bluuebunny/crossref_metadata_2025 huggingface dataset:
Quality control of herbal medicines by capillary electrophoresis: Potential, requirements and applications
Authors: Ganzera Markus
Published: September 2008

Herbal preparations, particularly those from traditional Chinese or Indian medicine, are becoming increasingly popular in Europe and the USA. Their application is often based on long‐term historic use rather than on scientific evidences; thus, analytical tools to assure their efficacy, safety and consistency are in great demand. This review evaluates the importance of CE for quality control of herbal medicinal products during the last five years. After briefly describing the general characteristics of natural products analysis by CE, numerous applications on medicinal plants or herbal products are summarized. These examples not only reflect the enormous variability of CE with respect to buffer systems and detection modes employed, but also indicate an increasing importance of this separation technique for quality control purposes compared with more established ones such as HPLC.
Determination of flurbiprofen enantiomers in plasma using a single‐isomer amino cyclodextrin derivative in nonaqueous capillary electrophoresis
Authors: Rousseau Anne , Pedrini Matteo , Chiap Patrice , Ivanyi Robert , Crommen Jacques , Fillet Marianne , Servais Anne‐Catherine
Published: September 2008

A nonaqueous capillary electrophoresis (NACE) assay was developed for the separation and determination of flurbiprofen enantiomers in plasma samples using 6‐monodeoxy‐6‐mono(3‐hydroxy)propylamino‐β‐cyclodextrin as chiral selector. The nonaqueous background electrolyte was made up of 40 mM ammonium acetate in methanol (MeOH), and flufenamic acid was employed as internal standard. Solid‐phase extraction was used for sample cleanup prior to the NACE separation.

The NACE method reproducibility was optimized by evaluating different capillary washing sequences between runs. After having tested various conditions, trifluoroacetic acid (1 M) in MeOH was finally selected. Concerning the solid‐phase extraction procedure, good and reproducible analyte recoveries were obtained using MeOH for protein denaturation and a polymeric phase combining hydrophobic interactions with anion exchange properties (Oasis® MAX) was selected as extraction sorbent. The method selectivity was not only demonstrated toward a blank plasma sample but also toward other non‐steroidal anti‐inflammatory drugs. The method was then successfully validated with respect to response function, trueness, precision, accuracy, linearity and limit of quantification.
Kinetic study of cytochrome P450 by capillary electrophoretically mediated microanalysis
Authors: Zhang Jie , Hoogmartens Jos , Van Schepdael Ann
Published: September 2008

An electrophoretically mediated microanalysis method for the determination of CYP3A4 activity using testosterone and nifedipine as substrates was developed. Initially, the enzymatic reaction was performed off‐line and the samples were subsequently injected into the capillary by pressure. The CYP3A4 activity was determined by quantitation of the reactant cofactor, NADPH. To further optimize, speed‐up and miniaturize the enzyme assay, the enzymatic reaction was performed directly in the capillary, prior to separation and quantitation of the product cofactor, NADP, employing the plug–plug mode of electrophoretically mediated microanalysis. An amplification step was introduced by means of an on‐capillary incubation of 15 min, in order to accumulate enough reaction product to detect spectrophotometrically at 260 nm. This setup resulted in a fully automated assay, which can be carried out in less than 35 min. Using the Lineweaver–Burk equation, the Michaelis constants (Km) for the oxidation of testosterone and nifedipine by CYP3A4 were calculated to be 58.6±8.3 and 19.1±2.4 μM, respectively, which are consistent with off‐line assay and previously reported values.
A simple and rapid CZE method for the analysis of mycophenolic acid and its phenol glucuronide metabolite in human serum
Authors: Ohyama Kaname , Kinoshita Naoyuki , Kishikawa Naoya , Kuroda Naotaka
Published: September 2008

A simple and rapid capillary electrophoretic method was developed for simultaneous determination of mycophenolic acid and its metabolite, phenol glucuronide, in human serum. The sample preparation in the proposed method required only the precipitation by acetonitrile. Separation was performed by capillary zone electrophoresis using 75 mM phosphate buffer (pH 7.5) as running buffer, an applied voltage of 10 kV, and UV detection at 217 nm. Each serum sample analysis was completed within 15 min. The optimized method demonstrated good performance concerning specificity, linearity (r>0.9955), accuracy (95.9–113%), precision (<6.4%) and enough sensitivity for therapeutic drug monitoring. This method was successfully applied to measurements of mycophenolic acid and mycophenolic acid glucuronide in renal transplant patient samples and was a useful alternative to high‐performance liquid chromatography‐based methods.
Applications of CE SDS gel in development of biopharmaceutical antibody‐based products
Authors: Rustandi Richard R. , Washabaugh Michael W. , Wang Yang
Published: September 2008

CE SDS gel technique offers many advantages over the traditional labor‐intensive SDS PAGE slab gel technology. The CE‐based method has increasingly been applied to many protein analysis applications. Specific examples are provided for monoclonal antibody (mAb), though the technique can be adapted to many other therapeutic protein products. Applications of CE SDS gel method using Beckman PA800 with UV detection are presented and discussed with respect to mAb analysis, such as purity, quantitation of non‐glycosylated heavy chain (NGHC) peak, identity, and stability. The stability of mAb is evaluated with respect to formulation buffer, accelerated temperature stress, UV light‐exposure, and high pH conditions. Both reducing and non‐reducing CE SDS gel conditions were applied and optimized to characterize mAb products. The data presented provides a “taste” of what CE SDS gel method can do to support the development of mAb products from early clone screening for product quality to the final product characterization. Since the CE SDS gel method is automatable, quantitative, robust, and allows for relatively high throughput, it provides both great analytical capacity and product coverage for a wide spectrum of protein product development in biopharmaceutical industry.
On‐line stacking capillary electrophoresis for analysis of methotrexate and its eight metabolites in whole blood
Authors: Cheng Hui‐Ling , Liao Yu‐Mei , Chiou Shyh‐Shin , Wu Shou‐Mei
Published: September 2008

