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1
Bianco-Miotto, Tina. "Loss of ABO antigens in haematological malignancies / Tina Bianco-Miotto". Thesis, Adelaide, S.A, 2002. http://hdl.handle.net/2440/21857.
Testo completoAbstract (sommario):
"May 2002"Includes bibliographical references (leaves 229-251)
xv, 251 leaves : ill. (some col.) ; 30 cm.
Describes the investigation of the alteration of ABH antigen expression on the surface of red blood cells in patients with haematological malignancies.
Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 2003
2
Bianco-Miotto, Tina. "Loss of ABO antigens in haematological malignancies". Adelaide, S.A, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phb578.pdf.
Testo completoAbstract (sommario):
"May 2002" Includes bibliographical references (leaves 229-251) Describes the investigation of the alteration of ABH antigen expression on the surface of red blood cells in patients with haematological malignancies.
3
Chopra, M. S. "Some biochemical aspects of blood in rheumatoid arthritis and vascular diseases". Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381360.
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4
Jim, Jin-to, e 詹展韜. "Genetics and molecular characterization of degenerative disc disease". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B35720189.
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5
Lau, Kin-chong, e 劉健莊. "Microarray-based investigations of genetic diseases". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45894760.
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6
Chan, Shun-kwan, e 陳信君. "Molecular detection of streptococcus sinensis in blood culture samplesfrom hospitalized patients in Hong Kong: aneight-year retrospective study". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46632074.
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7
Lilliecreutz, Caroline. "Blood-and Injection Phobia in Pregnancy : Epidemiological, Biological and Treatment aspects". Doctoral thesis, Linköpings universitet, Hälsouniversitetet, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-59745.
Testo completoAbstract (sommario):
Introduction: Blood- and injection phobia is an anxiety disorder with a prevalence of approximately 3-5% in the general population. The etiology is often a combination of genetic factors and a conditioning experience. The symptoms of blood- and injection phobia are dizziness, confusion, nausea, epigastria discomfort, anxiety and sometimes panic attacks when receiving injections, seeing blood or having a blood sample taken. Unique for this specific phobia is the high probability of fainting when the phobic situation is encountered if there is no possibility to escape or to avoid the stimuli. During pregnancy and labor, women with blood- and injection phobia are exposed to most of their fears and they therefore find themselves in anxiety-ridden situations. Stress and anxiety during pregnancy is known to be risk factors for adverse obstetric and neonatal outcomes. Studies have shown an altered hypothalamic-adrenal-pituitary axis in women with stress or/and anxiety during pregnancy and increased cortisol concentrations can imply negative consequences for the unborn child. Cognitive behavioral therapy (CBT) is known to be effective in treating specific phobias such as blood- and injection phobia. Aim: The prevalence, obstetric and neonatal consequences, impact on the hypothalamic adrenal-pituitary axis and treatment aspects of blood- and injection phobia in a pregnant population have not been investigated before. The aims of this thesis were to study each of these phenomena. Material and methods: During 2005 a total of 1606 pregnant women were approached at their first visit in an antenatal care clinic in the southeast region in Sweden. They were asked to complete the “Injection Phobia Scale-Anxiety” questionnaire. All women who scored ≥ 20 on the “Injection Phobia Scale-Anxiety” questionnaire (N=347), were interviewed and either diagnosed for blood- and injection phobia or dismissed. In total, 110 women were diagnosed as having blood- and injection phobia. Among the women who scored <20 on the “Injection Phobia Scale-Anxiety” questionnaire, 220 women were randomly stratified for age and parity as a control group. The women in the study population answered questionnaires in gestational week 25, 36 and postpartum concerning symptoms of blood- and injection phobia, depression and anxiety. Samples of cortisol in the saliva were collected in the morning and evening in gestational week 25 and 36 in both groups of pregnant women. The medical records from the antenatal care visits, the delivery and postpartum check-up was used to collect data of importance. A treatment study was conducted using a two session cognitive behavioral therapy in a group of pregnant woman with blood- and injection phobia. Results: The prevalence of blood- and injection phobia is 7 % in a pregnant population. Pregnant women with blood- and injection phobia stated more often a fear of childbirth (p<0.001) and were more frequently delivered by elective cesarean section (p=0.032). The incidence of having a baby diagnosed with a complication (p=0.001) was also higher among these women. The women with blood- and injection phobia had increased cortisol concentrations in the saliva compared to the healthy controls (p=0.014). A two-session CBT in group for pregnant women with blood- and injection phobia reduced phobic (p<0.001) anxiety (p<0.001) and depressive (p<0.001) symptoms during pregnancy. Conclusions: Blood- and injection phobia during pregnancy is rather common. Pregnant women with blood- and injection phobia are more likely to be delivered by elective cesarean section and having a baby born with a complication compared to women not suffering from this specific phobia. Untreated blood- and injection phobia during pregnancy increases salivary cortisol concentrations indicating an altered hypothalamic-adrenal-pituitary axis during these weeks of pregnancy. To enhance psychological well being in pregnant women with blood- and injection phobia a two-session program providing CBT for groups of pregnant women is valuable and produces stable results for at least 3 months after delivery.
8
Chan, Cheuk-wing Wilson, e 陳卓榮. "ER stress in the pathogenesis of osteochondrodysplasia". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43085192.
Testo completo
9
Makubalo, Zola. "Mutation screening of candidate genes and the development of polymorphic markers residing on chromosome 19q13.3, the progressive familial heart block I gene search area". Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51838.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2000.ENGLISH ABSTRACT: Progressive familial heart block type I (PFHBI) is a cardiac ventricular conduction disorder of unknown cause associated with risk of sudden death, which has been described in several South African families. Clinically, PFHBI is characterised by right bundle branch block on ECG, which may progress to complete heart block, necessitating pacemaker implantation. The disease shows an autosomal dominant pattern of inheritance with evidence of genetic anticipation. Using genetic linkage analysis, the PFHBI-causative gene was mapped to a 10 eentimorgan (cM) gene-rich area of chromosome (C) 19q13.3, which has, subsequently, been reduced to 7cM by fine mapping with polymorphic dinucleotide (CA)n short tandem repeat (STR) markers. Several attractive candidate genes, including muscle glycogen synthase (GSY 1) and histidine-rich calcium binding protein (HRC), lie within this region. The aim of the present study was two-fold: 1) to identify and characterise tetranucleotide (AAAT)n STRs within the PFHBI critical region that could be developed as polymorphic markers for use in genetic fine mapping and 2) to screen selected regions of GSY 1and HRC, positional candidate genes, for the presence ofPFHBI-causing mutation(s). Cosmids harbouring CI9q13.3 insert DNA were screened for the presence of (AAAT)n STRs by dot blot and Southern blot hybridisation using a radiolabelled (AAAT)lO oligonucleotide probe. To characterise the harboured (AAAT)n STRs, the positively hybridising fragments identified by Southern blot were sub-cloned, sequenced and primers designed from the unique repeat-flanking sequences. These primers were used to genotype the (AAAT)n repeat locus to assess its polymorphic nature in a panel of unrelated individuals. Alternatively, vectorette PCR, a rapid method of identifying repeat sequences and obtaining the flanking sequences in large inserts, was employed to develop polymorphic markers from the positively hybridising clones. Selected exons of GSY1 and HRC were screened for the presence of potentially disease-causing mutations by PCR-SSCP analysis and direct sequencing, respectively, in PFHBI-affected and unaffected family members. Of the available cosmid clones that gave strong signals on dot blot and Southern blot hybridisation, three, 29395, 24493 and 20381, were located within the critical PFHBI area and were used for marker development. An interrupted (AAAT)n repeat motif (n less than 5) was identified in cosmid 29395, however, the repeat locus was not polymorphic in the tested population. No (AAAT)n motif, single or repeated was observed in the partial sequence of the sub-cloned fragment of cosmid 24493. Using vectorette peR, no repeated (AAAT)n motif was identified on sequencing the generated products in either cosmid 24493 or 2038l. However, diffuse single AAAT motifs were detected in both cosmids. Exons 4, 5, 11, 12 and 16 of GSY 1, containing domains that are conserved across species, and the conserved eterminus- encoding exons 2-6 of HRC were selected for screening for potential PFHBI-causing mutation(s). However, no sequence variations were detected. The interrupted (AAAT)n repeat identified in cosmid 29395 was not polymorphic, which confirmed reports that complex repeats, especially those containing AAAT motifs of less than 6 repeats, are not polymorphic. One possible explanation for the absence of a repeated AAAT motif in cosmids 24493 and 20381, which both gave positive hybridisation signals, is that the low annealing temperature of the AfT -rich repeat-anchored primers used in vectorette peR may have resulted in transient annealing to the diffuse single AAAT motifs detected on sequencing. The screened regions of candidate genes GSYI and HRC were excluded from carrying the disease-causing mutation(s). The availability of new sequence data generated by the Human Genome Project will influence future strategies to identify the PFHBI gene. Electronic searches will allow identification of STR sequences for development of polymorphic markers and gene annotation will allow selection of new candidate genes for mutation screening.
AFRIKAANSE OPSOMMING: Sien volteks vir opsomming
10
Hall, Richard James, e n/a. "Chromosome 18 and autoimmune disease". University of Otago. Department of Biochemistry, 2005. http://adt.otago.ac.nz./public/adt-NZDU20070221.141018.
