Image-guided subject-specific modeling of glymphatic transport and amyloid deposition.

The glymphatic system is a brain-wide system of perivascular networks that facilitate exchange of cerebrospinal fluid (CSF) and interstitial fluid (ISF) to remove waste products from the brain. A greater understanding of the mechanisms for glymphatic transport may provide insight into how amyloid beta (Aß) and tau agglomerates, key biomarkers for Alzheimer's disease and other neurodegenerative diseases, accumulate and drive disease progression. In this study, we develop an image-guided computational model to describe glymphatic transport and Aß deposition throughout the brain. Aß transport and deposition are modeled using an advection-diffusion equation coupled with an irreversible amyloid accumulation (damage) model. We use immersed isogeometric analysis, stabilized using the streamline upwind Petrov-Galerkin (SUPG) method, where the transport model is constructed using parameters inferred from brain imaging data resulting in a subject-specific model that accounts for anatomical geometry and heterogeneous material properties. Both short-term (30-min) and long-term (12-month) 3D simulations of soluble amyloid transport within a mouse brain model were constructed from diffusion weighted magnetic resonance imaging (DW-MRI) data. In addition to matching short-term patterns of tracer deposition, we found that transport parameters such as CSF flow velocity play a large role in amyloid plaque deposition. The computational tools developed in this work will facilitate investigation of various hypotheses related to glymphatic transport and fundamentally advance our understanding of its role in neurodegeneration, which is crucial for the development of preventive and therapeutic interventions.

Fractionation of foam-mat dried rice bean hydrolysates using membrane filtration and solid phase extraction: Peptide- and phenolic-based fractions with bioactive potential.

Flavourzyme was used to hydrolyze the germinated rice bean, and the hydrolysates were separated using membrane ultrafiltration with a molecular weight (MW) cut-off of 3 kDa. The ultrafiltration permeate fraction (UFP), non-fractionated hydrolysate (RH), and ultrafiltration retentate fraction (UFR) were foam-mat dried at two temperatures, 60 and 70 °C. The content of each phenolic composition in dried RH samples decreased with increasing drying temperature particularly gallic acid, p-coumaric acid, vanillin, rutin, and, quercetin dropped by 27, 24, 21, 35 and 33%, however the kind of phenolic compositions identified in dried samples was unaffected by drying temperature. Dried UFR and dried UFP had different chromatograms. When the dried UFP and dried UFR chromatograms were examined, it was discovered that the intensity of the peaks in the dried UFR chromatogram was much lower. The majority of phenolics can pass through ultrafiltration membranes with a molecular weight cut-off of 3 kDa, according to this finding. Individual phenolic compound levels in dried UFP samples were similar to RH, implying that the majority of phenolic components in dried rice bean protein hydrolysate were smaller than 3 kDa. With increasing drying temperature, gallic acid, p-coumaric acid, catechol, epicatechin and naringenin levels in dried UFP samples were decreased. The antioxidant capacity of dried rice bean hydrolysate was discovered to be due to phenolic components (gallic acid, epicatechin, catechol, ferulic acid, and rutin), which were found to be more prevalent than peptide fractions. As a result, rice bean hydrolysates could bring novel health advantages, which could lead to the development of nutraceuticals and food products.

Patient specific, imaging-informed modeling of rhenium-186 nanoliposome delivery via convection-enhanced delivery in glioblastoma multiforme.

