (GFP) cell line was incubated for 24 h using SPIO nanoparticles at a concentration of 20 microg Fe/mL. Cell samples were prepared for iron content analysis and cell function evaluation. The labeled cells were imaged using fluorescent microscopy and MRI.

RESULTS

SPIO was used to label GFP cells effectively, with no effects on cell function and GFP expression. Iron-loaded GFP cells were successfully imaged with both fluorescent microscopy and T2*-weighted MRI. Prussian blue staining showed intracellular iron accumulation in the cells. All cells were labeled (100% labeling efficiency). The average iron content per cell was 4.75+/-0.11 pg Fe/cell (P<0.05 versus control).

DISCUSSION

This study demonstrates that the GFP expression of cells is not altered by the SPIO labeling process. SPIO-labeled GFP cells can be visualized by MRI; therefore, GFP, a gene marker, was tracked indirectly with the SPIO-loaded cells using MRI. The technique holds promise for monitoring the temporal and spatial migration of cells with a gene marker and enhancing the understanding of cell- and gene-based therapeutic strategies.

[Studies on immunoprotection in mice after immunization with Schistosoma japonicum 22.6 kDa recombinant protein]

AIM

To evaluate the immunoprotective effect of Schistosoma japonicum recombinant 22.6 kDa (rSj22.6) and Sj22.6/Sj26 GST fusion protein.

METHODS

The Sj22.6/Sj26 GST fusion protein was prepared by affinity chromatography using glutathione Sepharose 4B. The purified rSj22.6 could be cleaved easily from the fusion protein with Thrombin. 17 and 12 mice immunized with rSj22.6 and Sj22.6/Sj26 GST separately were each challenged with 40 +/- 1 S. japonicum cercariae.

RESULTS

In BALB/c mice, the rSj22.6 and Sj22.6/Sj26 GST could induce 32.1 (P < 0.005) and 34.9% (P < 0.02) worm reduction, respectively, as well as 28.4% (P < 0.02) and 45.1% (P < 0.005) total egg reduction, respectively.

CONCLUSION

Bpth rSj22.6 and Sj22.6/Sj26 GST fusion protein are partially effective against S. japonicum.

Morphology-controlled synthesis and a comparative study of the physical properties of SnO2 nanostructures: from ultrathin nanowires to ultrawide nanobelts

Controlled synthesis of one-dimensional materials, such as nanowires and nanobelts, is of vital importance for achieving the desired properties and fabricating functional devices. We report a systematic investigation of the vapor transport growth of one-dimensional SnO(2) nanostructures, aiming to achieve precise morphology control. SnO(2) nanowires are obtained when SnO(2) mixed with graphite is used as the source material; adding TiO(2) into the source reliably leads to the formation of nanobelts. Ti-induced modification of crystal surface energy is proposed to be the origin of the morphology change. In addition, control of the lateral dimensions of both SnO(2) nanowires (from approximately 15 to approximately 115 nm in diameter) and nanobelts (from approximately 30 nm to approximately 2 microm in width) is achieved by adjusting the growth conditions. The physical properties of SnO(2) nanowires and nanobelts are further characterized and compared using room temperature photoluminescence, resonant Raman scattering, and field emission measurements.

QTL analyses of seed weight during the development of soybean (Glycine max L. Merr.)

At harvest traits such as seed weight are the sum of development and responses to stresses over the growing season and particularly during the reproductive phase of growth. The aim here was to measure quantitative trait loci (QTL) underlying the seed weight from early development to drying post harvest. One hundred forty-three F(5) derived recombinant inbred lines (RILs) developed from the cross of soybean cultivars 'Charleston' and 'Dongnong 594' were used for the analysis of QTL underlying mean 100-seed weight at six different developmental stages. QTL x Environment interactions (QE) were analyzed by a mixed genetic mode based on 3 years' data. At an experiment-wise threshold of a=0.05 and by single-point analysis 94 QTL unaffected by QE underlay the mean seed weight at different developmental stages. Sixty-eight QTL affected by QE that also underlay mean seed weight were identified. From the 162 QTL 42 could be located on 12 linkage groups by composite interval mapping (LOD>2.0). The numbers, locations and types of the QTL and the genetic effects were different at each developmental stage. On linkage group C2 the distantly linked QTL swC2-1, swC2-2 and swC2-3 each affected mean seed weight throughout the different developmental stages. The DNA markers linked to the QTL possessed potential for use in marker-assisted selection for soybean seed size. The identification of QTL with genetic main effects and QE interaction effects suggested that such interactions might significantly alter seed weight during seed development.

