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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.
21

MECHANISMS OF THE ZINC PROTECTIVE EFFECTS AGAINST CARBON-TETRACHLORIDE HEPATOTOXICITY

Ludwig, Janet Elizabeth, 1950- January 1981 (has links)
Several trace metals have been shown to modify cell injury as indicated by reduction of observable pathological tissue changes after metal ion supplementation. An example of this is zinc ion induced protection against some of the liver injury caused by a single injection of carbon tetrachloride (CCl₄) to male Sprague-Dawley rats. Carbon tetrachloride liver injury is associated with membrane labilization as indicated by lysosomal and endoplasmic reticulum anomalies. Depressed hepatic levels of NADPH are observed during CCl₄ poisoning. Lipid metabolism is also impaired due to CCl₄ administration to animals. These biochemical manifestations of CCl₄ hepatotoxicity were studied in the presence of zinc ions in order to understand the mechanisms of the zinc protective effect against CCl₄ injury. The effect of zinc ions on the stability of rat liver lysomes was studied. Zinc was added by several methods: (1) feeding the animals a high zinc diet, (2) infusion of zinc into the liver in situ through the portal vein, or (3) by adding zinc to the lysosomal fraction either before or after isolation of this fraction from rat liver homogenates. By all techniques, addition of zinc reduced the release of β-glucuronidase from liver lysosomes, indicating increased stability of the suborganelles. The zinc induced protection against CCl₄ liver damage was evident in observations made using both light microscopy and electron microscopy. The increased release of lysosomal β-glucuronidase observed in the CCl₄ treated rats was significantly reduced by zinc administration. Also, decreases in microsomal protein synthesis and seromucoid levels due to the CCl₄ treatment were significantly ameliorated by zinc. Thus, disruption of lysosomal and endoplasmic reticulum membranes, one of the earliest signs of CCl₄ hepatotoxicity, appeared to be inhibited by pretreating the animals with zinc chloride. Depressed hepatic levels of NADPH are observed in rats administered CCl₄. Zinc chloride pretreatment of these rats significantly increased the NADPH levels in the liver. Since zinc ions bind NADPH, then the protective effect of zinc against CCl₄ toxicity may be due to stabilization of the pyridine nucleotide by zinc and the subsequent prevention of CCl₄ induced alterations of biochemical reactions dependent upon NADPH. Zinc chloride pretreatment of CCl₄ treated rats significantly reduced the CCl₄ induced hepatic triacylglycerol accumulation. Concomitant with this event is the appearance of elevated levels of newly synthesized triacylglycerols in the serum of the CCl₄ treated rats given zinc above that of the CCl₄ treated rats. Hepatic triacylglycerol synthesis is unchanged by CCl₄ or zinc treatment. Hepatic phospholipid levels which are depressed by the CCl₄ hepatotoxin are not affected by zinc treatment. However, the synthesis of phospholipids in the livers of rats treated with CCl₄ plus zinc is significantly increased. The lipid changes induced by CCl₄ and zinc dosing of rats are indicative of alterations in liver membranes thus affecting hepatic liver transport mechanisms. On the basis of the data presented, the effects of zinc ions on CCl₄ hepatotoxicity are discussed and applied to understanding the regulating role of metal ions in tissue injury. The protective effects of zinc ions against CCl₄ hepatotoxicity suggest a relationship between the zinc nutritional status of animals exposed to environmental contaminants, and the expression of the ensuing tissue damage.
22

Characterization and plant availability of zinc in British Columbia orchard soils

Neilsen, Denise. January 1986 (has links)
No description available.
23

Effect of dietary ethanol and zinc on vitamin B-6 metabolism in the rat

Wan, Daisy 13 November 1992 (has links)
Graduation date: 1993
24

Responses of chickpea (Cicer arietinum L.) to zinc supply and water deficits / by Habib Ur Rahman Khan.