Convection-enhanced delivery of rhenium-186 (186Re)-nanoliposomes is a promising approach to provide precise delivery of large localized doses of radiation for patients with recurrent glioblastoma multiforme. Current approaches for treatment planning utilizing convection-enhanced delivery are designed for small molecule drugs and not for larger particles such as186Re-nanoliposomes. To enable the treatment planning for186Re-nanoliposomes delivery, we have developed a computational fluid dynamics approach to predict the distribution of nanoliposomes for individual patients. In this work, we construct, calibrate, and validate a family of computational fluid dynamics models to predict the spatio-temporal distribution of186Re-nanoliposomes within the brain, utilizing patient-specific pre-operative magnetic resonance imaging (MRI) to assign material properties for an advection-diffusion transport model. The model family is calibrated to single photon emission computed tomography (SPECT) images acquired during and after the infusion of186Re-nanoliposomes for five patients enrolled in a Phase I/II trial (NCT Number NCT01906385), and is validated using a leave-one-out bootstrapping methodology for predicting the final distribution of the particles. After calibration, our models are capable of predicting the mid-delivery and final spatial distribution of186Re-nanoliposomes with a Dice value of 0.69 ± 0.18 and a concordance correlation coefficient of 0.88 ± 0.12 (mean ± 95% confidence interval), using only the patient-specific, pre-operative MRI data, and calibrated model parameters from prior patients. These results demonstrate a proof-of-concept for a patient-specific modeling framework, which predicts the spatial distribution of nanoparticles. Further development of this approach could enable optimizing catheter placement for future studies employing convection-enhanced delivery.

Starch Digestion Enhances Bioaccessibility of Anti-Inflammatory Polyphenols from Borlotti Beans (Phaseolus vulgaris).

The consumption of beans has been associated with chronic disease prevention which may be attributed to the polyphenols present in the seed coat and endosperm. However, their bioaccessibility is likely to be limited by interactions with bean matrix components, including starch, protein and fibre. The aim of this project was to evaluate the effect of domestic processing and enzymatic digestion on the bioaccessibility of polyphenols from Borlotti beans (Phaseolus vulgaris) and to test their anti-inflammatory properties in a macrophage cell model. In vitro digestion of cooked beans released twenty times more polyphenols (40.4 ± 2.5 mg gallic acid equivalents (GAE)/g) than domestic processing (2.22 ± 0.1 mg GAE/g), with starch digestion contributing to the highest release (30.9 ± 0.75 mg GAE/g). Fluorescence microscopy visualization of isolated bean starch suggests that polyphenols are embedded within the granule structure. LC-MS analysis showed that cooked Borlotti bean contain flavonoids, flavones and hydroxycinnamic acids, and cooked bean extracts exerted moderate anti-inflammatory effects by decreasing mRNA levels of IL1ß and iNOS by 25% and 40%, respectively. In conclusion, the bioaccessibility of bean polyphenols is strongly enhanced by starch digestion. These polyphenols may contribute to the health benefits associated with bean consumption.

In vivo evidence supporting a metastasis suppressor role for Stard13 (Dlc2) in ErbB2 (Neu) oncogene induced mouse mammary tumors.

Overexpression of dominant oncogenes and the loss of tumor suppressor genes are basic genetic events in the acquisition of the malignant phenotype. The erb-b2 receptor tyrosine kinase 2 (ERBB-2) proto-oncogene is overexpressed in 20-30% of human breast cancers. The StAR related lipid transfer domain containing 13 gene (STARD13), also known as Deleted in Liver Cancer-2 (DLC-2), maps to chromosome band 13q12.3 and is frequently downregulated in human cancers, including 72% of breast cancers. It encodes a RhoGAP protein with sterile α motif (SAM) and StAR-related lipid transfer (START) domains. The objective of this study was to determine if loss of Stard13 plays a role in mammary tumor progression using transgenic mice expressing the activated ErbB-2 (Neu) oncogene and Cre recombinase (NIC) in mammary epithelium under transcriptional control of the murine mammary tumor virus (MMTV) promoter (MMTV-NIC). These mice were crossed with a conditional Stard13 knockout mouse (floxed exon 3), resulting in simultaneous Neu expression and Stard13 deletion, specifically in the mammary epithelium. We found that loss of Stard13 did not alter tumor growth nor significantly modify overall survival and tumor free survival. However, there was an increase in the total number of lung metastases in the Stard13 heterozygous or homozygous mice compared with the parental MMTV-NIC strain. Altogether our results indicate that Stard13 acts as a metastasis suppressor rather than a tumor suppressor gene, in Neu oncogene induced mammary tumorigenesis.

Effect of acid pretreatment and the germination period on the composition and antioxidant activity of rice bean (Vigna umbellata).