Ferroelectric transistors with nanowire channel: toward nonvolatile memory applications

We report the fabrication and characterization of ZnO nanowire memory devices using a ferroelectric Pb(Zr(0.3)Ti(0.7))O(3) (PZT) film as the gate dielectric and the charge storage medium. With a comparison to nanowire transistors based on SiO(2) gate oxide, the devices were evaluated in terms of their electric transport, retention, and endurance performance. Memory effects are observed as characterized by an eminent counterclockwise loop in I-V(g) curves, which is attributed to the switchable remnant polarization of PZT. The single-nanowire device exhibits a high (up to 10(3)) on/off ratio at zero gate voltage. Our results give a proof-of-principle demonstration of the memory application based on a combination of nanowires (as channels) and ferroelectric films (as gate oxide).

Atomic structure of the epitaxial BaO/Si(001) interface

We present the structure of the interface responsible for epitaxy of crystalline oxides on silicon. Using synchrotron x-ray diffraction, we observe a 2 x 1 unit cell reconstruction at the interface of BaO grown on Si(001) terminated with 1/2 ML of Sr. Since this symmetry is not present in bulk BaO or Si, only the interface contributes to diffracted intensity. First principles calculations accurately predict the observed diffraction and identify the structure of the BaO/Si interface, including the elemental composition and a sub-A rumpling due to epitaxial strain of the 7 adjacent BaO and Si layers.

Two pathways for water interaction with oxygen adatoms on TiO2(110)

Scanning tunneling microscopy and density functional theory studies show that oxygen adatoms (Oa), produced during O2 exposure of reduced TiO2(110) surfaces, alter the water dissociation and recombination chemistry through two distinctive pathways. Depending on whether H2O and Oa are on the same or adjacent Ti4+ rows, Oa facilitates H2O dissociation and proton transfer to form a terminal hydroxyl pair, positioned along or across the Ti4+ row, respectively. The latter process has not been reported previously, and it starts from a "pseudodissociated" state of water. In both pathways, the reverse H transfer results in H2O reformation and O scrambling, as manifested by an apparent along- or across-row motion of Oa's.

Multifunctional CuO nanowire devices: p-type field effect transistors and CO gas sensors

We report the properties of a field effect transistor (FET) and a gas sensor based on CuO nanowires. CuO nanowire FETs exhibit p-type behavior. Large-scale p-type CuO nanowire thin-film transistors (10(4) devices in a 25 mm(2) area) are fabricated and we effectively demonstrate their enhanced performance. Furthermore, CuO nanowire exhibits high and fast response to CO gas at 200 degrees C, which makes it a promising candidate for a poisonous gas sensing nanodevice.

Screening and characterization of monoclonal antibodies to the surface antigens of Listeria monocytogenes serotype 4b

AIMS

This study aims to develop and characterize monoclonal antibodies (Mabs) with high specificity and affinity for surface antigens of an epidemiologically important serotype 4b of Listeria monocytogenes.

METHODS AND RESULTS

Hybridoma clones were derived from B lymphocytes of mice immunized with L. monocytogenes serotype 4b and screened against this strain by an enzyme-linked immunosorbent assay. Twenty-nine clones secreting Mabs reactive with formalin-killed bacteria were obtained; 15, 8, 5 and 1 Mabs were immunoglobulin subclasses IgG2a, IgG2b, IgM and IgG1, respectively. Immunofluorescence or immunogold labelling demonstrated all except five IgM and one IgG2a Mabs bound to the surface of a live L. monocytogenes serotype 4b. The majority of the 23 surface-binding Mabs recognized linear epitopes on a 77-kDa protein. These surface-binding Mabs exhibited little or no cross-reactivity with non-4b serotypes (1/2a, 1/2b, 3a, etc.) of L. monocytogenes, five other Listeria species, Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium.

CONCLUSIONS

The Mabs recognizing a 77-kDa surface protein are novel antibodies with specificity and affinity for L. monocytogenes serotype 4b.

