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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.
31

Predictors of glycaemic control in Type 2 diabetes patients at Helen Joseph Hospital diabetic clinic

Roux, Daniel Jacobus January 2014 (has links)
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Internal Medicine Johannesburg, 2014 / Background Diabetes is a global epidemic. The International Diabetes Federation estimates that there are at least 285 million diabetics worldwide and this is estimated to grow to over 440 million by 2030 1 . A study was conducted at the Helen Joseph Hospital Diabetic clinic in an attempt to identify predictors of glycaemic control and to compare the level of care to the 2012 Society for Endocrinology, Metabolism and Diabetes of South Africa (SEMDSA) guidelines. Methods Patients were recruited from the Helen Joseph Hospital Diabetic clinic. To be included the patient had to be part of the coloured (mixed race) community, be willing to give informed consent, be older than 18 years, have an HBA1C taken within 6 months, have a diagnosis of Type 2 diabetes mellitus and be a clinic attendee for at least 1 year. Pregnant patients, Type 1 diabetic patients, patients with a psychotic disorder or aphasia were excluded. Data collection consisted of face-to-face interviews, review of treatment, medication knowledge evaluation, a short examination and collection of recent blood results. Statistical analysis was done by stratifying patients into two groups by using the mean HBA1C. Variables with a p < 0.1 from this analysis were used in a logistic regression model. In addition, the correlation between continuous variables were tested. A comparison was made between the level of care and the 2012 SEMDSA guidelines. v Results A total of 100 patients were recruited into the study. The mean age was 62.8 years with mean duration of diabetes of 15.8 and clinic attendance of 10.9 years. The group had very poor education level and the median income of R1200 per month was also low. The mean HBA1C was found to be 9.74%, well above the target recommended by SEMDSA. Knowledge of diabetes with respect to management and complications was very poor. Age > 50 years (OR 0.372 CI 0.06-2.26), estimated glomerular filtration rate ≥ 60 ml/min/1.73m2 (OR 0.90 CI 0.25-3.27), experiencing a microvascular complication (OR 0.73 CI 0.11-5.07) or any other diabetic complication (OR 0.56 CI 0.07-4.38) and having experienced a hypoglycaemic episode (OR 0.31 CI 0.09-1.10) predicted better glycaemic control. Duration of diabetes < 10 years (OR 1.36 CI 0.37-5.02), diastolic blood pressure ≥ 70 mmHg (OR 2.80 CI 0.80-9.78), aspirin dosage ≥ 150 mg daily (OR 6.47 CI 1.60-26.05), simvastatin dosage = 40 mg daily (OR 2.35 CI 0.31-18.10) and body mass index > 25 kg/m2 (OR 1.09 CI 0.49-2.41) all predicted a poorer glycaemic result. HBA1C was found to positively correlate with diastolic blood pressure (p = 0.0024, r = 0.31). Systolic blood pressure positively correlated with diastolic blood pressure (p < 0.0001, r = 0.56). Apart from correlating with systolic blood pressure and HBA1C, diastolic blood pressure also positively correlated with the triglyceride level (p = 0.0003, r = 0.36). Positive correlations between total cholesterol, triglycerides, HDL-C and LDL-C were found. As expected, body mass index and waist circumference correlated positively (p < 0.0001, r = 0.82). Level of care was not at the level recommended by the 2012 SEMDSA guidelines. Only 6% of patients met the waist circumference goal. Only 15% of patients achieved blood v i pressure goal. Most of the patients (86%) who qualified for aspirin did not receive it. In the group of patients receiving aspirin 33% did not qualify. According to the SEMDSA guidelines, most of the patients not receiving a statin (90%) should have been on statin therapy. Only 23.5% of patients on statins were at lipid goal. The frequency of laboratory testing did not meet SEMDSA guidelines. There were 31 (31%) patients without a urea, creatinine and electrolyte test for the previous year and 37 (37%) patients without a lipogram for the previous year. Only 21 patients had a listed urine albumin/creatinine ratio and only 33% of these had been done in the previous year. Conclusions Various new variables were identified in the search for predictors of glycaemic control. It was surprising to find that education level, monthly income, smoking status and knowledge of diabetes did not have a statistical impact on glycaemic control. Increased age, duration of diabetes, glomerular filtration rate, hypoglycaemic frequency and diabetic complications experienced were associated with improved glycaemic control. Increased diastolic blood pressure, aspirin dosage, statin dosage and body mass index were associated with worse glycaemic control. The standard of care in the clinic was found on the whole to be inferior to the level of care recommended by SEMDSA.
32