This research evaluated effect of germination period and acid pretreatment on chemical composition and antioxidant activity of rice bean sprouts. Moisture, total phenolics, reducing sugar and B vitamins (thiamine, riboflavin, and niacin) content of steamed sprouts increased with increasing germination time (p⩽0.05). Pretreatment with 1% (w/v) citric acid for 6h significantly increased the total phenolic content. The 18-h-germinated rice beans showed the highest crude protein content, as determined using the Kjeldahl method. During germination, acid pretreatment led to a significant decrease in the intensity of the 76-kDa band. Germination caused a significant increase in radical scavenging activity and ferric reducing antioxidant power, especially in sprouts from citric acid-treated seeds. The antioxidant activities of the ethanolic extracts from both pretreated beans and the control were 1.3-1.6 times higher than those obtained from the water extracts. Major phenolics found in both 0-h and 18-h-germinated rice beans were catechin and rutin.

Dlc1 interaction with non-muscle myosin heavy chain II-A (Myh9) and Rac1 activation.

The Deleted in liver cancer 1 (Dlc1) gene codes for a Rho GTPase-activating protein that also acts as a tumour suppressor gene. Several studies have consistently found that overexpression leads to excessive cell elongation, cytoskeleton changes and subsequent cell death. However, none of these studies have been able to satisfactorily explain the Dlc1-induced cell morphological phenotypes and the function of the different Dlc1 isoforms. Therefore, we have studied the interacting proteins associated with the three major Dlc1 transcriptional isoforms using a mass spectrometric approach in Dlc1 overexpressing cells. We have found and validated novel interacting partners in constitutive Dlc1-expressing cells. Our study has shown that Dlc1 interacts with non-muscle myosin heavy chain II-A (Myh9), plectin and spectrin proteins in different multiprotein complexes. Overexpression of Dlc1 led to increased phosphorylation of Myh9 protein and activation of Rac1 GTPase. These data support a role for Dlc1 in induced cell elongation morphology and provide some molecular targets for further analysis of this phenotype.

The Deleted in Liver Cancer 1 (Dlc1) tumor suppressor is haploinsufficient for mammary gland development and epithelial cell polarity.

BACKGROUND: Deleted in Liver Cancer 1 (Dlc1) is a tumor suppressor gene, which maps to human chromosome 8p21-22 and is found frequently deleted in many cancers including breast cancer. The promoter of the remaining allele is often found methylated. The Dlc1 gene encodes a RhoGAP protein that regulates cell proliferation, migration and inhibits cell growth and invasion when restored in Dlc1 deficient tumor cell lines. This study focuses on determining the role of Dlc1 in normal mammary gland development and epithelial cell polarity in a Dlc1 gene trapped (gt) mouse. METHODS: Mammary gland whole mount preparations from 10-week virgin heterozygous Dlc1(gt/+) gene-trapped mice were compared with age-matched wild type (WT) controls. Hematoxylin-Eosin (H&E) and Masson's Trichrome staining of histological sections were carried out. Mammary glands from Dlc1(gt/+) mice and WT controls were enzymatically digested with collagenase and dispase and then cultured overnight to deplete hematopoietic and endothelial cells. The single cell suspensions were then cultured in Matrigel for 12 days. To knockdown Dlc1 expression, primary WT mammary epithelial cells were infected with short hairpin (sh) RNA expressing lentivirus or with a scrambled shRNA control. RESULTS: Dlc1(gt/+) mice showed anomalies in the mammary gland that included increased ductal branching and deformities in terminal end buds and branch points. Compared to the WT controls, Masson's Trichrome staining showed a thickened stromal layer with increased collagen deposition in mammary glands from Dlc1(gt/+) mice. Dlc1(gt/+) primary mammary epithelial cells formed increased solid acinar spheres in contrast with WT and scrambled shRNA control cells, which mostly formed hollow acinar structures when plated in 3D Matrigel cultures. These solid acinar structures were similar to the acinar structures formed when Dlc1 gene expression was knocked down in WT mammary cells by shRNA lentiviral transduction. The solid acinar structures were not due to a defect in apoptosis as determined by a lack of detectible cleaved caspase 3 antibody staining. Primary mammary cells from Dlc1(gt/+) mice showed increased RhoA activity compared with WT cells. CONCLUSIONS: The results illustrate that decreased Dlc1 expression can disrupt the normal cell polarization and mammary ductal branching. Altogether this study suggests that Dlc1 plays a role in maintaining normal mammary epithelial cell polarity and that Dlc1 is haploinsufficient.