SIGNIFICANCE AND IMPACT OF THE STUDY

These anti-77 kDa surface protein Mabs may be explored as reagents for the development of Mabs-based diagnostic immunoassays for L. monocytogenes serotype 4b strains.

Influence of exposure intensity on the efficiency and speed of transmission of Foot-and-mouth disease

Foot-and-mouth disease virus (FMDV) can be spread by direct animal-to-animal contact, indirect contact facilitated by contaminated materials or by airborne spread. The rate of spread and the incubation period, as well as the severity of disease, depends on many variables including the dose received, the route of introduction, the virus strain, the animal species and the conditions under which the animals are kept. Quantitative data related to these variables are needed if model predictions are to be used in practical disease control. This experimental study quantifies the risk of transmission of FMDV in pigs exposed by contact, sheep exposed by indirect contact with pigs and sheep exposed to airborne FMDV. Groups of pigs were inoculated with the FMDV O UKG 34/2001 strain and susceptible pigs were then exposed to the inoculated animals at different stages of the infection cycle. The mean incubation period in the susceptible pigs ranged from 1 to 10 days. The length of the incubation period, severity of clinical disease and efficiency of spread were related to dose (i.e. infectiousness of source and intensity of contact). Low intensity transmission increased the proportion of subclinical or abortive infections. Local conditions are important in the efficiency and speed of transmission of FMDV. The results of the experiments described above suggest that transmission is frequency dependent rather than density dependent. The sheep experiments provided further evidence that development of infection and clinical disease is dependent upon local conditions. Dose, infectiousness, intensity of contact and local factors are thus important determinants for the outcome of an initial outbreak and must be truthfully accounted for in mathematical models of epidemiological spread.

Quantitative trait loci for porcine white blood cells and platelet-related traits in a White Duroc x Erhualian F resource population

White blood cell count and platelets are implicated as risk factors for common complex diseases. Genetic factors substantially affect these traits in humans and mice. However, little is known about the genetic architecture of these traits in pigs. To identify quantitative trait loci (QTL) for leucocyte- and platelet-related traits in pigs, the total leucocyte number and differential leucocyte counts including the fraction of basophils, eosinophils, lymphocytes, monocytes, neutrophils, and a series of platelet parameters including platelet count, mean platelet volume, platelet distribution width and plateletcrit were measured in 1033 F(2) animals on 240 days from a White Duroc x Erhualian intercross resource population. A total of 183 informative microsatellites distributed across 19 pig chromosomes (SSC) were genotyped across the entire resource population. Thirty-three QTL were identified for the examined traits, including eight genome-wide significant QTL for white blood cells and differential leucocyte counts on SSC2, 7, 8, 12 and 15 and six significant QTL for platelet-related traits on SSC2, 8, 13 and X. Erhualian or White Duroc alleles were not systematically associated with increased phenotypic values. These results not only confirmed many QTL identified previously in the mouse and swine, but also revealed a number of novel QTL for the traits recorded. Moreover, it is the first time that QTL for platelet-related traits in pigs have been reported.

Genetic evidence for the introgression of Western NR6A1 haplotype into Chinese Licha breed associated with increased vertebral number

There is evidence that NR6A1 is a strong candidate for being a causal gene underlying vertebral number in pigs. The Licha Black is one of the leanest Chinese indigenous pig breeds, having an average vertebral number of 21.5. The introgression of Western germplasm into Licha Black, resulting in increased vertebral number, has been assumed but is not confirmed. This study detected allele frequencies of the NR6A1 causative mutation (c.575T>C) in 519 pigs from three Western and seven Chinese breeds including Licha Black, and evaluated the genetic variation in a 650-kb region containing NR6A1 in the 10 breeds. Allele T for increased vertebral number was fixed in Western breeds. In contrast, this allele was very rare in most of the Chinese native breeds. Notably, the T allele was present in the Licha Black at a rather higher frequency (0.585) and in the Laiwu at lower frequency (0.250). As expected, selection pressure has wiped out the genetic variability in the 650 kb region in Western breeds. Conversely, Chinese indigenous breeds showed a high degree of genetic variability in this region. However, the Licha Black displayed dramatically reduced heterozygosity at the loci proximal to the causative mutation. Moreover, a high proportion (45.9%) of Licha Black pigs and a small number (21%) of Laiwu pigs had the Western NR6A1 haplotype, and the two breeds showed closer relationships with Western commercial breeds than other Chinese breeds in the phylogenic tree. When the results are taken together, this study supports the assumption that the Western NR6A1 haplotypes were introduced into Licha Black and possibly Laiwu and are associated with increased vertebral number.