A comparative immunohistochemical study of the "biphasic ductules" in adenoid cystic carcinoma, pleomorphic adenoma and epi-myoepithelial carcinoma

Patel, Kunel 21 February 2014 (has links)
Immunohistochemistry has been used as an aid in the histological diagnosis of salivary gland neoplasms as they often show overlapping histomorphological growth patterns.
33

The theory of LEGO

Pollack, Robert January 1995 (has links)
LEGO is a computer program for interactive typechecking in the Extended Calculus of Constructions and two of its subsystems. LEGO also supports the extension of these three systems with inductive types. These type systems can be viewed as logics, and as meta languages for expressing logics, and LEGO is intended to be used for interactively constructing proofs in mathematical theories presented in these logics. I have developed LEGO over six years, starting from an implementation of the Calculus of Constructions by Gérard Huet. LEGO has been used for problems at the limits of our abilities to do formal mathematics. In this thesis I explain some aspects of the meta-theory of LEGO's type systems leading to a machine-checked proof that typechecking is decidable for all three type theories supported by LEGO, and to a verified algorithm for deciding their typing judgements, assuming only that they are normalizing. In order to do this, the theory of Pure Type Systems (PTS) is extended and formalized in LEGO. This extended example of a formally developed body of mathematics is described, both for its main theorems, and as a case study in formal mathematics. In many examples, I compare formal definitions and theorems with their informal counterparts, and with various alternative approaches, to study the meaning and use of mathematical language, and suggest clarifications in the informal usage. Having outlined a formal development far too large to be surveyed in detail by a human reader, I close with some thoughts on how the human mathematician's state of understanding and belief might be affected by possessing such a thing.
34

Mechanisms of Androgen Receptor Stimulation of Insulin Secretion in the Male

January 2018 (has links)
acase@tulane.edu / Although men with testosterone deficiency are at increased risk for type 2 diabetes (T2D), previous studies have ignored the role of testosterone and the androgen receptor (AR) in pancreatic β–cell. Our study shows that male pancreatic β–cell specific AR knockout (βARKOMIP) mice develop glucose intolerance because AR potentiates glucose-stimulated insulin secretion (GSIS) through increasing cyclic AMP (cAMP) accumulation and amplifying the insulinotropic effect of glucagon-like peptide-1 (GLP-1). Using transcriptome analysis, we find that AR-deficient islets exhibit altered expression of genes involved in inflammation and insulin secretion demonstrating the importance of androgen action in β-cell health in the male. Our recent study shows that male βARKOMIP mice exhibit impaired intraperitoneal (IP) glucose tolerance- because of impaired IP-GSIS- without alteration in oral glucose tolerance, suggesting that AR amplifies the islet-derived, but not the gut-derived GLP-1 to potentiate GSIS. Dihydrotestosterone (DHT) increases the insulinotropic effect of GLP-1, not gastric inhibitory polypeptide (GIP) and glucagon, in male insulin-secreting β-cell line 832/3 cells and wild-type male mouse islets. Accordingly, using 832/3 cells transduced with exchange factor directly activated by a cAMP (EPAC)-based fluorescence resonance energy transfer (FRET) sensor, we observe that the AR agonist dihydrotestosterone (DHT) specifically allows GLP-1, not GIP and glucagon, to increase cAMP production above level of the individual hormones. The insulinotropic effect of DHT is abolished using EPAC and PKA inhibitors as well as rapamycin indicating that DHT stimulates GSIS via a cAMP/PKA/EPAC pathway and activation of mTOR. This study identifies AR as a novel receptor that enhances β–cell function, a finding with implications for the prevention of type 2 diabetes (T2D) in aging men. / 1 / Weiwei Xu
35

Nuclear magnetic resonance and nuclear quadrupole resonance study of atomic motion in YBa���Cu���O���

Klein, Susan P. 25 October 1995 (has links)
Graduation date: 1996
36

Epigenetic modifications and conserved, non-coding DNA play a role in regulation of type IV collagen gene expression

