Irreversible pressure-induced transformation of boron nitride nanotubes

We have used Raman spectroscopy to study the behavior of multi-walled boron nitride nanotubes and hexagonal boron nitride crystals under high pressure. While boron nitride nanotubes show an irreversible transformation at about 12 GPa, hexagonal boron nitride exhibits a reversible phase transition at 13 GPa. We also present molecular dynamics simulations which suggest that the irreversibility of the pressure-induced transformation in boron nitride nanotubes is due to the polar nature of the bonds between boron and nitrogen.

Hepatic Metabolism of MK-0457, a Potent Aurora Kinase Inhibitor: Interspecies Comparison and Role of Human Cytochrome P450 and Flavin-Containing Monooxygenase

MK-0457 (N-[4([4-(4-methylpiperazin-1-yl)-6-[(3-methyl-1H-pyrazol-5 -yl)amino]pyrimidin-2-yl]thio)phenyl]cyclopropanecarboxamide), an Aurora kinase inhibitor in development for the treatment of cancer, was evaluated for its in vitro metabolism in different species. This compound primarily underwent N-oxidation and N-demethylation in human, monkey, dog, and rat liver preparations. However, N-demethylation was less significant in dogs. The formation of minor metabolites varied with species, but all metabolites generated in human hepatocytes were observed in animals. Results of immunoinhibition, selective chemical inhibition, thermal inactivation, and metabolism by recombinant cytochromes P450 and flavin-containing monoogygenases (FMOs) strongly suggest that CYP3A4 and FMO3 comparably contributed to MK-0457 N-oxidation in human liver microsomes, where the reaction conformed to Michaelis-Menten kinetics. These studies indicate a major role of CYP2C8 in the N-demethylation reaction, whereas CYP3A4 only made a minor contribution. However, significant substrate inhibition was observed with MK-0457 N-demethylation at high substrate concentrations (>10 microM) in human liver microsomes relative to the anticipated therapeutic exposure. A multienzyme metabolic pathway such as this may mitigate the potential of drug interactions in clinical treatment with MK-0457.

Genotypic variation in phosphorus utilisation of soybean [Glycine max (L.) Murr.] grown in various sparingly soluble P sources

This study compared the utilisation of sparingly soluble P among soybean genotypes selected from 3 geographical regions with contrasting soil pH. Plants of 5 genotypes from each region were grown for 72 days in soil columns supplied with hydroxyapetite (Ca-P), AlPO4 (Al-P), or FePO4 (Fe-P) at a rate of 25 mg P/kg soil. NaH2PO4 (Na-P) was used as control at the same rate. Shoot weights ranged from 2.4 to 5.9 g/plant. On average, the genotypes selected from calcareous soils of north-west China produced the highest shoot biomass whereas those from neutral soils of the north-east region the least. Root biomass and root surface area followed the same trend. In contrast, the root-to-shoot weight ratio was highest in Fe-P and lowest in Na-P while root length in Na-P and Fe-P was greater than in the other P forms. The genotypes from the north-east region had higher P concentration in the shoot than those from the other 2 regions. Total P uptake ranged from 9.0 to 15.9 mg/plant for Na-P, and from 6.3 to 12.4 for the sparingly soluble P. Average total P uptake was the highest for the genotypes from the north-west region, and was greatest in Na-P and lowest in Fe-P. The genotypes from the north-east region displayed the greatest ability to use sparingly soluble P, and those from the north-west the least relative to Na-P. Total P uptake from the sparingly soluble P correlated highly with plant biomass production, N2 fixation and nodulation, and seed P, while the relative P uptake correlated highly with P concentration in shoots but neither correlated with root carboxylate release nor leachate pH. The results suggest that there is a substantial genotypic variation in utilisation of sparingly soluble P, which is related to early vigour, nodulation, and seed P reserve but not to origin site pH or root exudation.

