Enhanced Percutaneous Delivery of Methotrexate Using Micelles Prepared with Novel Cationic Amphipathic Material.

BACKGROUND: Methotrexate (MTX) is an antiproliferative drug widely used to treat inflammatory diseases and autoimmune diseases. The application of percutaneous administration is hindered due to its poor transdermal penetration. To reduce side effects and enhanced percutaneous delivery of MTX, novel methotrexate (MTX)-loaded micelles prepared with a amphiphilic cationic material, N,N-dimethyl-(N',N'-di-stearoyl-1-ethyl)1,3-diaminopropane (DMSAP), was designed. MATERIALS AND METHODS: DMSAP was synthesized via three steps using simple chemical agents. H nuclear magnetic resonance and mass spectroscopy were used to confirm the successful synthesis of DMSAP. A safe and non-toxic phosphatidylcholine, soybean phosphatidylcholine (SPC), was added to DMSAP at different ratios to form P/D-micelles. Then, MTX-entrapped micelles (M/P/D-micelles) were prepared by electrostatic adsorption. The physicochemical properties and blood stability of micelles were examined thoroughly. In addition, the transdermal potential of the micelles was evaluated by permeation experiments. RESULTS: In aqueous environments, DMSAP conjugates could self-assemble spontaneously into micelles with a low critical micelle concentration (CMC) of 0.056 mg/mL. Stable, spherical MTX-entrapped micelles (M/P/D-micelles) with a size of 100-120 nm and high zeta potential of +36.26 mV were prepared. In vitro permeation studies showed that M/P/D-micelles exhibited superior skin permeability and deposition of MTX in the epidermis and dermis compared with that of free MTX. CONCLUSION: These special novel cationic M/P/D-micelles can enhance the permeability of MTX and are expected to be a promising percutaneous delivery system for therapy skin diseases.

Impact of fomesafen on the soil microbial communities in soybean fields in Northeastern China.

Fomesafen, a widely adopted residual herbicide, is used throughout the soybean region of northern China for the spring planting. However, the ecological risks of using fomesafen in soil remain unknown. The aim of this work was to evaluate the impact of fomesafen on the microbial community structure of soil using laboratory and field experiments. Under laboratory conditions, the application of fomesafen at concentrations of 3.75 and 37.5mg/kg decreased the basal respiration (RB) and microbial biomass carbon (MBC). In contrast, treatment with 375mg/kg of fomesafen resulted in a significant decrease in the RB, MBC, abundance of both Gram+ and Gram- bacteria, and fungal biomass. Analysis of variance showed that the treatment accounted for most of the variance (38.3%) observed in the soil microbial communities. Furthermore, the field experiment showed that long-term fomesafen application in continuously cropped soybean fields affected the soil bacterial community composition by increasing the relative average abundance of Proteobacteria and Actinobacteria species and decreasing the abundance of Verrucomicrobia species. In addition, Acidobacteria and Chloroflexi species showed a pattern of activation-inhibition. Taken together, our results suggest that the application of fomesafen can affect the community structure of soil bacteria in the spring planting soybean region of northern China.

Alteration of interaction between astrocytes and neurons in different stages of diabetes: a nuclear magnetic resonance study using [1-(13)C]glucose and [2-(13)C]acetate.

Increasing evidence has shown that the brain is a site of diabetic end-organ damage. This study investigates cerebral metabolism and the interactions between astrocytes and neurons at different stages of diabetes to identify the potential pathogenesis of diabetic encephalopathy. [1-(13)C]glucose or [2-(13)C]acetate is infused into 1- and 15-week diabetic rats, the brain extracts of which are analyzed by using (1)H and (13)C magnetic resonance spectroscopy. The (13)C-labeling pattern and enrichment of cerebral metabolites are also investigated. The increased (13)C incorporation in the glutamine, glutamate, and γ-aminobutyric acid carbons from [2-(13)C]acetate suggests that the astrocytic mitochondrial metabolism is enhanced in 1-week diabetic rats. By contrast, the decreased labeling from [1-(13)C]glucose reflected that the neuronal mitochondrial metabolism is impaired. As diabetes developed to 15 weeks, glutamine and glutamate concentrations significantly decreased. The increased labeling of glutamine C4 but unchanged labeling of glutamate C4 from [2-(13)C]acetate suggests decreased astrocyte supply to the neurons. In addition, the enhanced pyruvate recycling pathway manifested by the increased lactate C2 enrichment in 1-week diabetic rats is weakened in 15-week diabetic rats. Our study demonstrates the overall metabolism disturbances, changes in specific metabolic pathways, and interaction between astrocytes and neurons during the onset and development of diabetes. These results contribute to the mechanistic understanding of diabetes pathogenesis and evolution.

