bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stimulatory effect of polyethylene glycol (PEG) on gene expression in mouse liver following hydrodynamics‐based transfection
Authors: Ishida Tatsuhiro , Li Wenhao , Liu Zhihui , Kiwada Hiroshi 
Published: November 2005

AbstractBackgroundRapid intravenous injection of a large volume of plasmid DNA (pDNA), i.e. a transfection procedure based on hydrodynamics, is known to be an efficient and liver‐specific method ofin vivogene delivery. However, the gene expression is transient.MethodsWe investigated the effect of addition of polyethylene glycol (PEG) to a solution of naked pDNA (luciferase) on the expression of the gene in mouse liver following transfection by the hydrodynamics‐based technique. In addition, the mechanism leading to the enhancement of the gene expression was studied.ResultsThe addition of 1% (w/v) PEG2000 to the pDNA solution enhanced the resulting gene expression in the liver. Increasing the PEG2000 concentration to more than 1 and up to 10% (w/v) rather diminished the gene expression level. By contrast, increasing the molecular weight of PEG to over 2000 up to 10 000 did not affect the level of gene expression. Histopathological and serum‐chemistry examinations indicated that hydrostatic or osmotic pressure increased tissue and hepatocellular damage in a PEG‐concentration‐dependent manner, and resulted in a decrease in gene expression. Quantitative evaluation showed that the enhanced gene expression resulted from stabilization of the pDNA introduced into the hepatocytes and an enhancement of the transport ofintactpDNA to the nucleus.ConclusionsFor most gene therapy applications and gene function studies, sustained expression of the introduced gene(s) is necessary. This simple method to achieve enhanced gene expression in liver may have a great potential for a wide variety of laboratory studies in molecular and cellular biology as well as possibly for future clinical applications in humans. Copyright © 2005 John Wiley & Sons, Ltd.
Development of a gas chromatographic/mass spectrometric method to quantify R(–)‐apomorphine, R(–)‐apocodeine and R(–)‐norapomorphine in human plasma and urine
Authors: Libert Frédéric , Coudoré François , Richard Damien , Durif Franck , Eschalier Alain 
Published: November 2005

AbstractA method was developed and validated for the analysis of R(−)‐apomorphine, (R−)‐apocodeine and R(−)‐norapomorphine in human plasma and urine with N‐propylnorapomorphine as internal standard using gas chromatography/mass spectrometry (GC/MS) and single‐ion monitoring after a single liquid–liquid extraction and silylation of compounds. The quantification limits were 1 ng/ml for apomorphine and apocodeine and 25 ng/ml for norapomorphine. Calibration curves were linear, within the range 1–100 ng/ml. Variation in intraday and interday precision was below 10%. This method was applied to study apomorphine bioavailability in nine patients with Parkinson's disease before and after coadministration of a catechol‐O‐methyl transferase inhibitor. Copyright © 2005 John Wiley & Sons, Ltd.
Isotope dilution SPME GC/MS for the determination of methylmercury in tuna fish samples
Authors: Centineo Giuseppe , González Elisa Blanco , García Alonso J. Ignacio , Sanz‐Medel Alfredo 
Published: November 2005

AbstractThe development of a rapid, precise and accurate analytical method for the determination of methylmercury in tuna fish samples is described. The method is based on the use of isotope dilution GC/MS with electron impact ionization, a widespread technique in routine testing laboratories. A certified spike containing 202Hg‐enriched methylmercury was used for the isotope dilution of the samples. After extraction of the methylmercury from the sample, methylmercury was propylated using sodium tetrapropyl borate in SPME vials and the analytes were sampled from the headspace for 15 min. For isotope measurements, the molecular ion (MePrHg+) was used in the SIM mode. Five molecular ions were monitored, corresponding to the 198Hg, 199Hg, 200Hg, 201Hg and 202Hg isotopes. The detection at masses corresponding to 198Hg was used to correct for m + 1 contributions of 13C from the organic groups attached to the mercury atom on the 199Hg, 200Hg, 201Hg and 202Hg masses with simple mathematical equations, and the concentration of methylmercury was calculated on the basis of the corrected 200Hg/202Hg isotope ratio. The 202Hg‐enriched methylmercury spike was applied, with satisfactory results, to the determination of methylmercury in the certified reference material BCR 464. The method was successfully applied to the determination of methylmercury in tuna fish samples, and the obtained results were included in the CCQM‐P39 interlaboratory exercise, organized by the Institute for Reference Materials and Measurements (IRMM, Geel, Belgium) with excellent agreement between our results and the average obtained by the other participants. Copyright © 2005 John Wiley & Sons, Ltd.
Cultured astrocytes from heme oxygenase‐1 knockout mice are more vulnerable to heme‐mediated oxidative injury
Authors: Chen‐Roetling Jing , Benvenisti‐Zarom Luna , Regan Raymond F. 
Published: November 2005