Transport of trans-tiliroside (kaempferol-3-ß-D-(6"-p-coumaroyl-glucopyranoside) and related flavonoids across Caco-2 cells, as a model of absorption and metabolism in the small intestine.

1. Absorption and metabolism of tiliroside (kaempferol 3-ß-D-(6"-p-coumaroyl)-glucopyranoside) and its related compounds kaempferol, kaempferol-3-glucoside and p-coumaric acid were investigated in the small intestinal Caco-2 cell model. Apparent permeation (Papp) was determined as 0.62 × 10(-6) cm/s, 3.1 × 10(-6) cm/s, 0 and 22.8 × 10(-6) cm/s, respectively. 2. Mechanistic study showed that the transportation of tiliroside, kaempferol-3-glucoside and p-coumaric acid in Caco-2 model were transporter(s) involved, while transportation of kaempferol was solely by passive diffusion mechanism. 3. Efflux transporters, multi-drug-resistance-associated protein-2 (MRP2), were shown to play a role in limiting the uptake of tiliroside. Inhibitors of MRP2, (MK571 and rifampicin) and co-incubation with kaempferol (10 µM), increased transfer from the apical to the basolateral side by three to five fold. 4. Metabolites of kaempferol-3-glucoside and p-coumaric acid were not detected in the current Caco-2 model, while tiliroside was metabolised to a limited extent, with two tiliroside mono-glucuronides identified; and kaempferol was metabolised to a higher extent, with three mono-glucuronides and two mono-sulfates identified. 5. In conclusion, tiliroside was metabolised and transported across Caco-2 cell membrane to a limited extent. Transportation could be increased by applying MRP2 inhibitors or co-incubation with kaempferol. It is proposed that tiliroside can be absorbed by human; future pharmacokinetics studies are warranted in order to determine the usefulness of tiliroside as a bioactive agent.

Determination of amygdalin in apple seeds, fresh apples and processed apple juices.

Cyanogenic glycosides are natural plant toxicants. Action by endogenous plant enzymes can release hydrogen cyanide causing potential toxicity issues for animals including humans. We have quantified amygdalin in seeds from different apple varieties, determined the effects of processing on the amygdalin content of apple juice and quantified amygdalin in commercially-available apple juices. Amygdalin contents of seeds from fifteen varieties of apples ranged from 1 mg g(-1) to 4 mg g(-1). The amygdalin content of commercially-available apple juice was low, ranging from 0.01 to 0.04 mg ml(-1) for pressed apple juice and 0.001-0.007 mg ml(-1) for long-life apple juice. Processing led to juice with low amygdalin content, ranging from 0.01 mg ml(-1) to 0.08 mg ml(-1). The results presented show that the amygdalin contents of commercially-available apple juices are unlikely to present health problems to consumers.

Comparative chemical and biochemical analysis of extracts of Hibiscus sabdariffa.

Hibiscus sabdariffa extracts have attracted attention because of potentially useful bioactivity. However, there have been no systematic studies of extraction efficiencies of H. sabdariffa. The nature of extracts used in different studies has varied considerably, making comparisons difficult. Therefore, a systematic study of extracts of H. sabdariffa made with different solvents was carried out using water, methanol, ethyl acetate and hexane in the presence/absence of formic acid, using different extraction times and temperatures. The extracts were analysed for total polyphenol content, antioxidant capacity using DPPH, FRAP and TEAC assays, and specific anthocyanins were determined using HPLC and LC-MS. The results showed the highest antioxidant capacities were obtained by extracting using water, with or without formic acid, for 10 min at 100°C. These extracts provided the highest concentrations of cyanidin 3-sambubioside and delphinidin 3-sambubioside. It will be important to use extraction conditions giving optimal extraction efficiencies for subsequent bioactivity experiments.