Khan, Habib Ur Rahman January 1998 (has links)
Bibliography: leaves 201-228. / xvii, 228 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Widespread deficiencies of mineral nutrients in soils along with limited moisture supply are considered major environmental stresses leading to yield losses in chickpea. This study was conducted to determine the zinc requirement of chickpea and the effect on plant water relations. Critical zinc concentration was estimated. It was found that high and low moisture regimes had no effect on critical zinc concentration and that the value remained almost the same in all chickpea genotypes. Sensitivity of 28 chickpea genotypes were evaluated at two zinc levels. Field studies on zinc fertilization in both Australia and Pakistan showed that the application of zinc increased grain yield in all chickpea genotypes. It was found that plants grown under zinc deficiency could not exploit available soil moisture and water use and water use efficiency was reduced, and concluded that high zinc availability may enhance the ability of plants to endure periods of drought by promoting osmotic adjustment. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1999
25

Responses of chickpea (Cicer arietinum L.) to zinc supply and water deficits / by Habib Ur Rahman Khan.

Khan, Habib Ur Rahman January 1998 (has links)
Bibliography: leaves 201-228. / xvii, 228 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Widespread deficiencies of mineral nutrients in soils along with limited moisture supply are considered major environmental stresses leading to yield losses in chickpea. This study was conducted to determine the zinc requirement of chickpea and the effect on plant water relations. Critical zinc concentration was estimated. It was found that high and low moisture regimes had no effect on critical zinc concentration and that the value remained almost the same in all chickpea genotypes. Sensitivity of 28 chickpea genotypes were evaluated at two zinc levels. Field studies on zinc fertilization in both Australia and Pakistan showed that the application of zinc increased grain yield in all chickpea genotypes. It was found that plants grown under zinc deficiency could not exploit available soil moisture and water use and water use efficiency was reduced, and concluded that high zinc availability may enhance the ability of plants to endure periods of drought by promoting osmotic adjustment. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1999
26

Estado nutricional e perfil bioquímico de zinco e selênio em pacientes com deficiência de UgA