AbstractHemin, the oxidized form of heme, is released from hemoglobin after CNS hemorrhage and may contribute to injury to surrounding tissue. The heme oxygenase (HO) enzymes catalyze the breakdown of hemin to biliverdin, carbon monoxide, and ferric iron. Although HO‐2, the isoform expressed predominantly in neurons, accelerates heme‐mediated neuronal injury, inhibitor studies suggest that HO‐1 induction has a protective effect on astrocytes. In the present study, we directly compared the vulnerability of cultured HO‐1 knockout and wild‐type astrocytes to hemin. Consistent with prior observations, exposure of wild‐type cultures to hemin for 24 hr resulted in protein carbonylation and concentration‐dependent cell death between 10 and 60 μM, as determined by MTT and lactate dehydrogenase release assays. In cultures prepared from mice lacking the HO‐1 gene, oxidative cell injury was approximately doubled. Both protein oxidation and cell death in HO‐1 knockout astrocytes were significantly reduced by pretreating cultures with an adenovirus encoding the HO‐1 gene prior to hemin exposure. HO‐2 expression was observed in both knockout and wild‐type cultures and was not altered by HO‐1 gene deletion. Cell hemin accumulation after 20 hr hemin exposure was 4.7‐fold higher in knockout cells. These results support the hypothesis that HO‐1 protects astrocytes from heme‐mediated oxidative injury. Selectively increasing its expression in astrocytes may be beneficial after hemorrhagic CNS injuries. © 2005 Wiley‐Liss, Inc.
Blockade of nicotinic acetylcholine receptors suppresses hippocampal long‐term potentiation in wild‐type but not ApoE4 targeted replacement mice
Authors: Yun Sung Hwan , Park Kyung A. , Sullivan Patrick , Pasternak Joseph F. , LaDu Mary Jo , Trommer Barbara L. 
Published: November 2005

AbstractBoth impaired nicotinic neurotransmission and the inheritance of apoE4 are associated with increased risk for Alzheimer disease (AD) as well as other deficiencies in memory‐related behavior. Long‐term potentiation (LTP), a cellular model of memory, is known to be altered by nicotinic agents. Recent studies also support an emergent role for apoE in LTP. We compared the effects of mecamylamine, a nonspecific antagonist of nicotinic acetylcholine receptors (nAChRs), on basal synaptic transmission and LTP in hippocampal slices from wild‐type (wt) mice and targeted replacement mice expressing human apoE4 (apoE4‐TR). Field excitatory postsynaptic potentials (EPSPs) were recorded in the dentate gyrus (DG) in response to medial perforant path activation, and theta burst stimulation was used to induce LTP. Bath application of mecamylamine (3 μM) did not alter input–output relationships or paired pulse depression in either mouse strain. Under control conditions, apoE4‐TR mice showed significantly less LTP than wt mice (17.5% ± 3.2%, n = 9, vs. 30.1% ± 3.9%, n = 11, P < 0.02). Mecamylamine reduced LTP in wt mice to a level that was similar to control levels for apoE4‐TR mice (15.7% ± 3.4%, n = 9), whereas apoE4‐TR showed no further reduction of LTP (16.6% ± 3.7%, n = 8) by mecamylamine. Thus mice expressing human apoE4 differ from wt mice both in their capacity for LTP and in the effect on LTP of nicotinic cholinergic blockade. It is possible that nicotinic neurotransmission is already compromised in apoE4‐TR mice and, hence, that interference with the integrity of this cholinergic system represents a mechanism by which inheritance of the apoE4 allele contributes to cognitive risk. © 2005 Wiley‐Liss, Inc.
Activation and circuitry of uterine‐cervix‐related neurons in the lumbosacral dorsal root ganglia and spinal cord at parturition
Authors: Puder B.A. , Papka R.E. 
Published: November 2005