Therapeutic drug monitoring of methotrexate (MTX) and its metabolites is significant for the evaluation of treatment response of acute lymphoblastic leukemia and the prevention of adverse effects. Those eight metabolites including 7‐hydroxymethotrexate, MTX‐polyglutamate derivatives (MTX‐(Glu)n,n=2–7), and 2,4‐diamino‐N10‐methylpteroic acid, especially the MTX‐(Glu)n, only exist in blood cells and also present antifolate effects. Therefore, whole blood analysis has importance in clinical therapy. This study combined solid‐phase extraction and on‐line stacking capillary electrophoresis to examine the levels of MTX and its eight metabolites in whole blood. A higher conductivity buffer (HCB) was used to accumulate large amount of samples into a narrow zone, which resulted in effective stacking and sharp peaks. A fused‐silica capillary was filled with phosphate buffer (80 mM, pH 2.5) containing 15% v/v tetrahydrofuran and 100 mM sodium dodecyl sulfate. Then HCB (100 mM phosphate, pH 2.5; 1 psi, 60 s) was injected for accumulating large volume of analytes (1 psi, 200 s). Owing to the pH difference between sample zone and HCB, dynamic pH junction was generated for focusing. Meanwhile, sweeping made further stacking by using sodium dodecyl sulfate in phosphate buffer. The limits of detection (S/N=3) were 0.1 µM for MTX, 0.2 µM for 7‐hydroxymethotrexate and 2,4‐diamino‐N10‐methylpteroic acid, 0.3 µM for MTX–(Glu)n=2––5, and 0.5 µM for MTX–(Glu)n=6––7. During validation, this method showed good linearity (r⩾0.9914) and reproducibility (relative standard deviation and relative error, both less than 13%). The applications were performed to monitor blood MTX and its metabolites in acute lymphoblastic leukemia patients. The blood concentrations could provide some information related to therapeutic response and adverse effects.
Method for determination of total cysteamine in human plasma by high performance capillary electrophoresis with acetonitrile stacking
Authors: Kubalczyk Paweł , Bald Edward
Published: September 2008

An analytical procedure enabling routine analysis of human plasma for total cysteamine (CASH) has been developed and validated. The method includes reduction of CASH disulfides to thiol with tri‐n‐butylphosphine, derivatization of the thiol with 2‐chloro‐1‐methylquinolinium tetrafluoroborate, separation of CASH 2‐S‐quinolinium derivate from those of plasma endo‐ and exogenous thiol derivatives by capillary zone electrophoresis based on acetonitrile stacking and quantitation with the use of ultraviolet detection. A large volume of sample is injected to achieve analyte concentration directly on the capillary, according to the transient pseudo‐isotachophoresis principle, before the separation step takes place. Method performance characteristics, for example recovery, calibration, precision, limit of detection and limit of quantitation are presented. The procedure was applied to analysis of plasma samples donated by apparently healthy volunteers spiked with known amounts of cystamine standard solution.
Micellar electrokinetic capillary chromatography determination of alginic acid in pharmaceutical formulations after treatment with alginate lyase and UV detection
Authors: Volpi Nicola
Published: September 2008

A new highly specific and sensitive capillary electrophoresis method (electrokinetic chromatography with SDS) for the determination of the total alginic acid (AA) content in pharmaceutical formulations is described by means of capillary electrophoresis at 230 nm after treatment with alginate lyase [4.2.2.3] and separation of unsaturated products, Δ‐oligomers (ΔHexA–[HexA]n), in particular, DP3 (ΔHexA–HexA–HexA) and DP4 (ΔHexA–HexA–HexA–HexA). Using a buffer constituted with 10 mM sodium borate and 50 mM SDS at pH 9.0, micellar electrokinetic capillary chromatography was able to determine with very high resolution the AA Δ‐oligomers produced by the action of the lyase (mainly DP3 and DP4) as one single species. The intra‐ and inter‐day variations (CV%) were between 6.3 and 9.1 for migration time and between 2.5 and 5.7 for peak area, respectively. The calibration curve showed good linearity for the examined concentration range (60–360 ng) with an average correlation coefficient greater than 0.980. The lowest detection limit and the lowest quantitation limit of the method were 15 ng (0.25 mg/mL) and 40 ng (0.67 mg/mL), respectively. The intra‐ and inter‐day variations in terms of CV% were 5.5 and 8.6%, respectively, and the intra‐ and inter‐day accuracy was estimated to range from 4.1 to 8.9%, while the percent recoveries of AA were calculated to be 102, 97 and 93% for different AA amounts. Variations in temperatures, voltage and buffer composition in comparison with adopted conditions within a 10% limit do not modify the electrophoresis results. The evaluation of AA was performed in both solid and liquid pharmaceutical formulations also in the presence of other ingredients, in particular, aluminium, sodium and potassium bicarbonate, and emulsifying and flavouring agents. The quantitative results obtained were 101.2±3.4% of AA content in tablets and 98.4±2.8% in liquid formulation, in total conformity with the label claims.
Determination of pharmaceuticals classified as emerging pollutants using capillary electrophoresis with capacitively coupled contactless conductivity detection
Authors: Quek Ngee Mien , Law Wai Siang , Lau Hiu Fung , Zhao Jian Hong , Hauser Peter C. , Li Sam Fong Yau
Published: September 2008