FTY720 attenuates lesional interleukin-17(+) cell accumulation in rat experimental autoimmune neuritis

AIMS

Experimental autoimmune neuritis (EAN) is a well-known animal model of human demyelinating polyneuropathies. Here we have studied the spatiotemporal accumulation of interleukin (IL)-17(+) cells in sciatic nerves of EAN rats and effects of FTY720, an agonist of sphingosine-1-phosphate (S1P) receptors.

METHODS

In this study, we examined the spatiotemporal expression of IL-17 using immunohistochemistry and RT-PCR, and analysed the IL-17(+) cell proportion in blood and lymph nodes using flow cytometry.

RESULTS

In sciatic nerves of EAN rats, IL-17(+) cells were mainly found to concentrate around blood vessels and IL-17(+) cell accumulation was temporally correlated with severity of neurological signs. FTY720, which has been shown to reduce severity of EAN, attenuated accumulation of IL-17(+) cells in sciatic nerves, decreased IL-17(+) cell proportion in peripheral blood, but increased IL-17(+) cell proportion in lymph nodes, suggesting the involvement of S1P signal pathway in regulating IL-17(+) cell trafficking.

CONCLUSIONS

our data are consistent with the possibility that IL-17(+) cells might contribute to the pathogenesis of EAN and the S1P signal pathway may be involved in the in vivo trafficking of IL-17(+) cells.

Identification of the proteome composition occurring during the course of embryonic development of bees (Apis mellifera)

To investigate the proteome during embryonic development of honeybees, Apis mellifera, proteins were identified by two-dimensional gel electrophoresis, mass spectrometry and protein engine identification tools that were applied to MASCOT and Xproteo search engines. 312, 320, 315 proteins were detected in 24, 48 and 72 h embryos. Thirty-eight highly abundant proteins were identified at the three time points by MS fingerprinting. All 21 proteins could be identified as products of annotated genes of the honeybee. Identified proteins included six proteins related to the metabolism of carbohydrates and energy production, six proteins belonging to the heat shock protein family, three cytoskeletal proteins, four proteins related to the antioxidant system of the embryo and two proteins related to growth regulation of the embryo. Quantitative proteomics was applied to analyze differences in amounts of these proteins during the three above mentioned developmental stages. Our data present an initial molecular picture of honeybee embryos, and will hopefully pave the way for future research on this animal.

Collapsin response mediator protein-2 is a calmodulin-binding protein

Collapsin response mediator protein-2 (CRMP-2) plays a crucial role in axonal guidance and neurite outgrowth during neural development and regeneration. We have studied the interaction between calmodulin (CaM) and CRMP-2 and how Ca(2+)/CaM binding modulates the biological functions of CRMP-2. We have shown that CRMP-2 binds to CaM directly in a Ca(2+)-dependent manner. The CaM binding site of CRMP-2 is proposed to reside in the last helix of the folded domain, and in line with this, a synthesized peptide representing this helix bound to CaM. In addition, CaM binding inhibits a homotetrameric assembly of CRMP-2 and attenuates calpainmediated CRMP-2 proteolysis. Furthermore, a CaM antagonist reduces the number and length of process induced by CRMP-2 overexpression in HEK293 cells. Take together, our data suggest that CRMP-2 is a novel CaM-binding protein and that CaM binding may play an important role in regulating CRMP-2 functions.