Repellent and insecticidal activities of essential oils from Artemisia princeps and Cinnamomum camphora and their effect on seed germination of wheat and broad bean

Repellent and insecticidal activities of essential oils extracted from leaves of Artemisia princeps Pamp and seeds of Cinnamomum camphora (L.) Presl. against storage pests Sitophillus oryzae L. and Bruchus rugimanus Bohem were investigated. Results showed that the two individual oils displayed good, but their mixture (1:1) exhibited much better repellent activities at concentrations from 250 to 1000 microg g(-1) and insecticidal actions at concentrations 1000 microg g(-1) against the test beetles S. oryzae and B. rugimanus. Oils from A. princeps and C. camphora applied individually were significantly toxic to seed germination of wheat at 500 microg ml(-1). However, no toxic effects were found when the two oils were mixed (1:1 w/w) at the same concentration. These observations indicated that the mixture of the two plant-derived oils had a synergic effect and could be used in the control of storage pests.

Protective role of 3-nitro-N-methyl-salicylamide on isolated rat heart during 4 hours of cold storage and reperfusion

OBJECTIVE

Cardiac ischemia/reperfusion (I/R) injury, a necessary consequence of transplantation, is probably related to the formation of reactive oxygen species (ROS). The ROS burst within the first moments of reperfusion is associated with injury, continuously generate O2- at about 3% to 5% of total O2 consumption owing to electron leak by mitochondrial oxidoreductases, especially complexes I and III. 3-nitro-N-methyl-salicylamide (NNMS) displays inhibitory effects on succinate-cytochrome C reductase, but also reduces effects on creation of O2- radical and H2O2 by isolated rat mitochondria. Presumably NNMS inhibits electron leakage from the mitochondrial respiratory chain. We investigated effect of NNMS on heart protection after hypothermic ischemia.

METHODS

A Langendorff-prepared rat heart model was employed after the heart had been preserved for 4 hours under hypothermic conditions of ischemia with subsequent reperfusion/rewarming for 60 minutes.

RESULTS

The group of hearts treated with NNMS showed increased recovery of heart function compared with a group of mEC. The lactate dehydrogenase (LDH) activity in coronary flow (CF) by hearts treated with NNMS was lower than that with mECs, as was the content of malonedialdehyde (MDA) and conjugated diene (CD).

CONCLUSIONS

NNMS improved heart physiology after reperfusion following 4 hours of hypothermic ischemia.

Essential role of nitric oxide in VEGF-induced, asthma-like angiogenic, inflammatory, mucus, and physiologic responses in the lung

VEGF, nitric oxide (NO), inflammation, and vascular- and extravascular remodeling coexist in asthma and other disorders. In these responses, VEGF regulates angiogenesis. VEGF also induces inflammation and remodeling. The mechanisms of the latter responses have not been defined, however. We hypothesized that VEGF-induces extravascular tissue responses via NO-dependent mechanisms. To evaluate this hypothesis, we compared the effects of transgenic VEGF165 in lungs from normal mice, mice treated with pan-NO synthase (NOS) or endothelial NOS (eNOS) inhibitors, and mice with null mutations of inducible NOS (iNOS) or eNOS. These studies demonstrate that VEGF selectively stimulates eNOS and iNOS. They also demonstrate that VEGF induces pulmonary alterations via NO-dependent and -independent mechanisms with angiogenesis, edema, mucus metaplasia, airway hyperresponsiveness, lymphocyte accumulation, dendritic cell hyperplasia and S-nitrosoglutathione reductase stimulation being NO-dependent and dendritic cell activation being NO-independent. Furthermore, they demonstrate that eNOS and iNOS both contribute to these responses. NO/NOS-based interventions may be therapeutic in VEGF-driven inflammation and remodeling.

