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OL
Terms modified by OL Selected AbstractsAnion-Dependent Facile Route to Magnetic Dinuclear and Dodecanuclear Cobalt ClustersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2010Ling-Ling Zheng Abstract An unprecedented dodecanuclear CoIII3CoII9 and a dinuclear CoII2 cluster were synthesized facilely from reactions of different coblt(II) salts with the ligand (1H -benzimidazol-2-yl)methanol. The cobalt ions in the Co12 supercluster are linked into a disclike structures through ,3 -OL, ,-OL, ,3 -O2,, ,1,1 -N3, and ,1,1,1 -N3, bridges. Magnetic studies reveal that strong ferromagnetic coupling through double end-on (EO) azido bridges exists in 1, while both ferromagnetic coupling through the ,3 -OL and ,-OL pathways and antiferromagnetc coupling through the ,1,1,1 -N3, pathway exist in 2, which results in a ferrimagnetic behaviour of 2. [source] Activation of PPAR-, and PTEN cascade participates in lovastatin-mediated accelerated differentiation of oligodendrocyte progenitor cellsGLIA, Issue 14 2010Ajaib S. Paintlia Abstract Previously, we and others documented that statins including-lovastatin (LOV) promote the differentiation of oligodendrocyte progenitor cells (OPCs) and remyelination in experimental autoimmune encephalomyelitis (EAE), an multiple sclerosis (MS) model. Conversely, some recent studies demonstrated that statins negatively influence oligodendrocyte (OL) differentiation in vitro and remyelination in a cuprizone-CNS demyelinating model. Therefore, herein, we first investigated the cause of impaired differentiation of OLs by statins in vitro settings. Our observations indicated that the depletion of cholesterol was detrimental to LOV treated OPCs under cholesterol/serum-deprived culture conditions similar to that were used in conflicting studies. However, the depletion of geranylgeranyl-pp under normal cholesterol homeostasis conditions enhanced the phenotypic commitment and differentiation of LOV-treated OPCs ascribed to inhibition of RhoA-Rho kinase. Interestingly, this effect of LOV was associated with increased activation and expression of both PPAR-, and PTEN in OPCs as confirmed by various pharmacological and molecular based approaches. Furthermore, PTEN was involved in an inhibition of OPCs proliferation via PI3K-Akt inhibition and induction of cell cycle arrest at G1 phase, but without affecting their cell survival. These effects of LOV on OPCs in vitro were absent in the CNS of normal rats chronically treated with LOV concentrations used in EAE indicating that PPAR-, induction in normal brain may be tightly regulated-providing evidences that statins are therapeutically safe for humans. Collectively, these data provide initial evidence that statin-mediated activation of the PPAR-,-PTEN cascade participates in OL differentiation, thus suggesting new therapeutic-interventions for MS or related CNS-demyelinating diseases. © 2010 Wiley-Liss, Inc. [source] Phosphorylation and lipid raft association of fibroblast growth factor receptor-2 in oligodendrocytes,GLIA, Issue 9 2009M. R. Bryant Abstract Fibroblast growth factors (FGFs) and their receptors (FGFRs) initiate diverse cellular responses that contribute to the regulation of oligodendrocyte (OL) function. To understand the mechanisms by which FGFRs elicit these cellular responses, we investigated the phosphorylation of signal transduction proteins and the role of cholesterol-glycosphingolipid-enriched "lipid raft" microdomains in differentiated OLs. Surprisingly, we found that the most abundant tyrosine-phosphorylated protein in OLs was the 120-kd isoform of FGFR2 and that it was phosphorylated even in the absence of FGF2, suggesting a potential ligand-independent function for this receptor. Furthermore, FGFR2, but not FGFR1, was associated with lipid raft microdomains in OLs and myelin (but not in astrocytes). This provides the first evidence for the association of FGFR with TX-100-insoluble lipid raft fractions. FGFR2 phosphorylated the key downstream target, FRS2 in OLs. Raft disruption resulted in loss of phosphorylated FRS2 from lipid rafts, coupled with the loss of Akt but not of Mek or Erk phosphorylation. This suggests that FGFR2-FRS2 signaling in lipid rafts operates via the PI3-Kinase/Akt pathway rather than the Ras/Mek/Erk pathway, emphasizing the importance of microenvironments within the cell membrane. Also present in lipid rafts in OLs and myelin, but not in astrocytes, was a novel 52-kd isoform of FGFR2 that lacked the extracellular ligand-binding region. These results demonstrate that FGFR2 in OLs and myelin possess unique characteristics that are specific both to receptor type and to OLs and provide a novel mechanism to elicit distinct cellular responses that mediate both FGF-dependent and -independent functions. © 2008 Wiley-Liss, Inc. [source] Organizational learning as an organization development intervention in six high-technology firms in Taiwan: An exploratory case studyHUMAN RESOURCE DEVELOPMENT QUARTERLY, Issue 2 2007Bella Ya-Hui Lien Organizational learning (OL) is about how individuals collect, absorb, and transform information into organizational memory and knowledge. This case study explored how six high-technology firms in Taiwan chose OL as an organization development intervention strategy. Issues included how best to implement OL; how individuals, teams, and organizations learn; and the extent to which OL activities contributed to organizational performance. Five themes emerged as findings: (1) using language with which employees are familiar, (2) implementing OL concepts that are congruent with employees' work or personal life, (3) putting individual learning first and diffusing it to team learning and organizational learning, (4) using the knowledge management system to create an opportunity for