Testo completoAbstract (sommario):
The autoimmune diseases embody a diverse range of common human conditions that are caused by a loss of self-tolerance in the host immune system to a specific organ or tissue type. Approximately 5% of the general population are affected by autoimmune diseases which include type 1 diabetes (T1D), rheumatoid arthritis (RA) and Graves disease (GD). The majority of the autoimmune diseases are multifactorial in origin, brought about by a combination of both environmental and genetic factors. Numerous susceptibility loci have been identified for each autoimmune disease and a number of these loci have been shown to be shared amongst the autoimmune diseases. The fine-mapping of susceptibility loci to the underlying disease genes remains the current challenge facing complex disease genetics. This project aimed to further characterise the autoimmune disease susceptibility locus IDDM6 on chromosome 18q12-21. This was achieved by using a comparative mapping approach that incorporates the study of genetic association in human autoimmune disease alongside the consomic mapping of the orthologous region in the non-obese diabetic (NOD) mouse model of autoimmunity.
Deleted in colorectal carcinomas (DCC) provided a strong candidate gene at IDDM6 and the resident R201G polymorphism was identified as a functional candidate A potential mechanism for the R201G polymorphism involvement in T1D aetiology was identified where the polymorphism may affect the ability of DCC to induce apoptosis in vitro. However, no evidence for R201G association could be detected in autoimmune disease case-control datasets from the New Zealand (NZ) population (T1D n = 428, RA n = 730, autoimmune thyroid disease n = 192 (AITD); versus n = 1246 healthy controls). In addition, no evidence for R201G involvement in T1D could be provided in a transmission disequilibrium test (TDT) incorporating 382 affected sib-pair families (54.2% transmission; P = 0.15). Significant association of R201G with GD was detected in a United Kingdom (UK) dataset (P = 0.002) from the Newcastle population (423 cases vs. 393 controls) but this was not replicated in an additional dataset from the UK Birmingham population (731 cases vs 668 controls; P = 0.81). It was concluded that the R201G polymorphism may encode susceptibility to GD but is unlikely to be the sole aetiological variant that accounts for the linkage previously observed at IDDM6 in autoimmune disease. To further investigate DCC as a positional candidate at IDDM6, five SNPs were selected from a 100 kb window surrounding a DCC-resident microsatellite that had previously been associated with T1D, called "88,21". The five SNPs were genotyped in the NZ T1D dataset, and the ascertainment of estimated haplotypes in this dataset revealed association of a rare haplotype with T1D, called haplotype H (3.31% cases vs 1.17% controls; P = 0.0044), in addition to global association of all haplotypes (P = 0.018). Haplotype H was also associated in an independent case-control dataset from the UK comprised of 400 T1D subjects and 443 healthy controls (P = 0.038). Maximum support for association of haplotype H was extended when both the UK and NZ T1D datasets were combined (P = 0.0017). Association of haplotype H could not be verified in a family-based test for association using the 382 UK T1D families (P = 0.40). However, the inclusion of the DCC SNPs in a TDT analysis of the published DCC-resident microsatellites "88,21" and "55,26", that had been used to identify IDDM6, extends support for the previously-associated 2-10 haplotype (2-10 refers to the published allele nomenclature at "88,21" and "55,26" respectively; 2-10-haplotype A; 59.6% T; P = 0.0058). There was no evidence for association of the five SNPs with RA or AITD when using either individual SNP analyses or estimated haplotypes in the NZ datasets. A similar lack of association was reported for the UK Newcastle GD dataset. Taken together, these data further support DCC, or a nearby gene, as conferring susceptibility to T1D.
The human genetic data that supports IDDM6 involvement in autoimmune disease is further strengthened by consomic mapping of the orthologous region in mouse, using the non-obese diabetic mouse (NOD) model of autoimmune disease. In this thesis, the first evidence for a diabetes and thyroiditis susceptibility locus on mouse chromosome 18 is presented, which have been designated Idd21 and Sat1 respectively. This was achieved by using a chromosome-replacement strain with chromosome 18 derived from the diabetes-resistant Biozzi ABH strain on a diabetes-susceptible NOD genome, called NOD.ABH[Chr�⁸]. Mouse chromosome 18 contains orthology to both IDDM6 and the rat diabetes-susceptibility locus Iddm3. The NOD.ABH[Chr�⁸] mice showed a dramatic and significant reduction in diabetes incidence (30% of females were affected by 7 months of age versus 85% in NOD; P <0.0001) and that of thyroiditis (15.5% at 12 months compared to 37.4% in NOD; P <0.002).
The comparative mapping of the chromosome 18 autoimmune susceptibility locus IDDM6 in human and mouse presented in this thesis provides further support for this locus. This research also clearly defines the next steps required to fine-map IDDM6 to the underlying disease genes, especially in regard to the DCC gene.
11
Choi, Wai-yee Junet, e 蔡偉儀. "Serum neopterin for early assessment of severity of severe acute respiratory syndrome and Dengue virus infection". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B32031579.
Testo completo
12
Thwaites, Richard Mark. "Molecular studies on the variability and basis of pathogenicity of vascular bacterial pathogens of Musa spp". Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325011.
Testo completo
13
Yang, Min, e 杨敏. "Role of regulatory B cells in autoimmune disease". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48079832.
Testo completoAbstract (sommario):
Although B cells are well-known for their functions in antibody production and antigen presentation, certain B cell subsets have been recently identified as regulatory B cells to modulate immune responses through cytokine production. However, the microenvironmental factors involved in the induction of regulatory B cells remain largely uncharacterized. B cell-activating factor (BAFF), a member of TNF family cytokines produced by myeloid cells, is a key regulator for B cell maturation and function. However, it remains unknown whether BAFF plays a role in modulating the generation of regulatory B cells and how regulatory B cells suppress autoimmune pathogenesis. In this study, treatment with BAFF significantly increased IL-10-producing B cells in culture of mouse splenic B cells, an effect specifically abrogated by neutralization with TACI-Fc. BAFF-induced IL-10-producing B cells showed a distinct CD1dhiCD5+(B10) phenotype. Phenotypic analysis further indicated that these BAFF-induced B10 cells were marginal-zone (MZ)-like B cells. Interestingly, BAFF treatment in vivo also increased the number of IL-10-producingB cells in splenic MZ regions. Moreover, chromatin immunoprecipitation analysis revealed that BAFF activated the transcription factor AP-1 for binding to IL-10 promoter, demonstrating a novel function for BAFF in inducing IL-10 production. Furthermore, those BAFF-induced B10 cells exhibited significant suppressive effects on CD4+T cell proliferation and Th1 cytokine production in culture.
To explore whether these BAFF-induced B10 cells possess a regulatory function in suppressing autoimmune progression in vivo, collagen-induced arthritis (CIA) mouse model was employed. In vitro-expanded B10 cells and other control B cells were intravenously transferred into DBA/1J mice on the day of 2ndcollagen II (CII)-immunization. After adoptive transfer of BAFF-induced B10 cells, CII-immunized mice exhibited a delayed onset of arthritis and substantially reduced severity of clinical symptoms. The pathogenesis of IL-17-producing CD4+T cells (Th17) in the development of arthritis has been well-recognized, which has led me to test the hypothesis whether B10 cells ameliorate the development of arthritis via modulating Th17 cells. During the progression of CIA, IL-10-producing B cells were decreasedwhereasTh17 cells were significantly increased at the acute phase of CIA. Upon transfer of BAFF-induced B10 cells, a substantially reduction ofTh17 cells in both lymphoid organs and inflamed joints were detected. To verify whether B10 cells inhibit Th17 cell generation in culture, CFSE-labeled na?ve CD4+T cells were cocultured with B10 cells in Th17 cell polarization medium. It was found that B10 cells suppressed Th17 cell differentiation via reducing STAT3 phosphorylation and RORt expression. Although adoptive transfer of Th17 cells triggered the development of CIA in IL-17-/-DBA mice, cotransfer of B10 cells with Th17 cells profoundly delayed the onset of delayed the onset of arthritisand remarkably reduced the infiltration of Th17 cells in synovial fluid.
Taken together, I have identified a novel function of BAFF in the induction of IL-10-producing regulatory B cells. My findings that adoptive transfer of BAFF-expanded B10 cells can effectively suppress the development of experimental arthritisin mice via the inhibition of Th17 cell generation may contribute to the development of new therapeutic strategies in treating human rheumatoid arthritis.published_or_final_version
Pathology
Doctoral
Doctor of Philosophy
14
Wong, Tsz-yeung, e 王子揚. "Molecular characterization of IBDV-induced apoptosis in vitro using cDNA microarrays". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36375998.
Testo completo
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Hollis-Moffatt, Jade Elissa, e n/a. "Fine mapping and characterisation of an autoimmune diabetes locus, insulin dependent diabetes 21, (Idd21) on mouse chromosome-18". University of Otago. Department of Biochemistry, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070130.151657.
Testo completoAbstract (sommario):
Autoimmune disease is comprised of a wide variety of disorders characterised by a loss of self-tolerance towards a target organ or systemic region leading to its eventual destruction. Type 1 diabetes (T1D), autoimmune thyroid disease (AITD) and inflammatory bowel disease (IBD) are debilitating organ-specific disorders. These disorders arise from a combination of genetic factors and environmental triggers. A greater level of basic understanding of these disorders is required to delay and/or prevent their effects. Numerous autoimmune susceptibility loci have been implicated in the development of these disorders, but only a few causative genes have been identified. The aim of this project was to use comparative mapping between the human and mouse genomes to provide a greater understanding of the human autoimmune susceptibility locus, IDDM6, shown to be involved in a number of autoimmune disease conditions.
