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  • 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.
11

The effects of interferon on cultured cells persistently infected with viruses

Crespi, Madeleine 09 September 1986 (has links)
A Thesis Submitted to the Faculty of Medicine University of the Witwatersrand, Johannesburg for the Degree of Doctor of Philosophy in Medicine Johannesburg 1986 / An investigation was done to examine the role of IFN in viral persistence at the cellular level. For this purpose two types of persistent infections were chosen. The first type was cell lines which contained hepatitis B virus (HBV) DNA (PLC/PRF/5 and Hep 3B cells) uninfected control hepatoma cells, (Mahlavu, HA22T and Hep G2 cells) or simian virus 40 (SV40) DNA (C2, C6, Cll cells) and control uninfected (CV-1 cells). In the second type of infection Vero cells persistently infected with SSPE or Sendai virus were used. / IT2018
12

The effect of differentiation on the expression of phosphoprotein phosphatase in the human promyelocytic leukaemic cell line HL-60

Bhoola, Rajesh 16 November 2006 (has links)
Student Number : 9000554P - PhD thesis - School of Molecular Medicine and Haematology - Faculty of Science / Dynamic cellular activity is fundamental to all life. Virtually all life processes, are modulated by the reversible phosphorylation of proteins, mediated by protein kinases and phosphoprotein phosphatases, respectively. This thesis focuses on three enzymes, namely: phosphoprotein phosphatase 1, phosphoprotein phosphatase 2A and protein tyrosine phosphatase-1B. Temporal variations in the expression of the enzyme proteins were examined in the human acute promyelocytic leukaemic cell line, HL-60. The cells were induced to differentiate along the macrophage pathway using phorbol-12-myristate- 13-acetate and along the granulocytic pathway using dimethyl sulfoxide, all-trans retinoic acid and 9-cis retinoic acid. Modulation of the rhythmic patterns of protein and messenger RNA was monitored in the absence and presence of inducing agents. Expression of protein in cell extracts prepared at various time intervals was determined by western immunoblotting, while mRNA expression was assessed by northern blotting and RT-PCR. The probe used for northern blotting was generated during the RT-PCR procedure. In addition, PTP-1B mRNA was cloned into an expression vector to produce recombinant protein. Results indicate that the expression of phosphoprotein phosphatase 1, phosphoprotein phosphatase 2A and protein tyrosine phosphatase-1B protein is dynamically regulated in proliferating HL-60 cells and modulated after being induced to differentiate along either the macrophage or granulocytic pathway. Similar changes were also noted with PTP-1B mRNA when using northern blot analysis. Using molecular cloning techniques, PTP-1B mRNA was successfully cloned into pGex-4T-1 expression vector to produce recombinant PTP-1B protein, which was checked by sequence and western blot analysis.
13

Study of expression, production, and degradation of ghrelin/Etude de l'expression, de la production et de la dégradation de la ghréline

