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Biodisponibilidade de fontes orgânicas e inorgânicas de zinco em ovinos; Bioavailability of organic and inorganic zinc sources in sheep

VILELA, F.G.; ZANETTI, M.A.; NETTO, A. Saran; FREITAS JUNIOR, J.E.; YOSHIKAWA, C.Y.C.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica
Português
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Compararam-se os efeitos de diferentes fontes e doses de zinco na dieta de ovinos Santa Inês sobre os níveis de zinco plasmático e de fosfatase alcalina. Foram utilizados 40 cordeiros, recém-desmamados, com média de peso de 18,4kg, distribuídos em 10 tratamentos: 1- dieta basal sem suplementação de zinco; 2- dieta basal + 200mg de Zn/kg de MS na forma de óxido de zinco; 3- dieta basal + 400mg de Zn/kg de MS na forma de óxido de zinco; 4- dieta basal + 600mg de Zn/kg de MS na forma de óxido de zinco; 5- dieta basal + 200mg de Zn/kg de MS na forma de zinco aminoácido; 6- dieta basal + 400mg de Zn/kg de MS na forma de zinco aminoácido; 7- dieta basal + 600mg de Zn/kg de MS na forma de zinco aminoácido; 8- dieta basal + 200mg de Zn/kg de MS na forma de zinco proteinato; 9- dieta basal + 400mg de Zn/kg de MS na forma de zinco proteinato; 10- dieta basal + 600mg de Zn/kg de MS na forma de zinco proteinato. A cada 28 dias, os animais foram pesados e tiveram seu sangue colhido para análise de zinco (Zn), análise de fosfatase alcalina e análises de imunoglobulinas G (IgG) e M (IgM). No final do experimento, foram coletadas amostras de fígado para estudo dos níveis de zinco hepático. Não houve diferença entre tratamentos nos níveis de fosfatase alcalina e de zinco hepático...

Biomarkers of metabolic syndrome and its relationship with the zinc nutritional status in obese women

FERRO, F. Ennes Dourado; LIMA, V. B. de Sousa; SOARES, N. R. Mello; COZZOLINO, S. Ma Franciscato; MARREIRO, D. do Nascimento
Fonte: AULA MEDICA EDICIONES Publicador: AULA MEDICA EDICIONES
Tipo: Artigo de Revista Científica
Português
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Introduction: Obesity is a chronic disease that induces risk factors for metabolic syndrome and, is associated with disturbances in the metabolism of the zinc. Therefore, the aim of this study was to investigate the existence of relationship between the biomarkers of metabolic syndrome and the zinc nutricional status in obese women. Method: Seventy-three premenopausal women, aged between 20 and 50 years, were divided into two groups: case group, composed of obese (n = 37) and control group, composed of no obese (n = 36). The assessment of the body mass index and waist circumference were carried out using anthropometric measurements. The plasmatic and erythrocytary zinc were analyzed by method atomic absorption spectrophotometry (lambda=213.9 nm). Results: In the study, body mass index and waist circumference were higher in obese women than control group (p < 0.05). The mean plasmatic zinc was 72.2 +/- 9.0 mu g/dl in obese women and 73.4 +/- 8.5 mu g/dl in control group (p > 0.05). The mean erythrocytary zinc was 36.4 +/- 15.0 mu g/gHb and 45.4 +/- 14.3 mu g/gHb in the obese and controls, respectively (p < 0.05). Regression analysis showed that the body mass index (t=-2.85) and waist circumference (t=-2.37) have a negative relationship only with the erythrocytary zinc (R(2)=0.32...

Effect of zinc supplementation in pregnant mice during experimental Trypanosoma cruzi infection

GONCALVES-NETO, Janaina Fernanda; TOLDO, Miriam Paula Alonso; SANTOS, Carla Domingues; PRADO JR., Jose Clovis do; FONSECA, Colete; ALBUQUERQUE, Sergio
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.74%
Zinc is an essential micronutrient and has significant effects on human growth, development, and immune function. Zinc supplementation or deficiency may affect the course of infection. Zinc enhances immune response against a wide range of viral, bacterial, and parasitic pathogens. In the present study, we investigated the effects of zinc sulphate (ZnSO(4)) supplementation (20 mg/kg/day) during pregnancy in mice, Swiss Webster strain infected by the Y strain of Trypanosoma cruzi. Oral supplementation of zinc sulphate in pregnant and non-pregnant infected animals did not affect the count of blood parasites as well as tissue parasitism in the heart, liver, and spleen. Zinc supplementation did not alter female body weight, the length of fetuses and neonates, placental size/weight and mortality rate. Among zinc supplied animals, no significant plasmatic zinc concentrations were observed. Concerning to tissue zinc concentrations, only the liver displayed enhanced values as compared to other organs. For placental parasitism, zinc supplied group displayed a significant decrease in amastigote burdens (P < 0.05). However due to the reduced number of parasite burdens in placenta of animals supplied with zinc, these data suggest that zinc was partially effective in up-regulating the host`s immune response against parasite...