A study on the simultaneous separation of 13 pharmaceutical products by capillary electrophoresis with capacitively coupled contactless conductivity detection was presented. The parameters of the background electrolyte, such as pH, organic additives as well as types and concentrations of cyclodextrins (CD) were studied. The optimal separation conditions were achieved with a background electrolyte consisting of 9 mM Tris/5 mM lactic acid at pH 8.0, containing 5% n‐propanol, 0.025% γ‐CD, 0.075% hydroxyl‐β‐CD and 0.15% dimethyl‐β‐CD. Limits of detections ranged from 61 to 1676 μg/L (S/N=3) and the relative standard deviations for migration time and peak area were below 2 and 6%, respectively. This demonstrated the potential of the capillary electrophoresis‐capacitively coupled contactless conductivity detection method for biomedical and environmental analysis, as shown in the determination of pharmaceuticals identified as emerging pollutants in water samples.
Comparison between the charring rate model and the conductive model of Eurocode 5
Authors: Cachim Paulo B. , Franssen Jean‐Marc
Published: September 2008

Eurocode 5, Part 1–2, presents several models for the calculation of fire resistance of timber structures. These models are based on the hypothesis that for temperatures above 300°C , wood is no longer able to sustain any stress, which makes the determination of the location of the 300°C isotherm decisive for the result provided by the models. In this paper, the charring rate model and the conductive model presented in Eurocode 5, Part 1–2 are compared regarding the determination of the location of the 300°C isotherm. The main wood parameters investigated are density, moisture content and anisotropy. The almost complete independence of the charring rate model from these parameters leads to some inconsistencies between the models. To reduce these inconsistencies some proposals to improve the conductive and the charring rate models are presented. Copyright © 2008 John Wiley & Sons, Ltd.
Strategic bias and professional affiliations of macroeconomic forecasters
Authors: Ashiya Masahiro
Published: September 2008

This paper investigates strategic motives of macroeconomic forecasters and the effect of their professional affiliations. The ‘wishful expectations hypothesis’ suggests that a forecaster predicts what his employer wishes. The ‘publicity hypothesis’ argues that forecasters are evaluated by both accuracy and ability to generate publicity, and that forecasters in industries that emphasize publicity most will make most extreme and least accurate predictions. The ‘signaling hypothesis’ asserts that an extreme forecast signals confidence in own ability, because incompetent forecasters would mimic others to avoid public notice. Empirical evidence from a 26‐year panel of annual GDP forecasts is con‐sistent with the publicity hypothesis. This indicates that conventional tests of rationality are biased toward rejecting the rational expectations hypothesis. Copyright ? 2008 John Wiley & Sons, Ltd.
Fibrogenesis in pediatric cholestatic liver disease: Role of taurocholate and hepatocyte-derived monocyte chemotaxis protein-1 in hepatic stellate cell recruitment #
Authors: Ramm Grant A. , Shepherd Ross W. , Hoskins Anita C. , Greco Sonia A. , Ney Agnieszka D. , Pereira Tamara N. , Bridle Kim R. , Doecke James D. , Meikle Peter J. , Turlin Bruno , Lewindon Peter J.
Published: September 2008

Cholestatic liver diseases, such as cystic fibrosis (CF) liver disease and biliary atresia, predominate as causes of childhood cirrhosis. Despite diverse etiologies, the stereotypic final pathway involves fibrogenesis where hepatic stellate cells (HSCs) are recruited, producing excess collagen which initiates biliary fibrosis. A possible molecular determinant of this recruitment, monocyte chemotaxis protein-1 (MCP-1), an HSC-responsive chemokine, was investigated in CF liver disease and biliary atresia. The bile-duct-ligated rat and in vitro coculture models of cholestatic liver injury were used to further explore the role of MCP-1 in HSC recruitment and proposed mechanism of induction via bile acids. In both CF liver disease and biliary atresia, elevated hepatic MCP-1 expression predominated in scar margin hepatocytes, closely associated with activated HSCs, and was also expressed in cholangiocytes. Serum MCP-1 was elevated during early fibrogenesis. Similar observations were made in bile-duct-ligated rat liver and serum. Hepatocytes isolated from cholestatic rats secreted increased MCP-1 which avidly recruited HSCs in coculture. This HSC chemotaxis was markedly inhibited in interventional studies using anti-MCP-1 neutralizing antibody. In CF liver disease, biliary MCP-1 was increased, positively correlating with levels of the hydrophobic bile acid, taurocholate. In cholestatic rats, increased MCP-1 positively correlated with taurocholate in serum and liver, and negatively correlated in bile. In normal human and rat hepatocytes, taurocholate induced MCP-1 expression. Conclusion: These observations support the hypothesis that up-regulation of hepatocyte-derived MCP-1, induced by bile acids, results in HSC recruitment in diverse causes of cholestatic liver injury, and is a key early event in liver fibrogenesis in these conditions. Therapies aimed at neutralizing MCP-1 or bile acids may help reduce fibro-obliterative liver injury in childhood cholestatic diseases. (Hepatology 2008.)
Role of overexpression of CD151 and/or c-Met in predicting prognosis of hepatocellular carcinoma #
Authors: Ke Ai-Wu , Shi Guo-Ming , Zhou Jian , Wu Fei-Zhen , Ding Zhen-Bin , Hu Mei-Yu , Xu Yang , Song Zheng-Ji , Wang Zhi-Jun , Wu Jin-Cai , Bai Dou-Sheng , Li Jia-chu , Liu Kang-Da , Fan Jia
Published: September 2008