Regulation of chemokine production in response to pro-inflammatory cytokines in first trimester decidual cells

OBJECTIVE

Chemokines initiate the immune response by controlling leukocyte migration and lymphocyte development. Macrophage infiltration of the decidua has been implicated in the genesis of recurrent miscarriage and preeclampsia. Therefore, we determined whether cultured human decidual cells produce monocyte/macrophage-recruiting chemokines in response to a potent pro-inflammatory cytokine, interleukin-1beta (IL-1beta), and whether decidual cell-conditioned medium contains monocyte- and macrophage-chemoattractant activity.

METHODS

Leukocyte-free first trimester decidual cells were treated for 6h with estradiol (E(2)) and medroxyprogesterone acetate (MPA) to mimic the steroidal milieu of pregnancy, or E(2) and MPA and IL-1beta (1 ng/ml) to mimic inflamed decidua. Total RNA was used for cDNA synthesis. Biotinylated cRNAs were generated and chemically fragmented for hybridization on Affymetrix HG_U133 Plus 2.0 chips followed by fluorescence labeling and optical scanning. Raw data generated from Affymetrix GCOS 1.2 (GeneChip Operating Software) were analyzed by GeneSpring 7.2 software. Subsequently microarray results were validated by real time RT-PCR and Western blotting. A functional study of monocyte migration was carried out also using conditioned media from culture.

RESULTS

Five chemokines responsible for monocyte/macrophage chemoattraction and activation, including C-C motif ligand 2 (CCL2), CCL5, C-X-C motif ligand 2 (CXCL2), CXCL3 and CXCL8, were markedly elevated from 29- to 975-fold after exposure to IL-1beta in cultured first trimester decidual cells. The results of real-time RT-PCR (up-regulation from 43- to 3069-fold) and Western blotting (up-regulation from 15- to 300-fold) confirmed the microarray findings. Monocyte migration was significantly induced by the conditioned medium from IL-1beta-treated decidual cells.

CONCLUSIONS

Treatment of first trimester decidual cells with IL-1beta induces secretion of monocyte/macrophage recruiting-chemokines and promotes monocyte migration. Extrapolation of these in vitro results to the milieu of implantation site suggests a mechanism whereby IL-1beta could mediate excessive macrophage infiltration of the decidua.

Salt priming improves establishment of Distichlis spicata under saline conditions

Salt priming as a tool to establish Distichlis spicata (L.) Greene cv. Yensen-4a (NyPa Forage) plants into saline conditions was investigated in sand culture. Plants were pre-treated with 3 levels of salinity (0, 2, and 4 g NaCl/kg sand) for 36 days and then transplanted into 4 salinity treatments of 0, 2, 4, and 8 g NaCl/kg sand. Soil electrical conductivity (EC), Na and Cl concentrations in the sand, growth initiation, tiller formation, dry matter production, and salt excretion and uptake were measured. Plants pre-treated with 4 g NaCl/kg sand produced 6-fold more dry matter than plants pre-treated with 0 and 2 g NaCl/kg sand when transplanted into sand containing 2 g NaCl/kg. Survival and tiller formation were also higher with plants that had been pre-treated with 4 g NaCl/kg sand compared with plants pre-treated with 0 and 2 g NaCl/kg, when transplanted into 2 and 4 g NaCl/kg sand. The results suggest that salt priming improves establishment of Distichlis spicata when transplanted into low to moderate salinity conditions.

Metal oxide coating on carbon nanotubes by a methanol-thermal method

A methanol-thermal method has been developed to fabricate one-dimensional composite nanowires by coating multiwalled carbon nanotubes with lanthanum oxide and iron oxide, respectively. The coating structure and composition have been investigated by transmission electron microscopy and the X-ray energy dispersive spectrum. Magnetic measurement for the iron oxide coatings indicated that the coercivity has been enhanced after coating. The method reported here provides a novel procedure for the fabrication of one-dimensional composite nanostructures.