AbstractStimulation of the uterine cervix at parturition activates neural circuits involving primary sensory nerves and supraspinally projecting neurons of the lumbosacral spinal cord, resulting in output of hypothalamic neurohormones. Dorsal root ganglia (DRG) and spinal neurons of these circuits are not well‐characterized. The objectives of this study were to detail the activation of DRG and spinal neurons of the L6/S1 levels that are stimulated at late pregnancy, verify hypothalamic projections of activated spinal neurons, and determine whether activated neurons express estrogen receptor‐α (ERα). Expression of phosphorylated cyclic‐AMP response element‐binding protein (PCREB) and Fos immunohistochemistry were used to “mark” activated DRG and spinal neurons, respectively. Retrograde tracing identified uterine‐cervix‐related and spinohypothalamic neurons. Baseline PCREB expression in the DRG increased during pregnancy and peaked during the last trimester. Some PCREB‐expressing neurons contained retrograde tracer identifying them as cervix‐related neurons. Fos‐expressing neurons were few in spinal cords of nonpregnant and day 22 pregnant rats but were numerous in parturient animals. Some Fos‐expressing neurons located in the dorsal half of the spinal cord contained retrograde tracer identifying them as spinohypothalamic neurons. Some DRG neurons expressing PCREB also expressed ERα, and some spinal neurons activated at parturition projected axons to the hypothalamus and expressed ERα. These results indicate that DRG and spinal cord neurons are activated at parturition; that those in the spinal cord are present in areas involved in autonomic and sensory processing; that some spinal neurons project axons to the hypothalamus, ostensibly part of a neuroendocrine reflex; and that sensory and spinal neurons can respond to estrogens. Moreover, some activated sensory neurons may be involved in the animal's perception of labor pain. © 2005 Wiley‐Liss, Inc.
Molecular alterations resulting from frameshift mutations in peripheral myelin protein 22: Implications for neuropathy severity
Authors: Johnson J.S. , Roux K.J. , Fletcher B.S. , Fortun J. , Notterpek L. 
Published: November 2005

AbstractAlterations in peripheral myelin protein 22 (PMP22) expression are associated with a heterogeneous group of hereditary demyelinating peripheral neuropathies. Two mutations at glycine 94, a single guanine insertion or deletion in PMP22, result in different reading frameshifts and, consequently, an extended G94fsX222 or a truncated G94fsX110 protein, respectively. Both of these autosomal dominant mutations alter the second half of PMP22 and yet are linked to clinical phenotypes with distinct severities. The G94fsX222 is associated with hereditary neuropathy with liability to pressure palsies, whereas G94fsX110 causes severe neuropathy diagnosed as Dejerine‐Sottas disease or Charcot‐Marie‐Tooth disease type IA. To investigate the subcellular changes associated with the G94 frameshift mutations, we expressed epitope‐tagged forms in primary rat Schwann cells. Biochemical and immunolabeling studies indicate that, unlike the wild‐type protein, which is targeted for the plasma membrane, frameshift PMP22s are retained in the cell, prior to reaching the medial Golgi compartment. Similar to Wt‐PMP22, both frameshift mutants are targeted for proteasomal degradation and accumulate in detergent‐insoluble, ubiquitin‐containing aggregates upon inhibition of this pathway. The extended frameshift PMP22 shows the ability to form spontaneous aggregates in the absence of proteasome inhibition. On the other hand, Schwann cells expressing the truncated protein proliferate at a significantly higher rate than Schwann cells expressing the wild‐type or the extended PMP22. In summary, these results suggest that a greater potential for PMP22 aggregation is associated with a less severe phenotype, whereas dysregulation of Schwann cell proliferation is linked to severe neuropathy. © 2005 Wiley‐Liss, Inc.
Antioxidant and antiinflammatory activities of xanthorrhizol in hippocampal neurons and primary cultured microglia
Authors: Lim Chol Seung , Jin Da‐Qing , Mok Hyejung , Oh Sang Jin , Lee Jung Uk , Hwang Jae Kwan , Ha Ilho , Han Jung‐Soo 
Published: November 2005