individuals, teams, and the organization to learn, and (5) linking OL to organizational strategy to improve organizational performance. [source] Consumer advisors revisited: What drives those with market mavenism and opinion leadership tendencies and why?JOURNAL OF CONSUMER BEHAVIOUR, Issue 2-3 2009Nicola E. Stokburger-Sauer Consumers with a tendency toward market mavenism (MM) and opinion leadership (OL) represent powerful forces in the marketplace because of their influence on other consumers' consumption decisions. They are thus important consumer groups for both other individuals and companies. Little is known, however, about the motives that drive these individuals. Additionally, research has not explored the consequences of the market mavenism tendency (MMT) and OL. Research is thus needed to tap into and compare factors that influence MMT and OL as well as variables that are influenced by MMT and OL. A key goal of the current study is to determine whether individuals with a tendency toward MM and opinion leaders are consumers who are more or less satisfied and loyal than other consumers. This study investigates product involvement and need for variety (NFV) as antecedents of MMT and OL and looks into their relationship with satisfaction and loyalty. Using data from 1145 German consumers in four product categories (i.e., wine, clothing, cars, and cameras) and applying structural equation modeling, it was found that opinion leaders have higher levels of product category involvement than individuals with a tendency toward mavenism, while the latter have a higher NFV than opinion leaders. Finally, opinion leaders and individuals with a tendency toward mavenism have higher levels of satisfaction, and the first are more loyal consumers, but this varies across product categories. Important implications for marketing theory and marketing practice can be derived. Individuals with a tendency toward MM and/or opinion leaders could, for instance, be integrated as powerful sources in the context of co-producing products and services. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modulation of peroxisome proliferator-activated receptor-, activity by N -acetyl cysteine attenuates inhibition of oligodendrocyte development in lipopolysaccharide stimulated mixed glial culturesJOURNAL OF NEUROCHEMISTRY, Issue 3 2008Manjeet K. Paintlia Abstract Glial cells secrete proinflammatory mediators in the brain in response to exogenous stimuli such as infection and injury. Previously, we documented that systemic maternal lipopolysaccharide (LPS)-exposure at embryonic gestation day 18 causes oligodendrocyte (OL)-injury/hypomyelination in the developing brain which can be attenuated by N -acetyl cysteine (NAC; precursor of glutathione). The present study delineates the underlying mechanism of NAC-mediated attenuation of inhibition of OL development in LPS-stimulated mixed glial cultures. Factors released by LPS-stimulated mixed glial cultures inhibited OL development as shown by decrease in both proliferation 3bromo-deoxyuridine+/chondroitin sulfate proteoglycan,NG2+, hereafter BrdU+/NG+ and differentiation (O4+ and myelin basic protein+) of OL-progenitors. Correspondingly, an impairment of peroxisomal proliferation was shown by a decrease in the level of peroxisomal proteins in the developing OLs following exposure to LPS-conditioned media (LCM). Both NAC and WY14643, a peroxisome proliferator-activated receptor (PPAR)-, agonist attenuated these LCM-induced effects in OL-progenitors. Similar to WY14643, NAC attenuated LCM-induced inhibition of PPAR-, activity in developing OLs. Studies conducted with cytokines and diamide (a thiol-depleting agent) confirmed that cytokines are active agents in LCM which may be responsible for inhibition of OL development via peroxisomal dysfunction and induction of oxidative stress. These findings were further corroborated by similar treatment of developing OLs generated from PPAR-,(,/,) and wild-type mice or B12 oligodendroglial cells co-transfected with PPAR-, small interfering RNAs/pTK-PPREx3-Luc plasmids. Collectively, these data provide evidence that the modulation of PPAR-, activity, thus peroxisomal function by NAC attenuates LPS-induced glial factors-mediated inhibition of OL development suggesting new therapeutic interventions to prevent the devastating effects of maternal infections. [source] Regulation of development of oligodendrocytesJOURNAL OF NEUROCHEMISTRY, Issue 2002K. Ikenaka Oligodendrocyte (OL) is the myelin-forming glial cell in the central nervous system. In the spinal cord, molecular markers for OL precursor cells (OPCs), such as PDGF a-receptor (PDGFR a), are first expressed in a strictly restricted focus of the ventral ventricular lumen at E12.5 in mouse and later spread throughout the cord. To investigate how they originate from these specific regions, we used an explant culture system of E12 mouse cervical spinal cord. When we cultured the ventral and dorsal spinal cords separately, a robust increase in the number of O4+ cells was observed in the ventral fragment. This phenomenon suggests the presence of factors inhibiting OL development from dorsal spinal cord. BMP4 is secreted from dorsal spinal cord and is a strong candidate for this factor; however, it did not affect OL development in our system. Here we show that Wnt-1 and Wnt-3a, in contrast, may have a role in OL maturation. The developmental profile of wnt-1/3a gene expressions in the dorsal spinal cord showed a significant correlation with that of the dorsal activity, which was very strong at E11, and then reduced to an undetectable level by E14. When Wnt-3a was added to the dissociation culture prepared from E14 mouse ventral cervical cords, the numbers of OL decreased. b-Catenin and LEF family proteins are known to form a transcription factor complex at the down