Moody, Jessica Ashley 15 May 2009 (has links)
Type IV collagens are components of basement membranes throughout the body and are involved in maintenance of the structural integrity of tissues as well as cellular differentiation, growth, and adhesion. Members of this collagen family are uniquely arranged in pairs in a head-to-head orientation and share a proximal promoter region. The COL4A5-COL4A6 gene pair is involved in numerous human diseases and cancer metastasis. For these reasons, defining the mechanisms that regulate collagen gene expression is of specific interest. To study type IV collagens, an in vitro model system was characterized. Comparative genomics was utilized to identify conserved, non-coding DNA in COL4A5 and COL4A6. These sequences were transfected into cell lines differing in type IV collagen expression and tested for the ability to regulate transcription of a reporter gene. Each cell line was also treated with the epigenetic modifying agents, 5-Aza and TSA. The effects on type IV collagen expression were determined. The COL4A5-COL4A6 promoter region was extensively characterized using ChIP analysis; antibodies against RNAPII, acetylated histone H3, and H3K9me2 were used. Additionally, bisulfite sequencing was carried out on each cell line to determine the methylation status of CpG dinucleotides in the promoter. Cell lines differing in expression of COL4A5 and COL4A6 were identified: 1) SCC-25 keratinocytes and HEK-293 cells transcribed both COL4A5 and COL4A6, 2) HT-1080 cells selectively activated COL4A5, and 3) SK-N-SH neuroblastoma cells did not express either gene. In SK-N-SH cells, histone modifications were shown to facilitate formation of condensed chromatin to prevent transcription initiation; repression was independent of DNA methylation. Activation of COL4A5 and COL4A6 in SCC-25 and HEK-293 cells involved acetylation of histones, although differences between the two cell types were seen. In addition, conserved, non-coding sequences were shown to affect transcription of a reporter gene; these sequences may be interacting with the transcription machinery to modulate collagen expression. Finally, repression of COL4A6 in HT-1080 cells appeared to be mediated through DNA methylation of the promoter; selective activation of COL4A5 may involve conserved, non-coding DNA. In summary, epigenetic modifications as well as conserved sequences are intimately involved in regulation of type IV collagen gene expression.
37

Novel action of Botulinum Toxin in the rat prostate

Wu, Mo-ya 29 August 2007 (has links)
Intraprostatic injection of BTX-A has demonstrated clinical improvement in men with bladder out let obstruction. Firstly, we investigated the mechanisms of action of BTX-A on the prostate. Secondly, an animal model for nonbacterial prostatitis in rats was developed using intraprostatic injection of capsaicin, an agent thought to excite c-afferent fibers and cause neurogenic inflammation. The analgesic and anti-inflammatory properties of Botulinum toxin type A (BoNT-A) was tested in this model. (1) Adult male Spragu-Dawley rats were injected with varying doses of BTX-A into the prostate, and the prostates were harvested after 1 or 2 weeks. The effects of BTX-A on prostate histology, and the proliferative and apoptotic indexes were determined using hematoxylin and eosin staining, proliferative cell nuclear antigen staining and TUNEL staining, respectively. Changes in a1A adrenergic receptor and androgen receptor were evaluated by Western blotting. (2) Adult male Spragu-Dawley rats were injected with varying doses of capsaicin into the prostate. The nociceptive effects of capsaicin were evaluated for 30 min by using a behavior approach; the prostate was removed for histology and cyclooxygenase (COX) 2 concentration measurement. Evans blue (50mg/kg) was also injected intravenously to assess for plasma protein extravasation. The other set of animals were injected with up to 20U of BoNT-A into the prostates 1 wk prior to intraprostatic injection of 1000umol/l capsaicin. (1) One week after BTX-A injection generalized prostate atrophy was observed. There was a significant increase in apoptotic cells (12, 16 and 22-fold), and decrease in proliferative cells (38%, 77% and 80%) and a1A adrenergic receptor (13%, 80% and 81%) for 5U, 10U and 20U, respectively. There was no significant change in androgen receptors. The effects were decreased 2 weeks after BTX-A treatment. (2) Capsaicin dose dependently induced modifications in pain behavior closing of the eyes, hypolocomotion, and inflammatory changes: increase of inflammatory cell accumulation, COX2 expression, and plasma extravasation at the acute stage, but completely recovered at 1 wk. BoNT-A pretreatment dose dependently reversed pain behavior and inflammation. BoNT-A 20U significantly decreased inflammatory cell accumulation, COX2 expression, and Evans blue extraction (82.1%, 93.0% and 50.4, respectively), and reduced pain behavior (66.% for eye score and 46.5% for locomotion score). Conclusion (1): BTX-A injection into the prostate alters cellular dynamics by inducing apoptosis, inhibiting proliferation and down-regulating a1A adrenergic receptors. BTX-A may potentially be the drug that has dual actions on the static and dynamic components of benign prostatic hyperplasia. (2): Intraprostatic capsaicin injection induced neurogenic prostatitis and prostatic pain, and may be a useful research model. BoNT-A produced anti-inflammatory and analgesic effects, and support clinical evaluation in prostatitis.
38

Epigenetic modifications and conserved, non-coding DNA play a role in regulation of type IV collagen gene expression