It has been reported that tetraspanin CD151 acts as a promoter of metastasis in several tumors and plays an important role in c-Met/hepatocyte growth factor signaling. However, the role of CD151 alone and coexpression of CD151/c-Met in hepatocellular carcinoma (HCC) remains unclear. We found that expression of CD151 was positively related to metastatic potential of HCC cell lines, and modified cells with CD151high showed higher secretion of matrix metalloproteinase 9 and aggressiveness in vitro and higher metastatic ability in vivo. Furthermore, HCC patients with vascular invasion, large tumors, multiple tumors, high tumor-node-metastasis stage, and undifferentiated tumor were prone to have higher CD151 expression. The postoperative 3-, 5-, and 7-year overall survival (OS) of patients in HCCs with CD151high were significantly lower than those in the CD151low group, and correspondingly cumulative recurrence rates in HCCs with CD151high were significantly higher than those in the CD151low group. Both CD151 and c-Met were remarkably overexpressed in HCCs, compared with adjacent nontumorous and normal liver tissues. Pearson correlation analysis showed a slight correlation between CD151 and c-Met in HCCs. Importantly, the 5- and 7-year OS rates in CD151high/c-Methigh patients were 50.5% and 37.8%, respectively, significantly lower than those of CD151low/c-Metlow patients (63.9% and 54.6%, respectively). Five- and 7-year cumulative recurrence rates in CD151high/c-Methigh patients were 53.3% and 71.9%, respectively, markedly higher than those of CD151low/c-Metlow patients (39.0% and 52.5%, respectively). Multivariate analysis revealed that CD151 and combination of CD151/c-Met were independent prognostic indicators for OS and cumulative recurrence. Conclusion: CD151 is positively associated with invasiveness of HCC, and CD151 or combination of CD151/c-Met is a novel marker in predicting the prognosis of HCC and a potential therapeutic target. (Hepatology 2008.)
Smoking and serum CA19‐9 levels according to Lewis and secretor genotypes
Authors: Kawai Sayo , Suzuki Koji , Nishio Kazuko , Ishida Yoshiko , Okada Rieko , Goto Yasuyuki , Naito Mariko , Wakai Kenji , Ito Yoshinori , Hamajima Nobuyuki
Published: September 2008

CA19‐9, a marker for cancers of biliary tract, pancreas and colorectum, is not synthesized in those with no enzyme activity genotype (le/le) of Lewis (Le) gene. No enzyme activity genotype (se/se) of secretor (Se) gene is known to have an association with high serum CA19‐9 levels. There are also variations in serum CA19‐9 levels independent of the genotypes. This study aimed to examine the associations of serum CA19‐9 levels with smoking, alcohol drinking and body mass index (BMI; kg/m2), after the adjustments of Le and Se genotypes. Subjects were 486 health check‐up examinees (158 males and 328 females) aged from 39 to 90 years in Hokkaido, Japan. Genotyping was conducted for 3 polymorphisms; Le T59G (59T for Le allele and 59G for le allele), Se A385T (385A for Se allele and 385T for sej allele), and Se pseudogene (se5 allele). The genotypes of Le and Se were deterministic factors of serum CA19‐9. Those with Le/Le & se/se had the highest mean, while CA19‐9 was not detected or very low in those with le/le. Although no associations were observed with alcohol drinking and BMI, a significant association was observed with smoking. Among those with Le/Le, the geometric mean of CA19‐9 was significantly lower for current smokers than for noncurrent smokers (p = 0.011 in 4‐way ANOVA with age, sex and Se genotype). When hemoglobin A1c was further adjusted, the association became stronger (p = 0.0027). In addition to polymorphic variations, some components of cigarette smoke may influence the production or destruction of CA19‐9. © 2008 Wiley‐Liss, Inc.
Nevus density and melanoma risk in women: A pooled analysis to test the divergent pathway hypothesis
Authors: Olsen Catherine M. , Zens Michael S. , Stukel Therese A. , Sacerdote Carlotta , Chang Yu‐Mei , Armstrong Bruce K. , Bataille Veronique , Berwick Marianne , Elwood J. Mark , Holly Elizabeth A. , Kirkpatrick Connie , Mack Thomas , Bishop Julia Newton , Østerlind Anne , Swerdlow Anthony J. , Zanetti Roberto , Green Adèle C. , Karagas Margaret R. , Whiteman David C.
Published: September 2008

A “divergent pathway” model for the development of cutaneous melanoma has been proposed. The model hypothesizes that melanomas occurring in people with a low tendency to develop nevi will, on average, arise more commonly on habitually sun‐exposed body sites such as the head and neck. In contrast, people with an inherent propensity to develop nevi will tend to develop melanomas most often on body sites with large melanocyte populations, such as on the back. We conducted a collaborative analysis to test this hypothesis using the original data from 10 case–control studies of melanoma in women (2,406 cases and 3,119 controls), with assessment of the potential confounding effects of socioeconomic, pigmentary and sun exposure‐related factors. Higher nevus count on the arm was associated specifically with an increased risk of melanoma of the trunk (p for trend = 0.0004) and limbs (both upper and lower limb p for trends = 0.01), but not of the head and neck (p for trend = 0.25). The pooled odds ratios for the highest quartile of nonzero nevus count versus none were 4.6 (95% confidence interval (CI) 2.7–7.6) for melanoma of the trunk, 2.0 (95% CI 0.9–4.5) for the head and neck, 4.2 (95% CI 2.3–7.5) for the upper limbs and 3.4 (95% CI 1.5–7.9) for the lower limbs. Aggregate data from these studies suggest that high nevus counts are strongly associated with melanoma of the trunk but less so if at all of the head and neck. This finding supports different etiologic pathways of melanoma development by anatomic site. © 2008 Wiley‐Liss, Inc.
Are risk‐averse agents more optimistic? A Bayesian estimation approach
Authors: Ben Mansour Selima , Jouini Elyès , Marin Jean‐Michel , Napp Clotilde , Robert Christian
Published: September 2008

