JOURNAL OF PHYCOLOGY, Issue 6 2000
Ken-ichiro Ishida
Chloroplasts in heterokont algae are surrounded by four membranes and probably originated from a red algal endosymbiont that was engulfed and retained by eukaryotic host. Understanding how nuclear-encoded chloroplast proteins are translocated from the cytoplasm into the chloroplast across these membranes could give us some insights about how the endosymbiont was integrated into the host cell in the process of secondary symbiogenesis. In multiplastid heterokont algae such as raphidophytes, it has been unclear if the outermost of the four membranes surrounding the chloroplast (the chloroplast endoplasmic reticulum [CER] membrane) is continuous with the nuclear envelope and rough endoplasmic reticulum (ER). Here, we report detailed ultrastructural observations of the raphidophyte Heterosigma akashiwo (Hada) Hada ex Y. Hara et Chihara that show that the CER membranes were continuous with ER membranes that had attached ribosomes, implying that the chloroplast with three envelope membranes is located within the ER lumen, that is, topologically the same structure as that of monoplastid heterokont algae. However, the CER membrane of H. akashiwo had very few, if any, ribosomes attached, unlike the CER membranes in other heterokont algae. To verify that proteins are first targeted to the ER, we assayed protein import into canine microsomes using a precursor for a nuclear-encoded chloroplast protein, the fucoxanthin-chlorophyll a/c protein of H. akashiwo. This demonstrated that the precursor has a functional signal sequence for ER targeting and is cotranslationally translocated into the ER, where a signal sequence of about 17 amino acids is removed. Based on these data, we hypothesize that in H. akashiwo, nuclear-encoded chloroplast protein precursors that have been cotranslationally transported into the ER lumen are sorted in the ER and transported to the chloroplasts through the ER lumen. [source]

CHRONIC FLUVASTATIN TREATMENT ALTERS VASCULAR CONTRACTION BY INHIBITING THE RHO/RHO-KINASE PATHWAY

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2006
Yasuo Kansui
SUMMARY 1In the present study, we investigated the effects of chronic treatment of stroke-prone spontaneously hypertensive rats (SHRSP) with the statin fluvastatin on vascular Rho/Rho-kinase pathway mediated contraction, which has been shown to be upregulated in hypertension. 2Contribution of the Rho/Rho-kinase pathway to noradrenaline-induced contraction of arteries from SHRSP was assessed by the inhibitory effect of Y-27632, a Rho/Rho-kinase inhibitor. Stroke-prone spontaneously hypertensive rats were treated with fluvastatin (10 mg/kg per day) for 1 month. 3Treatment with fluvastatin tended to attenuate the contraction to noradrenaline and significantly decreased the Y-27632-sensitive component of the contraction in controls compared with fluvastatin-treated rats. 4RhoA, as assessed by western blotting, was also reduced by fluvastatin treatment. 5These findings suggest that chronic treatment with fluvastatin reduces the contractile response associated with Rho/Rho-kinase in arteries of hypertensive rats. [source]

HIGH GLUCOSE-INDUCED HUMAN UMBILICAL VEIN ENDOTHELIAL CELL HYPERPERMEABILITY IS DEPENDENT ON PROTEIN KINASE C ACTIVATION AND INDEPENDENT OF THE Ca2+,NITRIC OXIDE SIGNALLING PATHWAY

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2005
Lei Dang
SUMMARY 1.,Endothelial barrier dysfunction plays a pivotal role in the pathogenesis of diabetic vascular complications. The precise molecular mechanisms by which hyperglycaemia causes the increased permeability in endothelial cells are not yet well understood. In the present study, we investigated whether high concentrations of glucose induce endothelial permeability through the activation of protein kinase C (PKC) and/or the calcium,nitric oxide (NO) signalling pathway in human umbilical vein endothelial cells (HUVEC). 2.,Endothelial permeability was measured by albumin diffusion across endothelial monolayers under the stimuli of high glucose (HG; 20 mmol/L), 100 nmol/L phorbol-myristate-acetate (PMA) or 100 nmol/L histamine. The intracellular calcium concentration ([Ca2+]i) was detected in HUVEC using the fluorescent probe fura-2 AM. The effects of PKC inhibitors (LY379196 and hypocrellin A) and the NO synthase (NOS) inhibitor NG -monomethyl- l -arginine (l -NMMA) on endothelial permeability and [Ca2+]i were determined. 3.,High glucose and PMA increased endothelial permeability associated with decreased [Ca2+]i, whereas histamine triggered significant increases in endothelial permeability, accompanied by increases in [Ca2+]i in HUVEC. Hypocrellin A (HA) and LY379196 reversed both HG- and histamine-induced endothelial permeability. The NOS inhibitor l -NMMA only abolished histamine- and not HG-induced endothelial permeability. Neither LY379196, HA nor l -NMMA had any significant effects on alterations in [Ca2+]i caused by HG and histamine. 4.,These results indicate that increased endothelial permeability in HUVEC induced by HG is dependent on PKC activity and is independent of the [Ca2+]i,NO pathway. Increased endothelial permeability due to other inflammatory factors, such as histamine, may also be mediated by the PKC pathway. Thus, PKC inhibitors would be a potential therapeutic approach to endothelial dysfunction induced by hyperglycaemia, as well as other inflammatory factors, in diabetes. [source]