stream of Wnt signalling. OL,like differentiation of CG4 cells was inhibited by constitutively active LEF-b-Catenin, supporting the idea that Wnt signalling directly inhibits OL differentiation. [source] Differential clustering of Caspr by oligodendrocytes and Schwann cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 15 2009Menahem Eisenbach Abstract Formation of the paranodal axoglial junction (PNJ) requires the presence of three cell adhesion molecules: the 155-kDa isoform of neurofascin (NF155) on the glial membrane and a complex of Caspr and contactin found on the axolemma. Here we report that the clustering of Caspr along myelinated axons during development differs fundamentally between the central (CNS) and peripheral (PNS) nervous systems. In cultures of Schwann cells (SC) and dorsal root ganglion (DRG) neurons, membrane accumulation of Caspr was detected only after myelination. In contrast, in oligodendrocytes (OL)/DRG neurons cocultures, Caspr was clustered upon initial glial cell contact already before myelination had begun. Premyelination clustering of Caspr was detected in cultures of oligodendrocytes and retinal ganglion cells, motor neurons, and DRG neurons as well as in mixed cell cultures of rat forebrain and spinal cords. Cocultures of oligodendrocyte precursor cells isolated from contactin- or neurofascin-deficient mice with wild-type DRG neurons showed that clustering of Caspr at initial contact sites between OL processes and the axon requires glial expression of NF155 but not of contactin. These results demonstrate that the expression of membrane proteins along the axolemma is determined by the type of the contacting glial cells and is not an intrinsic characteristic of the axon. © 2009 Wiley-Liss, Inc. [source] A long-term follow-up study on the natural course of oral leukoplakia in a Swedish population-based sampleJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 2 2007A. Roosaar Aim:, To assess the natural course of screening-detected oral leukoplakia (OL) among non-consulting individuals. Methods:, A cohort of 555 individuals with OL, confirmed in 1973,1974 during a population-based survey, were followed through January 2002 via record linkages with nationwide and essentially complete registers. A sample of 104 drawn from the 297 surviving cohort members who still were living in the area in 1993,1995 was invited to a re-examination. Sixty-seven of them attended. Results:, At the time of re-examination OL had disappeared in 29 (43%) individuals. There was a statistically significant association between cessation of/no smoking habits in 1993,1995 and the disappearance of OL. Never/previous daily smokers were thus over-represented among individuals whose OL had disappeared compared to those with persisting OL [n = 23 (82%) vs. n = 18 (47%), P < 0.01]. Eighteen (78%) of the twenty three non-smokers with disappearing OL had quit after the initial examination. One man and two women developed oral cancer during follow-up while 0.7 and 0.07, respectively, were expected. Conclusion:, Smoking cessation was associated with an increased disappearance of OL. Hence, at least one-fourth had lesions that could be classified as tobacco-related. Small observed and expected numbers prohibited firm conclusions about a possible excess risk of developing oral cancer. [source] Identity of TUNEL-positive cells in the oral buccal epithelium of normal mucosa and lichen lesionsJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 5 2004Andreas Karatsaidis Background:,In situ detection of DNA fragmentation by TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick end labeling (TUNEL) is a widely used technique to identify apoptotic cells in the terminal phases of cell death. Several studies have shown that there are statistically increased numbers of TUNEL+ cells within the epithelium of oral lichen (OL). It was suggested that this indicates an increased rate of apoptosis among basal and suprabasal keratinocytes in OL epithelium. The aim of this study was to identify the TUNEL+ cells in the epithelium of erythematous (ERY) OL and normal oral mucosa (NOM). Methods:, Sections of biopsies from NOM and ERY OL were processed for TUNEL combined with immunostaining for pan-cytokeratin or for cell markers specifically expressed by different leukocytes. Results:, In NOM, TUNEL+ keratinocytes were almost exclusively seen in the outermost epithelial layers. This labeling was absent in ERY OL. In the basal and lower spinous layers, more TUNEL+ cell nuclei were seen in ERY OL as compared with NOM, in accordance with previous studies. The present observations show, however, that only very few of these cells were keratinocytes, but rather were CD4+ lymphocytes and CD68+ macrophages. There was no difference between the numbers of TUNEL+ keratinocytes in basal and lower spinous layers in ERY OL and NOM epithelium. No intraepithelial CD8+ lymphocytes, Langerhans cells, or mast cells were found to be TUNEL+. Conclusion:, The findings indicate that the pathologic changes in ERY OL epithelium cannot be explained by increased prevalence of terminal keratinocyte cell death identified by TUNEL. [source] Oxypropylation of Lignins and Preparation of Rigid Polyurethane Foams from the Ensuing PolyolsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005Hamid Nadji Abstract Summary: Different lignins were converted into polyols by a chain extension reaction with propylene oxide (PO). Thus, soda lignin from Alfa (Stipa tenacissima) (SL), organosolv lignin from hardwoods (OL), kraft lignin (KL) from softwood and oxidized organosolv lignin (OOL) were oxypropylated in a batch reactor at 180,°C in the presence of KOH as catalyst. The ensuing polyols were characterized by FTIR and 1H NMR spectroscopy, which showed that they had incorporated poly(propylene oxide) grafts into their