Hall et al., (2003) previously demonstrated that the mouse autoimmune diabetes locus, Idd21, on distal mouse chr18 contains orthology to human IDDM6, IDDM10, IDDM18 and rat Iddm3. As part of this project the Idd21 locus was fine mapped using the congenic mapping technique. Beginning with the consomic mouse strain, NOD.ABHChr18 (90Mb of Biozzi/ABH-derived diabetes-resistant chr18 introgressed onto a non-obese diabetic (NOD) genetic background), 13 NOD.ABHIdd21 congenic mouse strains were established. The diabetes incidences of these congenic mouse strains were statistically compared stepwise along mouse chr18 and Idd21 was fine mapped to at least four independent autoimmune diabetes loci. Idd21.1 and Idd21.2 were located on distal mouse chr18 in regions orthologous to human IDDM6 and rat Iddm3 and Idd21.3a/b and Idd21.4 were located on proximal mouse chr18 in regions orthologous to human IDDM18 and IDDM10 respectively. Candidate genes of notable interest include Map3k8, Spink5, Cd14, Dcc, Smad4 and 7, Miz1, Nfatc1 and Cd226.
Idd21.1 was further fine mapped. Beginning with the NOD.ABHD18Mit8-D18Mit214[(75-85.1Mb)] (Idd21.1) congenic strain (containing at least 10.1Mb of distal chr18 Biozzi/ABH diabetes-resistant DNA introgressed onto a NOD genetic background), seven subcongenic mouse strains were created. The diabetes incidence of these subcongenic mouse strains were statistically compared stepwise along mouse chr18 and Idd21.1 was fine mapped to at least three independent autoimmune diabetes loci; Idd21.11 (72.6-76.1Mb), Idd21.12a/b (75-76.1Mb and 80.6-81.4Mb) and Idd21.13 (84.8-85.1Mb). Candidate genes of interest in these regions include Dcc, Smad4 and 7, Miz1, Nfatc1, and Cd226.
Functional characterisation of the Idd21.1 locus was performed by adoptively transferring splenocytes from female NOD or NOD.ABHIdd21.1 mice into cohorts of severe combined immune deficient (scid) female mice, NOD/LtSz.Prkdc[scid] and NOD/LtSz.Prkdc[scid].ABHIdd21.1. There were two notable findings from this work. Firstly, NOD.ABHIdd21.1 splenocytes are not as effective as NOD at transferring diabetes to either NOD/LtSz.Prkdc[scid] (P = 0.0004) or NOD/LtSz.Prkdc[scid].ABHIdd21.1 (P = 0.0178), suggesting that Idd21.1 acquired immune cells are not as diabetogenic as NOD. Secondly, NOD/LtSz.Prkdc[scid].ABHIdd21.1 mice are more resistant to autoimmune attack than NOD/LtSz.Prkdc[scid] when injected with either NOD (P = 0.0015) or NOD.ABHIdd21.1 splenocytes (P = 0.0014), suggesting that Idd21.1 either acts by altering the intrinsic resistance of beta-cells to autoimmune attack or due to changes in the innate immune system.
Other NOD-based models of autoimmune disease, spontaneous and experimental autoimmune thyroiditis and spontaneous colitis, were also investigated to determine whether Idd21.1 is a common autoimmune disease locus. When bred onto the NOD.Cg-H2[h4] (thyroiditis model) genetic background Idd21.1 was demonstrated to increase the development of thyroiditis and reduce the incidence of insulitis in spontaneous (untreated) but not experimental (NaI-induced) NOD.Cg-H2[h4] mice. When bred onto the NOD.Cg-Il10[tm1Cgn] (colitis) genetic background Idd21.1 was demonstrated to inhibit the development of rectal prolapse in breeding female NOD.Cg-Il10[tm1Cgn] mice.
Data from this thesis demonstrate that the IDDM6 orthologous region in mouse, Idd21.1, contains several loci that influence autoimmune diabetes, thyroiditis and colitis in NOD-based mouse models. These findings are consistent with previous knowledge that IDDM6 is a common autoimmune susceptibility locus.
16
Litjens, Tom. "The molecular genetics of mucopolysaccharidosis type VI /". Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phl776.pdf.
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Fazeli, Claudia Fariba. "Molecular detection of grapevine leafroll associated closteroviruses (GLRaVs) and the genome organisation of GLRaV-1". 1998, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phf2868.pdf.
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18
Zhou, Li, e 周莉. "The molecular mechanisms of aristolochic acid nephropathy". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43224349.
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19
Li, Yick-yeung, e 李亦揚. "Molecular and phylogenetic analysis of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2(PCV2)". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29297102.
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20
Cheng, Tak Sum. "Molecular identification and characterization of novel osteoclast V-ATPase subunits". University of Western Australia. School of Surgery and Pathology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0068.
Testo completoAbstract (sommario):
[Truncated abstract] Osteoclasts are multinucleated giant cells responsible for the resorption of the mineralized bone matrix during the process of bone remodelling. During activation towards bone resorption, polarization of the osteoclast results in the formation of a unique plasma membrane, the ruffled border, the actual resorptive organelle of the osteoclast. Through this domain protons are actively pumped into the resorption lacuna creating an acidic microenvironment that favours the dissolution of the mineralized bone matrix. The polarised secretion of protons is carried out by the action of the vacuolar-type (H+)-ATPase (V-ATPase), composed of functionally and structurally distinct subunits of the V1 and V0 domains. The general structure of the V-ATPase complex is highly conserved from yeast to mammals, however, multiple isoforms for specific V-ATPase subunits do exist exhibiting differential subcellular, cellular and tissue-specific localizations. This study focuses on the molecular identification and characterization of V-ATPase accessory subunit Ac45 and the d2 isoform of the V0 domain d subunit in osteoclasts. Using the techniques of cDNA Subtractive Hybridization and DNA Micro-Array analyses respectively, the accessory subunit Ac45 and the d2 isoform of the V0 domain d subunit were identified in RAW264.7-cells derived OcLs. ... Using web-based computational predictions, two possible transmembrane domains, an N-terminus 'signal anchor' sequence and a C-terminus dilysine- like endoplasmic reticulum (ER) retention signal were identified. By confocal microscopy, EYFP-tagged e was found to localize to the perinuclear region of transfected COS-7 cells in compartments representing the ER and Golgi apparatus with some localization in late endosomal/lysosomal-like vesicles. ER truncation of e did not alter its subcellular localization but exhibited significantly weaker association with Ac45 compared to the wild-type as depicted by BRET analyses. Association with the other V0 subunits remain unaffected. This may hint at a possibility that Ac45 may play a role in the masking of the ER signal of e following it's incorporation into the V0 domain. Although no solid evidence for a role in the assembly of the mammalian VATPase have been established, subunit e still represents a potential candidate whose role in the V-ATPase complex requires further investigation. Collectively, the data presented in this thesis has provided further insight into the composition of the osteoclast V-ATPase proton pump by: 1) identifying an accessory subunit, Ac45 which shows promise as a potential candidate for the regulation and/or targeting of the V-ATPase complex in osteoclasts and truncation of its targeting signal impairs osteoclastic bone resorption; 2) identification and preliminary characterization of the d2 isoform of the V0 domain d subunit whose exact role in the V-ATPase complex and in osteoclasts remains to be determined, although its has been implicated to be essential for osteoclastic function; and 3) Preliminary characterization of subunit-e, a potential assembly factor candidate for the mammalian V-ATPase V0 domain.
21
Agenbag, Gloudi. "Molecular genetic analysis of familial breast cancer in South Africa". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/953.
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22
Vallée, Alexandre. "Molecular thermodynamic aspects of dissipative structures in oncology, inflammatory and degenerative processes of Central Nervous System diseases". Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT1409.
Testo completoAbstract (sommario):
Le métabolisme énergétique est le principal facteur déterminant de la viabilité cellulaire. Les maladies présentent de nombreuses anomalies métaboliques et énergétiques. En effet, les cellules altérées proviennent de procédés exergoniques et émettent de la chaleur vers leur environnement proche. De nombreux processus irréversibles peuvent se produire en modifiant le taux de production d'entropie. Ce niveau représente une quantité thermodynamique qui mesure ces processus irréversibles. Le niveau d'entropie est augmenté par plusieurs anomalies métaboliques et thermodynamiques dans les tumeurs cérébrales, les processus inflammatoires et les maladies neurodégénératives. Les travaux de recherche de cette thèse ont démontré et mis en évidence l'existence d'une diaphonie entre la voie canonique WNT/beta-caténine et le PPAR gamma qui joue un rôle majeur dans la reprogrammation du métabolisme de l'énergie cellulaire entre la phosphorylation oxydative, la glycolyse aérobie et la glycolyse anaérobie, dont le point d'équilibre de cette diaphonie entre ces voies moléculaires varie selon les maladies. Ces maladies sont des structures dissipatives, qui échangent de l'énergie ou de la matière avec leur environnement. Ce sont des systèmes ouverts, loin de l'équilibre thermodynamique qui opèrent sous un régime non linéaire évoluant vers des états non stationnaires. La thermodynamique loin de l'équilibre est une notion axée sur les rythmes circadiens. En effet, les rythmes circadiens participent directement à la régulation de cette diaphonie étudiée. Celle-ci représente une cible innovante dans le cadre l'imagerie moléculaire pour le diagnostic positif et différentiel de ces maladiesEnergy metabolism is the primary determinant of cellular viability. Diseases are the sites of numerous metabolic and energetic production abnormalities. Indeed, the altered cells are derived from exergonic processes and emit heat that flows to the surrounding environment. Many irreversible processes can occur through changing the rate of entropy production. This rate represents a thermodynamic quantity that measures these irreversible processes. Entropy rate is increased by several metabolic and thermodynamics abnormalities in brain tumors, inflammatory processes and neurodegenerative diseases. The research works of this thesis have demonstrated and highlighted the existence of a crosstalk between canonical WNT/beta-catenin pathway and PPAR gamma which plays a major role in the reprogramming of cellular energy metabolism between oxidative phosphorylation, aerobic glycolysis and anaerobic glycolysis, of which the equilibrium point of crosstalk between these molecular pathways varies according to tumor, inflammatory and neurodegenerative diseases. These diseases are dissipative structures, that exchange energy or matter with their environment. They are open systems, far-from the thermodynamic equilibrium that operate under non-linear regime evolving to non-stationary states. Far-from-equilibrium thermodynamics are notions driven by circadian rhythms. Indeed, circadian rhythms directly participate in regulating the crosstalk of the studied molecular pathways. This crosstalk represents an innovative therapeutic target, and molecular data usable for molecular imaging in both positive and differential diagnosis of these diseases
23
Barlow, S. L. "Temperature sensitivity of red blood cell physiology in Atlantic cod, Gadus morhua : comparative, molecular, evolutionary and environmental aspects". Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3004526/.