CARDIOTOXIN III INDUCES APOPTOSIS IN K562 CELLS THROUGH A MITOCHONDRIAL-MEDIATED PATHWAY

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 7 2005
Sheng-Huei Yang
SUMMARY 1.,Cardiotoxin (CTX) III is a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom. This is the first report on the mechanism of the anticancer effect of CTX III on human leukaemia K562 cells. 2.,Cardiotoxin III was found to inhibit the growth of K562 cells in a time- and dose-dependent manner, with an IC50 value of 1.7 ,g/mL, and displayed several features of apoptosis, including apoptotic body formation, an increase in the sub-G1 population, DNA fragmentation and poly (ADP-ribose) polymerase (PARP) cleavage. 3.,Investigation of the mechanism of CTX III-induced apoptosis revealed that treatment of K562 cells with CTX III resulted in the loss of mitochondrial membrane potential, cytochrome c release from mitochondria into the cytosol and activation of caspase-9 and caspase-3 and the subsequent cleavage of the caspase-3 substrate PARP; however, CTX III did not generate reactive oxygen species (ROS). 4.,Taken together, the results indicate that CTX III induces apoptosis in K562 cells through an ROS-independent mitochondrial dysfunction pathway. [source]

PATHWAYS TO SEX-BASED DIFFERENTIATION IN CRIMINAL COURT SENTENCING

CRIMINOLOGY, Issue 2 2003
SAMANTHA JEFFRIES
Using a matched sampling method, this research examined the process of sex-based differentiation in sentencing outcomes for 194 men and 194 women, sentenced over a seven-year period in Christchurch, New Zealand. Consistent with past research, our results showed that judicial processing treated women more leniently than men. Path analyses revealed that judges were less likely to sentence women than men to imprisonment terms because of gendered information and decisions made earlier in the judicial process, such as criminal history, length of custodial remands, and pre-sentence recommendations by probation officers. In contrast, judges exercised considerable leniency towards women (compared with men) in setting the length of prison terms, even after statistically controlling for all sex-differentiated factors such as criminal history. Explanations and implications are discussed. [source]

METAMODELS AND PHYLOGENETIC REPLICATION: A SYSTEMATIC APPROACH TO THE EVOLUTION OF DEVELOPMENTAL PATHWAYS

EVOLUTION, Issue 11 2009
Artyom Kopp
Molecular genetic analysis of phenotypic variation has revealed many examples of evolutionary change in the developmental pathways that control plant and animal morphology. A major challenge is to integrate the information from diverse organisms and traits to understand the general patterns of developmental evolution. This integration can be facilitated by evolutionary metamodels,traits that have undergone multiple independent changes in different species and whose development is controlled by well-studied regulatory pathways. The metamodel approach provides the comparative equivalent of experimental replication, allowing us to test whether the evolution of each developmental pathway follows a consistent pattern, and whether different pathways are predisposed to different modes of evolution by their intrinsic organization. A review of several metamodels suggests that the structure of developmental pathways may bias the genetic basis of phenotypic evolution, and highlights phylogenetic replication as a value-added approach that produces deeper insights into the mechanisms of evolution than single-species analyses. [source]

METAMORPHOSIS AND NEOTENY: ALTERNATIVE PATHWAYS IN AN EXTINCT AMPHIBIAN CLADE

EVOLUTION, Issue 7 2006
Rainer R. Schoch
Abstract The Branchiosauridae was a clade of small amphibians from the Permo-Carboniferous with an overall salamander-like appearance. The clade is distinguished by an extraordinary fossil record that comprises hundreds of well-preserved specimens, representing a wide range of ontogenetic stages. Branchiosaurids had external gills and weakly ossified skeletons, and due to this larval appearance their status as neotenic (perennibranchiate) froms has long been accepted. Despite their extensive fossil record large specimens with an adult morphology appeared to be lacking altogether, but recently two adult specimens were identified in a rich sample of Apateon gracilis collected in the 19th century from a locality near Dresden, Saxony. These specimens are unique among branchiosaurids in showing a high level of ossification, including bones that have never been reported in a branchiosaur. These highlight the successive formation of features believed to indicate terrestrial locomotion, as well as feeding on larger prey items. Moreover, these transformations occurred in a small time window (whereas the degree of size increase is used as a proxy of time) and the degree of concentration of developmental events in branchiosaurids is unique among tetrapods outside the lissamphibians. These specimens are compared with large adults of the neotenic branchiosaurid Apateon caducus from the Saar-Nahe Basin, which despite their largetr body size lack the features found in the adult. A. gracilis specimens. These specimens give new insight into patterns of metamorphosis (morphological transformation) in branchiosaurids that are believed to be correlated to a change of habitat, and clearly show that different life-history pathways comparable to those of modern salamanders were already estabilshed in this Paleozoic clade. [source]

