Cell adaptation to a physiologically relevant ECM mimic with different viscoelastic properties

To successfully induce tissue repair or regeneration in vivo, bioengineered constructs must possess both optimal bioactivity and mechanical strength. This is because cell interaction with the extracellular matrix (ECM) produces two different but concurrent signaling mechanisms: ligation-induced signaling, which depends on ECM biological stimuli, and traction-induced signaling, which depends on ECM mechanical stimuli. In this report, we provide a fundamental understanding of how alterations in mechanical stimuli alone, produced by varying the viscoelastic properties of our bioengineered construct, modulate phenotypic behavior at the whole-cell level. Using a physiologically relevant ECM mimic composed of hyaluronan and fibronectin, we found that adult human dermal fibroblasts modify their mechanical response in order to match substrate stiffness. More specifically, the cells on stiffer substrates had higher modulus and a more stretched and organized actin cytoskeleton (and vice versa), which translated into larger traction forces exerted on the substrate. This modulation of cellular mechanics had contrasting effects on migration and proliferation, where cells migrated faster on softer substrates while proliferating preferentially on the stiffer ones. These findings implicate substrate rigidity as a critical design parameter in the development of bioengineered constructs aimed at eliciting maximal cell and tissue function.

T cell leukemia-associated human Notch/translocation-associated Notch homologue has I kappa B-like activity and physically interacts with nuclear factor-kappa B proteins in T cells

Translocation-associated Notch homologue (TAN-1), a gene originally cloned from the translocation breakpoint of a human T cell leukemia carrying a 9:7(q34.3) translocation, encodes a protein belonging to the Notch/Lin-12/Glp-1 receptor family. These receptors mediate the specification of numerous cell fates during development in invertebrates and vertebrates. The intracellular portion of Notch/TAN-1 contains six ankyrin repeats that are similar to those found in cytoplasmic I kappa B proteins. I kappa B proteins are specific inhibitors of nuclear factor (NF)-kappa B/Rel transcription factors. Here we show that TAN-1 has functional properties of an I kappa B-like regulator with specificity for the NF-kappa B p50 subunit. A recombinant polypeptide corresponding to the cytoplasmic portion of TAN-1 (TAN-1C) specifically inhibited the DNA binding of p50-containing NF-kappa B complexes. When overexpressed in an appropriate cell line, TAN-1C prevented kappa B-dependent transactivation in transient reporter gene assays in a fashion similar to the structurally related protein, Bcl-3. TAN-1C could activate kappa B-dependent gene expression by attenuating the inhibitory effect of an excess of p50 homodimers. Immunoprecipitation experiments showed that the TAN-1 from a T cell line is associated with NF-kappa B containing p50 and p65 subunits. These observations indicate that TAN-1C may directly engage NF-kappa B transcription factors and modulate nuclear gene expression.

Human Notch-1 inhibits NF-kappa B activity in the nucleus through a direct interaction involving a novel domain

Notch participates in diverse cell fate decisions throughout embryonic development and postnatal life. Members of the NF-kappaB/Rel family of transcription factors are involved in the regulation of a variety of genes important for immune function. The biological activity of the NF-kappaB transcription factors is controlled by IkappaB proteins. Our previous work demonstrated that an intracellular, constitutively active form of human Notch-1/translocation-associated Notch homologue-1 (Notch(IC)) functions as an IkappaB molecule with specificity for the NF-kappaB p50 subunit and physically interacts with NF-kappaB in T cells. In the current study, we investigated the roles of different domains of Notch(IC) in the regulation of NF-kappaB-directed gene expression and NF-kappaB DNA binding activity. We found that Notch(IC) localizes to the nucleus and that a region in the N-terminal portion of Notch(IC), not the six ankyrin repeats, is responsible for the inhibitory effects of Notch on NF-kappaB-directed gene expression and NF-kappaB DNA binding activity. The N-terminal portion of Notch(IC) inhibited p50 DNA binding and interacted specifically with p50 subunit, not p65 of NF-kappaB. The interaction between Notch and NF-kappaB indicates that in addition to its role in the development of the immune system, Notch-1 may also have critical functions in the immune response, inflammation, viral infection, and apoptosis through control of NF-kappaB-mediated gene expression.