Our aim is to analyze the link between optimism and risk aversion in a subjective expected utility setting and to estimate the average level of optimism when weighted by risk tolerance. Its estimation leads to a non‐trivial statistical problem. We start from a large lottery survey (1536 individuals). We assume that individuals have true unobservable characteristics. We adopt a Bayesian approach and use a hybrid MCMC approximation method to numerically estimate the distributions of the unobservable characteristics. We find that individuals are on average pessimistic and that pessimism and risk tolerance are positively correlated. Copyright © 2008 John Wiley & Sons, Ltd.
p53 codon 72 proline/arginine polymorphism and autoimmune thyroid diseases
Authors: Chen Rong‐Hsing , Chang Chwen‐Tzuei , Wang Tzu‐Yuan , Huang Wen‐Liang , Tsai Chang‐Hai , Tsai Fuu‐Jen
Published: September 2008

p53 protein participates in the processes of apoptosis, which is involved in a number of immunological reactions. In order to test whether the p53 gene could be used as a genetic marker for the prediction of the development of autoimmune thyroid diseases (AITD), we screened, by using polymerase chain reaction (PCR) analysis, for the C (CC_C)/G (CG_C) polymorphism at the p53 codon 72 (Pro 72/Arg 72) to determine the genotypes of 107 Hashimoto's thyroiditis (HT) and 90 Graves' disease (GD) patients, and 105 normal controls. The data demonstrated that, for the genotype analysis, HT patients featured an enhanced numerical ratio for the Arg/Arg homozygous genotype (33.7%) and a diminished ratio for the Arg/Pro heterozygous genotype (41.1%) at the p53 codon 72 than was the case for normal controls (Arg/Arg: 17.1% and Arg/Pro: 61.9%; P=0.005). The odds ratio for the risk of the Arg/Arg genotype's appearance, compared with that of the Arg/Pro and Pro/Pro genotypes combined, for the HT patient group was 2.450 (95% confidence interval: 1.274–4.716). With respect to allelic analysis, we did not observe significant difference in the frequency of appearance of the Arg allelic variant and the Pro allelic variant for the p53 codon 72 when comparing the HT patient group with the control group (P=0.208). On the other hand, GD patients presented no significant difference in distribution for both genotype and allelic frequencies (P=0.344 and 0.245, respectively) when compared with normal controls. In conclusion, HT patients feature a greater ratio of arginine homozygosity at p53 codon 72 than in the case for normal subjects. The p53 codon 72 proline/arginine polymorphism may be a genetic marker to predict the increased susceptibility of development of HT. J. Clin. Lab. Anal. 22:321–326, 2008. © 2008 Wiley‐Liss, Inc.
Neurotrophin‐3 stimulates neurogenetic proliferation via the extracellular signal‐regulated kinase pathway
Authors: Ohtsuka Masanari , Fukumitsu Hidefumi , Furukawa Shoei
Published: September 2008

The effects of neurotrophin‐3 (NT3) administered into the ventricular space of 13.5‐day‐old mouse embryos on neurogenesis in the developing cerebral cortex were examined. 5‐Bromo‐2′‐deoxyuridine (BrdU) was injected into pregnant mice 3 hr after the NT3 administration to label the neural progenitor cells. NT3 increased the number of BrdU‐positive cells without altering their distribution. The increment in BrdU‐positive cells 24 hr after the BrdU injection was attributed to Pax6‐/BrdU‐positive cells (neural stem cells), which was followed by a significant elevation of the number of Tuj1‐/BrdU‐positive cells (neurons) 36 or 48 hr after the BrdU injection, suggesting that NT3 facilitated neurogenesis by acting in two sequential steps, i.e., causing proliferation of neural stem cells and generation of neurons from these progenitors. NT3 stimulated phosphorylation of extracellular signal‐regulated kinase (ERK) 1/2 and ERK5 in the cortical progenitors, and the effects of NT3 on the increase in total BrdU‐positive cells and Pax6‐/BrdU‐positive cells were diminished by an MEK inhibitor, suggesting the involvement of MEK‐mediated ERK signal transduction in the NT3 actions. © 2008 Wiley‐Liss, Inc.
Vascular endothelial growth factor acutely reduces calcium influx via inhibition of the Ca2+ channels in rat hippocampal neurons
Authors: Ma Yuan‐Yuan , Li Ke‐Yong , Wang Ji‐Jiang , Huang Ya‐Lin , Huang Ying , Sun Feng‐Yan
Published: September 2008

Vascular endothelial growth factor (VEGF) protects neurons against ischemic injury. An overload of intracellular calcium ions (Ca2+) caused by the excessive release of glutamate is widely considered to be one of the molecular mechanisms of ischemic neuronal death. In the present study, we investigated whether VEGF could modulate the activity of Ca2+ channels on the neuronal membrane. We used the Fluo‐3 image method assisted by confocal laser scan microscopy to detect any Ca2+ influx in primary cultured hippocampal neurons. Whole‐cell patch‐clamp techniques were used to record the activity of the high‐voltage‐activated (HVA) Ca2+ currents in the CA1 pyramidal neurons of hippocampal slices that were freshly prepared from neonatal brains of rats. The results obtained from the Fluo‐3 image experiments showed that VEGF pretreatment of cultured neurons at a final concentration of 50, 100, or 200 ng/ml acutely and dose dependently attenuated the Ca2+ influx induced by application of KCl (60 mM) or glutamate (50 μM). This effect was blocked by SU1498, an antagonist of Flk‐1 VEGF receptor. The influx of Ca2+ returned to basal levels after removal of VEGF. Furthermore, electrophysiological recording data showed that VEGF could acutely reduce the amplitudes of the HVA Ca2+ currents in a dose‐ and voltage‐dependent manner. The HVA Ca2+ currents also returned to the levels of the control after removal of VEGF from the system. Taken together, the results obtained from the present study demonstrated that VEGF specifically reduced the influx of Ca2+ via the inhibitory activity of the HVA Ca2+ channels in hippocampal neurons. © 2008 Wiley‐Liss, Inc.
Silencing of choline acetyltransferase expression by lentivirus‐mediated RNA interference in cultured cells and in the adult rodent brain
Authors: Santamaria Julie , Khalfallah Olfa , Sauty Claire , Brunet Isabelle , Sibieude Mathieu , Mallet Jacques , Berrard Sylvie , Lecomte Marie‐José
Published: September 2008