Testo completo
24
Ehrström, Sophia. "Aspects on chronic stress and glucose metabolism in women with recurrent vulvovaginal candidiasis and in women with localized provoked vulvodynia /". Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-169-2/.
Testo completo
25
Wang, Cathy Ting-Peng. "Molecular dissection of RANKL signaling pathways in osteoclasts". University of Western Australia. School of Surgery and Pathology, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0037.
Testo completoAbstract (sommario):
[Truncated abstract] Bone remodeling is intricately regulated by osteoclast-mediated bone resorption and osteoblast-mediated bone formation. The elevation in osteoclast number and/or activity is a major hallmark of several common pathological bone disorders including post-menopausal osteoporosis, osteoarthritis, Paget's disease, and tumour-mediated osteolysis. Receptor activator of nuclear factor kappa B ligand (RANKL) is a key cytokine for osteoclast differentiation and activation. The association of RANKL to its cognate receptor, RANK, which is expressed on osteoclast precursors and mature osteoclasts, is essential for osteoclast formation and activation. The intimate interaction between RANKL and RANK triggers the activation of a cascade of signal transduction pathways including NF-κB, NFAT, MAPK and PI3 kinase. Although osteoclast signaling pathways have been intensively studied, the precise molecules and signaling events which underlie osteoclast differentiation and function remain unclear. In order to dissect the molecular mechanism(s) regulating osteoclast differentiation and activity, this thesis herein explores the key RANKL/RANK-mediated signaling pathways. Four truncation mutants within the TNF-like domain of RANKL [(aa160-302), (aa160-268), (aa239-318) and (aa246-318)] were generated to investigate their potential binding to RANK and the activation to RANK-signal transduction pathways. All were found to differentially impair osteoclastogenesis and bone resorption as compared to the wild-type RANKL. The impaired function of the truncation mutants of RANKL on osteoclast formation and function correlates with their reduced ability to activate crucial RANK signaling including NF-κB, IκBα, ERK and JNK. Further analysis revealed that the truncation mutants of RANKL exhibited differentially affinity to RANK as observed by in vitro pull-down assays. ... It is possible that Bryostatin 1 acts via upregulation of a fusion mechanism as the RANKL-induced OCLs are morphologically enlarged, exhibiting increased nuclei number expressing high level of DC-Stamp. Furthermore, Rottlerin was shown to inhibit NF-κB activity, whereas Bryostatin 1 showed the opposing effects. Both inhibitor and activator were also found to modulate other key osteoclastic signaling pathways including NFAT and total c-SRC. These findings implicate, for the first time, Protein Kinase C delta signaling pathways in the modulation of RANKL-induced osteoclast differentiation and activity. Taken together, the studies presented in this thesis provide compelling molecular, biochemical and morphological evidence to suggest that: (1) RANKL mutants might potentially serve as peptide mimic to inhibit RANKL-induced signaling, osteoclastogenesis and bone resorption. (2) A cross talk mechanism between extracellular Ca2+ and RANKL exist to regulate on osteoclast survival. (3) TPA suppressed RANKL-induced osteoclastogenesis predominantly during the early stage of osteoclast differentiation via modulation of NF-κB. (4) Selective inhibition of Protein Kinase C signaling pathways involved in osteoclastogenesis might be a potential treatment method for osteoclast-related bone diseases. (5) Protein Kinase C delta signaling pathways play a key role in regulating osteoclast formation and function.
26
Cheng, King-yip, e 鄭競業. "APPL1 as a novel signaling mediator of adiponectin and insulin: molecular mechanisms and physiologicalimplications". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42182177.
Testo completo
27
Gu, Zhengming. "Studies on molecular mechanisms of transformation by human papillomavirus : the role of E6 and E5 oncogenes". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40133.
Testo completoAbstract (sommario):
The ability of the HPV-18 E6 gene to impair p53-mediated transcriptional activity induced by DNA damaging agents was investigated. It is demonstrated that E6 can abolish DNA damage induced p53-mediated transcription and that a region from amino acid residue 113 to 117 of HPV-18 E6 protein was necessary for E6 to direct the degradation of p53. The biological importance of the E6/p53 interaction was then directly examined in HPV-16 containing cervical carcinoma derived cells by introducing the monomeric p53 mutant which is resistant to E6 mediated degradation. The two major observations made from this study were: (i) loss of p53 activity plays an important role in maintaining the malignant phenotype of these cells with respect to cell proliferation; (ii) the monomeric p53 mutant without its C-terminal regulatory region was biologically functional with respect to impairing cell proliferation in HPV-16 containing cervical carcinoma derived cells. Finally, it was revealed that the cellular MAP kinase signal transduction pathway was more active in cells expressing the HPV-16 E5 gene than in control cells or cells expressing E6 and E7. These observations help to define the mechanisms by which HPV oncogenes contribute to the development and maintenance of the neoplastic phenotype.
28
Blignaut, Marguerite. "The molecular and biological characterisation of ORF5 of three South African variants of Grapevine Vitivirus A". Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2421.
Testo completoAbstract (sommario):
Thesis (MSc (Genetics))--University of Stellenbosch, 2009.Grapevine Vitivirus A (GVA), genus Vitivirus, family Flexiviridae is a well characterised single-stranded RNA virus that has been implicated in the grapevine diseases, Kober stem grooving and Shiraz disease. The virus infects both its host, Vitis vinifera and the experimental model plant, Nicotiana spp.. Biological studies performed on the virus in its herbaceous host, Nicotiana benthami- ana, revealed that many divergent variants of the virus exists in South Africa and can induce di erent symptoms in the model plant. Further molecular analysis divided the variants into three molecular groups based on molecular heterogeneity and nucleotide identity. The establishment of an infectious full-length cDNA clone of GVA contributed towards the elucidation of gene functions for 4 of the 5 open reading frames (ORF's), and indicated ORF5 as the pathogenicity determinant within the genome. Further studies also showed that ORF5 encodes for a nucleic acid binding protein that exhibits suppression activity of a plants' natural virus silencing mechanism. Many proteins that have previously been identi ed as the pathogenicity determinant within a viral genome have been found to encode for suppression activity. Although suppression activity has been elucidated within the ORF5 of the Italian cDNA clone of GVA, IS 151, no such study has yet been performed on the divergent South African variants of GVA. Three variants, GTR1-1, GTR1- 2 and GTG11-1, which represent each of the molecular groups (Group III, II and I), were selected for this study. The aim of this study was to visually elucidate suppression activity of RNA transgene silencing by the ORF5's of GTR1-1, GTR1-2 and GTG11-1 in a transient expression assays in transgenic N. benthamiana (line 16c). Pathogenicity studies for these variants were also performed. The ORF5 of the infectious full-length clone, GVA118, which can also serve as an expression vector, was deleted and provided with restriction enzyme sites into which the respective ORF5s and the marker genes, GFP and GUS could be cloned directionally. Infectivity, symptom development and systemic movement were compared between the di erent full length clones after co-in ltration in N. benthamiana. Preliminary results obtained in this study failed to visually indicate any suppression activity encoded by the ORF5 of GTR1-1, GTR1-2 and GTG11-1. The deletion of ORF5 within GVA118 was successful and rendered the infectious full length clone asymptomatic. Directional cloning of the ORF5 of GTR1-1 into the unique restriction enzymes provided previously, resulted in much milder symptoms than those observe for GTR1-2 and GTG11-1. No GFP and GUS accumulation could be detected. This study has established an infectious full-length cDNA clone, pBINSN-e35SGVA118 ORF5-1-1-pA, that can possibly induce much milder symptoms in the herbaceous host, N. benthamiana. This construct can be further characterised as a possible expression vector of foreign proteins in herbaceous hosts and grapevine.
29
Yogalingam, Gouri. "Molecular characterisation of feline MPS VI and evaluation of gene therapy /". Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phy54.pdf.
Testo completo
30
Lim, Ai Ing, e 林艾盈. "Shedding of kidney injury molecule-1 by kidney proximal tubular epithelial cells: the role of matrixmetalloproteinase-3". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49799745.
