[Enantiomer separation of alpha-amino acid methyl esters and some aliphatic amines as 9-anthraldimine derivatives by high performance liquid chromatography].

The liquid chromatographic enantiomer separation of several alpha-amino acid methyl esters as 9-anthraldehyde Schiff base derivatives on five polysaccharide-derived chiral stationary phases (CSPs) was described. The 9-anthraldehyde imine derivatives of a-amino acid esters were prepared by stirring 9-anthraldehyde with the alpha-amino acid ester hydrochloride salts. The chromatographic conditions were 3%-10% (v/v) 2-propanol-n-hexane as the mobile phases at the flow rate of 1.

Chiral HPLC studies on chemical behavior of 6-methoxydihydrosanguinarine in alcoholic solvent system.

All the enantiomers of methoxydihydrosanguinarine (MS), ethoxydihydrosanguinarine (ES) and iso-propoxydihydrosanguinarine (PS) were separated by chiral HPLC. They were further identified by comparing the retention times of authentic standards as well as LC-MS. Interestingly, the approximately same conversion rates for the formation MS from ES or PS and the slower conversion of MS in isopropanol compared to ethanol demonstrated two step mechanism in the reaction of alkoxysanguinarine in alcohols, which is composed of the initial formation of sanguinarine as a planar intermediate and the addition of alcohol to intermediate as possible rate limiting step.

Microarray expression profiling of Spodoptera litura in response to oxidative stress.

To examine the expression profile of oxidative stress responsive genes in Spodoptera litura, we constructed a cDNA library from S. litura injected with hydrogen peroxide (H(2)O(2)). Using a microarray chip composed of 2,964 cDNAs, we screened gene expression at 1, 3, 5, 7, and 9 h post H(2)O(2) injection.

Formation and characterization of nanoparticles based CuInS2 absorbing layer for solar cell.

CuInS2 powders have been successfully prepared by simple heating a mixture of copper nitrate, indium nitrate and thiourea in ethylene glycol. The prepared powders were fully characterized by SEM, XRD and UV-Vis spectroscopy. The particle shape of the powders obtained with an optimal condition showed spherical shape with about 50 nm in size.

A novel method of screw placement for extremely small thoracic pedicles in scoliosis.

Study Design: A retrospective clinical study.

Objective: To introduce a novel method of pedicle screw placement for extremely small thoracic pedicles in scoliosis and evaluate the safety and accuracy of the method.

Summary Of Background Data: Few studies have provided technical guidelines for screw placement in patients with extremely small thoracic pedicles in scoliosis.

Reverse migration order of sibutramine enantiomers as a function of cyclodextrin concentration in capillary electrophoresis.

The current study demonstrates the reversal of enantiomer migration order (EMO) in capillary electrophoresis (CE) based separations of sibutramines (SIB) as a function of the concentration of two types of cyclodextrin (CD), native β-CD and acetyl-β-CD. At normal working concentrations (<10mM) of either CD, (S)-SIB migrated first. However, at CD concentrations greater than 10mM, (R)-SIB was the first to migrate.

Enhanced efficacy of TD53, a novel algicidal agent, against the harmful algae via the liposomal delivery system.

The present study aimed to design the liposomal delivery system for TD53, a novel algicial drug in order to improve the delivery properties of TD53 and evaluate its algicidal effects as well as selectivity against harmful and non-harmful algae. Liposomes of TD53 were prepared with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) by a lyophilization, resulting in relatively small size vesicles (234±38nm) and narrow size distribution (PI=0.130±0.

Hydrophobic nanoparticles improve permeability of cell-encapsulating poly(ethylene glycol) hydrogels while maintaining patternability.

Cell encapsulating poly(ethylene glycol) hydrogels represent a promising approach for constructing 3D cultures designed to more closely approximate in vivo tissue environment. Improved strategies are needed, however, to optimally balance hydrogel permeability to support metabolic activities of encapsulated cells, while maintaining patternability to restore key aspects of tissue architecture. Herein, we have developed one such strategy incorporating hydrophobic nanoparticles to partially induce looser cross-linking density at the particle-hydrogel interface.