EVOLUTIONARY PATHWAYS IN SHOREBIRD BREEDING SYSTEMS: SEXUAL CONFLICT, PARENTAL CARE, AND CHICK DEVELOPMENT

EVOLUTION, Issue 10 2005
Gavin H. Thomas
Abstract Sexual selection, mating opportunities, and parental behavior are interrelated, although the specific nature of these relationships is controversial. Two major hypotheses have been suggested. The parental investment hypothesis states that the relative parental investment of the sexes drives the operation of sexual selection. Thus, the sex that invests less in offspring care competes more intensely and monopolizes access to mates. The sexual conflict hypothesis proposes that sexual selection (the competition among both males and females for mates), mating opportunities, and parental behavior are interrelated and predicts a feedback loop between mating systems and parental care. Here we test both hypotheses using a comprehensive dataset of shorebirds, a maximum-likelihood statistical technique, and a recent supertree of extant shorebirds and allies. Shorebirds are an excellent group for these analyses because they display unique variation in parental care and social mating system. First, we show that chick development constrains the evolution of both parental care and mate competition, because transitions toward more precocial offspring preceded transitions toward reduced parental care and social polygamy. Second, changes in care and mating systems respond to one another, most likely because both influenced and are influenced by mating opportunities. Taken together, our results are more consistent with the sexual conflict hypothesis than the parental investment hypothesis. [source]

DEVELOPMENT OF PATIENT PATHWAYS FOR THE SURGICAL MANAGEMENT OF BURN INJURY

ANZ JOURNAL OF SURGERY, Issue 9 2006
John E. Greenwood
Background: There are many reasons for the development of patient pathways in burn surgery introduced at the Royal Adelaide Hospital in South Australia at the beginning of January 2005. These include education, standardization of technique, scheduling of surgical episodes and rationalization of the use of expensive therapies. Methods: A critical appraisal of both evidence based on published work and personal/peer experience has been used to generate the current pathways. Results: The year 2005 was the busiest in the history of the hospital, both in numerical terms and in the proportion of major burn injuries. These protocols were effective in enabling us to cope with negligible mortality. Conclusion: Although the first draft pathways work in our unit, they will undergo regular audit. It is hoped that they will form a template that can assist other services to create their own pathways. [source]

INVOLVEMENT OF BOTH ENDOPLASMIC RETICULUM- AND MITOCHONDRIA-DEPENDENT PATHWAYS IN CARDIOTOXIN III-INDUCED APOPTOSIS IN HL-60 CELLS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2008
Ching-Ming Chien
SUMMARY 1Cardiotoxin (CTX) III, a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. In the present study, we investigated the mechanisms underlying the anticancer activity of CTX III in human leukaemia (HL-60 cells). 2Cardiotoxin III activated the endoplasmic reticulum (ER) pathway of apoptosis in HL-60 cells, as indicated by increased levels of calcium and glucose-related protein 78 (Grp78), and triggered the subsequent activation of µ-calpain and caspase 12. 3In addition, CTX III initiated the mitochondrial apoptotic pathway in HL-60 cells, as evidenced by an increased Bax/Bcl-2 ratio, the release of cytochrome c and activation of caspase 9. 4In the presence of 50 µmol/L Z-ATAD-FMK (a caspase 12 inhibitor) and 100 µmol/L Z-LEHD-FMK (a caspase 9 inhibitor), the CTX III-mediated activation of caspase 9 and caspase 3 was significantly reduced. There was no significant effect of the caspase 12 inhibitor Z-ATAD-FMK on mitochondrial cytochrome c release. 5Cardiotoxin III-mediated activation of caspase 12 was not abrogated in the presence of the caspase 9 inhibitor Z-LEHD-FMK, indicating that caspase 12 activation was not downstream of caspase 9. 6These results indicate that CTX III induces cell apoptosis via both ER stress and a mitochondrial death pathway. [source]

MODULATION OF SIGNAL TRANSDUCERS AND ACTIVATORS OF TRANSCRIPTION (STAT) FACTOR PATHWAYS DURING FOCAL CEREBRAL ISCHAEMIA: A GENE EXPRESSION ARRAY STUDY IN RAT HIPPOCAMPUS AFTER MIDDLE CEREBRAL ARTERY OCCLUSION

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2007
Sheng-Li Sun
SUMMARY 1Signal transducers and activators of transcription (STAT) factors are a family of transcription factors that mediate intracellular signalling initiated at cytokine cell surface receptors and transmitted to the nucleus. In the present study, we determined the global changes in STAT gene expression in the hippocampus of rats after focal cerebral ischaemia and reperfusion using microarray analysis. 2The present study used middle cerebral artery occlusion (MCAO) to induce ischaemia and reperfusion in Sprague-Dawley rats. Using superarray Q series Janus tyrosine kinases (Jak)/STAT signalling pathway gene array, a total of 96 genes was screened in adult male rat hippocampus after transient focal cerebral ischaemia. 3The results showed that 23 genes were upregulated at least twofold by ischaemia treatment and that 12 genes were downregulated at least threefold by ischaemia treatment compared with controls. 4After confirmation by quantitative real-time polymerase chain reaction, the data suggest that the gene expression of STAT2, 5a, 5b, 6 and suppressor of cytokine signalling (SOCS) 4 was increased by ischaemia, probably due to a compensatory response of the brain, which may play a protective role in damaged brain tissue. 5The results of the present study provide evidence on global changes in STAT gene expression in the hippocampus of rats after focal cerebral ischaemia and reperfusion, in which STAT2, 5a, 5b, 6 and SOCS4 were confirmed to be significantly modulated during focal cerebral ischaemia. [source]