AbstractXanthorrhizol, a natural sesquiterpenoid isolated from the rhizome of Curcuma xanthorrhiza Roxb (Zingiberaceae), has antibacterial activities and protective effects against cisplatin‐induced hepatotoxicity. In this study, we investigated the activities of xanthorrhizol as an antioxidant or antiinflammatory agent using neuronal and microglial cells. Xanthorrhizol had potent neuroprotective effects on glutamate‐induced neurotoxicity and reactive oxygen species (ROS) generation in the murine hippocampal HT22 cell line. Also, xanthorrhizol inhibited H2O2‐induced lipid peroxidation in rat brain homogenates. The properties of xanthorrhizol as an antiinflammatory agent were investigated in microglial activation by lipopolysaccharide. It reduced the expression of cyclooxygenase‐2 and the inducible nitric oxide synthase, which consequently resulted in the reduction of nitric oxide. The production of proinflammatory cytokines, such as interleukin‐6 and tumor necrosis factor‐α in activated microglial cells, was reduced by xanthorrhizol. These results suggest that xanthorrhizol could be an effective candidate for the treatment of Alzheimer's disease‐ and other neurological disease‐related ROS and inflammation. © 2005 Wiley‐Liss, Inc.
Toward a psychological and cultural model of downsizing
Authors: Mentzer Marc S. 
Published: November 2005

AbstractOrganizational downsizing is often counterproductive and applied irrespective of past financial performance. The popularity of this tactic leads to the question of whether an executive's propensity to downsize is linked to characteristics such as uncertainty avoidance and risk tolerance, which can be examined at either an individual or societal level. Copyright © 2005 John Wiley & Sons, Ltd.
Cultural diversity recomposition and effectiveness in monoculture work groups
Authors: Hopkins Willie E. , Hopkins Shirley A. , Gross Michael A. 
Published: November 2005

AbstractIn this article, we discuss different types of cultural diversity recomposition that can occur in monoculture work groups. Several direct effect propositions are set forth about the impact of cultural diversity recomposition type on monoculture group effectiveness, as are several moderating effect propositions. We identify potential moderators that have not been explored in prior research and discuss the implications that each has for organizational behavior and practice. We then discuss some implications for future research. We conclude this article with a call for establishing a research agenda that will guide our thinking as we explore this topic in more depth. Copyright © 2005 John Wiley & Sons, Ltd.
Multiplex PCR identification of Listeria monocytogenes isolates from milk and milk‐processing environments
Authors: Zeng Haiyan , Zhang Xiaofeng , Sun Zhen , Fang Weihuan 
Published: November 2005

AbstractA multiplex PCR procedure based on genes iap (coding for the invasion‐associated 60 kDa protein or p60) and hly (coding for listeriolysin O) of Listeria monocytogenes was to used to investigate the status of its contamination along the major milk‐processing environments. Duplex PCR amplified fragments of the iap gene at about 1.45 kb from all strains of major Listeria spp. tested and a 420 bp fragment of hly from L. monocytogenes reference strains. With triplex PCR, all L. monocytogenes strains exhibited a 420 bp fragment of hly as well as a 700 bp fragment of iap instead of its 1.45kb PCR product. The tentative L. monocytogenes isolates (n = 27) out of 566 samples of milk and milk‐processing environments in the PALCAM agar from cultures of buffered listeria enrichment broth were further subjected to both API and triplex PCR identification. Both methods identified the same 20 isolates as L. monocytogenes. The triplex PCR procedure detected as low as 3.2 × 101 cfu mL−1 of listerial cells even in the presence of L. innocua (108 cfu mL−1). It could detect 1.4 × 102 listerial cells mL−1 directly from milk artificially contaminated with the bacteria. Lower levels of L. monocytogenes cells in milk (1.45 × 101 to 1.45 × 100 cfu mL−1) could be detectable if the inoculated milk samples were cultured for 3–6 h. The bacterium was found not only in raw milk, sewage water and vessel surfaces but also in pasteurized milk. Copyright © 2005 Society of Chemical Industry
Quality of the lipid fraction of Italian biscuits
Authors: Caponio Francesco , Summo Carmine , Delcuratolo Debora , Pasqualone Antonella 
Published: November 2005

AbstractAlthough not perceived as fatty foods by consumers, biscuits contain a consistent quantity of lipids. Since they are daily present in the diet, an experimental study was carried out with the aim of evaluating the quality of the lipid fraction of biscuits. Amounts of fat ranging from 75 to 231 g kg−1, mainly constituted by refined vegetable oils and margarine, were present. A high variability in fatty acid composition was found and in some cases high amounts of trans isomers of unsaturated fatty acid were observed. In addition, HPSEC analysis of polar compounds indicated an extensive hydrolytic degradation of triacylglycerols and also a high level of oxidative degradation. The latter, demonstrated by means of the contemporary measure of oxidised triacylglycerols and of triacylglycerol oligopolymers, was comparable to that found in hydrogenated oils and fats. Copyright © 2005 Society of Chemical Industry
Sugar and selected amino acid influences on the structure of pyrazines in microwave heat‐treated formulations
Authors: Coleman William M , Steichen Thomas J 
Published: November 2005