De Vriese, Carine 23 June 2006 (has links)
La ghréline est un peptide de 28 acides aminés, produit principalement par l’estomac et caractérisé par la présence d’un groupement octanoyl sur la sérine en position 3 (Kojima et al. 1999). La ghréline stimule la libération de l’hormone de croissance (GH) et régule la prise alimentaire et le métabolisme énergétique (Gualillo et al. 2003). Ces activités biologiques sont principalement médiées par le « growth hormone secretagogue receptor » (GHS-R). Deux sous-types de GHS-R, produits par épissage alternatif d’un même gène, ont été clonés : le GHS-R 1a, dont l’activation entraîne une libération de calcium via la formation d’inositol 1,4,5-trisphosphate (IP3), et le GHS-R 1b, qui ne semble pas lié à une activité biologique (Howard et al. 1996). La première partie de mon travail de thèse consistait en l’étude de la dégradation de la ghréline. La ghréline circule dans le sang principalement sous forme de des-acyl ghréline, une forme de ghréline dépourvue du groupement octanoyl qui ne se lie pas au GHS-R 1a. Peu d’études ont été réalisées sur le catabolisme de la ghréline. Les enzymes impliquées dans la dégradation de la ghréline étant des régulateurs importants de son activité biologique, le but de cette étude était d’identifier les sites de clivage et les enzymes impliquées dans la dégradation de la ghréline par du sérum, des sous-fractions plasmatiques et des homogénats de tissus. Nous avons montré qu’au contact de sérum humain et de rat, la ghréline est désoctanoylée, sans protéolyse. Dans le sérum humain, nous avons montré que la butyrylcholinestérase et la « platelet-activating factor acetylhydrolase » (PAF-AH), une phospholipase associée aux lipoprotéines de basse densité (LDL), sont impliquées dans ce phénomène (articles n°1 et n°2). En parallèle, nous avons montré que la ghréline peut être transportée dans la circulation sanguine par les lipoprotéines riches en triglycérides (TRL), les LDL, et les lipoprotéines de haute et de très haute densité (HDL et VHDL) (article n°2). Dans le sérum de rat, la désoctanoylation de la ghréline implique une carboxylestérase (article n°1). Au contact d’homogénats de tissus, la ghréline est dégradée à la fois par désoctanoylation et protéolyse N-terminale, suggérant la participation d’estérases et d’aminopeptidases. Nous avons identifié cinq sites de clivage dans la ghréline : entre les résidus Ser2-(acyl)Ser3 (dans l’estomac et le foie), (acyl ?)Ser3-Phe4 (dans l’estomac, le foie et le rein), Phe4-Leu5 (dans l’estomac et le rein), Leu5-Ser6 et Pro7-Glu8 (dans le rein) (article n°1). La deuxième partie de mon travail de thèse consistait à étudier l’expression et la production de ghréline par différentes lignées leucémiques (HEL, HL-60, THP-1, SupT1), par des leucocytes poly- et mononucléés et par des plaquettes sanguines, et à étudier l’effet de la ghréline sur la prolifération cellulaire. Pour cela, nous avons mis au point des dosages radioimmunologiques (RIA) permettant de quantifier et de distinguer les formes octanoylées et non octanoylées de la ghréline, et nous avons caractérisé en détail les anticorps SB801 et SB969 obtenus. Par HPLC en phase inverse suivie des RIAs, nous avons mis en évidence la présence de ghrélines octanoylée et non octanoylée dans chaque population de cellules. Plus de 80 % de la ghréline produite est octanoylée dans les cellules HEL, les leucocytes et les plaquettes. Nous avons montré que la ghréline endogène stimule la prolifération des cellules HEL de façon autocrine impliquant un récepteur encore non identifié, distinct du GHS-R 1a (article n°3). La ghréline et la des-acyl ghréline inhibent la prolifération des leucocytes mononucléés mais sont dépourvues d’effet sur les cellules HL-60, THP-1 et SupT1. Malgré la présence du GHS-R 1a dans les leucocytes mononucléés, cet effet pourrait être médié par un récepteur différent puisque la des-acyl ghréline exerce le même effet que la ghréline sur la prolifération (article n°4).
14

Studies on the cryopreservation and in vitro culture of Amyloodinium ocellatum

Yang, Chu-Ya 04 August 2006 (has links)
The Amyloodinium ocellatum was collected from cobia ( Rachycentron canadum ) gill and four tests including 4 ¢J storage, toxicity of cryoprotectant, cryopreservation and in vitro cultivation on fish cell line were conducted to establish the methods of preservation of Amyloodinium ocellatum. Survival of trophont, morphology and division of tomont and number of dinospore released were evaluated the effects of this study. The results showed that division irregulated, delayed and stopped of the tomont were found after stored at 4 ¢J over 48 hours. It was produced 1.08 x 10 4 cell/ml dinospores from 1 x 10 3 trophont at 4 ¢J, 24 hours storage group and significant higher ( p¡Õ0.0001 ) than other storage groups. For the toxicity of cryoprotectant, the concentration of DMSO 3~10¢M, Glycerol 3~10¢M, Methanol 3~10¢M, Ethanol 3~5¢M, PrOH 3~5¢M, DMAc 3~5¢M, Sucrose 3~15¢M, Trehalose 3~15¢M, Dextran 3~5¢Mand Ficoll 3~10¢Mwere safety to use on A. ocellatum trophont preservation. It was unsuccessful to cryopreserve the trophont of A. ocellatum when stored at direct liquid N2 freezing, different -20 ¢J freezing time, -1 ¢J min-1 freezing container and different cryoprotectant equilibration time contain 10¢MGlycerol and DMSO, respectively. Using the U-shaped tube of sigle and double loop could gain pure and bacteria-free dinospores. The results of in vitro cultivation of A. ocellatum showed that eel epidermis and cobia fin cell line with different culture mediums were unable to grow the trophont and tomont of A. ocellatum.
15