NEW INSIGHT INTO THE SIGNALLING PATHWAYS OF HEAT STRESS-INDUCED MYOCARDIAL PRECONDITIONING: PROTEIN KINASE C, TRANSLOCATION AND HEAT SHOCK PROTEIN 27 PHOSPHORYLATION

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 3 2004
Claire Arnaud
SUMMARY 1.,Heat stress (HS) is known to induce delayed preconditioning against myocardial infarction 24 h later, but the exact signalling pathway of this response remains to be elucidated. In previous studies, we have shown evidence for the implication of protein kinase C (PKC) and p38 mitogen-activated protein kinase (MAPK) in the HS-induced reduction in infarct size. Furthermore, in their phosphorylated state, small heat shock proteins (Hsp27) seem to confer cytoskeletal protection. In the present study, we sought to determine the effect of HS on the subcellular distribution of PKC isoforms and on Hsp27 phosphorylation. 2.,Rats were subjected to either HS (42°C for 15 min; HS group) or sham anaesthesia (sham group) before their hearts were excised. Myocardial tissue extracts obtained 20 min or 24 h after HS were processed for western blot analysis. 3.,In the HS group, PKC, translocated from the cytosolic to the particulate fraction (4426 ± 128 vs 6258 ± 316 arbitrary units; P = 0.002). Chelerythrine (5 mg/kg, i.p.), a PKC inhibitor, abolished this translocation. Western blot analysis of Hsp27 24 h after HS showed a marked increase in protein expression and phosphorylation in the particulate fraction. 4.,In the present study, we have shown that HS induces the translocation of PKC, from the cytosolic to the particulate fraction. Along with our previous observation that PKC is a trigger of HS-induced myocardial preconditioning, the results of the present study suggest an important role of the , isoform of PKC in this cardioprotective mechanism. Furthermore, we have also demonstrated that the cytoprotective protein Hsp27 is phosphorylated following HS. Therefore, we can conclude that PKC and MAPK/Hsp27 are involved in the signalling pathway of HS-induced cardioprotection. [source]

Octopus Papillary Muscle Associated with a Left Lateral Accessory Pathway

CONGENITAL HEART DISEASE, Issue 6 2009
Manisha S. Patel MD
ABSTRACT Left ventricular papillary muscle abnormalities are rare malformations. They have been related to significant mitral valve dysfunction and left ventricular midcavitary obstruction. We report our experience with a young adult who presented with palpitations. An echocardiogram on the patient showed an "octopus-like" left ventricular papillary muscle. Subsequent electrophysiologic testing showed evidence of supraventricular tachycardia via a left lateral accessory pathway associated with the abnormal insertion of the papillary muscle attachments. [source]

A Single-Source Co/Li/O Organometallic Precursor for Nanocrystalline LiCoO2 , Synthesis, Formation Pathway, and Electrochemical Performance,

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 29 2010
Jayaprakash Khanderi
Abstract A single-source precursor route to phase-pure LiCoO2 by employing the organometallic precursor [(COD)2CoLi(thf)2] (1) to introduce a Co/Li/O 1:1:2 stoichiometry is described for the first time. Compound 1 undergoes decomposition in the presence of oxygen, forming nanoscaled, electrochemically active LiCoO2 starting at a temperature as low as 200 °C. Its temperature-dependent formation pathway was studied by various spectroscopic and microscopic techniques. The transition temperature for the evolution of layered LiCoO2 is above 400 °C. Electrochemical studies indicate that the low-temperature modification of LiCoO2 can be obtained at 500 °C, showing moderate electrochemical battery performance. [source]

Ultra-Fast Atomic Transport in Severely Deformed Materials,A Pathway to Applications?,

ADVANCED ENGINEERING MATERIALS, Issue 8 2010
Sergiy Divinski
Abstract Severe plastic deformation of pure Cu and Cu-rich alloys was found to create a hierarchical combination of fast and ultra-fast diffusion paths ranging from non-equilibrium grain boundaries to non-equilibrium triple junctions, vacancy clusters, nano- and micro-pores, and finally to general high-angle grain boundaries. Under certain conditions, a percolating network of porosity can be introduced in the ultra-fine grained materials by a proper mechanical and thermal treatment. This network may offer promising opportunities for creating materials with tailor-made properties, including combinations of improved mechanical performance with a possibility of self repair using "vascular structures" for atom transport. Applications in such areas as drug eluting bioimplants and lead or polymer eluting materials for reduction of friction based on impregnation of porosity networks with these agents are also envisaged. [source]

Pathogen-Mimicking MnO Nanoparticles for Selective Activation of the TLR9 Pathway and Imaging of Cancer Cells,