RNA interference (RNAi) is a potent mechanism for local silencing of gene expression and can be used to study loss‐of‐function phenotypes in mammalian cells. We used RNAi to knockdown specifically the expression of choline acetyltransferase (ChAT), the enzyme of acetylcholine biosynthesis, both in cultured cells and in the adult brain. We first identified a 19‐nucleotide sequence in the coding region of rat and mouse ChAT transcripts that constitutes a target for potent silencing of ChAT expression by RNAi. We generated a lentiviral vector that produces both a small hairpin RNA (shRNA) targeting ChAT mRNAs and the enhanced green fluorescent protein (EGFP) reporter protein to facilitate identification of transduced cells. In the cholinergic cell line NG108‐15, there was at least 90% less of the ChAT protein, as measured by assaying its enzymatic activity, 3 days postinfection with this vector than in cells infected with a control vector. The vector was used to transduce cholinergic neurons in vivo and reduced ChAT expression strongly and specifically in the cholinergic neurons of the medial septum in adult rats, without affecting the expression of the vesicular acetylcholine transporter. This lentiviral vector is thus a powerful tool for specific inactivation of cholinergic neurotransmission and can therefore be used to study the role of cholinergic nuclei in the brain. This lentiviral‐mediated RNAi approach will also allow the development of new animal models of diseases in which cholinergic neurotransmission is specifically altered. © 2008 Wiley‐Liss, Inc.
DFT simulations and Vibrational spectra of 4‐chloro and 4‐bromophenylboronic acid molecules
Authors: Kurt M.
Published: September 2008

The experimental and theoretical vibrational spectra of 4‐chloro‐ and 4‐bromophenylboronic acids (abbreviated as 4Clpba and 4Brpba) were studied. The Fourier transform Raman and Fourier transform infrared (FTIR) spectra of 4Clpba and 4Brpba molecules were recorded in the solid phase. The structural and spectroscopic analyses of the molecules were made by using Hartree–Fock and density functional harmonic calculations. In both 4Clpba and 4Brpba only one form was most stable using B3LYP level with the 6–311 + + G(d,p) basis set. Selected experimental bands were assigned and characterized on the basis of the scaled theoretical wavenumbers by their total energy distribution (TED). Finally, geometric parameters as well as infrared (IR) and Raman bands were compared with the experimental data of the molecules. Copyright © 2008 John Wiley & Sons, Ltd.
Raman spectroscopic study of the tellurite mineral: sonoraite Fe3+Te4+O3(OH)·H2O
Authors: Frost Ray L. , Keeffe Eloise C.
Published: September 2008

Tellurites may be subdivided according to formula and structure. Raman spectroscopy has been used to study sonoraite, an example of a tellurite with hydroxyl and water units in the mineral structure. The free tellurite ion will have C3v symmetry and four modes, 2A1 and 2E. An intense Raman band at 779 cm−1 is assigned to the ν1 (TeO3)2− symmetric stretching mode. A band at 666 cm−1 with a shoulder at 638 cm−1 is assigned to the ν3 (TeO3)2− antisymmetric stretching mode. Bands at 374 and 387 cm−1 and the two bands at 425 and 468 cm−1 are assigned to the (TeO3)2−ν2(A1) and (TeO3)2−ν4(E) bending modes, respectively. The sharp band at 3423 cm−1 assigned to the OH stretching vibration of the OH unit is superimposed upon a broader spectral profile with Raman bands at 3000, 3223, 3350 and 3450 cm−1 which are attributed to water stretching bands. The technique of Raman spectroscopy is excellent for the study of tellurite minerals. Copyright © 2008 John Wiley & Sons, Ltd.
Surface‐enhanced Raman scattering study of L‐tryptophan
Authors: Aliaga A. E. , Osorio‐Román I. , Leyton P. , Garrido C. , Cárcamo J. , Caniulef C. , Célis F. , Díaz F. G. , Clavijo E. , Gómez‐Jeria J. S. , Campos‐Vallette M. M.
Published: September 2008

Surface‐enhanced Raman scattering (SERS) spectra of tryptophan (Trp) were obtained. A unique SERS spectrum of Trp, corresponding to the most stable conformation and orientation on the metal surface, is observed after a stabilization period. The Trp molecules interact with the surface through both the carboxylate and amino groups; the aliphatic moiety is close to the surface. The pyrrole ring of the indole moiety is farther from the surface than the benzene fragment. The observed spectra vary depending on both the preparation of the silver colloid and the aggregation time. The interpretation of the experimental results is supported by theoretical treatment of the molecule on the silver surface. Copyright © 2008 John Wiley & Sons, Ltd.
Raman spectroscopic study of kuranakhite PbMn4+Te6+O6–a rare tellurate mineral
Authors: Frost Ray L. , Keeffe Eloise C.
Published: September 2008