structure. Their viscosity varied from 5 mPa,·,s to infinity, depending on the Lignin/PO ratio and their hydroxy index was in the range of 100,200, which made them suitable for rigid polyurethane foam (RPU) formulations. The RPUs thus obtained had a Tg of ca. 60,°C and a thermal conductivity of ,20 mW/m,·,K before ageing and ,25 mW/m,·,K after accelerated ageing for 10 d at 70,°C. The analyses of the gases inside the cells showed that these were mostly closed, since the partial pressure did not decrease significantly with ageing. Photograph of polyurethane foam made from OLOP. [source] Risk factors for early lactation problems among Peruvian primiparous mothersMATERNAL & CHILD NUTRITION, Issue 2 2010Susana L. Matias Abstract The aim of this study was to determine the incidence and risk factors for early lactation problems [suboptimal infant breastfeeding behaviour (SIBB), delayed onset of lactogenesis (OL) and excessive neonatal weight loss] among mother,infant pairs in Lima, Peru. All primiparous mothers who gave birth to a healthy, single, term infant at a government hospital in a peri-urban area of Lima during the 8-month recruitment period were invited to participate in the study. Data were collected at the hospital (day 0) and during a home visit (day 3). Infant breastfeeding behaviour was evaluated using the Infant Breastfeeding Assessment Tool; SIBB was defined as ,10 score. OL was determined by maternal report of breast fullness changes; delayed OL was defined as perceived after 72 h. Excessive neonatal weight loss was defined as ,10% of birthweight by day 3. One hundred seventy-one mother,infant pairs participated in the study. SIBB prevalence was 52% on day 0 and 21% on day 3; it was associated with male infant gender (day 0), <8 breastfeeds during the first 24 h (days 0 and 3), and gestational age <39 weeks (day 3). Delayed OL incidence was 17% and was associated with infant Apgar score <8. Excessive neonatal weight loss occurred in 10% of neonates and was associated with maternal overweight and Caesarean-section delivery. Early lactation problems may be influenced by modifiable factors such as delivery mode and breastfeeding frequency. Infant status at birth and maternal characteristics could indicate when breastfeeding dyads need extra support. [source] Oleuropein and hydroxytyrosol inhibit MCF-7 breast cancer cell proliferation interfering with ERK1/2 activationMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 6 2010Rosa Sirianni Abstract The growth of many breast tumors is stimulated by estradiol (E2), which activates a classic mechanism of regulation of gene expression and signal transduction pathways inducing cell proliferation. Polyphenols of natural origin with chemical similarity to estrogen have been shown to interfere with tumor cell proliferation. The aim of this study was to investigate whether hydroxytyrosol (HT) and oleuropein (OL), two polyphenols contained in extra-virgin olive oil, can affect breast cancer cell proliferation interfering with E2-induced molecular mechanisms. Both HT and OL inhibited proliferation of MCF-7 breast cancer cells. Luciferase gene reporter experiments, using a construct containing estrogen responsive elements able to bind estrogen receptor alpha (ER,) and the study of the effects of HT or OL on ER, expression, demonstrated that HT and OL are not involved in ER,-mediated regulation of gene expression. However, further experiments pointed out that both OL and HT determined a clear inhibition of E2-dependent activation of extracellular regulated kinase1/2 belonging to the mitogen activating protein kinase family. Our study demonstrated that HT and OL can have a chemo-preventive role in breast cancer cell proliferation through the inhibition of estrogen-dependent rapid signals involved in uncontrolled tumor cell growth. [source] Low grade diffuse gliomas: Shared cellular composition and morphometric differencesNEUROPATHOLOGY, Issue 5 2008Sawako Kinjo Low grade diffuse gliomas arising in the brain are challenging to treat because of their ability to infiltrate adjacent tissue. We attempted to clarify the cellular composition and histopathological features of low grade gliomas by utilizing morphometric and immunohistochemical analyses. Seventy-eight cases of low grade gliomas were examined including 21 diffuse astrocytomas (DA), 36 oligodendrogliomas (OL), and 21 oligoastrocytomas (OA), based on the WHO classification system. Moreover, OL were subdivided into three types based on the morphological characteristics advocated by Daumas-Duport et al.: OL type I, OL type II, and OL type III. The cellularity, nuclear form factor, and conditional entropy corresponding to the nuclear pleomorphism were measured in each sample by the image analysis software "Gunmetry." Twenty-two cases were immunohistochemically analyzed for the expression of several antigens. Morphometric data indicated that the cellularity of OL type II was significantly higher than that of DA, and that the conditional entropy of OL type III was significantly lower than that of DA. Although the results of the immunohistochemical studies were almost consistent with previous reports, there were significant differences in the expression of GFAP, nestin and p53 between DA and OL. Double immunostaining revealed that expression of Olig2 and GFAP, and Olig2 and nestin was mutually exclusive in most glioma cells. Moreover, the coexpression of nestin and GFAP occurred in DA and OA, but not in OL. We conclude that each glioma include cells expressing GFAP, cells expressing nestin, and cells expressing Olig2 in a characteristic proportion for each tumor type. We suggest that diffuse gliomas share cellular compositions in different ratios and that they can be distinguished by morphometrical analysis. [source] Wilms' tumor 1 message and protein expression in bone