ADVANCED FUNCTIONAL MATERIALS, Issue 23 2009
Mohammed Ibrahim Shukoor
Abstract Here, design of the first pathogen-mimicking metal oxide nanoparticles with the ability to enter cancer cells and to selectively target and activate the TLR9 pathway, and with optical and MR imaging capabilities, is reported. The immobilization of ssDNA (CpG ODN 2006) on MnO nanoparticles is performed via the phosphoramidite route using a multifunctional polymer. The multifunctional polymer used for the nanoparticle surface modification not only affords a protective organic biocompatible shell but also provides an efficient and convenient means for loading immunostimulatory oligonucleotides. Since fluorescent molecules are amenable to photodetection, a chromophore (Rhodamine) is introduced into the polymer chain to trace the nanoparticles in Caki-1 (human kidney cancer) cells. The ssDNA coupled nanoparticles are used to target Toll-like receptors 9 (TLR9) receptors inside the cells and to activate the classical TLR cascade. The presence of TLR9 is demonstrated independently in the Caki-1 cell line by western blotting and immunostaining techniques. The magnetic properties of the MnO core make functionalized MnO nanoparticles potential diagnostic agents for magnetic resonance imaging (MRI) thereby enabling multimodal detection by a combination of MR and optical imaging methods. The trimodal nanoparticles allow the imaging of cellular trafficking by different means and simultaneously are an effective drug carrier system. [source]

Increased Dopamine Is Associated With the cGMP and Homocysteine Pathway in Female Migraineurs

HEADACHE, Issue 1 2010
Hans-Jürgen Gruber PhD
(Headache 2010;50:109-116) Background., The group of catecholamines, which include dopamine, adrenaline, and noradrenaline, are neurotransmitters which have been considered to play a role in the pathogenesis of migraine. However, the impact of catecholamines, especially dopamine on migraine as well as the exact mechanisms is not clear to date as previous studies have yielded in part conflicting results. Objective., This study aimed to produce a comprehensive examination of dopamine in migraineurs. Methods., Catecholamines and various parameters of the homocysteine, folate, and iron metabolism as well as cyclic guanosine monophosphate (cGMP) and inflammatory markers were determined in 135 subjects. Results., We found increased dopamine levels in the headache free period in female migraineurs but not in male patients. Increased dopamine is associated with a 3.30-fold higher risk for migraine in women. We found no significant effects of aura symptoms or menstrual cycle phases on dopamine levels. Dopamine is strongly correlated with cGMP and the homocysteine,folate pathway. Conclusion., We show here that female migraineurs exhibit increased dopamine levels in the headache free period which are associated with a higher risk for migraine. [source]

The Effects of Cyclooxygenase2,ProstaglandinE2 Pathway on Helicobacter pylori -Induced Urokinase-Type Plasminogen Activator System in the Gastric Cancer Cells

HELICOBACTER, Issue 3 2008
Junichi Iwamoto
Abstract Background:, Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) play an important role in the destruction of the extracellular matrix and basement membrane. The induction of uPA and uPAR in the gastric cancer cells with H. pylori has been demonstrated previously. The involvement of COX-2-PGE2 pathway in the uPA system (uPA and uPAR) expression is unclear. Methods:, Gastric cancer cells (MKN45) were co-cultured with H. pylori standard strain (NCTC11637). The specific inductions of uPA and uPAR mRNA were examined by reverse transcription-polymerase chain reaction amplification. The secreted uPA antigen was measured by ELISA. To evaluate the involvement of COX-2 and PGE2 pathway in H. pylori -induced uPA and uPAR expressions, we examined the effects of COX-2 inhibitor and PGE2 receptor antagonist on H. pylori -induced uPA and uPAR expression in the gastric cancer cells. Results:, The expressions of both uPA and uPAR mRNAs in the gastric cancer cells increased obviously (12-fold and 3-fold, respectively) with H. pylori stimulation. The amount of uPA antigen into the culture medium increased dramatically with H. pylori stimulation. The COX-2 expression level in the gastric cancer cells increased remarkably with H. pylori stimulation. H. pylori -induced uPA and uPAR expression levels were suppressed with COX2 inhibitor treatment. The amount of PGE2 antigen into the culture medium increased dramatically 24 hours after H. pylori stimulation. The gastric cancer cells expressed EP2 and EP4 subtypes. EP2 receptor antagonist suppressed the H. pylori -induced uPA and uPAR expressions in the gastric cancer cells. Conclusions:, Our results indicated that COX2-PGE2 pathway may be involved in H. pylori- associated uPA and uPAR induction, and that COX-2 inhibitor or EP2 receptor antagonist may inhibit angiogenesis and tumor invasion via suppression of the uPA system. [source]

Enhanced Activation of Cyclooxygenase-2 Downregulates Th1 Signaling Pathway in Helicobacter pylori -infected Human Gastric Mucosa