Testo completoAbstract (sommario):
Regardless of the original cause and etiology, the progression of kidney disease follows a final common pathway associated with tubulointerstitial injury, in which proximal tubular epithelial cells (PTEC) are instrumental. Kidney injury molecule-1 (KIM-1) is an emerging biomarker of kidney tubular damage. It is markedly expressed and released into urine in various animal models and human kidney diseases. This study aimed to explore the underlying mechanism regulating the release of KIM-1 by PTEC.
First, expression and release of KIM-1 by primary cultured human PTEC were examined. In quiescent PTEC, KIM-1 was detected at the plasma membrane and in the cytoplasm. A transwell system, in which PTEC were grown as monolayer on permeable membrane, was used to examine the polarized release of KIM-1. PTEC constitutively released KIM-1 from their apical surface, and the release was independent of gene expression or protein synthesis. The KIM-1 release process by PTEC was enhanced dose- and time-dependently by two important kidney injury mediators, human serum albumin (HSA) and tumor necrosis factor (TNF)-α, and was inhibited by the presence of broad-spectrum inhibitors of matrix metalloproteinases (MMP).
Second, the potential sheddases responsible for KIM-1 shedding were identified by quantitative polymerase chain reaction (PCR) array system, in which the gene expression of a panel of MMP members was screened. The gene expression of MMP-3, MMP-7 and MMP-9 was up-regulated by PTEC under HSA or TNF-α activation. Blockade experiments with synthetic MMP inhibitors or MMP gene knockdown by small interfering RNA transfection, revealed that the constitutive or accelerated KIM-1 shedding was mediated by MMP-3, but not MMP-7 or MMP-9. The role of MMP-3 in KIM-1 shedding was further defined by additional data showing the enhanced MMP-3 synthesis by HSA- or TNF-α-stimulated PTEC, and the up-regulated KIM-1 shedding by PTEC following exogenous MMP-3 treatment.
Third, the regulatory mechanism of MMP-3-mediated KIM-1 shedding was investigated. Treatment of PTEC with HSA or TNF-α up-regulated the reactive oxygen species (ROS) generation, and its kinetics ran parallel to the increase of KIM-1 shedding and MMP-3 synthesis. In addition, exogenous hydrogen peroxide dose-dependently induced KIM-1 shedding and MMP-3 synthesis, which were abolished by the presence of an oxidation inhibitor. These evidence suggest that ROS play an essential role in regulating the MMP-3-mediated KIM-1 shedding by PTEC.
Finally, a mouse model of acute kidney injury induced by renal ischemia and reperfusion (I/R) was established to translate the in vitro findings. Reduced kidney function and increased urinary KIM-1 level were observed in mice after renal I/R treatment. Strikingly, the expression of MMP-3 and KIM-1 in the I/R treated mice was most profound in the S3 segments of the proximal tubules, where is the most susceptible area to oxidative stress. Taken together, these in vivo data have further strengthened the distinct roles of ROS and MMP-3 in KIM-1 shedding during PTEC injury.
In conclusion, ROS generated by the injured PTEC activate MMP-3, which release the soluble KIM-1 through the ectodomain shedding process.published_or_final_version
Medicine
Master
Master of Philosophy
31
Bradshaw, Jeremy Peter. "A study of the structure of biological macromolecules". Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:e7d9dce0-b5f8-4e24-96c2-8fe79c273ae6.
Testo completo
32
Efstathiou, Jason Alexander. "The role of adhesion molecules in colorectal carcinogenesis". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670210.
Testo completo
33
Daniel, Rhonda W. "Dysregulation of microRNAs in Blood as Biomarkers for Diagnosing Prostate Cancer". VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3975.
Testo completoAbstract (sommario):
Prostate cancer is the most common noncutaneous cancer among men, yet current diagnostic methods are insufficient and more reliable diagnostic markers need to be developed. The answer that can bridge this gap and enable more efficient diagnoses may lie in microRNAs. These small, single stranded RNA molecules impact protein expression at the translational level and regulate important cellular pathways. Dysregulation of these small RNA molecules can have tumorigenic effects on cells and lead to many types of cancers.
Currently the Prostate-Stimulating Antigen (PSA) is used as a diagnostic marker for prostate cancer. However, many factors can elevate PSA levels such as infections and certain medications, consequently leading to false positive diagnoses and unnecessary concern and over treatment with dire outcomes for the patient. Even worse, are the chances of false negative diagnoses, which result in prostate cancer not being diagnosed until its later stages. Therefore, although the use of the PSA level has had its uses in the clinic, it has failed to sufficiently bridge the gap or to distinguish indolent from aggressive disease.
It has long been suggested in the literature that microRNAs are drastically altered throughout the course of cancer progression. Here, RNA sequencing was used to identify changes in miR expression profiles diagnostic for prostate cancer patients compared to non-patient controls. The RNA sequencing results were also used to identify normalization miRs to be used as endogenous controls. Confirmatory qRT-PCR was then used to corroborate these results for the top seven dysregulated miRs found from the RNA sequencing data. Data analysis of the Area Under the Curve (AUC) of the Receiver Operating Curves (ROC) of the selected miRs exhibited a better correlation with prostate cancer (AUC Range= 0.819- 0.950) than PSA (AUC of PSA=0.667). In summary, a panel of seven miRs are proposed, many of which have prostate specific targets, which would represent a significant improvement over current testing methods.
34
Ma, Ching-man, e 馬靜雯. "Molecular epidemiology and characterization of the receptor binding ofporcine circovirus type 2 (PCV2)". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38227204.
Testo completo
35
Lee, Kui-Joo. "The detection of double product break point in individuals with peripheral arterial disease". Virtual Press, 2000. http://liblink.bsu.edu/uhtbin/catkey/1178340.
Testo completoAbstract (sommario):
Peripheral arterial disease (PAD) is a common manifestation of stenoses and occlusions of the arteries of the lower extremities. Clinically, PAD is an important effect on functional ability, and quality of life because symptomatic patients are typically able to walk less than one to three blocks before rest is required.The double product break point (DPBP), also defined as the oxygen consumption at which the first portion of nonlinear increase in rate pressure product (systolic blood pressure X heart rate) begins has been identified to determine the anaerobic threshold during exercise test. The purpose of this study was to determine whether the DPBP could be detected in patients with PAD during a symptom-limited GXT on the motor-driven treadmill. Six male subjects (68.2 ± 6.5 yrs) with history of diagnosis of PAD participated in this study. Double product (DP) was assessed every 15 seconds during the test via the Kyokko Bussan CM-4001 automated blood pressure unit. The DPBP and VT were determined visually by three blinded observers. The mean values of Peak V02 and maximal heart rate were 19.4 ± 5.8 (ml/kg/min) and 130 ± 13 (bpm), respectively. In 4 of the six exercise tests in the present study, the DPBP and the VT were determined. The mean V02 at the DPBP and the VT were 15.7 ± 2.6 ml/kg/min and 14.2 ± 0.6 ml/kg/min, corresponding to 73 ± 7.2 and 74.5 ± 5.4 % respectively. In 3 of the six exercise tests both of the DPBP and VT were determined. The Mean V02 at the DPBP and VT were 14.6 ± 1.8 and 14.3 ± 0.7, respectively. The difference of the mean VO2 at the VT and DPBP was -.0.33 ml/kg/min.In conclusion, the results of the present study suggest that the DPBP can be identified and used as a useful marker to determine the functional performance in PAD patients. Walking time or distance measurement depends on the patient's perception of the pain. Thus, this study provides an objective way to appraise the functional performance and therapeutic results obtained from the exercise training in PAD patients, and provides a reference for exercise prescription for this population.School of Physical Education
36
Jing, Yu, e n/a. "The acute effects of lithium on the rat kidney". University of Otago. Department of Physiology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080930.145652.
Testo completoAbstract (sommario):
The aim of the experiments reported in the present work was: first, to generate a rat model of lithium-induced nephrogenic diabetes insipidus (NDI), and, second, to use this to test the hypothesis that the effects of lithium were far more reaching than merely the inhibition of vasopressin induced translocation and synthesis of the water channel protein AQP2. Specifically, the effect of lithium on the abundance and distribution of the other water channel proteins, AQP1, AQP3 and AQP4 was investigated. It was found that AQP3 protein abundance was significantly reduced in the renal medulla while AQP4 was not affected. In addition, it was further hypothesized that, given the known effects of lithium on the urea transporter UT-A1 and on sodium channels and transporters, the renal medullary osmotic gradient would be dissipated by lithium. This was examined indirectly by determining the amounts of organic osmolytes in the renal medulla of rats with lithium-induced NDI. Myo-inositol was found to be 85 � 9 mmol kg⁻1 protein in the NDI rats, a reduction of 38% compared with control values, sotbitol fell from 35� 9 mmol kg⁻� in the control rats to 2.5 � 0.5 mmol kg⁻�, and glycerophosphorylcholine levels in the experimental animals were 91 � 18 mmol kg⁻� protein compared with 372 � 72 mmol kg⁻� in the controls. In addition, betaine decreased to 38 � 2 mmol kg⁻� protein from 69 � 10 mmol kg⁻� protein in the control. The urea content of the medulla was found to have fallen from 2868 � 558 mmol kg⁻� protein to 480 � 105 mmol kg⁻� protein. These data indicated that indeed the medullary osmotic gradient, the driving force for AVP-dependent fluid reabsorption in the kidney was greatly reduced during lithium-induced NDI.