Estado nutricional relativo ao zinco de crianças com fissura labiopalatina; Nutritional status of zinc in children with cleft lip palate

Mattos, Camila Frazão Nogueira de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 12/11/2010 Português
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A Fissura Labiopalatina é uma doença multifatorial que tem interferência sobre a qualidade da alimentação da criança, visto que na maioria das vezes os pacientes têm dificuldades de mastigação e deglutição. O zinco está envolvido em diversos processos fisiológicos, tem importante relação com mecanismos antioxidantes, imunitários, replicação celular e de transcrição protéica. De acordo com a Organização Mundial de Saúde, o zinco é o micronutriente mais importante para o desenvolvimento corporal e cognitivo da criança. Considerando a interferência da Fissura Labiopalatina sobre a qualidade da alimentação, e a importância do zinco para o desenvolvimento da criança, este estudo se propôs a avaliar o estado nutricional relativo ao zinco de crianças de 6 a 10 anos com Fissura Labiopalatina atendidas no Centro de Atendimento Integrado ao Fissurado Labiopalatino de Curitiba - PR. Foram dosadas as concentrações de zinco plasmático, eritrocitário e urinário. A quantidade de zinco dietético foi avaliada por meio dos métodos de recordatório de 24h e três registros alimentares. Foram avaliados peso e estatura, como dados antropométricos, e comparados ao escore Z. O estudo foi do tipo casocontrole. A concentração média de zinco plasmático...

Avaliação de fontes, absorção foliar e translocação de zinco (68Zn) em laranjeiras; Sources evaluation, foliar uptake and zinc translocation (68Zn) in Orange

Guedes, Elaine Maria Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/09/2012 Português
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Os estudos de adubação com zinco foliar em citros desenvolvidos no Brasil são na maioria das vezes limitados às informações das quantidades dos nutrientes absorvidos pelas folhas, porém o transporte do zinco das folhas para outras partes das plantas ainda precisa ser esclarecido. A maioria das investigações sobre tal assunto é vasta de resultados conflitantes. Em vista disso, o uso da técnica com isótopos estáveis é uma ferramenta viável para auxiliar na determinação direta da absorção e translocação de zinco aplicado via foliar no citros. O presente estudo tem como objetivos determinar (i) os teores de zinco nas folhas durante três dias após a pulverização; na fase de floração e frutificação do citros: (ii) teores e acúmulos de zinco nas folhas e frutos; (iii) concentração de zinco nos pluviolixiviados das folhas; (v) absorção e translocação do zinco proveniente das fontes nas folhas; (vi) translocação do zinco proveniente das fontes nos frutos; (vi) concentrações de zinco nos pluviolixiviados das folhas provenientes das fontes.Foram conduzidos dois experimentos na Estação Experimental de Citricultura de Bebedouro-SP. No primeiro experimento foram avalidas cinco fontes foliares de zinco, EDTA...

THE ASSESSMENT OF ZINC STATUS BY THE ZINC TOLERANCE-TEST IN THYROID-DISEASE

Pimenta, W. P.; Brandaoneto, J.; Curi, P. R.
Fonte: Dustri-verlag Dr Karl Feistle Publicador: Dustri-verlag Dr Karl Feistle
Tipo: Artigo de Revista Científica Formato: 34-37
Português
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Zinc status was evaluated in 12 hyperthyroid and in 7 hypothyroid patients in comparison with 8 euthyroid individuals by the oral zinc tolerance test and by the determination of urinary zinc excretion. Hyperthyroid patients presented a basal serum concentration similar to that of euthyroid individuals but greater urinary zinc excretion, indicating the occurrence of zinc depletion from tissues to the blood stream caused by the catabolism inherent in the hyperthyroid state. Hyperthyroidism also caused lower zinc assimilation by tissues after zinc ingestion. Hypothyroid individuals present lower basal zinc levels in serum than euthyroid and hyperthyroid individuals and urinary zinc excretion similar to that of euthyroid individuals. No changes in the parameters measured were observed after zinc load, suggesting reduced or delayed intestinal absorption and zinc assimilation by tissues. The present data are indicative of zinc deficiency, the lower intestinal zinc absorption probably being one of the contributing factors.