marrow failure syndrome and acute leukemiaPATHOLOGY INTERNATIONAL, Issue 10 2007Takashi Iwasaki Wilms' tumor 1 (WT1) is a useful marker for the diagnosis of acute leukemia and myelodysplastic syndromes (MDS). In the current study quantitative reverse transcription,polymerase chain reaction and immunostaining were used simultaneously to examine the relationship between WT1 RNA and protein level and also to evaluate WT1 as a tool to differentiate aplastic anemia (AA) and MDS refractory anemia (RA). Three types of WT1 messages (total, exon 5(+) and KTS(+)) and WT1 immunostaining of these diseases were analyzed. An increase of all three WT1 messages in high-grade MDS and acute leukemia was observed as compared with the normal control, whereas there was no significant difference in WT1 message between AA and RA, suggesting that WT1 message is not a good tool to discriminate AA and RA. No significant difference was observed between normal and RA, except for exon 5 message. Three WT1 message levels had a significant correlation, suggesting that the total WT1 message is sufficient for clinical practice. Positive immunostaining of WT1 was observed only in the portion of acute leukemia and overt leukemia (OL) transformed from MDS with a high WT1 message level, suggesting the relatively high detection threshold of WT1 protein with the immunostaining method. [source] Conjugated Macrocycles as Active Materials in Nonlinear Optical Processes: Optical Limiting Effect with Phthalocyanines and Related CompoundsTHE CHEMICAL RECORD, Issue 3 2002Michael Hanack Abstract An overview of the optical limiting (OL) processes in phthalocyanines and related compounds is presented, particularly a description of the synthesis and relevant optical properties of a series of axially substituted indium(III), titanium(IV), phthalo- and naphthalocyanines, and octaarylporphyrazines. Several techniques, such as transient absorption, Z-scan, and degenerate four-wave mixing, were used to assess the optical properties and OL performance of the investigated compounds. The versatility of the methods of organic synthesis leads to the achievement of effective systems in terms of OL performance through the appropriate combination and modulation of several structural components. The chemistry of the macrocycles here considered allows the variation of the different chemical features, such as the degree of electronic conjugation of the macrocycle and the nature of the ring substituents, the central atom, and the ligands attached to the central atom. © 2002 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 2: 129,148, 2002: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10024 [source] Dicer ablation in oligodendrocytes provokes neuronal impairment in mice,ANNALS OF NEUROLOGY, Issue 6 2009Daesung Shin PhD Objective MicroRNAs (miRNAs) regulate gene expression and have many roles in the brain, but a role in oligodendrocyte (OL) function has not been demonstrated. Methods A Dicer floxed conditional allele was crossed with the proteolipid protein promoter-driven inducible Cre allele to generate inducible, OL-specific Dicer -floxed mice. Results OL-specific Dicer mutants show demyelination, oxidative damage, inflammatory astrocytosis and microgliosis in the brain, and eventually neuronal degeneration and shorter lifespan. miR-219 and its target ELOVL7 (elongation of very long chain fatty acids protein 7) were identified as the main molecular components that are involved in the development of the phenotype in these mice. Overexpressing ELOVL7 results in lipid accumulation, which is suppressed by miR-219 co-overexpression. In Dicer mutant brain, excess lipids accumulate in myelin-rich brain regions, and the peroxisomal ,-oxidation activity is dramatically reduced. Interpretation Postnatal Dicer ablation in mature OLs results in inflammatory neuronal degeneration through increased demyelination, lipid accumulation, and peroxisomal and oxidative damage, and therefore indicates that miRNAs play an essential role in the maintenance of lipids and redox homeostasis in mature OLs that are necessary for supporting axonal integrity as well as the formation of compact myelin. Ann Neurol 2009;66:843,857 [source] RESEARCH ARTICLE: Myelin Abnormalities without Oligodendrocyte Loss in Periventricular LeukomalaciaBRAIN PATHOLOGY, Issue 2 2008Saraid S. Billiards Abstract The cellular basis of myelin deficits detected by neuroimaging in long-term survivors of periventricular leukomalacia (PVL) is poorly understood. We tested the hypothesis that oligodendrocyte lineage (OL) cell density is reduced in PVL, thereby contributing to subsequent myelin deficits. Using computer-based methods, we determined OL cell density in sections from 18 PVL and 18 age-adjusted control cases, immunostained with the OL-lineage marker Olig2. Myelination was assessed with myelin basic protein (MBP) immunostaining. We found no significant difference between PVL and control cases in Olig2 cell density in the periventricular or intragyral white matter. We did find, however, a significant increase in Olig2 cell density at the necrotic foci, compared with distant areas. Although no significant difference was found in the degree of MBP immunostaining, we observed qualitative abnormalities of MBP immunostaining in both the diffuse and necrotic components of PVL. Abnormal MBP immunostaining in PVL despite preserved Olig2 cell density may be secondary to arrested OL maturation, damage to OL processes, and/or impaired axonal-OL signaling. OL migration toward the "core" of injury may occur to replenish OL cell number. This study provides new insight into the cellular basis of the myelin deficits observed in survivors of PVL. [source] Critical Aspects of Organizational Learning Research and Proposals for Its MeasurementBRITISH JOURNAL OF MANAGEMENT, Issue 2 