Thirdly, it was proposed that the sodium-channel blocker, amiloride, by acting to prevent lithium entry into the cells of the collecting duct, should ameliorate or abolish the adverse effects of lithium on the kidney. Treatment of rats with established NDI, with amiloride, reversed to a large extent the reduction in aquaporin protein expression and re-established the medullary osmotic gradient, as assessed by the ability of treated rats to concentrate their urine, and by the rise in amounts of medullary osmolytes. Administration of 0.5 mmol l⁻� amiloride to lithium-treated rats led to medullary AQP2 and AQP3 protein abundance increasing by 82% � 16% and 110% � 4% of the control level respectively. The content of urea in the medulla also increased to 2474 � 557 mmol kg⁻� protein.
Finally, since in humans it is known that the chronic effect of lithium on the kidney is to cause cortical fibrosis and renal failure, microarray studies were commenced to look for evidence of early changes in gene activity in response to lithium-administration. The results showed that 77 genes were either up- or down-regulated, in particular, genes that are involved in the apoptosis pathway.
In the light of these results it is plausible to suggest that the acute renal effects of lithium to induce NDI can be effectively mitigated, and reversed, by administration of amiloride. Whether this can serve to offset the chronic effects of lithium on the kidney awaits further investigation.
37
李亦揚 e Yick-yeung Li. "Molecular characterization and co-infection of North American and European porcine reproductive and respiratory syndrome virus in HongKong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B39558174.
Testo completo
38
Ockert, Candice. "Identification of molecular markers for the diagnostic identification of the intracellular prokaryote associated with the appearance of withering syndrome in the abalone Haliotis midae". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1148.
Testo completo
39
Morren, Carel-Jan Hendrikus. "Die bepaling van sekere plaagdoderreste in die bloed van plaaswerkers op appelplase in die Elgin-distrik". Thesis, Cape Technikon, 1994. http://hdl.handle.net/20.500.11838/1478.
Testo completoAbstract (sommario):
Thesis (Masters Diploma (Technology)--Cape Technikon, Cape Town,1994Pesticides are generally used in south-Africa for the control of various pests; from insects and fungi to weeds. The agricultural industry is probably the biggest user of pesticides and therefore workers in this part of the labour force have the biggest risk of being exposed to the hazards of these essential products. During the 1988/89 deciduous fruit season the deciduous fruit industry earned approximately R1000 million in foreign exchange. It is therefore very important for this industry to produce fruit of high quality in a very competitive market. Of the total deciduous exports, apples comprised approximately 62,5%. The EIgin-Grabouw area is the biggest producer of apples. This industry is clearly very dependant on pesticides to protect its crops against pests. From time to time farm - workers are exposed to pesticides, a study was therefore performed to access the levels of exposure of farm workers. Blood and urine samples were collected in a comprehensive biological monitoring program in the Elgin area to determine, uusing clinical tests, the level of exposure to pesticides. It was decided later that the determination of pesticide residues in blood would form part of this main study. Other tests included serum and red cell cholinesterase. Samples were collected during August (start of spraying season), November (midseason) and February (end of spraying season). A multi-residue method was developed to extract organophosphate and organochlorine pesticides in whole blood. Although various methods exist, they allow only for the extraction of either organophosphates or organochlorines and not multi-residue extractions. This multi-residue method is based on the liquid/liquid extraction of a blood/Celite/ethanol mixture to extract the following pesticides: Azinphos-methyl, Chlorpyrifos, Endosulfan, Methidathion and Prothiophos. The pesticide residue levels were determined on gas chromatographs equipped with DB-5 and DB-2I0 capillary columns and flame photometric-, electron capture- and nitrogen/phosphorous detectors. The results were confirmed on a gas chromatograph with mass-selective detector in selective ion mode. Of the 402 blood samples analysed, 23 samples showed positive for organophoshates and 29 for organochlorines, and were sent for analysis on the mass spectrometer. Of those samples only one could be positively identified. The presence of the pesticide Endosulfan-B was confirmed. The confirmation of the pesticides was complicated by interfering substances that leached from the rubber stoppers of the collection vessels into the blood. Although the study showed that for practical purposes no pesticides were present, other important information was obtained about the handling and analyses of blood samples for pesticides.
40
Maeda, Emiko. "The Effects of Green Smoothie Consumption on Blood Pressure and Health-Related Quality of Life: A Randomized Controlled Trial". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/974.
Testo completoAbstract (sommario):
Chronic diseases are among the leading causes of death globally, and as much as 80% of these deaths are reported to be preventable with proper diet and lifestyle. Although extensive research has demonstrated that the increased consumption of fruits and vegetables offers protective health effects from many chronic illnesses, populations in both developed and developing nations consistently fall short of the recommended intake of 5 or more servings a day. This study investigated the effects of daily consumption of Green Smoothies for 4 consecutive weeks on blood pressure and health-related quality of life. Green Smoothies are a blended drink consisting of fruit, leafy greens and water. The study was a randomized controlled trial with a final sample of 29 volunteer participants. Data were collected at baseline and post-intervention and included anthropometric and physiologic measures, as well as a nutrition survey. The treatment group demonstrated trends toward improvements in waist circumference (p = 0.026), waist-to-hip ratio (p = 0.05), and symptoms of burden linked to diet (p = 0.04), small intestine (p = 0.04), large intestine (p = 0.05), and mineral needs (p = 0.04). Despite the lack of statistically significant reductions in blood pressure, the trend toward improvements in waist circumference and waist-to-hip ratio are considered to be useful and informative of health risk. Thus, the results of this study provide preliminary support for the consumption of Green Smoothies as a possible primary prevention effort for chronic conditions. It may also help to reduce health risks or even reverse the effects of chronic conditions.
41
Hou, Tianfei. "MECHANISMS AND POTENTIAL THERAPY ON DISRUPTED BLOOD PRESSURE CIRCADIAN RHYTHM IN DIABETES". UKnowledge, 2018. https://uknowledge.uky.edu/pharmacol_etds/26.
Testo completoAbstract (sommario):
Arterial blood pressure (BP) undergoes a 24-hour oscillation that peaks in the active day and reaches a nadir at night during sleep in humans. Reduced nocturnal BP fall (also known as non-dipper) is the most common disruption of BP circadian rhythm and is associated with increased risk of untoward cardiovascular events and target organ injury. Up to 75% of diabetic patients are non-dippers. However, the mechanisms underlying diabetes associated non-dipping BP are largely unknown. To address this important question, we generated a novel diabetic db/db-mPer2Luc mouse model (db/db-mPer2Luc) that allows quantitatively measuring of mPER2 protein oscillation by real-time mPer2Luc bioluminescence monitoring in vitro and in vivo. Using this model, we demonstrated that the db/db-mPer2Luc mice have a diminished BP daily rhythm. The phase of the mPER2 daily oscillation is advanced to different extents in explanted peripheral tissues from the db/db-mPer2Luc mice relative to that in the control mice. However, no phase shift is found in the central oscillator, the suprachiasmatic nucleus (SCN). The results indicate that the desynchrony of mPER2 daily oscillation in the peripheral tissues contributes to the loss of BP daily oscillation in diabetes.
Extensive research over the past decades has been focused on how the components of food (what we eat) and the amount of food (how much we eat) affect metabolic diseases. Only recently has it become appreciated that the timing of food intake (when we eat), independent of total caloric and macronutrient quality, is also critical for metabolic health. To investigate the potential effect of the timing of food intake on the BP circadian rhythm, we simultaneously monitored the BP and food intake profiles in the diabetic db/db and control mice using radiotelemetry and BioDAQ systems. We found the loss of BP daily rhythm is associated with disrupted food intake rhythm in the db/db mice. In addition, the normal BP daily rhythm is altered in the healthy mice with abnormal feeding pattern, in which the food is available only during the inactive-phase. To explore whether imposing a normal food intake pattern is able to prevent and restore the disruption of BP circadian rhythm, we conducted active-time restricted feeding (ATRF) in the db/db mice. Strikingly, ATRF completely prevents and restorers the disrupted BP daily rhythm in the db/db mice. While multiple mechanisms likely contribute to the protection of ATRF on the BP daily rhythm, we found that ATRF improves the rhythms of energy metabolism, sleep-wake cycle, BP-regulatory hormones and autonomic nervous system (ANS) in the db/db mice. To further investigate the molecular mechanism by which ATRF regulates BP circadian rhythm, we determined the effect of ATRF on the mRNA expressions of core clock genes and clock target genes in the db/db mice. Of particular interest is that we found among all the genes we examined, the mRNA oscillation of Bmal1, a key core clock gene, is disrupted by diabetes and selectively restored by the ATRF in multiple peripheral tissues in the db/db mice. More importantly, we demonstrated that Bmal1 is partially required for ATRF to protect the BP circadian rhythm.
In summary, our findings indicate that the desynchrony of peripheral clocks contributes to the abnormal BP circadian pattern in diabetes. Moreover, our studies suggest ATRF as a novel and effective chronotherapy against the disruption of BP circadian rhythm in diabetes.
42
Lucca, Julie Ann. "ASSOCIATIONS BETWEEN ALCOHOL CONSUMPTION AND FASTING BLOOD GLUCOSE IN YOUNG ADULTS". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1057.