Amyloid β-induced FOXRED2 mediates neuronal cell death via inhibition of proteasome activity.

Proteasome inhibition has been regarded as one of the mediators of Aβ neurotoxicity. In this study, we found that FOXRED2, a novel endoplasmic reticulum (ER) residential protein, is highly up-regulated by Aβ in rat cortical neurons and SH-SY5Y cells. Over-expression of FOXRED2 inhibits proteasome activity in the microsomal fractions containing ER and interferes with proteasome assembly, as evidenced by gel filtration and native gel electrophoresis analysis.

Direct enantiomer separation of thyroxine in pharmaceuticals using crown ether type chiral stationary phase.

Thyroxine is the tyrosine based hormone produced by the thyroid gland, containing a chiral center in its molecular structure. Synthetic thyroxine is commercially available to treat thyroid dysfunctions, but only a few direct analytical methods to determine its optical purity have been reported. This study attempted to find an optimized liquid chromatographic condition for direct enantiomer separation on crown ether type chiral stationary phase.

Improved pH-independent dissolution and oral absorption of valsartan via the preparation of solid dispersion.

This study aimed to improve the pH-independent solubility and dissolution characteristics of valsartan via the preparation of solid dispersions (SD) with poloxamer 407. SDs was prepared by using the solvent method at various drug-polymer ratios and their dissolution characteristics were examined at different pHs. Oral pharmacokinetics of SDs was also evaluated in rats.

Diversity of innate immune recognition mechanism for bacterial polymeric meso-diaminopimelic acid-type peptidoglycan in insects.

In Drosophila, the synthesis of antimicrobial peptides in response to microbial infections is under the control of the Toll and immune deficiency (Imd) signaling pathway. The Toll signaling pathway responds mainly to the lysine-type peptidoglycan of Gram-positive bacteria and fungal β-1,3-glucan, whereas the Imd pathway responds to the meso-diaminopimelic acid (DAP)-type peptidoglycan of Gram-negative bacteria and certain Gram-positive bacilli. Recently we determined the activation mechanism of a Toll signaling pathway biochemically using a large beetle, Tenebrio molitor.

Celecoxib does not attenuate the antiplatelet effects of aspirin and clopidogrel in healthy volunteers.

Background And Objectives: The prevalence of arthritis, which is often treated with celecoxib, is high in patients with coronary artery disease. Furthermore, celecoxib has been reported to reduce restenosis after coronary stenting by inhibiting expression of the proto-oncogene Akt. A concern is that celecoxib increases thrombogenicity by inhibiting the synthesis of prostacyclin in endothelial cells.

Dual oxidase in mucosal immunity and host-microbe homeostasis.

Mucosal epithelia are in direct contact with microbes, which range from beneficial symbionts to pathogens. Accordingly, hosts must have a conflicting strategy to combat pathogens efficiently while tolerating symbionts. Recent progress has revealed that dual oxidase (DUOX) plays a key role in mucosal immunity in organisms that range from flies to humans.

Periodic variation and its effect on management and prognosis of Korean patients with acute myocardial infarction.

Background: The characteristics of the periodic variation in acute myocardial infarction (AMI) and the subsequent effect on management and prognosis have not been fully investigated in a large number of Asian populations.

Methods And Results: From a prospective, observational multicenter online registry, 4,573 patients diagnosed as AMI in Korea from January to December 2006 were included. The highest incidence of AMI was between 8 a.

Synthesis and in vitro activity of 4' and 5'-modified analogues of apiosyl nucleosides as potent anti-HCV agents.

Novel doubly branched apio dideoxynucleosides were synthesized starting from 1,3-dihydroxyacetone using an ozonolysis and Grignard addition as key steps, and evaluated for anti-hepatitis C virus (HCV) activity. The adenine derivative 24 showed significant anti-HCV activity, indicating that the branches at the 4',5'-position of the apiosyl ring led to favorable interaction with HCV polymerase.

Enantioseparation of alpha-amino acids on an 18-crown-6-tetracarboxylic acid-bonded silica by capillary electrochromatography.