2001Satu Lähteenmäki Based on an extensive literature review, this paper reveals several gaps in organizational learning (OL) research that need filling before we can really talk about a theory of organizational learning or verify the traits and very existence of learning organizations (LO) as a phenomenon. The critique, however, is not targeted at any single model or theory of organizational learning, but at theory building, which constantly drifts away with new definitions and approaches that break up rather than construct a theory. Despite the fact that numerous consultation tools for turning organizations into learning models have been developed and applied, the concept of organizational learning itself still remains vague and there is an urgent need for a holistic model of OL. Too much emphasis is put on studying the learning of individuals instead of concentrating on the learning of organizations. Since the theory is highly dispersed and does not really build on earlier findings, rich empirical studies are needed in order to validate measures of organizational learning. Modelling of the organizational learning process and clarification of how learning of individuals is turned into learning of organizations is needed. This paper introduces one set of OL measures developed to study whether organizational learning occurred during the operational and business culture change process of a single case company. Suggestions for further OL research are made on the basis of experiences gained when empirically testing this model. [source] Synthesis, Structure and Optical Limiting (OL) Properties of a Novel Incomplete Cubane-like Cluster [PPh4] [(,5 -C5Me5) WS3 -(CuBr) (Cul)2 (,-dppm)]CHINESE JOURNAL OF CHEMISTRY, Issue 12 2003Hong Yu Abstract Reaction of [PPh4][,5 -C5Me5)WS3] with Cul, CuBr and bis-(diphenylphosphino)methane (dppm) (molar ratio = 1:2:1:1) in MeCN gave rise to [PPh4][(,5 -C5Me5)WS3 (CuBr)(Cul)2 -(,-dppm)] (1) in high yield. Compound 1 crystallizes in the monoclinic, space group P21/n with lattice parameters: a = 1.2906(4) nm, b = 1.5006(8) nm, c = 3.1484(6) nm, , = 92.12(2)°, V = 6.093(3) nm3, Z = 4. The structure of the anion of 1 contains an incomplete WS3Cu3 cubane-like core in which two Cul units are bridged by a dppm ligand. The W-Cu distances vary in the range of 0.2644(1),0.2793(1) nm. The optical limiting (OL) properties of 1 in MeCN were measured with the laser pulse-width of 12-ns at 532 nm, and the nanosecond OL effect may be due to the reverse saturable absorption (RSA) related to the excited triplet states. [source] Group contribution prediction of surface charge density profiles for COSMO-RS(Ol)AICHE JOURNAL, Issue 12 2007Tiancheng Mu Abstract A new method for predicting the surface charge density distribution (, profile) and cavity volume of molecules based on group contributions was developed. The original , profiles used for the regression were obtained using Gaussian 03 B3LYP/6-311G(d,p). In total 1363 , profiles were used for the regression of group parameters. Group definitions are identical to those used previously for boiling point estimation. Original and estimated , profiles were used to predict activity coefficients at infinite dilution and VLE data of binary systems using the COSMO-RS(Ol) model. The results were compared with the experimental data stored in the Dortmund Data Bank. In many cases the results were of comparable accuracy. However, for a few compounds, poor results were obtained, in particular for conjugated components like nitrobenzenes. The method offers a fast and reliable generation of , profiles to be used with COSMO-RS(Ol) within its range of applicability. © 2007 American Institute of Chemical Engineers AIChE J, 2007 [source] An investigation into the influence of counterion on the RS -propranolol and S -propranolol skin permeabilityJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2010Francesco Cilurzo Abstract The effects of two contra-ions, namely benzoate (Bz) and oleate (Ol), on the in vitro human skin permeability of propranolol racemate (RS -PR) or S -enantiomer (S -PR) were studied. Saline solution (SS) or mineral oil (MO) were selected as vehicles. The MO increased the permeability coefficient (Kp) of PR-Bz (pKp,,,4) of about four times with respect to SS (pKp,,,8) probably due to the ion pair formation. The steady-state flux of S -enantiomers resulted about twofold higher than that of racemates according to their lower melting temperatures with the exception of (S)-PR-Ol and (RS)-PR-Ol vehicled in SS which not resulted statistically different. This anomalous result could be explained considering the behavior of (RS)-PR-Ol or (S)-PR-Ol in aqueous solutions: these salts formed ion pairs which associated to form aggregates up to a concentration of 20,µg/mL as verified by light scattering. Therefore, their effective concentrations in SS resulted similar and justified the overlapped skin permeation profiles. All three considered variables, namely counterion, vehicle, and chirality, resulted mutually interfering on and deeply influenced the passive diffusion process of PR. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1217,1224, 2010 [source] Electroacupuncture attenuates visceral hyperalgesia and inhibits the enhanced excitability of colon specific sensory neurons in a rat model of irritable bowel syndromeNEUROGASTROENTEROLOGY & MOTILITY, Issue 12 2009G.