Role of tyrosine phosphorylation in ligand-independent sequestration of CXCR4 in human primary monocytes-macrophages

The chemokine stromal cell-derived factor (SDF)-1 and its receptor, CXCR4, play important roles in human immunodeficiency virus type 1 (HIV-1) pathophysiology, leukocyte trafficking, inflammation, hematopoiesis, embryogenesis, angiogenesis, and cancer metastasis. The effects of cytokines on the regulation of CXCR4 function were investigated in human primary monocytes-macrophages. The expression of functional CXCR4 on the cell surface was demonstrated by the detection of ligand-induced Ca(2+) mobilization, chemotaxis, and ligand-induced receptor endocytosis. Surface CXCR4 expression was down-regulated by cytokines interleukin-4 (IL-4), IL-13, and granulocyte-macrophage colony-stimulating factor (GM-CSF) and up-regulated by IL-10 and transforming growth factor-beta 1. Down-regulation was mediated post-translationally, in the absence of protein degradation, through an endocytotic mechanism. In contrast to SDF-1 alpha-induced CXCR4 endocytosis, cytokine-induced endocytosis of this receptor was independent of actin filament polymerization. GM-CSF increased the expression of G protein-coupled receptor kinase 3 (GRK3), beta-arrestin-1, Pyk2, and focal adhesion kinase (FAK). Cytokine treatment also increased the total and tyrosine-specific phosphorylation of CXCR4 as well as the phosphorylation of FAK on tyrosine 397. It also induced the formation of GRK3.CXCR4 or FAK.CXCR4 complexes. Infection of macrophages by primary R5X4 and X4 isolates of HIV-1 was inhibited by IL-4, IL-13, and GM-CSF, an effect that was associated with down-regulation of surface CXCR4 expression. These data indicate that ligand-dependent and ligand-independent endocytoses of CXCR4 are mediated by different mechanisms. Cytokine-induced endocytosis of chemokine receptors may be of therapeutic value in HIV-1 infection, inflammation, tumor metastasis, and defective hematopoiesis.

Identification of human macrophage inflammatory proteins 1alpha and 1beta as a native secreted heterodimer

Chemokines are secreted proteins that function as chemoattractants for leukocytes. The chemokines macrophage inflammatory protein 1alpha and 1beta (MIP-1alpha and MIP-1beta) now have been shown to be secreted from activated human monocytes and peripheral blood lymphocytes (PBLs) as a heterodimer. Immunoprecipitation and immunoblot analysis revealed that antibodies to either MIP-1alpha or MIP-1beta precipitated a protein complex containing both MIP-1alpha and MIP-1beta under normal conditions from culture supernatants and lysates of these cells. Mass spectrometry of the complexes, precipitated from the culture supernatants of monocytes and PBLs, revealed the presence of NH(2)-terminal truncated MIP-1alpha (residues 5-70) together with either intact MIP-1beta or NH(2)-terminal truncated MIP-1beta (residues 3-69), respectively. The secreted MIP-1alpha/beta heterodimers were dissociated into their component monomers under acidic conditions. Exposure of monocytes or PBLs to monensin induced the accumulation of heterodimers composed of NH(2)-terminal truncated MIP-1alpha and full-length MIP-1beta in the Golgi complex. The mixing of recombinant chemokines in vitro demonstrated that heterodimerization of MIP-1alpha and MIP-1beta is specific and that it occurs at physiological conditions, pH 7.4, and in the range of nanomolar concentrations. The data presented here provide the first biochemical evidence for the existence of chemokine heterodimers under natural conditions. Formation of heterodimers of MIP-1alpha/beta may have an impact on intracellular signaling events that contribute to CCR5 and possibly to other chemokine receptor functions.

