• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 394
  • 247
  • 80
  • 22
  • 21
  • 14
  • 10
  • 10
  • 8
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • Tagged with
  • 932
  • 327
  • 156
  • 113
  • 101
  • 100
  • 72
  • 72
  • 63
  • 61
  • 56
  • 50
  • 49
  • 48
  • 46
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An investigation of acyl glucuronides

Kenny, Jane Ruth January 2002 (has links)
No description available.
2

The intracellular transport and translocation of ricin

Simpson, Jeremy Charles January 1995 (has links)
No description available.
3

Studies of the recognition and activation of natural killer cells /

Une, Clas, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.
4

The mosquitocidal #delta#-endotoxins of Bacillus thuringiensis

Drobniewski, Francis Anthony January 1987 (has links)
No description available.
5

Studies on CB1954 and its analogues

Quinn, Jonathan January 1996 (has links)
No description available.
6

Complexes métalliques pour utilisation en imagerie médicale : application à la maladie d’Alzheimer / Metal complexes for medical imaging : application to alzheimer's disease

Santo domingo porqueras, Diego 12 December 2016 (has links)
La détection du peptide bêta-amyloïde (Aβ) avec des techniques d’imagerie médicale est utilisée pour le diagnostic de la maladie d’Alzheimer. Des complexes métalliques de cuivre et des lanthanides pourraient être utilisés à ce propos, en supposant qu’ils soient capables d’entrer au cerveau. Nous avons étudié la cytotoxicité et la cinétique d’incorporation intracellulaire de deux complexes macrocycliques ayant des bras picolinates, [Eu(do2pa)]+ et [Cu(te1pa)]+. Les deux complexes sont capables de traverser la membrane plasmique des cellules K562 et K562/ADR. Le rapport entre la concentration intracellulaire et la concentration extracellulaire est de 5 et 1,4 respectivement. Aucune différence significative concernant l’accumulation intracellulaire n’a été trouvée entre les cellules K562 et K562/ADR, ce qui suggère que ces composés ne sont pas des substrats de la P-gp, la protéine d’efflux la plus étudiée au niveau de la barrière hémato-encéphalique. Ces résultats et les propriétés physicochimiques des complexes suggèrent que ces deux complexes pourraient être intéressants pour la production d’agents d’imagerie médicale visant le cerveau. A partir de la structure du complexe [Cu(te1pa)]+, nous avons synthétisé un complexe métallique visant le peptide Aβ par la liaison d’un dérivé d’aryl-benzofuranne (appelé ONO) au bras picolinate du ligand grâce à une réaction de Buchwald-Hartwig. L’ONO est un marqueur des plaques amyloïdes qui est capable de traverser la membrane plasmique des cellules K562 et K562/ADR. Ni l’ONO ni le [Cu(te1pa-ONO)]+ ne sont toxiques sur les cellules SH-SY5Y aux concentrations appropriées pour l’utilisation clinique. Finalement, nous avons aussi étudié une série de N-alkanol-N-cyclohexanol amine aryl esters, synthétisés comme inhibiteurs de la P-gp. Tous les inhibiteurs ont des [I]0,5 entre 60 nM et 510 nM, montrant une inhibition efficace de l’activité de la P-gp. Les inhibiteurs sont de 3 à 27 fois plus efficaces que le vérapamil, les isomères trans étant plus efficaces que leurs homologues cis. / Detection of beta-amyloid peptide (Aβ) using medical imaging techniques is used for the diagnosis of Alzheimer’s disease. Copper and lanthanide metallic complexes may be used for that goal, if they were able to enter the brain.We studied the cytotoxicity and the cellular incorporation kinetics of two macrocyclic complexes with picolinate arms, [Eu(do2pa)]+ and [Cu(te1pa)]+. Both complexes are able to cross the plasma membrane, entering K562 and K562/ADR cells. The ratios between their intracellular and extracellular concentrations are 5 and 1.4 respectively. No significant difference was observed between K562 and K562/ADR cells, meaning that these complexes are not substrates of P-gp, a well-known efflux transport protein in the blood-brain barrier. The results obtained and the physicochemical properties of complexes suggest that the complexes studied are appropriate platforms for the synthesis of brain-targeted medical imaging agents. Based on the structure of [Cu(te1pa)]+, an Aβ-targeted metallic complex was developed by attaching an aryl-benzofuran derivative (named ONO) to the picolinate arm of the ligand via a Buchwald-Hartwig reaction. ONO is a marker of amyloid plaques that is able to cross the plasma membrane of K562 and K562/ADR cells. Neither ONO nor [Cu(te1pa-ONO)]+ are toxic to SH-SY5Y cells at concentrations that would be appropriate for clinical use. Finally, we studied a series of N-alkanol-N-cyclohexanol amine aryl esters, synthesized as P-gp inhibitors. All inhibitors have [I]0.5 between 60 nM and 510 nM, showing good P-gp inhibition activity. The P-gp inhibitors are 3 to 27 times more powerful than verapamil, being the trans isomers more effective than their cis counterparts.
7

Chemical Constituents and Cytotoxicity of Formosan Soft Corals Lemnalia laevis (GN62) and Sarcophyton tenuispiculatum (GN53)