AbstractThe amount and type of selected sugars and selected amino acids have been shown to significantly impact the structure of headspace‐volatile pyrazines produced in aqueous microwave heat‐treated formulations. Selection of sugar and amino acid can dictate the structure, yield and distribution of headspace‐volatile pyrazines. Under the same reaction conditions and sugar to ammonium hydroxide ratios, rhamnose was found to produce more pyrazines than did high‐fructose corn syrup (HFCS). With rhamnose, the yield of pyrazines approached 4500 µg mL−1. Formulations selectively enriched in ethyldimethylpyrazines can be prepared by stepwise substitution of HFCS with rhamnose. Formulations preferably enriched in methyl‐ and dimethyl‐(3‐methylbutyl)‐ as well as methyl‐ and dimethyl‐(2‐methylpropyl)pyrazines were prepared through selective combinations of rhamnose/HFCS and amino acids. Stepwise substitution of HFCS with rhamnose coupled with the use of selected amino acids allowed for the control of the yield, structure and distribution of volatile pyrazines in microwave heat‐treated aqueous formulations. Reaction temperature was also found to significantly influence pyrazine yield and distribution. Statistical modeling of the reaction yields as functions of reaction variables produced surfaces with acceptable modeling coefficients. Mechanisms were postulated to account for the increased yields and selected distributions pyrazines when rhamnose was employed. Copyright © 2005 Society of Chemical Industry
Expression of basic genes involved in tea polyphenol synthesis in relation to accumulation of catechins and total tea polyphenols
Authors: Mamati George Edward , Liang Yuerong , Lu Jianliang 
Published: November 2005

AbstractCatechins, a group of polyphenolic compounds in the green leaf of tea [Camellia sinensis (L.) O. Kuntze], are major components conferring quality attributes and health benefits on processed tea. Expression patterns of the basic genes related to accumulation of the catechins and total polyphenols at different stages of tea leaf development and their relationship with catechin concentration were investigated by reverse transcriptase polymerase chain reaction and high‐performance liquid chromatographic methods. The results showed that the concentration of total catechins and polyphenols in leaves at different stages of development declined with age of the leaf but changes of the individual catechins varied, with a general decrease in catechin gallate and epigallocatechin gallate and increase in epigallocatechin and epicatechin gallate. Genes of phenylalanine ammonium lyase (PAL), dihydroflavonol reductase (DFR) and three chalcone synthase genes (CHS1, CHS2, CHS3) were highly expressed in bud, first leaf and second leaf but were barely detected in mature leaves. The expression of DFR, a downstream gene in the catechin biosynthesis pathway, was closely related to the concentration of total catechins and polyphenols in various stages of leaf development. Copyright © 2005 Society of Chemical Industry
Influence of growth stage and postharvest storage on ascorbic acid and carotenoid content and visual quality of baby spinach (Spinacia oleracea L.)
Authors: Bergquist Sara ÅM , Gertsson Ulla E , Olsson Marie E 
Published: November 2005

AbstractTo investigate the variations in quality with growth stage and postharvest storage, spinach was sown on three occasions. For each occasion, the spinach was harvested at three growth stages at 6‐day intervals. The second stage corresponded to a growth period used for baby spinach by commercial growers. After harvest, the leaves were stored in polypropylene bags at 2 °C or 10 °C. The highest ascorbic acid content in fresh material was found at stage I. During storage, the ascorbic acid content decreased considerably and the dehydroascorbic acid/vitamin C ratio increased. Storage at 2 °C gave a smaller reduction in ascorbic acid content than storage at 10 °C. Total carotenoid content increased or remained stable during storage. Lutein was the major carotenoid, making up about 39% of the total carotenoid content, followed by violaxanthin, β‐carotene and neoxanthin. Visual quality decreased during storage in most cases, and was correlated to initial ascorbic acid and dry matter contents. The initial AA content might therefore be used as a parameter for predicting the shelf‐life of baby spinach. The results also indicate that by harvesting baby spinach a few days earlier than the current commercial stage of harvest the postharvest visual quality and nutritional quality may be improved. Copyright © 2005 Society of Chemical Industry