Tellurates are rare minerals as the tellurate anion is easily reduced to the tellurite ion. An example of a tellurate‐containing mineral is kuranakhite. Two bands at 617 and 686 cm−1 are observed and assigned to the Te6+O6ν1 symmetric stretching mode. The observation of two bands suggests the non‐equivalence of the Te6+O6 in the structure. The broad band centred at 743 cm−1 is attributed to the Te6+O6ν3 antisymmetric stretching mode. Sharp intense bands at 452 and 462 cm−1 are assigned to the Te6+O6ν4 bending mode. A comparison of the Raman spectra of kuranakhite with that of tellurate‐containing minerals tlapallite and xocomecatlite is made in this article. Copyright © 2008 John Wiley & Sons, Ltd.
UV resonance Raman spectroscopy probes the localization of tryptophan‐containing antimicrobial peptides in lipid vesicles
Authors: Quan Bryan , Ianoul Anatoli
Published: September 2008

In this work we employed UV resonance Raman spectroscopy with 229 nm excitation to study two tryptophan‐containing antimicrobial peptides with a broad‐spectrum activity against Gram‐positive and Gram‐negative bacteria: lactoferricin B (LfB, RRWQWRMKKLG) and pEM‐2 (KKWRWWLKALAKK). UV resonance Raman spectra of both peptides are dominated by tryptophan bands. Raman spectra of LfB and pEM‐2 in D2O and 2,2,2‐trifluoro ethanol (TFE) have been measured and used to identify the hydrogen‐bond strength marker bands W6 and W17. The tryptophan doublet, W7, at 1340 and 1360 cm−1 was used to detect an increase in the hydrophobicity of Trp environment in TFE. The spectra of LfB in complex with model cell membranes composed of zwitterionic dipalmitoylglycero‐phosphocholine (DPPC) or anionic dipalmitoyglycero‐phosphoglycerol (DPPG) lipid vesicles revealed a more hydrophobic Trp environment in DPPG, suggesting stronger interactions between the cationic peptide and anionic model cell membrane. Copyright © 2008 John Wiley & Sons, Ltd.
Impact of hot water treatment on sprouting, membrane permeability, sugar content and chip colour of reconditioned potato tubers following long‐term cold storage
Authors: Kyriacou Marios C , Gerasopoulos Dimitrios , Siomos Anastasios S , Ioannides Ioannis M
Published: September 2008

BACKGROUND: The efficacy of hot water treatment in facilitating successful reconditioning of processing potato (Solanum tuberosum L.) cultivar Hermes following 6 months cold storage at 4.5 °C was examined. Tubers were subjected to hot water treatments (HWTs) at 52.5, 55.0, 57.5 and 60.0 °C for 0–60, 0–50, 0–40 and 0–20 min, respectively, and then reconditioned for 20 days at 16 °C before evaluated for sprouting, fresh weight loss, membrane permeability, sugar content and processing quality.

RESULTS: The study demonstrates that in order to achieve complete inhibition of sprouting during potato reconditioning HWTs must exceed the thermal tolerance threshold of the tubers. Short‐duration HWT was effective in retarding sprout growth and tuber dehydration without significantly affecting storage parenchyma membrane permeability, tuber sugar content or processing quality. On the contrary, prolonged HWT caused extensive heat damage, loss of membrane integrity and induced an increase in tuber sucrose and reducing sugar content resulting in deterioration of chip colour in proportion to treatment duration.

CONCLUSION: Although HWT at 52.5–60 °C following long‐term cold storage did not improve the processing quality of potato tubers after 20 days of reconditioning, future work is needed to evaluate the effect of short‐duration HWT on the permissible extent of reconditioning and subsequent processing quality. Copyright © 2008 Society of Chemical Industry
Column selection for comprehensive multidimensional ion chromatography
Authors: Shellie Robert A. , Tyrrell Éadaoin , Pohl Christopher A. , Haddad Paul R.
Published: September 2008

This paper discusses the selection of ion chromatography (IC) columns for use in comprehensive multidimensional ion chromatography (IC×IC). First, a single number was determined for a wide range of anions (one number for each anion) using the linear solvent strength model. These numbers were then used to compare the column selectivity characteristics for five different columns. Principal component analysis was used to illustrate selectivity differences between columns. Dionex AS16 and AS20 columns were selected for use in the development of an IC×IC method for the separation of ten anions. To achieve the required speed of analysis in both the first and second separation dimensions, custom column lengths were packed in‐house. The use of an eluent suppressor between the first and second columns permits a relatively low flow ratio regime of only <1:20 in the first and second dimensions, respectively, which reduces dilution effects common in comprehensive multidimensional LC. Selection of the second dimension eluent conditions was aided by the development of a spreadsheet based on the linear solvent strength model.
Docosahexaenoic acid downregulates phenobarbital‐induced cytochrome P450 2B1 gene expression in rat primary hepatocytes via the c‐Jun NH2‐terminal kinase mitogen‐activated protein kinase pathway
Authors: Lu Chia‐Yang , Li Chien‐Chun , Liu Kai‐Li , Lii Chong‐Kuei , Chen Haw‐Wen
Published: September 2008