(-)-(18-Crown-6)-2,3,11,12-tetracarboxylic acid-bonded silica was used as the chiral stationary phase in capillary electrochromatography (CEC) for enantioseparation of some alpha-amino acids. Separation data in CEC were measured in mobile phases of varying pH, and composition of methanol and buffer, and compared with those in capillary liquid chromatography (CLC). In CEC better enantioseparation was generally obtained in the eluent of lower pH, higher buffer concentration and intermediate MeOH content, usually at the expense of analysis time.

Innate immunity and gut-microbe mutualism in Drosophila.

Metazoan guts face a wide variety of microorganisms upon exposure to the environment, including beneficial symbionts, non-symbionts, food-borne microbes and life-threatening pathogens. Recent evidence has shown that the innate immunity of gut epithelia, such as anti-microbial peptide- and reactive oxygen species-based immune systems, actively participate in gut-microbe homeostasis by shaping the commensal community while efficiently eliminating unwanted bacteria. Therefore, elucidation of the regulatory mechanism by which gut innate immunity occurs at the molecular level will provide a novel perspective of gut-microbe mutualisms as well as of gut diseases caused by alterations in the innate immunity.

Comparison of medical student responses and course achievement according to different types of patient simulations in an introductory advanced life support course.

Purpose: The optimal type of patient simulation for different levels of learners has not been extensively studied. The purpose of the study was to compare preclerkship medical student responses and course achievement according to different types of patient simulations in an introductory advanced life support (IALS) course.

Methods: A full-day, simulation-based IALS course was developed for preclerkship medical students who attended a four-week introduction to a clinical medicine program.

[Comparative enantiomer separation of beta-blockers on polysaccharide derived chiral stationary phases using high performance liquid chromatography with acid or base additive in the mobile phases].

The liquid chromatographic enantiomer separation of beta-blockers on several polysaccharide derived chiral stationary phases (CSPs) (Chiralpak AD, Chiralcel OD, Chiralpak IA and Chiralpak IB) was performed and compared in the normal phase mode using hexane-ethanol in the presence of acid or base additives. The chromatographic conditions were 10% - 30% (v/v) ethanol-hexane containing 0.1% trifluoroacetic acid or triethylamine as the mobile phase at the flow rate of 1.

Bacterial-modulated host immunity and stem cell activation for gut homeostasis.

Although it is widely accepted that dynamic cross-talk between gut epithelia and microorganisms must occur to achieve gut homeostasis, the critical mechanisms by which gut-microbe interactions are regulated remain uncertain. In this issue of Genes & Development, Buchon and colleagues (pp. 2333-2344) revealed that the reaction of the gut to microorganisms is not restricted to activating immune systems, but extends to integrated responses essential for gut tissue homeostasis, including self-renewal and the differentiation of stem cells.

The reliable targeting of specific drug release profiles by integrating arrays of different albumin-encapsulated microsphere types.

Biodegradable polymer microspheres have been successfully utilized as a medium for controlled protein or peptide-based drug release. Because the release kinetics has been typically controlled by modulating physical or chemical properties of the medium, these parameters must be optimized to obtain a specific release profile. However, due to the complexity of the release mechanism and the complicated interplay between various design parameters of the release medium, detailed prediction of the resulting release profile is a challenge.

Racemization of 6-methoxydihydrosanguinarine in methanol investigated by enantioselective dynamic HPLC.

A biologically active benzophenanthridine alkaloid, 6-methoxydihydrosanguinarine (MS), was isolated from Hylomecon plants. Although enantiomers of MS can be separated by chiral HPLC, its isomers rapidly form a racemic mixture in methanol. The rate constants for the racemization of MS enantiomers were 9.

JNK/FOXO-mediated neuronal expression of fly homologue of peroxiredoxin II reduces oxidative stress and extends life span.

Activation of c-Jun N-terminal kinase (JNK) signaling in neurons increases stress resistance and extends life span, in part through FOXO-mediated transcription in Drosophila. However, the JNK/FOXO target genes are unknown. Here, we identified Jafrac1, a Drosophila homolog of human Peroxiredoxin II (hPrxII), as a downstream effecter of JNK/FOXO signaling in neurons that enhances stress resistance and extends life span.