CAPC expression correlates with breast tumor progression and invasion

Abstract #4044

Background: Recent studies identified a uncharacterized gene that encodes a molecule named as cytokeratin-associated protein in cancer (CAPC). RT-PCR analysis detected significant elevation of CAPC mRNA in 26 of 33 human breast cancers. Our current study attempted to elucidate CAPC protein expression profile in human breast tissues, to assess: [1] if CAPC expression is associated with tumor progression and invasion, and [2] if CAPC is co-expressed with BP1 and c-erbB2, two known invasiveness and aggressiveness-related proteins.&#x2028; Materials and Methods: Consecutive sections were prepared from paraffin-embedded breast tissues from 100 female patients with breast tumors that harbored co-existing normal, hyperplastic, in situ, and invasive components. Sets of four adjacent sections from each case were subjected to immunohistochemistry for CAPC, BP1, c-erbB2, and Ki-67. The expression status of these molecules in different tissue components were statistically compared.&#x2028; Results: In normal breasts and hyperplastic or in situ breast lesions, CAPC positive cells were generally distributed as duct or acinar clusters with a distinct boundary with their CAPC negative counterparts. Under low magnification of H&E stained sections, these CAPC positive duct or acinar clusters were morphologically indistinguishable from their CAPC negative counterparts. Under high magnification, however, the myoepithelial cell layers of these CAPC positive clusters were focally disrupted, and the associated epithelial cells often showed malignancy-associated nuclear alterations. Both the number of CAPC positive cells and the intensity of CAPC immunostaining linearly increased with tumor progression and invasion. In invasive lesions, a vast majority of cancer cells in over 80% of the cases expressed high levels of CAPC. A majority of the normal, benign, and malignant tumors with high levels of CAPC showed substantially higher expression of BP1 and c-erbB2, along with a higher proliferation index, compared to their morphologically similar CAPC negative counterparts . In non-mitotic cells, CAPC was localized mainly in the cytoplasm. In malignant mitotic cells, high levels of CAPC expression were localized close to the cell membrane, forming a ring-like structure surrounding condensed chromosomes. In contrast, no distinct CAPC was detected in normal or hyperplastic mitotic cells.&#x2028; Discussion: These findings suggest CAPC might be a tumor specific marker that could be used for the development of diagnostic and/or therapeutic agents.&#x2028; Acknowledgment: Supported in part by grant BCTR0706983 from The Susan G. Komen Breast Cancer Foundation and grant 2006CB910505 from the Ministry of Chinese Science and Technology Department.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4044.

Effect of PTK/ZK on the angiogenic switch in head and neck tumors

Transformation of small avascular masses of tumor cells into rapidly progressive cancers is triggered by the angiogenic switch, a process that involves vascular endothelial growth factor (VEGF) signaling. We have shown that VEGF enhances the survival and angiogenic potential of endothelial cells by activating the Bcl-2-CXCL8 signaling axis. The purpose of this study was to evaluate the effect of a small-molecule inhibitor of VEGF receptors (PTK/ZK) on the initial stages of head and neck tumor angiogenesis. In vitro, PTK/ZK blocked head and neck tumor cell (OSCC3 or UM-SCC-17B)-induced Bcl-2 and CXCL8 expression in endothelial cells. Oral administration of PTK/ZK decreased xenograft head and neck tumor microvessel density, and inhibited Bcl-2 and CXCL8 expression in tumor-associated endothelial cells. Analysis of these data demonstrates that PTK/ZK blocks downstream targets of VEGF signaling in endothelial cells, and suggests that PTK/ZK may inhibit the angiogenic switch in head and neck tumors.

The role of FDG-PET imaging and involved field radiotherapy in relapsed or refractory diffuse large B-cell lymphoma

We examined the role of fluorodeoxyglucose-positron emission tomography (FDG-PET) and the addition of involved field radiotherapy (IFRT) as potential modifiers of salvage therapy. From January 2000 to June 2007, 83 patients with chemosensitive relapsed or primary refractory diffuse large B-cell lymphoma (DLBCL) underwent FDG-PET scans following second-line chemotherapy before high-dose therapy with autologous stem cell rescue (HDT/ASCR). We evaluated the prognostic value of having a negative FDG-PET scan before HDT/ASCR and whether IFRT improved the outcomes. Median follow-up was 45 months, and the 3-year PFS, disease-specific survival (DSS) and OS were 72, 80 and 78%, respectively. Multivariate analysis revealed that a positive FDG-PET scan had worse PFS (hazard ratio=(HR) 3.4; P=0.014), DSS (HR=7.7; P=0.001) and OS (HR=5.4; P=0.001), and that patients not receiving IFRT had worse PFS (HR=2.7; P=0.03) and DSS (HR=2.8, P=0.059). Patients who received IFRT had better local control with fewer relapses within prior involved sites compared with those that did not receive IFRT (P=0.006). These outcomes confirm the important prognostic value of FDG-PET scans before undergoing HDT/ASCR. It also suggests that the role of IFRT should be evaluated further.