Effect of ozone treatment on deoxynivalenol and quality evaluation of ozonised wheat

Deoxynivalenol (DON) is the secondary metabolite of Fusarium graminearum, which is always found in Fusarium head blight of wheat. In this study, gaseous ozone was used to treat both DON solution and scabbed wheat to investigate the effectiveness of ozone treatment on DON degradation and the effect of ozone on the quality parameters of wheat. It was found that gaseous ozone had a significant effect on DON reduction in solution, when 10 mg l(-1) gaseous ozone was used to treat a 1 μg ml(-1) of DON solution, the degradation rate of DON was 93.6% within 30 s. Lower initial concentrations of DON solution treated with higher concentrations of ozone, and longer times showed higher DON degradation rates. Gaseous ozone was effective against DON in scabbed wheat. The degradation rate of DON increased with ozone concentration and processing time. The correlation between the time and degradation rate was y = -1.1926x(2) + 11.427x - 8.7787. In the process of ozone oxidation, a higher moisture content of wheat was more sensitive than that of lower moisture content to ozone under the same conditions. All samples were treated with different concentrations of ozone for 4 h to investigate the effect of ozone on wheat quality. No significant detrimental changes in the starch pasting properties of wheat were observed after all the samples were treated with ozone within 4 h. On the other hand, there was a slight rise in the dough development time and stability time, which meant the quality of flour improved after ozone treatment.

Sulfasalazine in ionic liquid form with improved solubility and exposure

An ionic liquid form of sulfasalazine demonstrates improved solubility (4000×), bioavailability (2.5×), andin vivoexposure over the neutral drug.

An in vivo study of the mechanical properties of facial skin and influence of aging using digital image speckle correlation

BACKGROUND/PURPOSE

The skin on the face is directly attached to the muscle through the superficial musculoaponeurotic system. We show that this can be used to probe skin mechanical properties, in vivo, using, digital image speckle correlation (DISC), a technique that measures the intrinsic cutaneous pore structure displacement following a natural facial deformation.

METHODS

We take a series of images, which are then analyzed with DISC to create a displacement vector diagram, from which we can obtain spatially resolved information regarding facial deformation. We then studied the functional form of the displacement as a function of age, location on the face, and skin treatment. Finally, through DISC vector field analysis we investigate the mechanism of wrinkle formation.

RESULTS

We first show that facial skin displacement follows the direction of muscular movement and reflects the magnitude of the applied forces. Using DISC vector field analysis, we find that as the skin ages the distribution of forces becomes more condensed, with a marked spatial asymmetry. Analysis of the data, in the perioral region, we find that the skin elasticity decreases exponentially with age, with a decay constant of approximately 32 years. Similar results, but with a larger amplitude, were also found for the periorbital region. Finally, DISC vector field analysis also shows that the location of maximal stress correlated with the location of existing facial wrinkles.

CONCLUSION

The DISC method, as a non-contact technique, is a potential clinical research tool for the diagnosis of facial skin condition and underlying muscular activity. We demonstrate how these factors can be used to monitor the effects of aging, formation of wrinkles, and the efficacy of topical applications of skin creams.

Impact of wheat globulin addition on dough rheological properties and quality of cooked noodles

Impact of globulin addition on the functional and protein structural properties of dough and cooked noodles were investigated. The underlying mechanism was explored through analyzing the interaction between globulin and gluten by using SDS-PAGE, size exclusion chromatography, free sulfhydryl/disulfide bond analysis, laser scanning confocal microscopy and Fourier transform infrared spectroscopy. Results showed that the stiffness/hardness and maximum resistance of dough and cooked noodles were both increased when globulin addition was 1.5% or higher. Besides, extensibility of cooked noodles was also improved when the addition up to 3.0%. The addition of globulin facilitated weakening the S-S bonds in the gluten network and cross-linked with SDS-soluble gluten mainly through non-covalent interactions, especially hydrophobic interactions. Meanwhile, a more rigid protein network structure was observed. Additionally, following cooking, globulin addition accelerated the aggregation of protein molecules. When the addition reached 3%, the protein conformation was transformed from β-sheets and random coils to β-turns.