Komatsu, Camila Gomes [UNESP] 14 December 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-12-14Bitstream added on 2014-06-13T18:50:30Z : No. of bitstreams: 1 komatsu_cg_me_arafcf_parcial.pdf: 79141 bytes, checksum: 0b4eb56ed80953314f75746a43311a53 (MD5) Bitstreams deleted on 2015-02-09T14:35:40Z: komatsu_cg_me_arafcf_parcial.pdf,Bitstream added on 2015-02-09T14:36:21Z : No. of bitstreams: 1 000706724.pdf: 336800 bytes, checksum: 23a7e4a01cf8ec0c9124706da993a93a (MD5) Bitstreams deleted on 2015-02-09T17:15:03Z: 000706724.pdf,Bitstream added on 2015-02-09T17:15:40Z : No. of bitstreams: 1 000706724.pdf: 336800 bytes, checksum: 23a7e4a01cf8ec0c9124706da993a93a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / A deficiência da imunoglobulina A (IgA) é definida como níveis séricos de IgA menores que 7mg/dL na presença de níveis séricos normais de IgG e IgM em indivíduos com idade maior que 4 anos. Seus sintomas podem estar associados com doenças como alergias, auto-imunidade, neoplasias e infecções. Diversos nutrientes têm sido descritos por exercerem papel no sistema imunológico, entre eles os minerais zinco e selênio. A deficiência do zinco pode comprometer o sistema imunológico e aumentar a suscetibilidade para doenças graves. Há comprometimento tanto da imunidade inata quanto adaptativa, aumentando a suscetibilidade a infecções por vários patógenos.O selênio é essencial para o funcionamento eficiente de muitos aspectos do sistema imunológico em humanos, e suas funções provavelmente são derivadas das proteínas contendo selênio (selenoproteínas). O presente estudo teve por objetivo avaliar os perfis antropométrico, bioquímico, nutricional e o status de zinco e selênio de pacientes deficientes em IgA, bem como avaliar uma possível correlação entre os micronutrientes avaliados com o estado nutricional. Somente 1 indivíduo apresentou déficit nutricional em relação à antropometria. O consumo de zinco se mostrou adequado em quase toda a amostra (75% das crianças, adolescentes e adultos), assim como ocorreu com o selênio (87,5% de todos os indivíduos), o que condiz com os níveis plasmáticos dos minerais (com níveis adequados de selênio em todos os participantes e de zinco em quase todos). Entretanto, os níveis eritrocitários mostram deficiência de ambos os oligoelementos. Apesar de a amostra estudada não apresentar déficit nutricional relativo à antropometria, há deficiência dos minerais analisados nos eritrócitos / The deficiency of immunoglobulin A (IgA) is defined as serum IgA levels lower than 7mg/dL in the presence of normal serum IgG and IgM levels in individuals older than four years. Your symptoms may be associated with diseases such as allergies, autoimmunity, cancer and infections.Several nutrients have been described by exercising role in the immune system, including the minerals zinc and selenium.The zinc deficiency can compromise the immune system and increase susceptibility to serious illnesses. Both innate and adaptive immunity are compromised, increasing susceptibility to infection by various pathogens. Selenium is essential for the efficient operation of many aspects of the immune system in humans, and their functions are probably derived from proteins containing selenium (selenoproteins). The present study aimed to evaluate the anthropometric, biochemical, and nutritional profiles and the status of zinc and selenium in IgA-deficient patients, and to evaluate a possible correlation between the micronutrients assessed nutritional status.Only one subject showed malnutrition in relation to anthropometry. The zinc intake was adequate in almost the entire sample (75% of children, adolescents and adults), as with selenium (87.5% of all individuals), which is consistent with the plasma levels of minerals (with adequate levels of selenium in all participants and zinc in almost all). However, levels of both trace elements were deficient in the erythrocyte. Although the sample has not shown nutritional deficit based on anthropometry, there is a deficiency of minerals analyzed in erythrocytes
27

Estado nutricional e perfil bioquímico de zinco e selênio em pacientes com deficiência de UgA /

Komatsu, Camila Gomes. January 2012 (has links)
Orientador: Anderson Marliere Navarro / Banca: Flávia Queiroga Aranha de Almeida / Banca: Telma Maria Braga Costa / Resumo: A deficiência da imunoglobulina A (IgA) é definida como níveis séricos de IgA menores que 7mg/dL na presença de níveis séricos normais de IgG e IgM em indivíduos com idade maior que 4 anos. Seus sintomas podem estar associados com doenças como alergias, auto-imunidade, neoplasias e infecções. Diversos nutrientes têm sido descritos por exercerem papel no sistema imunológico, entre eles os minerais zinco e selênio. A deficiência do zinco pode comprometer o sistema imunológico e aumentar a suscetibilidade para doenças graves. Há comprometimento tanto da imunidade inata quanto adaptativa, aumentando a suscetibilidade a infecções por vários patógenos.O selênio é essencial para o funcionamento eficiente de muitos aspectos do sistema imunológico em humanos, e suas funções provavelmente são derivadas das proteínas contendo selênio (selenoproteínas). O presente estudo teve por objetivo avaliar os perfis antropométrico, bioquímico, nutricional e o status de zinco e selênio de pacientes deficientes em IgA, bem como avaliar uma possível correlação entre os micronutrientes avaliados com o estado nutricional. Somente 1 indivíduo apresentou déficit nutricional em relação à antropometria. O consumo de zinco se mostrou adequado em quase toda a amostra (75% das crianças, adolescentes e adultos), assim como ocorreu com o selênio (87,5% de todos os indivíduos), o que condiz com os níveis plasmáticos dos minerais (com níveis adequados de selênio em todos os participantes e de zinco em quase todos). Entretanto, os níveis eritrocitários mostram deficiência de ambos os oligoelementos. Apesar de a amostra estudada não apresentar déficit nutricional relativo à antropometria, há deficiência dos minerais analisados nos eritrócitos / Abstract: The deficiency of immunoglobulin A (IgA) is defined as serum IgA levels lower than 7mg/dL in the presence of normal serum IgG and IgM levels in individuals older than four years. Your symptoms may be associated with diseases such as allergies, autoimmunity, cancer and infections.Several nutrients have been described by exercising role in the immune system, including the minerals zinc and selenium.The zinc deficiency can compromise the immune system and increase susceptibility to serious illnesses. Both innate and adaptive immunity are compromised, increasing susceptibility to infection by various pathogens. Selenium is essential for the efficient operation of many aspects of the immune system in humans, and their functions are probably derived from proteins containing selenium (selenoproteins). The present study aimed to evaluate the anthropometric, biochemical, and nutritional profiles and the status of zinc and selenium in IgA-deficient patients, and to evaluate a possible correlation between the micronutrients assessed nutritional status.Only one subject showed malnutrition in relation to anthropometry. The zinc intake was adequate in almost the entire sample (75% of children, adolescents and adults), as with selenium (87.5% of all individuals), which is consistent with the plasma levels of minerals (with adequate levels of selenium in all participants and zinc in almost all). However, levels of both trace elements were deficient in the erythrocyte. Although the sample has not shown nutritional deficit based on anthropometry, there is a deficiency of minerals analyzed in erythrocytes / Mestre
28