HELICOBACTER, Issue 3 2007
Antonia Pellicanò
Abstract Background:, Evidence suggests that an impaired T-cell response against Helicobacter pylori plays a role in the pathogenesis of H. pylori -related diseases. Cyclooxygenase (COX) 2 has been shown to inhibit the production of T-helper (Th) 1 cytokines. This study aimed to ascertain whether COX-2 downregulates Th1 signaling pathway in human gastric mucosa colonized by H. pylori. Methods:, COX-2 expression and prostaglandin E2 (PGE2) production were determined in total proteins extracted from freshly obtained gastric biopsies of H. pylori -infected and uninfected patients by Western blotting and enzyme-linked immunosorbent assay (ELISA). Phosphorylated (p)STAT4, pSTAT1, T-bet, and pSTAT6 expression and interleukin (IL)-12, interferon (IFN)-,, and IL-4 production were also determined by Western blotting and ELISA, respectively, in total protein extracts from gastric biopsy cultures of H. pylori -infected patients treated without and with COX-2 inhibitor NS-398. Results:, Enhanced expression of COX-2 and production of PGE2 was found in H. pylori -infected compared to uninfected patients. COX-2 inhibition significantly increased expression of Th1 transcription factors along with production of IL-12 and IFN-,. By contrast, no changes in the expression of STAT6 and production of IL-4 were found. Conclusion:, This study provides a mechanism by which H. pylori may actually interfere with normal T-cell activation in human gastric mucosa, possibly enhancing its pathogenicity. The use of COX-2 selective inhibitors as immunomodulators in the course of H. pylori infection deserves investigations. [source]

Structure-Based Design and Synthesis of the First Weak Non-Phosphate Inhibitors for IspF, an Enzyme in the Non-Mevalonate Pathway of Isoprenoid Biosynthesis

HELVETICA CHIMICA ACTA, Issue 6 2007
Corinne Baumgartner
Abstract In this paper, we describe the structure-based design, synthesis, and biological evaluation of cytosine derivatives and analogues that inhibit IspF, an enzyme in the non-mevalonate pathway of isoprenoid biosynthesis. This pathway is responsible for the biosynthesis of the C5 precursors to isoprenoids, isopentenyl diphosphate (IPP, 1) and dimethylallyl diphosphate (DMAPP, 2; Scheme,1). The non-mevalonate pathway is the sole source for 1 and 2 in the protozoan Plasmodium parasites. Since mammals exclusively utilize the alternative mevalonate pathway, the enzymes of the non-mevalonate pathway have been identified as attractive new drug targets in the fight against malaria. Based on computer modeling (cf. Figs.,2 and 3), new cytosine derivatives and analogues (Fig.,1) were selected as potential drug-like inhibitors of IspF protein, and synthesized (Schemes,2,5). Determination of the enzyme activity by 13C-NMR spectroscopy in the presence of the new ligands showed inhibitory activities for some of the prepared cytosine and pyridine-2,5-diamine derivatives in the upper micromolar range (IC50 values; Table). The data suggest that it is possible to inhibit IspF protein without binding to the polar diphosphate binding site and the side chain of Asp56,, which interacts with the ribose moiety of the substrate and substrate analogues. Furthermore, a new spacious sub-pocket was discovered which accommodates aromatic spacers between cytosine derivatives or analogues (binding to ,Pocket III') and rings that occupy the flexible hydrophobic region of ,Pocket II'. The proposed binding mode remains to be further validated by X-ray crystallography. [source]

Inhibition of Diamino Pelargonic Acid Aminotransferase, an Enzyme of the Biotin Biosynthetic Pathway, by Amiclenomycin: A Mechanistic Study

HELVETICA CHIMICA ACTA, Issue 11 2003
Stéphane Mann
The mechanism of action of amiclenomycin (1a), a naturally occuring inhibitor of diaminopelargonic acid aminotransferase, has been established. The enzyme catalyzes the formation of an aromatic adduct between the inhibitor and pyridoxal-5,-phosphate. The structure of the adduct, determined by mass spectrometry, is in agreement with the reported X-ray crystal structure. Kinetic parameters, characteristic of kcat inhibitors, have been observed, with a KI value of 2,,M and a kinact value of 0.4,min,1. The irreversibility of the inactivation observed, in spite of the absence of covalent bond between the inhibitor and the protein, reveals the high affinity of the adduct for the active site. Two other cis -1-amino-4-substituted-cyclohexa-2,5-dienes, 3a and 4a, were also found to efficiently inhibit the enzyme. The trans -isomers were either much less potent (1b) or inactive (3b and 4b). The aminocyclohexadiene moiety, which is, apparently, responsible for the inhibition, could constitute an original pharmacophore for the design of new herbicides. [source]

The development and implementation of the Pathway for Improving the Care of the Dying in general medical wards

INTERNAL MEDICINE JOURNAL, Issue 10 2009
K. Jackson
Abstract The majority of deaths in Australia occur in general hospital wards and most are neither sudden nor unexpected. The Pathway for Improving the Care of the Dying (PICD) is an adaptation of the Liverpool Care Pathway to the Australian healthcare setting (or ,to Australian conditions') and is designed to help ensure a ,good death' for patients dying outside the palliative care system. PICD consists of a series of prompts, guidelines, revised medical and nursing care plans and a number of medication algorithms. [source]

Chemical Interactions at Metal/Molecule Interfaces in Molecular Junctions,A Pathway Towards Molecular Recognition,