Synergistic induction of apoptosis in primary CD4(+) T cells by macrophage-tropic HIV-1 and TGF-beta1

Depletion of CD4(+) T lymphocytes is a central immunological characteristic of HIV-1 infection. Although the mechanism of such CD4(+) cell loss following macrophage-tropic (R5) HIV-1 infection remains unclear, interactions between viral and host cell factors are thought to play an important role in the pathogenesis of HIV-1 disease. Based on the observation that TGF-beta1 enhanced expression of HIV chemokine coreceptors, the role of this host factor in virus effects was investigated using PBLs cultured in a nonmitogen-added system in the absence or presence of TGF-beta1. Most CD4 cells in such cultures had the phenotype CD25(-)CD69(-)DR(-)Ki67(-) and were CD45RO(bright)CD45RA(dim). Cultured cells had increased expression of CCR5 and CXCR4 and supported both HIV-1 entry and completion of viral reverse transcription. Virus production by cells cultured in the presence of IL-2 was inhibited by TGF-beta1, and this inhibition was accompanied by a loss of T cells from the culture and an increase in CD4(+) T cell apoptosis. Whereas R5X4 and X4 HIV-1 infection was sufficient to induce T cell apoptosis, R5 HIV-1 failed to induce apoptosis of PBLs in the absence of TGF-beta1 despite the fact that R5 HIV-1 depletes CD4(+) T cells in vivo. Increased apoptosis with HIV and TGF-beta1 was associated with reduced levels of Bcl-2 and increased expression of apoptosis-inducing factor, caspase-3, and cleavage of BID, c-IAP-1, and X-linked inhibitor of apoptosis. These results show that TGF-beta1 promotes depletion of CD4(+) T cells after R5 HIV-1 infection by inducing apoptosis and suggest that TGF-beta1 might contribute to the pathogenesis of HIV-1 infection in vivo.

Ultrafine grinding of wheat flour: Effect of flour/starch granule profiles and particle size distribution on falling number and pasting properties

In the present paper, the properties of different ultrafine flour samples, including particle size distribution, damaged starch content, falling number, and pasting properties, were examined. The results indicated that the particle size decreased significantly after jet milling, as the rotation speed and grinding time increased, and the damaged starch content significantly increased as the size of the flour/starch decreased; this is in contrast to the significant decrease in falling number. Significant differences in pasting temperature were observed between straight-grade flour (68.6°C) and five ultrafine flour samples (from 86.3 to 87.9°C). We also observed significant increases in peak viscosity, trough, breakdown viscosity, final viscosity, and setback as the flour particle size decreased from 43.07 µm to 25.81 µm (D50). The same parameters significantly decreased as the flour particle size decreased from 25.81 µm to 10.15 µm (D50). Correlation analysis identified a significant negative correlation between flour particle size (D50) and damaged starch content and pasting temperature, while a significant positive correlation was found with the falling number values. The results of this work may have an important impact on the quality of processed foods.

Determining the mechanical properties of rat skin with digital image speckle correlation

BACKGROUND

Accurate measurement of the mechanical properties of skin has numerous implications in surgical repair, dermal disorders and the diagnosis and treatment of trauma to the skin. Investigation of facial wrinkle formation, as well as research in the areas of skin aging and cosmetic product assessment can also benefit from alternative methodologies for the measurement of mechanical properties.

OBJECTIVE

A noncontact, noninvasive technique, digital image speckle correlation (DISC), has been successfully introduced to measure the deformation field of a skin sample loaded by a material test machine. With the force information obtained from the loading device, the mechanical properties of the skin, such as Young's modulus, linear limitation and material strength, can be calculated using elastic or viscoelastic theory.

METHODS

The DISC method was used to measure the deformation of neonatal rat skin, with and without a glycerin-fruit-oil-based cream under uniaxial tension.

RESULTS

Deformation to failure procedure of newborn rat skin was recorded and analyzed. Single skin layer failures were observed and located by finding the strain concentration. Young's moduli of freshly excised rat skin, cream-processed rat skin and unprocessed rat skin, 24 h after excision, were found with tensile tests to be 1.6, 1.4 and 0.7 MPa, respectively.

CONCLUSION

Our results have shown that DISC provides a novel technique for numerous applications in dermatology and reconstructive surgeries.