Development and application of an enzyme-linked immunosorbent assay (ELISA) for the quantification of amygdalin, a cyanogenic glycoside, in food.

Amygdalin is a member of the cyanogenic glycoside group of plant secondary metabolites capable of generating hydrogen cyanide under certain conditions. As a consequence, the cyanogenic glycosides have been associated with incidents of acute and subacute food poisoning. Specific antibodies were raised against an amygdalin-bovine serum albumin immunogen synthesized using a novel approach. The antibodies were used in a microtitration plate enzyme-linked immunosorbent assay (ELISA) for the quantification, for the first time, of amygdalin in commercially available foods. Correlation of results with high-performance liquid chromatography was very high (r = 0.983). The limit of detection of the immunoassay was 200 ± 0.05 pg mL(-1), and the 50% inhibitory concentration of amygdalin was 50 ± 0.02 ng mL(-1), making the ELISA particularly sensitive.

Amygdalin content of seeds, kernels and food products commercially-available in the UK.

Cyanogenic glycosides are a large group of secondary metabolites that are widely distributed in the plant kingdom, including many plants that are commonly consumed by humans. The diverse chemical nature of cyanogenic glycosides means that extraction and analysis of individual compounds can be difficult. In addition, degradation can be rapid under appropriate conditions. Amygdalin is one of the cyanogenic glycosides found, for example, in apples, apricots and almonds. We have developed and applied a high performance liquid chromatographic procedure for amygdalin quantification to investigate extraction efficiency and to determine levels in a range of commercially-available foods for the first time. Our results show that seed from Rosaceae species contained relatively high amounts (range 0.1-17.5 mg g(-1)) of amygdalin compared to seed from non-Rosaceae species (range 0.01-0.2 mg g(-1)). The amygdalin content of processed food products was very low.

The role of Dlc1 isoform 2 in K-Ras2(G12D) induced thymic cancer.

The Deleted in liver cancer one (Dlc1) tumor suppressor gene encodes a RhoGTPase activating protein (RhoGAP). The Dlc1 gene has multiple transcriptional isoforms and we have previously established a mouse strain containing a gene trap (gt) insertion, which specifically reduces the expression of the 6.1 kb isoform (isoform 2). This gene trapped allele when homozygous results in embryonic lethality and the heterozygous gene trapped mice do not show an increased incidence of cancers, suggesting that cooperating oncogenic changes may be required for transformation. In the present work, we have studied the in vivo cooperation between oncogenic K-Ras2 and Dlc1 genes in tumourigenesis. We have observed an increase in invasive thymic cancers, including both thymomas and lymphomas, resulting in significantly shortened life spans in mice heterozygous for the gt Dlc1 allele and an inducible LSL-K-Ras2(G12D) allele compared with the LSL-K-Ras2(G12D) only mice. The heterozygous mice showed a high degree of metastasis in the lung. We have found tumour specific selective hypermethylation of the Dlc1 isoform 2 promoter and reduction of the corresponding protein expression in thymic lymphoma (TL) and thymic epithelial carcinoma (TEC) derived from the thymic tumours. The Dlc1 deficient thymic lymphoma cell lines exhibited increased trans-endothelial cell migration. TEC cell lines also exhibited increased stress fiber formation and Rho activity. Introduction of the three Dlc1 isoforms tagged with GFP into these cells resulted in different morphological changes. These results suggest that loss of expression of only isoform 2 may be sufficient for the development of thymic tumors and metastasis.

Effects of pH on the ability of flavonoids to act as Pickering emulsion stabilizers.