2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 6-methoxy-benzoxazolin-2-one (MBOA) levels in the wheat rhizosphere and their effect on the soil microbial community structure.

Despite increasing knowledge of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 6-methoxy-benzoxazolin-2-one (MBOA) as allelochemicals involved in the defense of wheat against pests, relatively little is known about their levels in the rhizosphere and interactions with the soil microbial community. This study quantified DIMBOA and MBOA in the wheat rhizosphere and analyzed the soil microbial community structure. MBOA rather than DIMBAO was found in the wheat rhizosphere, and its concentration varied with cultivars, plant densities, and growth conditions. Wheat could detect the presence of competing weeds and respond by increased MBOA in the rhizosphere. There was a linear positive relationship between the MBOA level in the wheat rhizosphere and soil fungi/bacteria. When DIMBOA was applied to soil, yielding MBOA increased soil fungi. There were different phospholipid fatty acid (PLFA) patterns in soil incubated with DIMBOA and MBOA. These results suggested that DIMBOA and MBOA could affect the soil microbial community structure to their advantage through the change in fungi populations.

[Effects of chlorimuron-ethyl on soil microbial community structure in soybean field].

By using phospholipid fatty acids (PLFA) method, this paper studied the soil microbial community structure in the soybean fields with different chlorimuron-ethyl application history in Weihe district of Heilongjiang Province. In the meantime, the residual amount of chlorimuron-ethyl in soil was determined. There was a very low residual of chlorimuron-ethyl in soil under the conditions of different chlorimuron-ethyl application history. With the increasing year of chlorimuron-ethyl application, the total concentration of soil microbial PLFA and the ratios of fungi/bacteria and Gram negative/Gram positive bacteria decreased, and the microbial stress level increased. Principal component analysis (PCA) showed that long-term application of chlorimuron-ethyl into soybean field changed the soil microbial community structure significantly.

Determination of bromoxynil octanoate in soil and corn by GC with electron capture and mass spectrometry detection under field conditions.

In this paper, a simple, and rapid analysis of bromoxynil octanoate is reported for soil, corn leaves, and corn seeds by utilizing one-step liquid-liquid extraction and partitioning, followed by GC with electron capture (ECD) and mass spectrometry (MS) detection. The method was validated by recovery experiments and assessment of matrix effects. Recoveries for GC-ECD and GC/MS were 82.3-110.7% with a relative standard deviation of <14% using matrix-matched calibration solutions for quantification. The limit of quantitation (LOQ) values were 0.005 and 0.2 mg/kg for the ECD and MS detector, respectively, depending on the sensitivity of the target compound. The concentration levels for bromoxynil octanoate residue found in soil, corn leaves, and corn seeds from field experiments were clearly below the LOQ of the ECD detector. The half-life times of bromoxynil octanoate were 2.2-4.2 days in soil and corn leaves. These results indicated that the developed method was appropriate for analysis of bromoxynil octanoate in soil and corn samples.

Determination of mepiquat chloride residues in cotton and soil by liquid chromatography/mass spectrometry.

A liquid chromatographic/mass spectrometric (LC/MS) method is reported for the determination of the onium-type plant growth regulator mepiquat chloride in cotton and soil. The pesticide was extracted from the sample with ethanol and water containing 2% NH4Cl. The extract was cleaned up on a solid-phase extraction C18 column, and the pesticide was determined by LC/MS. The average recoveries were 85.9-93.8, 81.3-91.7, and 78.1-94.7%, with corresponding relative standard deviations of 3.4-9.6, 3.7-12.3, and 4.0-9.8%, from soil, cotton leaves, and cotton seeds, respectively. A coefficient of determination of R2 = 0.9964 was obtained for the analyte calibration graph, from 0.05 to 100 microg/mL. Decision limits, CCalpha, and detection capability, CCbeta, were calculated. Electrospray ionization LC/MS in the positive-ion mode (ESI+) was used to detect mepiquat chloride in extracts of soil, cotton leaves, and cotton seeds. The ion at m/z 114 in the mass spectrum was monitored.