MgO nanowire growth from Mg metal and SiO2

Comparative study on the diameter distribution of MgO nanowires has been carried out. MgO nanowires could be synthesized by the direct reaction between metallic magnesium and silica, and the obtained nanowires have diameters ranging from 50 to 200 nm and lengths of several hundreds nanometers, exhibiting a straight wire. The diameter can be downscaled to smaller than 50 nm, and the nanowire exhibits a curved and twisted one-dimensional structure with lengths up to several micrometers, when a fine support catalyst was used as the reactant. The diameter-controlled growth mechanism was also explained in this work.

Finding regulatory modules through large-scale gene-expression data analysis

MOTIVATION

The use of gene microchips has enabled a rapid accumulation of gene-expression data. One of the major challenges of analyzing this data is the diversity, in both size and signal strength, of the various modules in the gene regulatory networks of organisms.

RESULTS

Based on the iterative signature algorithm [Bergmann,S., Ihmels,J. and Barkai,N. (2002) Phys. Rev. E 67, 031902], we present an algorithm-the progressive iterative signature algorithm (PISA)-that, by sequentially eliminating modules, allows unsupervised identification of both large and small regulatory modules. We applied PISA to a large set of yeast gene-expression data, and, using the Gene Ontology database as a reference, found that the algorithm is much better able to identify regulatory modules than methods based on high-throughput transcription-factor binding experiments or on comparative genomics.

Alteration of heme-oxygenase-carbon monoxide pathway in calcified rat vascular smooth muscle cells

OBJECTIVE

The aim of the present study was to investigate the changes in heme-oxygenase (HO)-carbon monoxide (CO)-cyclic guanosine monophosphate (cGMP) pathway in clacified rat vascular smooth muscle cells (VSMCs).

METHODS

Calcification of cultured rat VSMCs was induced by incubation of VSMCs with beta-glycerophosphate. Cellular calcium content, ALP activities and (45)Ca uptake were measured. HO activity, HbCO formation and content of cGMP in VSMCs were determined. Immunocytochemistry for HO-1 expression was observed.

RESULTS

In comparison of control VSMCs, the cellular calcium content, ALP activity and (45)Ca uptake in calcified VSMCs were obviously increased. Immunocytochemistry showed that HO-1 expression was weak and not well distributed in calcified cells as compared to non-calcified VSMCs, but interestingly, there was stronger staining in calcified nodules than in VSMCs. Compared with VSMCs, HO-1 activity in calcified cells decreased by 42.7% [36.4 +/- 2.8 pmol (mg Pr x h)(-1) vs 63.5 x 5.3 pmol (mg Pr x h)(-1), p < 0.01], and HbCO formation decreased by 39.2% (3.38 x 0.69 micromol/mg Pr vs 5.56 +/- 0.48 micromol/mg Pr, p < 0.05). The cGMP content in calcified VSMCs was 78.1% lower than that of non-calcified VSMCs (4.3 +/- 0.51 vs 19.6 +/- 1.2 pmol/mg, p < 0.01).

CONCLUSION

The results showed that HO-CO-cGMP pathway in calcified vascular cells obviously changed, which might contribute to disturbance of vascular function.

Taurine protected myocardial mitochondria injury induced by hyperhomocysteinemia in rats

Taurine can protect against cardiovascular diseases, whereas elevated levels of plasma homocysteine are associated with atherosclerotic and thromboembolic cardiovascular diseases. To illustrate the effects of taurine on hyperhomocysteinemia, we observed the myocardial mitochondria dysfunction in the rats with hyperhomocysteinemia induced by diet methionine loading, and the therapeutic effect of taurine. A methionine diet increased plasma homocysteine concentration (133.51 +/- 27.91 micromol/L vs 12.31 +/- 2.58 micromol/L in control, P < 0.01), stimulated the production of reactive oxygen species (ROS) in the myocardial mitochondria, and inhibited the activities of mitochondrial Mn-superoxide dismutase and catalase. The 45Ca uptake and Ca2+-ATPase activity in the myocardial mitochondria were significantly lowered in rats with hyperhomocysteinemia. Taurine supplements effectively attenuated the hyperhomocysteinemia-induced ROS production and inhibition of Mn-superoxide dismutase and catalase activities in the myocardial mitochondria, and increased its 45Ca uptake and Ca2+-ATPase activity. Thus, taurine antagonizes the oxidative stress injury in the myocardial mitochondria induced by the hyperhomocysteinemia.