The flavonoids tiliroside, rutin and naringin have been investigated as stabilizers of Pickering oil-in-water (O/W) emulsions. The mean droplet size of tetradecane emulsions was considerably smaller at higher pH, especially for rutin. The solubility of flavonoids in the aqueous phase was 4-6 times higher at pH 8 compared to pH 2 for tiliroside and rutin, although all absolute solubilities remained low (<1 mM). This agreed with a slight increase in surface activity of tiliroside and rutin at the O-W interface at pH 8 compared to pH 2. However, improved emulsion stabilization at higher pH is better explained by the significant increase in ζ-potential of the flavonoid particles to more negative values at pH 8, which will improve particle dispersion and increase the charge on the droplets stabilized by them. A buckwheat tea extract, rich in rutin, was also shown to be an effective stabilizer of sunflower O/W emulsions.

Flavanols and methylxanthines in commercially available dark chocolate: a study of the correlation with nonfat cocoa solids.

Intake of flavanols, a subgroup of dietary polyphenols present in many fruits and vegetables, may be associated with health benefits, particularly with reducing the risk of coronary diseases. Cocoa and chocolate products are rich in flavanol monomers, oligomers, and polymers (procyanidins). This study used normal phase HPLC to detect, identify, and quantify epicatechin, catechin, total monomers, procyanidin oligomers and polymers in 14 commercially available chocolate bars. In addition, methylxanthines (theobromine and caffeine) were also quantified. Nonfat cocoa solids (NFCS) were determined both gravimetrically and by calculation from theobromine contents. The flavanol levels of 12 commonly consumed brands of dark chocolate have been quantified and correlated with % theobromine and % NFCS. Epicatechin comprised the largest fraction of total chocolate flavonoids, with the remainder being catechin and procyanidins. Calculated NFCS did not reflect epicatechin (R(2) = 0.41) or total flavanol contents (R(2) = 0.49). Epicatechin (R(2) = 0.96) was a reliable marker of total flavanols, catechin (R(2) = 0.67) to a lesser extent. All dark chocolate tested contained higher levels of total flavanols (93.5-651.1 mg of epicatechin equiv/100 g of product) than a milk or a white "chocolate" (40.6 and 0.0 mg of epicatechin equiv/100 g, respectively). The amount and integrity of procyanidins often suffer in the manufacturing of chocolate, chiefly due to oxidation and alkalinization. In this study, the labeled cocoa content of the chocolate did not always reflect analyzed levels of flavonoids. Increasingly, high % NFCS is being used commercially to reflect chocolate quality. If the flavanol content of chocolate is accepted to be a key determinant of health benefits, then continued monitoring of flavanol levels in commercially available chocolate products may be essential for consumer assurance.

Particle-stabilizing effects of flavonoids at the oil-water interface.

It has been shown that some common food flavonoids can act as excellent stabilizers of oil-in-water emulsions through their adsorption as water-insoluble particles to the surface of the oil droplets, i.e., Pickering emulsions are formed. Flavonoids covering a wide range of octanol-water partition coefficients (P) were screened for emulsification behavior by low shear mixing of flavonoid+n-tetradecane in a vortex mixer. Most flavonoids with very high or very low P values were not good emulsifiers, although there were exceptions, such as tiliroside, which is very insoluble in water. When a high shear jet homogenizer was used with 20 vol% oil in the presence of 1 mM tiliroside, rutin, or naringin, much finer emulsions were produced: the average droplet sizes (d32) were 16, 6, and 5 µm, respectively. These results may be highly significant with respect to the delivery of such insoluble compounds to the gut, as well as their digestion and absorption.

Identification and characterization of Dlc1 isoforms in the mouse and study of the biological function of a single gene trapped isoform.