ADVANCED MATERIALS, Issue 3 2009
Mila Manolova
A 4-aminothiophenol self-assembled monolayer (see image) is prepared on top of a Au(111) crystal, which is subsequently metallized by a nearly closed Pd overlayer of monoatomic height. Analysis of its structural setup and electronic properties reveals that the monolayer consists of a minimum of two molecular layers, and strong chemical interactions between the metal overlayer and the amino groups are found to play a decisive role in determining the overall electronic, and thus the transport properties, of the layer/metal contact. [source]

Correlations between the Sonic Hedgehog Pathway and basal cell carcinoma

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2007
Omar Lupi MD
The Hedgehog (HH) family of intercellular signaling proteins has some essential functions in patterning both invertebrate and vertebrate embryos. Identified as an important regulator of segment polarity and tissue organization in flies, the HH pathway can also play a significant role in human development and in cutaneous carcinogenesis. The family received their name because when the D. melanogaster HH protein malfunctions the mutant fly ends up looking like a small prickly ball, similar to a curled up hedgehog. The Sonic hedgehog (SHH) pathway is implicated in the etiology of the most common human cancer, the basal cell carcinoma (BCC). Mutations in the receptor of SHH, the patched gene (PTCH), have been characterized in sporadic BCCs as well as those from patients with the rare genetic syndrome nevoid BCC. Human PTCH is mutated in sporadic as well as hereditary BCCs, and inactivation of this gene is probably a necessary if not sufficient step for tumorigenesis. Delineation of the biochemical pathway in which PTCH functions may lead to rational medical therapy for skin cancer and possibly other tumors. [source]

Gold Catalysis: Anellated Heterocycles and Dependency of the Reaction Pathway on the Tether Length

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
A. Stephen
Abstract A series of furan-yne substrates with an arylalkynylamide substructure were prepared and subjected to catalytic amounts of phosphanegold(I) complexes. With two carbon atoms in the tether between the arylalkynylamide and the furan subunits, the formation of benzoanellated heterocycles was observed, a number of interesting heterocyclic framworks could be accessed in this way. With three carbon atoms in the tether, the outcome was quite different, cyclopentadiene derivatives anellated to tetrahydropyridine rings were isolated. The two different pathways suggested are supported by calculations regarding the selectivity-determining step. [source]

Depressed Albumin and High-Density Lipoprotein Cholesterol: Signposts along the Final Common Pathway of Frailty

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2001
William R. Hazzard MD
No abstract is available for this article. [source]

Diosmetin Induces Human Osteoblastic Differentiation Through the Protein Kinase C/p38 and Extracellular Signal-Regulated Kinase 1/2 Pathway,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2008
Ya-Ling Hsu
Abstract Introduction: The survival of osteoblasts is one of the determinants of the development of osteoporosis. This study is the first to investigate the osteoblastic differentiation induced by diosmetin, a flavonoid derivative, in osteoblastic cell lines MG-63, hFOB, and MC3T3-E1 and bone marrow stroma cell line M2-10B4. Materials and Methods: Osteoblastic differentiation was determined by assaying alkaline phosphatase (ALP) activity and mineralization degree and measuring various osteoblast-related markers using ELISA. Expression and phosphorylation of Runt-related transcription factor 2 (Runx2), protein kinase C, (PKC,), extracellular signal-regulated kinase (ERK), p38, and c- jun -N-terminal kinase (JNK) was assessed by immunoblot. Rac1 activity was determined by immunoprecipitation, and Runx2 activity was assessed by EMSA. Genetic inhibition was performed by small hairpin RNA plasmids or small interfering RNA (siRNA) transfection. Results: Diosmetin exhibited an effect on osteoblastic maturation and differentiation by means of ALP activity, osteocalcin, osteopontin, and type I collagen production, as well as Runx2 upregulation. Induction of differentiation by diosmetin was associated with increased PKC, phosphorylation and the activations of Rac1 and p38 and ERK1/2 kinases. Blocking PKC, by siRNA inhibition significantly decreased osteoblastic differentiation by inhibiting Rac1 activation and subsequently attenuating the phosphorylation of p38 and ERK1/2. In addition, blocking p38 and ERK1/2 by siRNA transfection also suppressed diosmetin-induced cell differentiation. Conclusions: In this study, we show that diosmetin induced osteoblastic differentiation through the PKC,-Rac1-MEK3/6-p38 and PKC,-Rac1-MEK1/2- ERK1/2-Runx2 pathways and that it is a promising agent for treating osteoporosis. [source]