-y. Xu Abstract, The causes of irritable bowel syndrome remain elusive and there are few effective treatments for pain in this syndrome. Electroacupunture (EA) is used extensively for treatment of various painful conditions including chronic visceral hyperalgesia (CVH). However, mechanism of its analgesic effect remains unknown. This study was designed to investigate effect of EA on colon specific dorsal root ganglion (DRG) neurons in rats with CVH. CVH was induced by intracolonic injection of acetic acid (AA) in 10-day-old rats. Electromyography and patch clamp recordings were performed at age of 8,10 weeks. Colon DRG neurons were labelled by injection of DiI into the colon wall. EA was given at ST36 in both hindlimbs. As adults, neonatal AA-injected rats displayed an increased sensitivity to colorectal distension (CRD) and an enhanced excitability of colon DRG neurons. EA treatment for 40 min significantly attenuated the nociceptive responses to CRD in these rats; this attenuation was reversed by pretreatment with naloxone. EA treatment for 40 min per day for 5 days produced a prolonged analgesic effect and normalized the enhanced excitability of colon DRG neurons. Furthermore, in vitro application of [D-Ala2, N -MePhe4, Gly5 -Ol] enkephalin (DAMGO) suppressed the enhanced excitability of colon neurons from rats with CVH. These findings suggest that EA produced-visceral analgesia, which might be mediated in a large part by endogenous opioids pathways, is associated with reversal of the enhanced excitability of colon DRG neurons in rats with CVH. [source] Determination of 13C/12C ratios of urinary excreted boldenone and its main metabolite 5,-androst-1-en-17,-ol-3-oneDRUG TESTING AND ANALYSIS, Issue 5 2010Thomas Piper Abstract Boldenone (androsta,1,4,dien,17,,ol,3,one, Bo) is an anabolic steroid known to have been used in cattle breeding or equine sport as a doping agent for many years. Although not clinically approved for human application, Bo or its main metabolite 5,-androst-1-en-17,-ol-3-one (BM1) were detected in several doping control samples. For more than 15 years the possibility of endogenous Bo production in human beings has been discussed. This is a challenging issue for doping control laboratories as Bo belongs to the list of prohibited substances of the World Anti-Doping Agency and therefore the chance for false positive testing is significant. By GC/C/IRMS (gas chromatography/combustion/isotope ratio mass spectrometry) it should be possible to analyze the 13C/12C ratio of either Bo or BM1 and to distinguish whether their source is endogenous or exogenous. Therefore a method was developed to determine the 13C/12C ratios of Bo, BM1, pregnanediol, androsterone, etiocholanolone, and testosterone from a single urine specimen. The validity of the method was ensured by repeated processing of urine fortified with 2,50 ng/mL Bo and BM1. The specificity of the method was ensured by gas chromatography/mass spectrometry determinations. Out of 23 samples investigated throughout the last four years, 11 showed 13C/12C ratios of Bo or BM1 inconsistent with an exogenous origin. Two of these samples were collected from the same athlete within a one-month interval, strongly indicating the chance of endogenous Bo production by this athlete. Copyright © 2010 John Wiley & Sons, Ltd. [source] Biomarker discovery in rat plasma for estrogen receptor-, actionELECTROPHORESIS, Issue 23 2005Tom G. Holt Dr. Abstract To support in vivo screening efforts for estrogen receptor (ER) subtype selective therapeutic agents, we initiated work to discover surrogate markers (biomarkers) in blood plasma that would change in response to ER subtype-specific action. We used a proteomic approach employing strong anion exchange chromatography (SAX), PAGE, and MS to identify potential plasma markers for selective ER-, action. The methodology was used to compare blood from vehicle-treated rats to blood from rats treated with either 17,-estradiol (an ER-,/ER-, agonist) or compound 1 (17,-ethynyl-[3,2-c]pyrazolo-19-nor-4-androstene-17,-ol, an ER-,-selective agonist). Blood samples were first fractionated by SAX to separate fractions containing dominant common plasma proteins from fractions enriched for less-abundant plasma proteins. 1-D PAGE analysis of fractions depleted of dominant plasma proteins revealed treatment-specific changes in protein profiles. Protein bands that changed reproducibly in response to ER-, action were excised from the gel, separated by capillary LC, and identified by microspray ESI-MS. Using this method, the plasma levels of two proteins, transthyretin and apolipoprotein E, were shown to decrease in response to ER-, agonism. The method lacked the sensitivity to identify the known, 1000-fold less-abundant, estrogenic marker prolactin (PRL). However, using a commercial RIA and immunoblots, we showed that PRL levels increase significantly in response to treatment with the ER-, selective agonist, compound 1. [source] Kinetic Studies of the Oxidative Addition and Transmetallation Steps Involved in the Cross-Coupling of Alkynyl Stannanes with Aryl Iodides Catalysed by ,2 -(Dimethyl fumarate)(iminophosphane)palladium(0) ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2004Bruno Crociani Abstract The complexes [Pd(,2 -dmfu)(P,N)] {dmfu = dimethyl fumarate; P,N = 2-(PPh2)C6H4,1-CH=NR, R = C6H4OMe-4 (1a), CHMe2 (2a), C6H3Me2 -2,6 (3a), C6H3(CHMe2)2 -2,6 (4a)} undergo dynamic processes in solution which consist of a P,N ligand site exchange through initial rupture of the Pd,N bond at lower energy and an olefin dissociation-association at higher energy. According to equilibrium constant values for olefin replacement, the complex [Pd(,2 -fn)(P,N)] (fn = fumaronitrile, 1b) has a greater thermodynamic stability than its dmfu analogue 1a. The kinetics of the oxidative addition of ArI (Ar = C6H4CF3 -4) to 1a and 2a lead to the products [PdI(Ar)(P,N)] (1c, 2c) and obey the rate law, kobs = k1A + k2A[ArI]. The k1A step involves oxidative addition to a reactive species [Pd(solvent)(P,N)] formed from dmfu dissociation. The k2A step is better interpreted in terms of oxidative addition to a species [Pd(,2 -dmfu)(solvent)(,1 -P,N)] formed in a pre-equilibrium step from Pd,N bond breaking. The complexes 1c and 2c react with PhC,CSnBu3 