The photocatalytic degradation of reactive black 5 using TiO2/UV in an annular photoreactor

The textile effluent is a major industrial polluter because it is highly colored, containing about 15% unfixed dyes as well as high levels of salts that can potentially be discharged into the environment. Photocatalytic oxidation using an thin gap annular UV reactor with TiO2 was used to break down the colour of a synthetic effluent ranging up to 400 ppm in dye concentration of Reactive Black 5 and up to 80 g/L in NaCl. Results show that the reaction kinetics was dominated by the TiO2 loading, the initial dye concentration, and the dissolved oxygen concentration; with the other parameters showing less significant effects. High rates of decolorization were found, with a linear fit to the Langmuir-Hinshelwood equation yielding a reaction rate constant (k) of 2.45 ppm/min, and an adsorption equilibrium constant (K) of 0.048 ppm(-1) based on color removal. The presence of the combination of high dissolved oxygen (15 ppm) and sodium chloride (up to 80 g/L) was found to enhance the decolorization and mineralization rates of the reactive dye. However, pH was found to not significantly affect the degradation rate. Since textile effluent is strongly alkaline, this result is significant, as no solution neutralisation is required and direct treatment of the effluent is possible.

NO-1886 decreases ectopic lipid deposition and protects pancreatic beta cells in diet-induced diabetic swine

The synthetic compound NO-1886 (ibrolipim) is a lipoprotein lipase activator that has been proven to be highly effective in lowering plasma triglycerides. Recently, we found that NO-1886 also reduced plasma free fatty acids and glucose in high-fat/high-sucrose diet-induced diabetic rabbits. In the current study, we investigated the effects of NO-1886 treatment on ectopic lipid deposition and the islet pathology in miniature swine fed a high-fat/high-sucrose diet. Our results showed that feeding this diet to miniature swine caused insulin resistance, increased lipid deposition in non-adipose tissue, such as in the heart, skeletal muscle, liver and pancreas, and also caused pancreatic beta cell damage. However, supplementing 1% NO-1886 (200 mg/kg per day) into the high-fat/high-sucrose diet decreased ectopic lipid deposition, improved insulin resistance, and alleviated the beta cell damage. These results suggest that improvement of lipid disorder, non-adipose tissue steatosis and insulin resistance may be very important for the protection of beta cell damage. Therefore, NO-1886 is potentially beneficial for the treatment of insulin-resistance syndrome.

The disulfide-rich region of platelet glycoprotein (GP) IIIa contains hydrophilic peptide sequences that bind anti-GPIIIa autoantibodies from patients with immune thrombocytopenic purpura (ITP)