Dysregulation of the BMP-p38 MAPK Signaling Pathway in Cells From Patients With Fibrodysplasia Ossificans Progressiva (FOP),,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2006
Jennifer L Fiori
Abstract FOP is a disabling disorder in which skeletal muscle is progressively replaced with bone. Lymphocytes, our model system for examining BMP signaling, cannot signal through the canonical Smad pathway unless exogenous Smad1 is supplied, providing a unique cell type in which the BMP,p38 MAPK pathway can be examined. FOP lymphocytes exhibit defects in the BMP,p38 MAPK pathway, suggesting that altered BMP signaling underlies ectopic bone formation in this disease. Introduction: Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by progressive heterotopic ossification of connective tissues. Whereas the primary genetic defect in this condition is unknown, BMP4 mRNA and protein and BMP receptor type IA (BMPRIA) protein are overexpressed in cultured lymphocytes from FOP patients, supporting that altered BMP signaling is involved in this disease. In this study, we examined downstream signaling targets to study the BMP,Smad and BMP,p38 mitogen-activated protein kinase (MAPK) pathways in FOP. Materials and Methods: Protein phosphorylation was assayed by immunoblots, and p38 MAPK activity was measured by kinase assays. To examine BMP target genes, the mRNA expression of ID1, ID3, and MSX2 was determined by quantitative real-time PCR. Statistical analysis was performed using Student's t -test or ANOVA. Results: FOP lymphocytes exhibited increased levels of p38 phosphorylation and p38 MAPK activity in response to BMP4 stimulation. Furthermore, in response to BMP4, FOP cells overexpressed the downstream signaling targets ID1 by 5-fold and ID3 by 3-fold compared with controls. ID1 and ID3 mRNA induction was specifically blocked with a p38 MAPK inhibitor, but not extracellular signal-related kinase (ERK) or c-Jun N-terminal kinase (JNK) inhibitors. MSX2, a known Smad pathway target gene, is not upregulated in control or FOP cells in response to BMP, suggesting that lymphocytes do not use this limb of the BMP pathway. However, introduction of Smad1 into lymphocytes made the cells competent to regulate MSX2 mRNA after BMP4 treatment. Conclusions: Lymphocytes are a cell system that signals primarily through the BMP,p38 MAPK pathway rather than the BMP,Smad pathway in response to BMP4. The p38 MAPK pathway is dysregulated in FOP lymphocytes, which may play a role in the pathogenesis of FOP. [source]

Fluid Flow Induction of Cyclo-Oxygenase 2 Gene Expression in Osteoblasts Is Dependent on an Extracellular Signal-Regulated Kinase Signaling Pathway,,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2002
Sunil Wadhwa
Abstract Mechanical loading of bone may be transmitted to osteocytes and osteoblasts via shear stresses at cell surfaces generated by the flow of interstitial fluid. The stimulated production of prostaglandins, which mediates some effects of mechanical loading on bone, is dependent on inducible cyclo-oxygenase 2 (COX-2) in bone cells. We examined the fluid shear stress (FSS) induction of COX-2 gene expression in immortalized MC3T3-E1 osteoblastic cells stably transfected with ,371/+70 base pairs (bp) of the COX-2 5,-flanking DNA (Pluc371) and in primary osteoblasts (POBs) from calvaria of mice transgenic for Pluc371. Cells were plated on collagen-coated glass slides and subjected to steady laminar FSS in a parallel plate flow chamber. FSS, from 0.14 to10 dynes/cm2, induced COX-2 messenger RNA (mRNA) and protein. FSS (10 dynes/cm2) induced COX-2 mRNA within 30 minutes, with peak effects at 4 h in MC3T3-E1 cells and at ,8 h in POBs. An inhibitor of new protein synthesis puromycin blocked the peak induction of COX-2 mRNA by FSS. COX-2 promoter activity, measured as luciferase activity, correlated with COX-2 mRNA expression in both MC3T3-E1 and POB cells. FSS induced phosphorylation of extracellular signal-regulated kinase (ERK) in MC3T3-E1 cells, with peak effects at 5 minutes. Inhibiting ERK phosphorylation with the specific inhibitor PD98059 inhibited FSS induction of COX-2 mRNA by 55-70% and FSS stimulation of luciferase activity by ,80% in both MC3T3-E1 and POB cells. We conclude that FSS transcriptionally induces COX-2 gene expression in osteoblasts, that the maximum induction requires new protein synthesis, and that induction occurs largely via an ERK signaling pathway. [source]

RhoA/ROK Pathway Related to the Mechanism of Higher Susceptibility to Spasm in RA Than in IMA

JOURNAL OF CARDIAC SURGERY, Issue 6 2009
Xia Kun M.D.
Methods: RA, IMA, and GSV that would otherwise have been discarded were collected from 25 patients who underwent coronary artery bypass grafting. Eleven matched rings of RA, IMA, and GSV were used to evaluate the vasodilatory properties of 10,7,10,4 mol/l of fasudil, a Rho-kinase inhibitor, by using in vitro organ chambers. Another 14 matched RA, IMA, and GSV were used to demonstrate the immunohistochemistry (IHC) of RhoA and mRNA of RhoA and Rho kinase. Results: The maximal vasodilation of RA to fasudil was significantly greater than IMA. RhoA protein IHC staining was different in IMA, RA, and GSV (RA > GSV >IMA). The expression of RhoA and Rho kinase mRNA in the RA was significantly greater than in the IMA. Conclusions: The expression of RhoA/Rho kinase mRNA and protein and function in the RA were significantly stronger than in the IMA, suggesting that RhoA/Rho kinase pathway may be one mechanism by which RA is more susceptible to spasm than IMA. Rho kinase inhibitors can be effective drug candidates to prevent and treat vasospasm. [source]