Chiu, E-Ping 19 July 2004 (has links)
Chromatographic separation of methylene chloride extracts of Formosan soft coral Lemnalia laevis, Thomson and Dean (collected at Green Island off Taiwan) led to the isolation of eight sesquterpenoids and three norsesquterpenoids compounds, 4(S¡¯)-acetoxy,10(S¡¯)-hydro xy,5-oxo,1(S¡¯),12(S¡¯)neolemna-2(Z),8-diene (1)¡B4(S*)-acetoxy,10,5-oxo, 1(S*),12(S*)neolemna-1(Z),8-dieme (2)¡B(6
8

CONTRIBUTION OF DEFECTIVE CYTOTOXICITY TO DEVELOPMENT OF CANINE HEMOPHAGOCYTIC HISTIOCYTIC SARCOMA

Neta, Michal 15 September 2011 (has links)
Canine Hemophagocytic Histiocytic Sarcoma (CHHS) is an aggressive neoplasm of macrophages with local lymphocytic reaction. Similarities exist between CHHS and Familial Hemophagocytic Lymphohistiocytosis (FHL), a complex of histiocytic diseases in children, which is attributable to various defects in granule dependent killing (GDK). This led to the hypothesis that defective GDK compromises lymphocyte homeostasis and anti-tumor immunity which results in CHHS. The sequence of canine perforin, a key effector molecule of GDK, was determined by RT-PCR and RACE. Genomic DNA from healthy and CHHS-affected dogs was sequenced and analyzed, but mutations with functional implications were not identified. Subsequently, tumor infiltrating lymphocytes (TIL) of CHHS were examined for GDK functionality. CHHS-TIL were compared to their functional counterparts in canine cutaneous histiocytoma (CCH), a benign histiocytic tumor in dogs, known to regress via lymphocytic reaction. To facilitate such comparison, functionality of CCH-TIL was studied by immunohistochemistry and confocal microscopy and quantified by image analysis applications. This provided novel insights regarding the physiology of TIL in tumor microenvironment and further characterizing CCH as a model for anti-tumor immunity. The comparison revealed a clear, and highly significant structural difference in polarization and degranulation of CHHS-TIL which likely hampers GDK. This defect is similar to several variants of FHL, an association further supported by comparison of clinical and laboratory manifestations of CHHS and FHL. This study suggests that CHHS is a promising natural model for investigating the pathogenesis of FHL, for studying granule polarization and degranulation and assessing the role of TIL in anti-cancer immunity. / Pet Trust foundation
9

Natural killer cell function in chronic HCV infection

Collister, Mark 21 August 2013 (has links)
NK cells control viral replication through cytotoxicity and IFNγ production. These functions were assessed in chronic HCV infected patients undergoing treatment. Aboriginals have genetic polymorphisms that may enhance NK cell function suggesting more effective clearance of chronic HCV than Caucasians. NK cell function was similar at baseline between ethnicities. At 3 months of treatment, Caucasian had higher NK killing potential compared to Aboriginal patients. This had no effect on treatment outcomes. NK cell cytotoxicity negatively correlated with viral loads while NK IFNγ production, particularly within the CD56bright subset, positively correlated with viral load suggesting that viral loads control NK cells function through an unknown mechanism. NK cell killing reflect fibrosis, but not liver damage measured by liver enzymes. IFNγ production,by NK cells does not reflect fibrosis nor liver enzymes levels. Lastly, NK cell function does not associate with therapeutic outcomes of chronic HCV infection suggesting that they do not directly play a role in therapeutic clearance of HCV.
10

Hydrogen peroxide-induced cell damage : the role of free radicals and iron complexes

Jonas, S. K. January 1988 (has links)
This thesis presents data exploiting one of the important chemico-biological characteristics of the transition metal iron: its ability to exist in two oxidation states. Manipulation of the reactivity of iron by ligands has been reflected by the oxygen utilisation or the amount of ferrozine-detectable Fe2+. Ligand-dependent cell associated iron has been demonstrated by prussian blue staining and ferrozinedetectable iron. Iron/8-hydroxyquinoline enters the cell by diffusion, whereas iron dextran is endocytosed as is evident from extensive vesicular staining. The involvement of iron in the cytotoxicity of H202 has been examined (a) indirectly by introduction of reducing agents which restore the cytotoxicity of H202 at 4°C (an effect which is abolished by desferrioxamine) and (b) directly by extracellularly added iron, which enhances the cytotoxicity if the iron is internalised but protects the cell if the iron remains extracellular. Cytotoxicity has been estimated by plating efficiency and by a modified tritiated thymidine incorporation assay permitting a 24 hour delay before exposure to the label. Direct free radical interaction with a ligand itself is exemplified by the production of the nitroxide free radical in desferrioxamine. This causes extensive damage to yeast alcohol dehydrogenase but can be protected by ascorbate, methionine and iron/EDTA but not iron dextran. The findings lend further support for the suggestion that free radical generation by the Fenton reaction enhances the potential cytotoxic effect of H202 provided the reactions occur at critical sites within the cell.

Page generated in 0.0483 seconds