Effects of vacuum degree, mixing speed, and water amount on the moisture distribution and rheological properties of wheat flour dough

Effects of vacuum degrees (0.00, 0.02, 0.04, 0.06, 0.08 MPa) on water distribution state, tensile properties, stress relaxation properties, and viscoelasticity of dough, as well as the effects of mixing speed (50, 70, 90 rpm/min) and water content (40%, 45%, 50%) under optimum vacuum degree were studied. The results showed that the proper vacuum degree (0.06 MPa) could promote the full contact between flour and water and improved the water-holding capacity of the dough. Meanwhile, the dough had stronger tensile strength, the best viscoelasticity and the ability to recover from external deformation more quickly. Under the vacuum of 0.06 MPa, with the increasing of mixing speed, the response to the external force of dough increased first and then decreased. Adding more water reduced the strength of dough, weakened the response to external forces, and led to a significant decrease in tensile resistance and tensile area of the dough, as well as a decrease in viscoelasticity (p < 0.05). The proper vacuum mixing allowed the preparation of dough to require more water and less energy. PRACTICAL APPLICATION: In the processing of wheat flour products, vacuum mixing is considered to be beneficial to the quality of noodles and breads. As the intermediate of these products, the dough is of great significance for the monitoring of its rheological characteristics. In this study, a moderate vacuum degree led to a significant improvement in the rheological properties of the dough, and the processing performance was the best. Under the optimal vacuum degree, the influence of mixing speed and water amount cannot be ignored. Vacuum mixing is an efficient dough preparation method, which can produce certain economic benefits.

Effects of salt and kansui on rheological, chemical and structural properties of noodle dough during repeated sheeting process

Effects of different levels of salt (1-2%, fwb) and kansui (0.5-1%) on the rheological, chemical and structural characteristics of noodle dough developed by repeated sheeting were studied. The rupture stress was increased by salt and kansui. The rupture elongation was increased by salt while reduced by kansui. The rupture stress and elongation increased to a maximum at 3 or 4 sheeting passes then decreased. The larger polymeric glutenin (LPP) increased while glutenin macropolymer (GMP) and free SH contents declined with the increased sheeting passes except for the dough contained 1% kansui at which these indicators remained constant. The β-sheet was increased while the β-turn was decreased by salt and kansui. The results showed the LPP disaggregated from GMP through physical disentanglement and experienced a reaggregation process with the SS bonds participate in, but the addition of kansui especially at 1% concentration could inhibit the disaggregation of GMP through protein cross-linking.

Interactions between wheat globulin and gluten under alkali or salt condition and its effects on noodle dough rheology and end quality

The influences of wheat globulin on dough and noodle quality under alkali or salt conditionwere investigated, and the protein interactions were revealed. Results indicated that dough viscoelasticity, noodle hardness, springiness and extensibility of samples with globulin added were remarkably increased under alkali condition. However, the corresponding enhancement was less significant under salt condition. In dough system, added globulin decreased the protein surface hydrophobicity by 38.71%, implying the enhancement of hydrophobic interactions. Under salt and alkali conditions, added globulin further increased the β-sheets structure by 1.68% and 3.17%, respectively, indicating the enhancement of hydrogen bonds interaction. In addition, disulfide bonds interactions between globulin and gluten have also been demonstrated induced by alkali. The results were accountable for protein network polymerization observed in micro-structures. This paper provides new insights into the structural properties of wheat globulin, and demonstrates the excellent potential to improve noodle processing quality under alkali condition significantly.

Comparison of rheological behavior, microstructure of wheat flour doughs, and cooking performance of noodles prepared by different mixers

Large deformation characteristics in biaxial tensile and stress relaxation, and small deformation properties in frequency sweeping and microstructure of dough produced by three kinds of mixers were assessed in this study. Differences in noodle quality were also compared. Results indicated that dough made by vacuum or spiral mixer had good resistance to external force and good resilience. But the dough and noodles made by vacuum mixer showed the best tensile and cooking properties respectively, and had overall the best performance. Confocal microscopy revealed that the protein matrix of the three doughs formed along the direction of shear flow, whereas the starch granules of dough made by the vacuum mixer were tightly wrapped in gluten, resulting in a compact and sequential gluten network. Other samples showed signs of minor structural damage (pin mixer) or the presence of holes (spiral mixer). Assessment using Pearson correlation analysis identified a number of significant correlation coefficients between the dough rheological characteristics and noodle quality. Characterization of biaxial tensile and stress relaxation was advantageous for noodle assessment prediction. The index of flow and degree of deformation were negatively correlated with tensile properties. Frequency scanning is superior in predicting cooking and stretching characteristics of noodles. PRACTICAL APPLICATION: The research provides technical guidance for obtaining better dough in noodle processing.

