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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.
1

Antioxidant micronutrient intake and oxidative stress in persons with human immunodeficiency virus infection

McDermid, Joann M. January 1995 (has links)
An imbalance of the oxidant-antioxidant equilibrium has been associated with disease progression in HIV-seropositive individuals. In vitro and in vivo studies have demonstrated the efficacy of antioxidant supplementation in reducing the concentrations of oxidative stress markers. The objectives of the present cross-sectional study were to evaluate the dietary intake and nutritional supplementation practices of 24 HIV-seropositive persons in Montreal and explore the relationship between dietary intakes of antioxidant micronutrients (ascorbic acid, vitamin E, $ beta$-carotene, zinc, selenium), oxidative stress (plasma malondialdehyde (MDA), leukocyte glutathione (GSH)) and immunological indices (absolute CD4+ counts, polymorphonuclear leukocytes (PMN)). Unexpectedly, and paradoxically, a tendency to higher MDA concentrations in subjects with higher CD4+ counts was observed (r = 0.39, p $<$ 0.10). Moreover, supplementation with vitamin E was associated with significantly higher MDA concentrations (p $<$ 0.05). Ascorbic acid intake, even at levels in excess of the tissue saturation (200 mg/d) did not significantly lower MDA concentrations. Neither GSH concentrations nor CD4+ counts were significantly different between supplement users and non-users. In general, the small sample size of this study may have been in part responsible for the failure to detect statistical significance in some associations, however, trends were noted. These included the observation that vitamin supplement users were more likely to have a history of a clinical event associated with HIV infection (opportunistic infection, neoplasm, unintentional weight loss), have a longer duration of IV-seropositivity and have significantly higher MDA concentrations (p $<$ 0.05). In this study, it appears that antioxidants, and vitamin E in particular, were ineffective in reducing the elevated levels of reactive oxygen species (ROS) associated with HIV infection.
2

Antioxidant micronutrient intake and oxidative stress in persons with human immunodeficiency virus infection

McDermid, Joann M. January 1995 (has links)
No description available.
3

The role of rooibos (Aspalathus Linearis), green tea (Camellia Sinensis) and commercially available rooibos and green tea antioxidant supplements on rat testicular and epididymal function

Awoniyi, Dolapo Olaitan January 2010 (has links)
Thesis (MTech(Biomedical Technology) -- Cape Peninsula University of Technology, 2010 / Defective sperm function is the most prevalent cause of male infertility. Mammalian sperm are rich in polyunsaturated fatty acids (PUFA) and are susceptible to attack by reactive oxygen species (ROS), an important mediator of sperm function. Normally, a balance is maintained between the amount of ROS produced and the antioxidant defense system. When an imbalance exists between ROS production and antioxidants protection in the favour of ROS activity, oxidative stress (OS) occurs which could lead to cellular damage. A shift in the levels of ROS towards pro-oxidation in semen can induce oxidative stress on sperm. This study compares the modulation of OS by an indigenous herbal tea (rooibos), Chinese green tea, commercial rooibos and green tea supplements in rat epididymal sperm and testicular function. Sixty male Wistar rats were supplemented with fermented or “green” rooibos, Chinese green tea, rooibos supplement, green tea supplement or water for ten weeks while inducing OS during the last two weeks. Rats consuming fermented rooibos and “green” rooibos showed a significant higher sperm concentration and motility. The superoxide dismutase (SOD) activity was significantly higher in the sperm of rats that consumed fermented rooibos, “green rooibos” and green tea compared to the control. Also, the superoxide dismutase activity of the groups that received fermented rooibos, rooibos supplement and green tea increased significantly in the testicular tissue compared to control. Catalase (CAT) activity in the epididymal sperm was significantly increased in the rats consuming fermented rooibos, “green rooibos” and both rooibos and green tea supplements compared to the control. None of the tea treatments showed a significant effect on catalase activity in the testicular tissue. A tendency to increase this activity was observed in fermented rooibos, green tea, rooibos and green tea supplements. The glutathione levels of rats fed with fermented rooibos and “green” rooibos were significantly higher in the rat epididymal sperm compared to the control while the glutathione level of rats consuming green tea supplement also increased significantly in the testicular tissue compared to the control. None of the tea treatments showed a significant effect on lipid peroxidation and ROS levels in the rat sperm. Although rooibos fermented, “green” rooibos and rooibos supplements showed a tendency to lower the levels of these biomarkers when compared with the control group in epididymal sperm. However, the rooibos supplement showed a significantly reduced ROS levels in the testicular tissue. In conclusion, our study demonstrated that rooibos extract and green tea are effective as antioxidants by increasing the antioxidant enzyme activities and glutathione levels in oxidative stress-induced rats and could offer a measure of protection against oxidative damage, thereby improving sperm quality and function.
4

Oxidative stress and antioxidant intake in HIV-related wasting

Callow, Lisa Jane. January 2000 (has links)
Weight loss is a common occurrence in patients with human immunodeficiency virus (HIV) and contributes to further debilitation in the acquired immune deficiency syndrome (AIDS). Wasting syndrome (WS) is defined as 10% or more unintentional weight loss from usual body weight. The etiology of WS includes alterations in metabolism, which contribute to loss of lean body mass. Cytokine driven oxidative stress may play a critical role in the metabolic pathways that lead to HIV wasting. Studies have shown that that patients infected with HIV may have a depleted antioxidant (AO) defense system, the integrity of which is needed to efficiently scavenge reactive oxygen species (ROS). It has been theorised that low AO intake may contribute to a depressed AO defense system, which drives oxidative stress (OS). In this study we examined 16 subjects who had documented WS but no active infectious process, stratified into 10 to 15% weight loss (n = 7) and over 15% weight loss (n = 9) groups, and reported on oxidative stress measures and AO intake. (Abstract shortened by UMI.)
5