Testo completoAbstract (sommario):
Current research shows moderate alcohol consumption is associated with decreased risk of diabetes and excessive consumption or binge drinking can cause insulin resistance and diabetes. In 2010, diabetes was the seventh leading cause of death in the United Statesand was responsible for significant health complications: blindness, kidney failure, and limb amputations, and is a large national economic burden. Fasting blood glucose (FBG) is a tool used to help diagnose diabetes. Abnormally high FBG, ≥100 mg/dl, is indicative of diabetes and pre-diabetes. Few studies have observed diabetic prevalence among young adults or college students. Studying young adults can help provide added information about early risk factors for diabetes and pre-diabetes, facilitating public health efforts to stem the rising tide of the diabetes epidemic. This study aimed to research the associations between alcohol consumption (numbers of days alcohol consumed in the past month and binge alcohol consumption in the past month) and FBG in a college population as part of the FLASH cohort study. FBG levels were measured in 141 young adult participants and alcohol consumption was determined by self report. Other individual-level characteristics and potential confounding variables were also collected. The association between alcohol consumption and FBG followed a J-shaped curve whereby students who reported drinking 6-8 days within the last 30 days showed significantly lower FBG levels than those who did not drink and those who consumed alcohol on nine or more days (p=0.04). Binge drinking did not have a significant association with FBG (p=0.4). Sex and body mass index were also significantly associated with FBG. In conclusion, moderate frequency of alcohol consumption is found to have an inverse relationship with FBG and excessive drinking can reverse these effects.
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Zhian, Samaneh. "Molecular Genetic Analysis of CRELD1 in Patients with Heterotaxy Disorder". PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/410.
Testo completoAbstract (sommario):
Heterotaxy refers to the abnormal arrangement of internal organs in relation to each other. Model organism studies have shown that functions of more than eighty genes are required for normal asymmetric left-right organ development. CRELD1 has been shown to be necessary for proper heart development and mutations in CRELD1 are known to increase risk of cardiac atrioventricular septal defects (AVSD). AVSD is the most common form of heart defect associated with heterotaxy, and we have previously shown that some individuals with heterotaxy-related AVSD have mutations in CRELD1. Therefore, we propose to examine the CRELD1 gene in a large sample of patients with heterotaxy syndrome. Our goal was to determine if mutations in CRELD1 are associated with other manifestations of heterotaxy or if they only coincide with AVSD. To achieve this aim, a sample size of 126 patients with heterotaxy collected by Dr. Belmont, Baylor college of Medicine, Texas, with approximately 66% of the heterotaxy population with different types of heart defects, were used for this study. Ten exons, promoter regions, and regulatory elements in the introns of CRELD1 gene were sequenced and analyzed. In this study three different heterozygous missense mutations in CRELD1 were identified in three unrelated individuals. These three individuals were diagnosed with different forms of heart defects in addition to AVSD. All three mutations were identified in highly conserved regions of CRELD1 possibly altering the CRELD1 properties. This demonstrates that mutations in CRELD1 may increase the susceptibility of AVSD in heterotaxy population. This information can help us to find factors effecting disease susceptibility in heterotaxy patients since the heart defects are a complex trait with incomplete penetrance.
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Filkowski, Jody, e University of Lethbridge Faculty of Arts and Science. "The effect of pathogens on plant genome stability". Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, 2004, 2004. http://hdl.handle.net/10133/254.
Testo completoAbstract (sommario):
Resistance (R) genes, a key factor in determining the resistance of plants, have been shown often to be highly allelic entities existing in duplicated regions of the genome. This characteristic suggests that R-gene acquisition may have arisen through frequent genetic rearrangements as a result of transient, reduced genome stability. Tabacco plants transgenic for a recombination construct exhibited reduced genome stability upon infection with a virulent pathogen (tobacco mosaic virus). The reduced genome stability manifested as an increase in recombination events in the transgene. Such increases were observed following a virulent pathogen attack. This increase in recombination was shown to be systemic and was observed prior to systemic viral movement suggesting the presence of a systemic recombination signal. Further molecular analyses revealed that specific R-gene loci experience a large frequency of rearrangements following a virulent pathogen encounter. The possible targeting of instability to R-gene regions may be controlled through epigenetic processes, in particular, DNA methylation.xiii, 119 leaves ; 29 cm.
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Arthur, Jane Louise. "Analysis of the latency associated transcripts of Herpes simplex virus type 1 /". Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09pha788.pdf.
Testo completo
46
Mkhize, Thokozani M. "The detection of cherry leaf-roll nepovirus and the use of molecular markers for germplasm identification in walnuts (Juglans regia L.)". Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53624.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2003.ENGLISH ABSTRACT: The aim of this study was to combine two common diagnostic tools: serological kits and genetic fingerprinting to identify cherry leaf-roll nepovirus (CLRV), and to establish a marker system to characterize walnut germplasm. The detection of plant viruses is difficult. Restrictions are imposed for quarantine purposes on the importation of plant material from foreign countries. Modern techniques such as a PCR based screening method for CLRV are required to ensure material do not harbour viruses. A primer pair was designed to amplify a 430 bp non-coding homologous region. For the choice of primers, consensus sequences were considered and areas where the sequence data shared 98.5% homology, were chosen. The sensitivity of this detection method was 100-fold higher when compared to the ELISA. The PCR fragment was verified by nucleotide sequencing. AFLP technology was used to identify polymorphic fragments for 6 walnut cultivars and a rootstock, and SCARs were developed from AFLP specific bands. The AFLP technique distinguished all the walnut cultivars and the rootstock. However, conversion of AFLP fragments to SCAR markers for the development of a simple robust technique for cultivar discrimination, was not successful. Using 27 AFLP primer combinations, polymorphic fragments as high as 47.8% were scored. The reason for the lack of efficient conversion was as the result of the AFLP technique. The SCAR primers were generated from sequences internal to the AFLP primers but the specificity of the markers was in the AFLP primers not the internal sequence. In this study using AFLP, walnut cultivars were found to be closely related. The AFLP primer pairs used, provided polymorphic fragments. From these fragments, 7 SCAR markers were developed. It was expected that these SCARs derived from the AFLP markers would detect slight differences between cultivars. The Paradox SCAR marker was the only one that could divide the cultivars into two groups. When Chandler SCAR products were digested with the restriction enzyme Rsal, the same banding pattern as that of Paradox SCAR products was observed.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om twee algemene opsporingstegnieke te kombineer: serologiese toetsstelle en genetiese vingerafdrukke om cherry leaf-roll nepovirus (CLRV) te eien en om In merkersisteem te ontwikkel wat okkerneut kiemplasma kan karakteriseer. Die opsporing van plant virusse is baie moeilik. As gevolg van kwarantyn vereistes, word daar beperkinge geplaas word op die invoer van plant materiaal vanuit die buiteland. Moderne tegnieke soos hierdie een wat op PKR berus, word benodig om te verseker dat CLRV nie in plantmateriaal teenwoordig is nie. In Stel inleiers is ontwerp wat In 430 bp nie-koderende homoloë area amplifiseer. Hiervoor is konsensus volgordes bestudeer en slegs die volgordes wat 98,5% homologie getoon het, is gekies. In vergelyking met ELISA was die sensitiwiteit van hierdie deteksie metode 100 maal beter. DNA volgordebepaling is op die resulterende fragment gedoen om die PKR produk te verifieer. AFLP tegnologie is gebruik om polimorfiese fraqmente vir 6 okkerneut kultivars en 'n onderstok te identifiseer en SCARs is uit hierdie fragmente ontwikkel. Die AFLP tegniek kon tussen al die okkerneut kultivars en die onderstok onderskei. Die omskakeling van die AFLP fragmente in SCAR merkers om sodoende In eenvoudige kragtige tegniek vir kultivar onderskeiding te ontwikkel, was egter nie suksesvol nie. Met die gebruik van 27 AFLP inleier kombinasies, kon polimorfiese fragmente van so hoog as 47.8% verkry word. Die rede hoekom omskakeling onsuksesvol was lê by die aard van die AFLP tegniek. Die SCAR inleiers is ontwikkel uit volyordes intern tot die AFLP inleiers, maar die spesifisiteit van die merkers het juis in die AFLP inleiers gelê en nie in die interne volgordes nie. In hierdie studie, met die gebruik van AFLP, is gevind dat okkerneut kultivars baie naby verwant is. Die AFLP inleierstelle wat gebruik is, het polimorfiese fragmente gelewer. Uit hierdie fragmente is 7 SCAR merkers ontwikkel. Daar is verwag dat die SCARs wat uit die AFLP merkers ontwikkel is, klein verskille tussen kultivars sou opspoor. Dit was egter net die Paradox SCAR merker wat die kultivars in twee groepe kon verdeel. Restriksie ensiem vertering met Rsalop die Chandler SCAR produkte het dieselfde bandpatrone as die van die Paradox SCAR produkte gelewer.
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Mazaheri, Lucy. "Development of a Molecular Marker to Track APA G40199 Introgression in Common Bean for Bruchid Resistance". Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/29300.
Testo completoAbstract (sommario):
In common bean (Phaseolus vulgaris), the main seed storage pests are the bruchid beetles. Damage done to the seed by the larvae has a large impact on seed quality and yield. Arcelin (ARC), phytohaemagglutinin (PHA), and α-amylase inhibitor (α-AI) are linked seed storage proteins that form the APA locus on chromosome Pv04 and are associated with resistance. A major breeding objective is to introduce bruchid resistance into common bean from a resistant tepary genotype, G40199, by introgressing the resistant APA locus into susceptible common bean backgrounds. Here we developed a molecular marker that tracks the introgression. A set of PCR primers to the α-amylase inhibitor locus amplified a DNA fragment that showed a 45 base pair insertion in the middle of a lectin Leg_b domain. This enhanced locus characterization and insertion/deletion marker may preclude the need for bruchid resistance screening early in the breeding.United States. Agency for International Development
United States. Global Hunger and Food Security Initiative (Cooperative Agreement No. EDH-A-00-07-00005-00)
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ELIAS, CAROLINE C. "Obtenção, caracterizações estruturais e atividade enzimática do sítio C-catalítico da enzima conversora de angiotensina I - região ALAsup(959) até SERsup(1066)". reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/25320.