Intrathecal GDNF Gene Delivery Enhances Recovery from Neuropathic Pain in Rats

Wu, Ping-Ching 14 July 2003 (has links)
Neuronal cell death may be responsible for the pathogenesis of neuropathic pain. Glial cell line-derived neurotrophic factor (GDNF) protects sensory neurons after injury and offers a promising alternative for the management of intractable pain. However, continuous administration of trophic factors into the central nervous system is costly and difficult to maintain. Therefore, we evaluated the potential of intrathecal GDNF gene delivery for the treatment of neuropathic pain. Recombinant adenovirus encoding GDNF (Ad-GDNF) was characterized and shown to enhance viability of neuronal cultures. After intrathecal injection of Ad-GDNF, an elevated GDNF level was observed in spinal cord for four weeks. In rats with sciatic nerve axotomy,intrathecal injection of Ad-GDNF significantly ameliorated the duration of neuropathic pain. However, animals treated with Ad-GDNF developed hyperalgesia in the early stage of treatment. Immunofluorescence analysis indicated that intrathecal GDNF gene delivery prominently attenuated the neuronal loss due to nerve injury. Unexpectedly, varying degrees of hair loss was found in some rats receiving Ad-GDNF. Histological analysis revealed that hair loss resulted from severe degeneration of hair follicles in skin from Ad-GDNF-treated animals. In summary, the present study demonstrate the feasibility and limitations of GDNF gene delivery for the management of neuropathic pain.
16

The unfolded protein response increases production of pro-angiogenic factors by tumor cell lines

Liao, Nan, January 2008 (has links) (PDF)
Thesis (M.S. )--University of Tennessee Health Science Center, 2008. / Title from title page screen (viewed on July 17, 2008). Research advisor: Linda M. Hendershot, Ph.D. Document formatted into pages (x, 57 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 47-57).
17

Eukaryotic replication, cis-acting elements, and instability of trinucleotide repeats

Rindler, Paul Michael. January 2009 (has links) (PDF)
Thesis (Ph. D.)--University of Oklahoma. / Includes bibliographical references.
18

Somatic recombination in Bloom's syndrome cells /

Groden, Joanna Louise. January 1989 (has links)
Thesis (Ph. D.)--Cornell University, 1989. / Vita. Includes bibliographical references.
19

Gene expression profiles of liver cancer cell lines reveal two hepatocyte-like and fibroblast-like clusters / 肝癌セルラインにおける遺伝子発現プロファイルは、肝細胞様、線維芽細胞様の2つのクラスターを明らかにする

Fukuyama, Keita 26 July 2021 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第23409号 / 医博第4754号 / 新制||医||1052(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妹尾 浩, 教授 武藤 学, 教授 小川 誠司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
20

Nitric Oxide Production: A Mechanism of Chlamydia Trachomatis Inhibition in Interferon-γ-Treated RAW264.7 Cells

Chen, Bojun, Stout, Robert, Campbell, William F. 01 January 1996 (has links)
IFN-γ and/or LPS induced nitrite production and inhibition of Chlamynia trachomatis (CT) replication in the murine macrophage cell line, RAW264.7. Linear regression analysis demonstrated a strong correlation between nitrite production and inhibition of CT replication (correlation coefficients: -0.93, P < 0.001). L-NMMA specifically inhibited nitrite production and restored CT replication (55-71%). Inducible nitric oxide synthase (iNOS) mRNA was analyzed by Northern and dot blot hybridization with an iNOS cDNA probe. A strong correlation between iNOS mRNA expression and inhibition of CT replication also was observed (correlation coefficient: -0.97, P < 0.05). Furthermore, anti-TNF-α antibody, which completely neutralized biological activity of the secreted TNF-α neither inhibited nitrite production nor restored CT replication in the LPS- and/or IFN-γ-treated RAW264.7 cells. In mouse peritoneal macrophages treated with IFN-γ, both L-NMMA and anti-TNF-α antibody inhibited nitrite production and restored CT replication. However, L-NMMA and the antibody had no effect upon nitrite production and CT inhibition in LPS-treated peritoneal macrophages. These data indicate that NO production is one mechanism for inhibition of CT replication in IFN-γ-activated murine macrophages.

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