Moody, Jessica Ashley 15 May 2009 (has links)
Type IV collagens are components of basement membranes throughout the body and are involved in maintenance of the structural integrity of tissues as well as cellular differentiation, growth, and adhesion. Members of this collagen family are uniquely arranged in pairs in a head-to-head orientation and share a proximal promoter region. The COL4A5-COL4A6 gene pair is involved in numerous human diseases and cancer metastasis. For these reasons, defining the mechanisms that regulate collagen gene expression is of specific interest. To study type IV collagens, an in vitro model system was characterized. Comparative genomics was utilized to identify conserved, non-coding DNA in COL4A5 and COL4A6. These sequences were transfected into cell lines differing in type IV collagen expression and tested for the ability to regulate transcription of a reporter gene. Each cell line was also treated with the epigenetic modifying agents, 5-Aza and TSA. The effects on type IV collagen expression were determined. The COL4A5-COL4A6 promoter region was extensively characterized using ChIP analysis; antibodies against RNAPII, acetylated histone H3, and H3K9me2 were used. Additionally, bisulfite sequencing was carried out on each cell line to determine the methylation status of CpG dinucleotides in the promoter. Cell lines differing in expression of COL4A5 and COL4A6 were identified: 1) SCC-25 keratinocytes and HEK-293 cells transcribed both COL4A5 and COL4A6, 2) HT-1080 cells selectively activated COL4A5, and 3) SK-N-SH neuroblastoma cells did not express either gene. In SK-N-SH cells, histone modifications were shown to facilitate formation of condensed chromatin to prevent transcription initiation; repression was independent of DNA methylation. Activation of COL4A5 and COL4A6 in SCC-25 and HEK-293 cells involved acetylation of histones, although differences between the two cell types were seen. In addition, conserved, non-coding sequences were shown to affect transcription of a reporter gene; these sequences may be interacting with the transcription machinery to modulate collagen expression. Finally, repression of COL4A6 in HT-1080 cells appeared to be mediated through DNA methylation of the promoter; selective activation of COL4A5 may involve conserved, non-coding DNA. In summary, epigenetic modifications as well as conserved sequences are intimately involved in regulation of type IV collagen gene expression.
39

Study on the nitrogen doped CVD diamond

Liu, Tsung-Shian 27 January 2004 (has links)
In this work, argon, hydrogen and methane are used as gas sources and nitrogen is used as the doping source. Microwave plasma chemical vapor deposition and two-steps deposition processes have been applied to grow the nitrogen-doped diamond thin film on n-type (111) silicon substrate. Systematical experiments are performed to study the dependence of grown process on working pressure, temperature, microwave power, DC bias, the duration of growth time and the flow rates of gas mixture of argon, methane and nitrogen. The nitrogen-doped diamond thin films are examined by SEM, XRD, Raman and I-V. Raman spectroscopy is the most efficient tool for analyzes the quality of diamond thin films growth. The results show that a positive DC bias can enhance the doping concentration and the qualities of diamond thin films. Form the analyzing results, nitrogen is doped in the sp2 structural grain boundaries of crystallites. The longer diamond thin film grown is, the crystallites become larger and the grain boundaries become smaller, that leads to the larger resistivity of the thin films.
40

Synthesis of heterogeneous palladium catalyst assemblies by molecular imprinting

Baines, Nicholas John January 2002 (has links)
Heterogeneous palladium catalysts for use in Suzuki-type reactions have been prepared using the molecular imprinting technique. Using this technique allows the preparation of a heterogeneous catalyst with uniform active sites which have a metal complex configuration that favours processes in the catalytic cycle, thus enhancing the rate of reaction. It was reasoned, from the general catalytic cycle for palladium cross-couplings, that a bisphosphine complex with a cis ligand geometry would be beneficial. Polymerisable phosphines were synthesised and the cis bisphosphine palladium complexes prepared. The geometry of the complexes was fixed by addition of a bidentate ligand (catechol). The resulting complexes were incorporated into a macroporous polymer framework using the molecular imprinting technique. This produced the heterogeneous palladium catalysts with uniform active sites and known palladium content. The catalysts were ~ested in model Suzuki reactions and were shown to give far superior yields to the homogeneous catalyst and control heterogeneous catalyst (derived from commercial ligand). The favoured square-planar cis-geometry was likely to increase the rate of reductive elimination, which takes place from that conformation. It is also reasonable to imply that the catalytically active palladium(O) species would be strained, being tetrahedral not square-planar, and so the rate of oxidative addition (the slow step in some cases) could also be accelerated. The improved yields shown by the imprinted catalysts for the Suzuki reactions suggest that this is the case.

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