Oxidative stress and antioxidant intake in HIV-related wasting

Callow, Lisa Jane. January 2000 (has links)
No description available.
6

Antioxidants in Canadian boreal forest : indigenous medicinal plant treatments in relation to non-insulin dependent diabetes mellitus

McCune, Letitia M. January 1999 (has links)
No description available.
7

Antioxidants in Canadian boreal forest : indigenous medicinal plant treatments in relation to non-insulin dependent diabetes mellitus

McCune, Letitia M. January 1999 (has links)
Medicinal plants, as part of traditional ingestion practices, may contain antioxidants to combat the oxidative stress which is implicated in prediabetes as well as many of the complications of diabetes, As Indigenous Peoples move further from their traditional lifestyles, and therefore their use of medicinal plants, incidence of diabetes has increased dramatically, Those medicinal plants of the boreal forest that have been used for 3 or more symptoms of diabetes or its complications were selected for analysis. Three different assays (DPPH, NBT/xanthine oxidase and DCF/APPH) determined the antioxidant activity of 35 medicinal plant species. The majority of the species (89%) had free radical scavenging activity significantly greater than the market produce tested (Tukey, P < 0.05), 63% had superoxide scavenging activities similar to vitamin C, and eight species had free radical scavenging activity similar to green tea. Considering that many of these species are also used for food or beverage they represent an antioxidant benefit to the traditional lifestyle. Among the parts used medicinally, roots and barks were used the most frequently with activity in the order of fruit > bark > leaves > roots. The perennials selected had activity in rank trees > shrubs > herbs and the activity associated with habitat found rocky areas > woodland > wet/boggy habitats. Species used for symptoms such as diarrhea, rheumatism, tonic and heart/chest pain were typically high in antioxidant activity. Using cluster analysis it was determined that species used for diarrhea and heart disease as well as those used for a combination of tonic, sores, urinary, blood, pregnancy and boils could also be species with high antioxidant activity. The greater the number of symptoms a species was used for, the greater the activity. Three species with high antioxidant activities, Rhus hirta, Cornus stolonifera and Solidago canadensis, inhibited TNF production in human macrophage cells suggesting a po
8

The effects of the wild african potato (hypoxis hemerocallidea) supplementation on streptozotocin-induced diabetic wistar rats reproductive function

Jordaan, Audrey Emmerentia January 2015 (has links)
Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2015. / Diabetes mellitus (DM) has been reported to be one of the greatest global public health threats. Statistics of the fertility status of modern society has linked increased DM to a decrease in fertility rates. Hyperglycaemia is characteristic of DM that results in a disturbance of proteins, lipids and carbohydrate metabolism leading to an increase production of reactive oxygen species (ROS). In the case where ROS overwhelms antioxidant mechanisms, the body goes into state of oxidative stress (OS). OS plays a vital role in the progression of DM which leads to dysfunction and damage of various organs including that of the reproductive system. Os has shown to cause damage to the sperm membraneby oxidation of polyunsaturated fatty acids (PUFA’s) as the sperm membrane are rich in PUFA’s. This damage contributes to reduced sperm motility, concentration, morphological abnormalities and the sperms ability to fuse with the ZP of the oocyte. DM has been observed to cause testicular degeneration by interrupting sertoli cell production and maintenance thus resulting in a disturbance of the normal functioning of the reproductive system. Experimental studies have targeted more natural sources for treating DM and its complications of the reproductive system. Plants and natural dietary substances have shown to have high antioxidant contents that combat DM induced oxidative stress. This study explored the effect the Hypoxis hemerocallidea (H. hemerocallidea) supplementation on testicular and epididymal tissue, sperm motility and reproductive hormones in male wistar rats. The experiment were conducted for 6 weeks and the rats (230-260 grams) were randomly divided into 5 groups (n=12 per group). Diabetes was induced in 3 of the 5 groups. The first group was the normal control group (A), second the diabetic control group (B), third was the diabetic group treated with 800mg/kg H. hemerocallidea (group C), fourth the diabetic group treated with 200mg/kg H. hemerocallidea (group D) and fifth the non-diabetic group supplemented with 800mg/kg H. hemerocallidea (group E). Blood glucose showed a significant increase in the diabetic group when compared to the normal control and treated groups. H. hemerocallidea showed improvement in sperm motility and sperm morphology more at 800mg/kg when compared to diabetic group and diabetic group treated with 200mg/kg. Body, testicular and epipidymal weights of diabetic control were significantly lower when compared to the other groups. Testicular and epididymal Malondialdehyde levels were decreased in normal control, diabetic groups treated with different doses of H. hemerocallidea and the non-diabetic group supplemented with H. hemerocallideaon comparing with the diabetic control group. Antioxidants such as Superoxide dismutase, Catalase and total Glutathione activity was observed to be dosage dependent in certin groups but most showed a significant increase when compared to the diabetic control group. The total antioxidant capacity was measured using Oxygen radical absorbance capacity (ORAC) and Ferric ion reducing antioxidant power (FRAP); increase was observed when normal control group and treated groups were compared to the diabetic group. Testosterone and estradiol levels were also increased when the normal control group and treated groups were compared to the diabetic control group. Based on our findings it can be concluded that H. hemerocallidea supplementation can potentially be used to counteract deleterious effects of DM on the male reproductive system.

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