Reduction of Aflatoxin B1 in Corn by Water-Assisted Microwaves Treatment and Its Effects on Corn Quality

Aflatoxin B₁ (AFB₁) is one of the most commonly found mycotoxin in corn, which is highly toxic, carcinogenic, teratogenic, and mutagenic for the health of humans and animals. In order to reduce the AFB₁ in corn, corn kernels were processed with Water-assisted Microwaves Treatment (WMT) and the feasibility of WMT processing on AFB₁ reduction and its effects on corn quality were analyzed. Increasing the treatment time and microwave power could increase the reduction of AFB₁, and the maximum reduction rate could reach 58.6% and 56.8%, respectively. There was no significant correlation between the initial concentration of AFB₁ and the reduction rate of AFB₁. During WMT, the main toxigenic molds were sterilized completely, and the moisture content of corn climbed up and then declined to the initial level. WMT could obviously increase the fatty acid value and pasting temperature of corn and reduce the all paste viscosity of corn. However, it had little effect on the color of corn. The results indicated that WMT could reduce AFB₁ effectively and avoid the vast appearance of heat-damaged kernels simultaneously. Undoubtedly, water played an important role in WMT. This result provides a new idea for the reduction of AFB₁ by microwave.

Growth inhibition of human nasopharyngeal carcinoma in athymic mice by anti-epidermal growth factor receptor monoclonal antibodies

Monoclonal antibodies (MoAbs) were developed against epidermal growth factor (EGF) receptor on the human epidermoid carcinoma cell line A431. The A431 antigen recognized by the MoAbs has an apparent molecular weight of approximately 170,000, with the same molecular weight as the CNE-2 cell line (poorly differentiated nasopharyngeal carcinoma). Administration of anti-EGF receptor MoAbs inhibited tumor formation, caused by the CNE-2 and A431 cell lines, in athymic mice. When the same MoAbs were used in therapy against Tca8113 (a human tongue carcinoma) and HeLa cells (a human cervical carcinoma), tumor growth was not affected. The number of EGF receptors and the apparent dissociation constants for 125I-EGF on CNE-2 and A431 were 1.3 x 10(5)/cell (Kd 7.7 x 10(-8) M) and 1.4 x 10(6)/cell (Kd 2.4 x 10(-9) M), respectively. Three anti-EGF receptor MoAbs were used in these studies. MoAbs 3 and 176, capable of competing with EGF for receptor binding, showed significant tumor growth inhibition. MoAb 101 was incapable of blocking the binding of EGF to its receptor and was not as effective as MoAbs 3 and 176 in tumor growth inhibition. Our observation is that in vitro, MoAb anti-EGF receptor is cytostatic, rather than cytocidal, against CNE-2 and A431.

Effects of wheat flour particle size on flour physicochemical properties and steamed bread quality

In this study, differently sized particles of wheat flour (from 52.36 μm to 108.89 μm) were obtained by adjusting the distance between the rolls (0.02, 0.04, 0.06, 0.08, and 0.1 mm) of a heart mill. Results showed that reducing the particle size significantly increased the damaged starch (DS) content. Uniaxial tensile measurement of dough showed that reducing the particle size of wheat flour can effectively increase the maximum tensile resistance, but the extensibility reaches the maximum in samples at medium particle diameter (78 and 66 μm). Additionally, the ratio of dynamic moduli (G″/G') decreased with a reducing particle size. The results of disulfide bond content, gluten microstructure, showed that finer flour granulation can strengthen the gluten network. The steamed bread (SB) making test showed that SB made from wheat flour of a smaller particle size had a significantly smaller specific volume than that made from a larger particle size. The texture profile analysis showed that with a decrease of wheat flour particle size, the hardness, chewiness of SB increased, the resilience decreased, and there was no significant difference in adhesiveness. Overall, the quality of SB made flour of medium particles (78 μm) is better.