Immune thrombocytopenic purpura (ITP) is an autoimmune blood disease caused by autoantibody-mediated destruction of blood platelets. Platelet glycoprotein (GP) IIb/IIIa is a common target for antiplatelet autoantibodies. The present studies were undertaken (1). to confirm whether the disulfide rich repeat region of GPIIIa contains target epitopes for antiplatelet antibodies in patients with ITP; (2). to determine whether these antigens were defined by peptide sequences in the absence of post-translational modification; and (3). to correlate observed immunologic reactivity with the recently solved X-ray crystallographic structure of an analogous integrin complex, the vitronectin receptor, alpha(V)beta(3). Recombinant fusion proteins of four GPIIIa extracellular sequences were prepared and purified. Immunoblotting results with purified recombinant peptides showed potent reactivity of 16 of 24 ITP patient serum anti-GPIIb/IIIa antibodies with the fusion protein containing the GPIIIa sequence of residues from 468 to 691. These results are consistent with a report by Kekomaki et al. that a 50 kDa chymotryptic digestion product of GPIIIa isolated from blood platelets contains target epitopes for serum antiplatelet antibodies in 16 of 33 ITP patients. Smaller peptides including residues 446-501 and residues 593-691 each reacted with only 5 of the 24 patient sera; furthermore all but 3 of these interactions were very weak. Visualization of the conformation of the extracellular portion of alpha(V)beta(3) reveals the location of the 222-residue antigenic GPIIIa (beta(3)) peptide 'B' at the immediately extracellular region of the protein that includes a beta-tail domain and several integrin-EGF domains. In summary, predictions of hydrophilicity, surface accessibility and antigenicity and the three dimensional structure of the beta(3) integrin correlate with autoantibody binding to a recombinant GPIIIa peptide 'B' containing residues 468-691.

Evaluation of novel biodegradable cyclic carbonate polyester copolymers for cytocompatibility using MRC-5 cells

The objective of this work was to synthesize and characterize a novel series of biodegradable cyclic carbonate polyester copolymers based on lactide and 5-methyl-5-benzyloxy-carbonyl-1,3-dioxan-2-one (MBC). Two compositions were selected for characterization. One copolymer was based on a racemic mixture of 1-lactide with 15.4 mole % MBC and the other was based on 1-lactide with 8.2 mole % MBC. These polymers contain carboxylic acid moieties along the backbone that may be used for tethering bioactive agents, forming ionic crosslinks or be reacted with vinyl containing monomers to allow free radical crosslinking. The initial materials evaluated have the carboxylic acid functionalities blocked with benzene. These polymers and the de-blocked versions may have potential applications for hard and soft tissue scaffolds, control drug delivery matrixes or a variety of other applications in medicine. The copolymer samples were pressed into 7.0-mm diameter disk using a KBr press. The disks were then sterilized using U.V radiation under a laminar flow hood. After sterilization, the copolymer disks were submerged in 2 ml of media and placed in a CO2 regulated incubator at 37 degrees C. A total of six groups per phase (n = 7 test tubes per group) were used in this study. Test tubes in groups I and III were plated with MRC-5 and subsequently treated with media alone (controls). Test tubes in groups II and IV were plated with MRC-5 and subsequently treated with media before being introduced to copolymer samples. Cell number, as well as, biochemical markers such as protein and malondialdehyde (MDA) were determined at the end of the 24, 48 and 72-hour time periods. Representative test tubes were subjected to an H&E staining procedure for microscopic morphological evaluation. The results of this evaluation suggest that the exposure of both copolymers produced a non-cytotoxic environment with the MRC-5 cell line. Although both copolymers are non-cytotoxic, the sample having the higher MBC content is the preferred composition based upon MDA levels and morphological evaluations.

Effect of intermittent radiant warming on proliferation of human dermal endothelial cells in vitro

OBJECTIVE

This study investigated the effect of Warm-Up therapy on the proliferation of human microvascular dermal endothelial cells.

METHOD

Endothelial cells from an adult subject were seeded in six-well plates and placed in an incubator at 32.5 degrees C. The following day Warm-Up dressings were placed over the plates, with or without warming cards. Cards set at 38 degrees C or 42 degrees C raised the temperature in the medium to maxima of 34.5 degrees C and 37.5 degrees C respectively. Units were switched on daily for three one-hour periods. Cell numbers were counted by haemocytometer.

RESULTS

Maximum stimulation of endothelial cell proliferation occurred under the 38 degrees C card, with cells numbering 135-158% of the controls (p < 0.05). the 42 degrees C card also stimulated cells (110-155%) but this did not reach statistical significance.

CONCLUSION

The accelerated proliferation of microvascular dermal endothelial cells achieved by intermittent radiant warming may have contributed to the increase in granulation tissue reported previously in our clinic.