Zinc inhibition of cell division : its relevance to cancer cells and possible mechanism of action

Skeef, Noel Samuel January 1989 (has links)
A description of two techniques used extensively in this study namely cell counting with a "cell counting plate" and argentation TLC for the separation of ω -6 -fatty acids is given. Zn supplementation into GM of two malignant (BL-6 and Hep- 350) and a non-malignant (LLC-MK) cell line/s resulted in an increased uptake of Zn by the cells and progressively suppressed proliferation of particularly the malignant cells. Zn chelation by EDTA suppressed in vitro proliferation of all 3 cell line, this effect being more pronounced in the malignant cells. A dietary Zn deficiency resulted in alopecia in mice and both a dietary Zn deficiency and Zn excess reduced growth of BL-6 tumours implanted subcutaneously in mice. Zn supplementation into GM progressively increased the uptake of [1-¹⁴C]-LA by BL-6 and LLC-MK cells but had a very slight though irregular effect on this parameter in the Hep- 350 cells. Zn supplementation also stimulated desaturase activity in the BL-6 cells. These results suggested that there are select cell lines whose Δ⁶-desaturase activity responds positively to Zn supplementation (e.g. the BL-6 cells). Delta-6-desaturase activity was also assayed in microsome preparations from different tissues. No enzyme activity was detected in the microsomes prepared from the BL-6 tumours. There was no significant effect with the addition of Zn or EDTA, on Δ⁶-desaturase activity of the regenerating liver microsomes. In the resting liver microsomes this enzyme activity was reduced only when EDTA and Zn were added together and when EDTA was added to the reaction medium as well as to the microsome preparations 2 hr before the enzyme activity assay was initiated. The results of these experiments suggested that the Δ⁶-desaturase enzyme in the microsome preparations may have had an adequate amount of Zn with further additions having no stimulatory effect on the enzyme. Two independent mechanisms of control of cell proliferation by low and high Zn are suggested to operate.
29

Cadmium and zinc levels in the hair of smokers and nonsmokers

Simonsen, Neal R. 01 January 1981 (has links)
To determine the relationship of tobacco and marijuana smoking to levels of cadmium and zinc manifested in hair samples, a study was conducted at Portland State University using atomic.absorption spectrophotometry. 97 adult student volunteers participated in the main study.
30

Characterization and plant availability of zinc in British Columbia orchard soils

Neilsen, Denise. January 1986 (has links)
No description available.

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