BACKGROUND: The Dlc1 (deleted in liver cancer 1) tumour suppressor gene codes for a RhoGTPase activating protein that is found inactivated in many tumour types. Several transcriptional isoforms have been described but the functional significance and tissue distribution of each form is presently poorly understood. Also, differences in the number of isoforms and splice variants reported still exist between different mammalian species. In order to better understand the number and function of the different variants of the Dlc1 gene in the mouse, we have carried out a detailed analysis. Extensive 3' RACE experiments were carried out in order to identify all possible Dlc1 isoforms and splice variants in the mouse. In addition, we have generated a gene trapped mouse that targets one of these isoforms in order to study its biological function. The effect of this gene trap insertion on the splicing of other isoforms has also been studied. RESULTS: In addition to the known 6.1 and 6.2 Kb transcripts of Dlc1, our study revealed the existence of a novel 7.6 Kb transcriptional isoform in the mouse, which corresponds to the human 7.4 Kb (KIAA1723) cDNA transcript. A gene trapped embryonic cell line, with an insertion between Exon 1 and 2 of the 6.1 Kb transcriptional isoform, was used to generate a transgenic mouse. This line showed a significant reduction in the expression of the trapped isoform. However, reduced expression of the other isoforms was not seen. Mice heterozygous for the gene trapped allele were phenotypically normal, but homozygous mutant embryos did not survive beyond 10.5 days post coitum. Dlc1gt/gt embryos showed defects in the brain, heart, and placental blood vessels. Cultured serum-free mouse embryo cells from Dlc1 deficient embryos had elevated RhoA activity and displayed alterations in the organization of actin filaments and focal adhesions. The Dlc1 deficient cells also exhibited increased wound closure in an in vitro scratch assay. CONCLUSIONS: The mouse has three major transcriptional isoforms of the Dlc1 gene that are differentially expressed in various tissues. A mouse with exon 1 of the 6.1 Kb transcript gt resulted in hypomorphic expression of Dlc1 protein and an embryonic lethal phenotype in the homozygous condition, which indicates that this isoform plays a major role in mouse development. The Dlc1 deficient cells showed altered cytoskeleton structure, increased RhoA activity and cellular migration.

Duplication of Subcytoband 11E2 of Chromosome 11 Is Regularly Associated with Accelerated Tumor Development in v-abl/myc-Induced Mouse Plasmacytomas.

Chromosome 11 aberrations constitute the second most frequent chromosomal aberration in mouse plasmacytomas (PCTs) in which both the myc and abl oncogenes are constitutively expressed. In these tumors, previous G-banding studies had revealed numerical aberrations including duplication of the entire chromosome 11 or segments of telomeric bands D and E. The trisomy of chromosome 11 was always associated with accelerated pristane + v-abl/myc-induced PCT development. In the present study, PCT development was studied in a unique BALB/c congenic mouse strain, (T38HxBALB/c) F1, carrying a reciprocal translocation between chromosomes X and 11. After v-abl/myc induction, PCTs in this strain had acquired a nonrandom duplication of subcytoband 11E2. This duplication was always associated with accelerated PCT development. Corresponding synteny regions in the human and rat are changed in many tumors and involved in duplication, amplification, or translocation events. Thus, together with these synteny data, our findings strongly suggest a causal involvement of 11E2 in the acceleration of v-abl/myc-induced PCTs.

Optical resonance-enhanced absorption-based near-field immunochip biosensor for allergen detection.

An optical immunochip biosensor has been developed as a rapid method for allergen detection in complex food matrixes, and its application evaluated for the detection of the egg white allergens, ovalbumin and ovomucoid. The optical near-field phenomenon underlying the basic principle of the sensor design is called resonance-enhanced absorption (REA), which utilizes gold nanoparticles (Au NPs) as signal transducers in a highly sensitive interferometric setup. Using this approach, a novel, simple, and rapid colorimetric solid-phase immunoassay on a planar chip substrate was realized in direct and sandwich assay formats, with a detection system that does not require any instrumentation for readout. Semiquantitative immunochemical responses are directly visible to the naked eye of the analyst. The biosensor shows concentration-dependent color development by capturing antibody-functionalized Au NPs on allergen-coated chips and has a detection limit of 1 ng/mL. To establish a rapid method, we took advantage of the physicochemical microenvironment of the Au NP-antibody bioconjugate to be bound directly over an interacting poly(styrene-methyl methacrylate) interlayer by an immobilized antigen. In the direct assay format, a coating time with allergen of only 5 min under "soft" nondenaturing conditions was sufficient for accurate reproducibility and sensitivity. In conclusion, the REA-based immunochip sensor is easy to fabricate, is reproducible and selective in its performance, has minimal technical requirements, and will enable high-throughput screening of affinity binding interactions in technological and medical applications.