Testo completoAbstract (sommario):
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-12-17T09:13:12Z
No. of bitstreams: 0Made available in DSpace on 2015-12-17T09:13:12Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Viljoen, Janet Erica. "Strength training and cardiovascular risk post-menses, with particular emphasis on the plasma lipoproteins: a controlled trial". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013578.
Testo completoAbstract (sommario):
Introduction: Cardiovascular disease affects a greater proportion of females than it does males, and is responsible for an estimated 52 percent of female deaths per annum, globally. Due to the loss of oestrogen associated with the menopause, post-menopausal females are at elevated risk for hypercholesterolaemia which is a primary risk factor for cardiovascular disease. It has not yet been conclusively established whether resistance training can be used to ameliorate hypercholesterolaemia. Aim: This randomized controlled trial investigated what effect 12 weeks of progressive resistance training would have on plasma lipoproteins in a sample of post-menopausal females. Methods: Caucasian women (n=30 intervention and n=18 control) between the ages of 55 and 65 years who were not taking hormone replacement therapy were recruited. Participants did not smoke, were sedentary, were not taking any form of cholesterol-lowering medication, had at least one cholesterol abnormality at baseline but were otherwise healthy and able to participate in a strength training programme. Following extensive medical pre-screening, information dissemination and voluntary consent, the sample was divided into two groups. The exercise sample undertook 12 weeks of resistance training on five days of the week. The control group received no intervention. Measurements were obtained at baseline and every four weeks thereafter and included measures of strength, biochemistry (oestradiol, testosterone, full blood lipid profile, glycated haemoglobin and sex hormone binding globulin), anthropometry, morphology and self-reports (dietary intake, energy expenditure and the profile of mood states questionnaire). Results: There was no change to low density lipoprotein cholesterol, high density lipoprotein cholesterol, triglyceride content or total cholesterol as a result of the intervention. Back, chest and leg strength increased significantly (p<0.01) (increases of 51 percent, 35 percent and 43 percent respectively from baseline); waist circumference dropped (p<0.01) by 5 percent overall and diastolic blood pressure decreased significantly (-9 percent, p<0.01) in the exercise cohort but no change was noted in the matched control. Dietary intake, energy expenditure and body mass remained unchanged in both samples. Morphology (sum of skinfolds, estimated body fat content and girth measures) did not change and nor did other biochemical measures (HbA1c and sex hormone binding globulin) or hormone levels (oestradiol and testosterone). Despite the lack of overall change, an important finding was noted in individual results where a clear indication of ‘responders’ and ‘non-responders’ emerged. Conclusion: Overall mean results suggest that 12 weeks resistance training undertaken five days of the week was ineffective in reducing hypercholesterolaemia in this sample. Despite there being no identifying characteristics determined in this sample, evidence of responders and non-responders to the intervention indicates that reliance on mean data may not be sufficient when analysing data from exercise interventions. Therefore, while progressive resistance training had a positive effect on strength, waist circumference and diastolic blood pressure, it did not positively influence the plasma lipoproteins in this cohort of post-menopausal women.Maiden name: Kelly, Janet Erica
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Christians, Gillian Eleanore. "Identification of molecular markers linked to woolly apple aphid (Eriosoma lanigerum) (Hausmann) resistance in apple". Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53454.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2003.ENGLISH ABSTRACT: Apple (Malus x domestica Borkh.) is an important horticultural crop worldwide and in the Western Cape. The income generated from apple and other deciduous fruit production amounts to approximately 25% of the gross total value of horticultural production in the Western Cape. Unfortunately diseases and pests adversely affect fruit production in this region. Woolly apple aphids (Eriosoma lanigerum L. (Hausmann» have a significant effect on the apple industry in the Western Cape. Damage caused is two-fold, occurring aerially and terrestrially. Insects colonise the plants, feeding off the phloem sap. Aphid infestation around the root system results in repeated infestation of the foliage as it serves as a reservoir of aphids. In extreme cases, the apple cores are also infested, thus affecting the sale of apples. In 1962, Northern Spy was identified as a woolly apple aphid resistant rootstock and has since then formed the basis for traditional rootstock breeding programmes. The Er1 gene in Northern Spy confers resistance. According to one report, the natural resistance of Northern Spy was overcome in South Africa in 1968, but this was not confirmed in an independent study. The main objectives of this study was to firstly identify molecular markers more closely linked to the woolly apple aphid resistance gene, Er1, than existing markers, by applying AFLP technology to selected seedlings, identified to be resistant by conventional phenotyping. If identified, these markers can be incorporated into existing breeding programmes. Secondly, previously identified RAPD and SCAR markers were tested to determine their applicability in local populations for use in breeding programmes. Ultimately the segregation of the Er1 gene in South African populations can be determined if tightly linked markers are identified. Three families were derived from crosses of each of three resistant genotypes, namely Northern Spy, Rootstock 5 and Russian Seedling and a susceptible cultivar, Braeburn. For the three successive years of the study, each resistant genotype was allowed to cross-pollinate in isolation with the susceptible parent. Two hand-pollinated families, Russian Seedling x Liberty and Russian Seedling x Northern Spy, were also included in the study. The amplified fragment length polymorphism (AFLP) technique was used in an attempt to identify markers in the resistant and susceptible seedlings. No markers were identified using this technique. Known sequence characterised amplified regions (SCAR) and random amplified polymorphic DNA (RAPD) markers were used due to their suitability in marker-assisted selection for woolly apple aphid resistance. Varying results were obtained with these markers and no conclusive information was acquired with regard to the segregation of the Er] gene in any of these rootstocks and crosses. This underlines the need for the development of markers that can readily be applied in local breeding programmes. The identification and integration of such markers will greatly benefit the local and world wide apple industries.
AFRIKAANSE OPSOMMING: Appels (Malus x domestica Borkh.) is wêreldwyd en in die Wes-Kaap 'n belangrike landbougewas. Inkomste gegenereer deur appels en ander sagtevrugte vorm bykans 25% van die bruto inkomste uit vrugte in die Wes-Kaap. Siektes en insekpeste verlaag egter die produksie van vrugte in hierdie streek. Appelbloedluise (Eriosoma lanigerum L. (Hausmann» het 'n groot invloed op appelproduksie in die Wes-Kaap. Skade word bogronds en ondergronds aangerig. Insekte koloniseer die plant en leef op floeëmsap. Besmetting van die wortels lei tot herhaalde besmetting van bogrondse dele aangesien die insekte aanteelop die wortels. In uiterste gevalle word die vrugte geaffekteer, wat vrug-verkope beïnvloed. 'Northern Spy' is in 1962 geïdentifiseer as 'n onderstam met natuurlike weerstand teen appelbloedluis en het vir lank die basis gevorm vir tradisionele telingsprogramme. Weerstand word verleen deur die Erf geen. Volgens een verslag is die natuurlike weerstand van Northern Spy egter in 1968 in Suid-Afrika oorkom, maar dit is nog nie in 'n onafhanklike studie bevestig word nie. Die hoof doelstellings van hierdie studie was om eerstens deur middel van die AFLP tegniek molekulêre merkers te identifiseer wat nouer gekoppel is aan die appelbloedluis weerstandsgeen, En, as bestaande merkers. Hierdie tegniek is toegepas op saailinge wat deur konvensionele fenotipering geselekteer is. Indien merkers suksesvol geïdentifiseer is, kan dit in bestaande telingsprogramme geïntegreer word. Tweedens is bestaande RAPD en SCAR merkers ook getoets om hul toepaslikheid te bepaal vir gebruik in plaaslike teelprogramme. Oplaas sal die segregasie van die Erf geen in Suid- Afrikaanse populasies ook deur middel van nou gekoppelde merkers bepaal kan word. Kruisings van elk van die drie weerstandbiedende genotipes, naamlik 'Northern Spy', 'Rootstock 5' en 'Russian Seedling', en die vatbare kultivar, 'Braeburn' , het drie families daargestel. Elke weerstandbiedende genotipe is toegelaat om in isolasie te kruisbestuif met die vatbare ouer. Twee hand-bestuifde families, 'Russian Seedling' x 'Liberty' en 'Russian Seedling' x 'Northern Spy', is in 'n latere stadium van die studie ingesluit. Die AFLP tegniek is gebruik vir die identifikasie van polimorfiese merkers tussen vatbare en weerstandbiedende populasies. Geen merkers is egter geïdentifiseer nie. Bestaande SCAR en RAPD merkers is vervolgens gebruik om te bepaal of hulle geskik is vir gebruik in merker-bemiddelde seleksie vir appelbloedluis weerstand. Wisselende resultate is verkry ten opsigte van amplifikasie, herhaalbaarheid van resultate was swak en geen onweerlegbare bewyse oor die segregasie van die Erfgeen is bekom nie. Dit beklemtoon die noodsaaklikheid om merkers wat geredelik in plaaslike teelprogramme toegepas kan word, te ontwikkel. Die identifikasie en integrasie van sulke merkers sal die plaaslike en wêreld-wye appel industrieë aansienlik bevoordeel.