Mitogen‐activated protein kinase (MAPK) pathways play central roles in the transduction of extracellular stimuli into cells and the regulation of expression of numerous genes. Docosahexaenoic acid (DHA) was shown to be involved in the regulation of expression of drug metabolizing enzymes (DMEs) in rat primary hepatocytes in response to xenobiotics. Cytochrome P450 2B1 (CYP 2B1) is a DME that is dramatically induced by phenobarbital‐type inducers. The constitutive androstane receptor (CAR) plays a critical role in regulating the expression of DMEs, and the phosphorylation/dephosphorylation of CAR is an important event in CYP 2B1 expression. In the present study, we determined the effect of DHA on MAPK transactivation and its role in CYP 2B1 expression induced by phenobarbital. c‐Jun NH2‐terminal kinase (JNK) JNK1/2 and ERK1/2 were activated by phenobarbital in a dose‐dependent manner. DHA (100 μM) inhibited JNK1/2 and ERK2 activation induced by phenobarbital in a time‐dependent manner. Both SP600125 (a JNK inhibitor) and SB203580 (a p38 MAPK inhibitor) inhibited CYP 2B1 protein and mRNA expression induced by phenobarbital. SB203580 significantly increased the intracellular 3′‐5′‐cyclic adenosine monophosphate (cAMP) concentration compared with a control group (p < 0.05). Our results suggest that inhibition of JNK activation by DHA is at least part of the mechanisms of DHA's downregulation of CYP 2B1 expression induced by phenobarbital.
DFT calculations as a powerful technique to probe the crystal structure of Al(acac)3
Authors: Amini S. K. , Tafazzoli M.
Published: September 2008

27Al, 17O and 13C chemical shieldings of aluminum acetylacetonate complex, Al(acac)3, were calculated at some Density Functional Theory (DFT) levels of theory. In these calculations the X‐ray structures of its different polymorphs were used. Using these calculated data observed discrepancies between the X‐ray crystallography and solid state NMR experiment were explained in terms of the quality of the NMR data. In this survey we resorted to the simulated spectra using our calculated chemical shifts. In order to confirm our conclusions, electric field gradient (EFG) tensors of the 27Al and 17O nuclei were calculated at the same levels of theory as used in the chemical shielding calculations. On the other hand, these calculated chemical shifts and nuclear quadrupole coupling constants (NQCCs) made a correlation between X‐ray crystallography and solid state NMR experiments. Copyright © 2008 John Wiley & Sons, Ltd.
NMR analysis of a series of substituted pyrazolo[3,4‐d] pyrimidines‐4‐amines
Authors: Rodrigues Lígia M. , Sivasubramanian Aravind , Pinto Elisa M. , Oliveira‐Campos Ana M. F. , Seijas Julio A. , Vázquez‐Tato M. Pilar
Published: September 2008

A series of 21 substituted pyrazolo[3,4‐d]pyrimidines‐4‐amines were studied by 1H and 13C NMR. The application of two‐dimensional techniques, HMQC and HMBC, allowed the complete assignment of the spectra for all the compounds. Copyright © 2008 John Wiley & Sons, Ltd.
Complete NMR spectral assignments of two new iridoid diastereoisomers from the flowers of Plumeria rubra L. cv. acutifolia
Authors: Ye Guan , Yang Yan‐ling , Xia Guang‐xin , Fan Ming‐song , Huang Cheng‐gang
Published: September 2008

Two new iridoid diastereoisomers (1, 2), together with five known compounds, were isolated from the flowers of Plumerian rubra L. cv. acutifolia. Their structures were elucidated by the means of in‐depth spectroscopic and mass‐spectrometric analyses, particularly 1D and 2D NMR spectroscopy. Copyright © 2008 John Wiley & Sons, Ltd.
Neonicotinoid resistance in rice brown planthopper, Nilaparvata lugens
Authors: Gorman Kevin , Liu Zewen , Denholm Ian , Brüggen Kai‐Uwe , Nauen Ralf
Published: September 2008

BACKGROUND: Rice brown planthopper, Nilaparvata lugens Stål, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC95 and 5 × LC95 of a susceptible strain) were examined.

RESULTS: Ten of the 12 samples collected during 2005 were found to be susceptible to imidacloprid, but two late‐season samples from India showed reduced mortality at both diagnostic doses. All 13 strains collected in 2006 showed reduced mortality at both doses when compared with the susceptible strain. Dose–response lines showed resistance in one of the most resistant field strains to be approximately 100‐fold compared with the susceptible standard.

CONCLUSION: The data demonstrate the development and spread of neonicotinoid resistance in N. lugens in Asia and support reports of reduced field efficacy of imidacloprid. Copyright © 2008 Society of Chemical Industry
Electrical transport mechanisms in ensembles of silicon quantum dots
Authors: Balberg I.
Published: September 2008

The understanding of the conduction mechanism in ensembles of Si quantum dots is still at a rudimentary level in spite of the wide interest in the physics of Si nanostructures in the last two decades. In our work we tried to improve this understanding by deriving a self consistent and comprehensive framework for the discussion of the corresponding conduction mechanisms and the related optical properties. This trial was enabled by finding, in detail, the dependencies of the structural, the transport, the optical and the charge storage properties, on the density of these quantum dots, and interpreting these dependencies in terms of percolation cluster statistics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An experimental study of band gap states electrical properties in poly‐Si TFTs by the analysis of the transient currents
Authors: Michalas L. , Papaioannou G. J. , Kouvatsos D. N. , Voutsas A. T.
Published: September 2008

The present work presents, for the first time, a simultaneous analysis of the overshoot and undershoots effects in polycrystalline silicon Thin Film Transistors fabricated on SLS‐ELA films, as a function of temperature. The results suggest the presence of defects with different characteristics distributed across the bang gap, in agreement with theoretical model predictions. Furthermore a comparison of the estimated density of states in each half of the band gap denotes slightly n‐type poly‐silicon body, a result supported by the analysis of the transfer characteristics. Conclusively, it is presented that the analysis of the transient currents could act as a method for detailed characterization of poly‐silicon band gap. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)