in the presence of an activated olefin (ol = dmfu, fn) to yield the palladium(0) derivatives [Pd(,2 -ol)(P,N)] along with ISnBu3 and PhC,CAr. The kinetics of the transmetallation step, which is rate-determining for the overall reaction, obey the rate law: kobs = k2T[PhC,CSnBu3]. The k2T values are markedly enhanced in more polar solvents such as CH3CN and DMF. The solvent effect and the activation parameters suggest an associative SE2 mechanism with substantial charge separation in the transition state. The kinetic data of the above reactions in various solvents indicate that, for the cross-coupling of PhC,CSnBu3 with ArI catalysed by 1a or 2a, the rate-determining step is represented by the oxidative addition and that CH3CN is the solvent in which the highest rates are observed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Chemical constituents and antimicrobial activities of the essential oil of Acroptilon repens (L.) DCFLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2006Hassan Norouzi-Arasi Abstract The volatile oil from the aerial parts of Acroptilon repens (L.) DC. (Russian knapweed) growing wild in Iran was investigated by GC and GC,MS. Twenty-two components, representing 84.0% of the oil, were identified. The main constituents of the oil were caryophyllene oxide (36.6%), , -copaene (15.6%), , -caryophylene (10.0%) and , -copaene-4- , -ol (5.0%). In addition, the oil was assayed against six Gram-positive and Gram-negative bacteria by measuring the growth inhibitory zone. The oil of A. repens inhibited the growth of Gram-positive bacteria. Staphylococcus saprophyticus and Staphylococcus epidermidis showed strong inhibition zones, while Staphylococcus aureus showed a lower inhibition. The Gram-negative bacteria were insensitive to the oil. Copyright © 2005 John Wiley & Sons, Ltd. [source] Bioactive Chemical Constituents of Cladiella SpeciesHELVETICA CHIMICA ACTA, Issue 3 2004Athar Ata From the methanolic extract of Cladiella sp., collected from the Andaman Island, India, a new sesquiterpene, cladidiol (2), and three known diterpenes, cladiellaperoxide (3), (6E)-2,,9, -epoxyeunicella-6,11(12)-dien-3, -ol (4), and polyanthellin A (5) were isolated. The structures of these compounds were established by extensive spectroscopic studies. Compound 2 exhibited modest acetylcholinesterase-inhibition activity, and compounds 3,5 showed antibacterial activities against Streptococcus pyogenes, Escherichia coli, and Pseudomonas aeruginosa. [source] Competing kinetic pathways in the bromine addition to allylic ethers in 1,2-dichloroethane: Opposite temperature effectsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 4 2007Alessandro Cecchi The kinetics of the electrophilic bromination of three allylic ethers in a nonprotic solvent, 1,2-dichloroethane, has been investigated. Two of them followed a prevalent second-order pathway, while the third one exhibited a classical, clean third order. The second-order pathway in the first two olefins is attributed to electrophilic assistance of the ethereal oxygen to the attacking bromine molecule. In the molecular bromination of 2,4- cis -dimethyl-8-oxabicyclo[3.2.1]-6-octen-3- cis -ol, opposite temperature dependences were found for the two different kinetic pathways. An exoergonic process for the second-order reaction was explained by the lesser stability of the bromiranium,bromide ionic intermediate, compared to the bromiranium,tribromide in the third-order profile. © 2007 Wiley Periodicals, Inc. 39: 197,203, 2007 [source] Indications for laparoscopic adrenalectomy for non-functional adrenal tumor with hypertension: Usefulness of adrenocortical scintigraphyINTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2006HIROFUMI IZAKI Aim:, Laparoscopic adrenalectomy is currently indicated for biochemically and clinically functional adrenal tumors and potentially malignant tumors of the adrenal glands. Non-functional adenomas greater than 5 cm in diameter of the adrenal gland are generally considered to represent potentially malignant tumors. The present study shows indications of laparoscopic adrenalectomy for non-functional adrenal tumors with hypertension in a retrospective fashion. Methods:, Between 1994 and 2004, 110 laparoscopic adrenalectomies were performed at Tokushima University Hospital. All 110 patients underwent detailed endocrinological examination before surgery. Medical and operative records of these 110 patients (57 men, 53 women), including operative parameters, histopathological findings and pre- and postoperative hypertension, were reviewed. Forty-five patients underwent laparoscopic adrenalectomy for non-functional adrenal tumors, and [131I]6,-iodomethyl-19-norcholest-5(10)-en-3,-ol (NP-59) scintigraphy was performed for patients with preoperative hypertension. Results:, Mean patient age was 55.0 years (range, 22,77 years). Mean maximum tumor diameter was 42 mm (range, 20,105 mm). All adrenal tumors were removed successfully by laparoscopic surgery. Hypertension was postoperatively improved in seven of the 11 patients with preoperative hypertension, without subclinical Cushing syndrome. Importantly, all patients who improved hypertension after adrenalectomy displayed strong accumulation in adrenal tumors with visualization of the contralateral gland on NP-59 scintigraphy. Conversely, blood pressure did not improve in four patients for whom scintigraphy yielded negative results. Conclusions:, The indication of laparoscopic adrenalectomy for non-functional adrenal tumors is generally considered for lesions more than 5 cm diameter. However, the present study suggests that laparoscopic surgery should be considered even in patients with tumors less than 5 cm in diameter, if both hypertension and accumulation in tumors on NP-59 scintigraphy are present. [source] | ||||||||||||||||||||||||||||||||||