Optimum zinc supplementation level in Nile tilapia Oreochromis niloticus juveniles diets

Sa, MVDE; Pezzato, L. E.; Lima, MMBF; Padilha, P. D.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 385-401
Português
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The present study was designed to determine the optimum dietary zinc supplementation to Nile tilapia juveniles (13.3 +/- 1.13 g), by using vegetable-based diets supplemented with increasing levels of zinc from commercial-grade zinc sulfate monohydrate, a previously determined zinc source of higher bioavailability. The basal diet was supplemented with 25, 50, 100, 150, 200, 300, or 400 mg/kg Zn. The experiment was conducted in forty 250-l tanks arranged in a recirculating water system. The experimental period was divided in two phases. For the first 10-week experimental phase, fish were fed satiation diets supplemented with increasing levels of zinc. For the second 5-week experimental phase, fish that were fed diets supplemented with 0-300 mg/kg Zn during the first phase were fed the 400 mg/kg Zn-supplemented diet; fish fed the diet supplemented with 400 mg/kg Zn (first phase) were fed the nonzinc-supplemented diet (second phase). Broken-line analysis showed that the optimum dietary zinc supplementation ((ZnSO4H2O)-H-.) to Nile tilapia juveniles, using weight gain and bone zinc saturation as response criteria, was 44.50 and 79.51 mg/kg Zn, respectively. When challenged by a zinc-deficient diet, tilapia mobilized stored bone zinc to preserve its zinc status. By considering that bone zinc saturation is a more accurate response criterion than weight gain...

RENAL EXCRETION OF ZINC IN NORMAL INDIVIDUALS DURING ZINC TOLERANCE-TEST AND GLUCOSE-TOLERANCE TEST

Brandaoneto, J.; Shuhama, T.; Pimenta, W. P.; Piesco, R. V.; Castro, AVB; Mazeto, GMGS; Chung, J. S.; Franco, RJS; Curi, P. R.
Fonte: Dustri-verlag Dr Karl Feistle Publicador: Dustri-verlag Dr Karl Feistle
Tipo: Artigo de Revista Científica Formato: 62-67
Português
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The urinary excretion, renal clearance, and tubular reabsorption of zinc were investigated in 30 adult healthy subjects under basal conditions and during the zinc and glucose tolerance tests. After a 12h overnight fast, each subject was submitted to renal clearance of zinc. The procedures were performed between 8.00 and 12.00 a.m., after emptying the bladder and ingestion of 4 ml deionized water/kg body weight at 8.00 a.m. The first urine sample was collected at 10.00 a.m., and the second at 12.00 a.m. A dose of 110 mg ZnSO4.7H(2)O was administered orally to each subject, diluted in 20 mi deionized water, at time 0 min. Blood samples were collected from an antecubital vein at times -30, 0, and 30 min and at 30 min intervals up to 240 min. Glucose was administered intravenously (0.5 ml 50%/kg body weight) during the first 3 min of the test, and blood samples were collected from an unconstricted, contralateral, antecubital vein at times -30, 0, 3, 5, 10, 20, 30, 45, 60, and 90 min. The results showed that urinary zinc excretion, and renal zinc clearance were significantly higher during the zinc and glucose tolerance tests than in the control condition. on the other hand, renal zinc clearance was more elevated during the glucose tolerance test than during the zinc tolerance test. Variations in zinc tubular reabsorption and glomerular filtration rate were not detected. The results suggest that urinary excretion and renal clearance of zinc in healthy subjects increase during acute zinc ingestion and glucose infusion. Although zinc ingestion raised urinary zinc excretion...

Renal excretion of zinc in normal individuals during zinc tolerance test and glucose tolerance test

Brandao-Neto, J.; Shuhama, T.; Pimenta, W. P.; Piesco, R. V.; Castro, A. V B; Mazeto, G. M G S; Chung, J. S.; Franco, R. J S; Curi, P. R.
Tipo: Artigo de Revista Científica Formato: 62-67
Português
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The urinary excretion, renal clearance, and tubular reabsorption of zinc were investigated in 30 adult healthy subjects under basal conditions and during the zinc and glucose tolerance tests. After a 12h overnight fast, each subject was submitted to renal clearance of zinc. The procedures were performed between 8.00 and 12.00 a.m., after emptying the bladder and ingestion of 4 ml deionized water/kg body weight at 8.00 a.m. The first urine sample was collected at 10.00 a.m., and the second at 12.00 a.m. A dose of 110 mg ZnSO47H2O was administered orally to each subject, diluted in 20 ml deionized water, at time 0 min. Blood samples were collected from an antecubital vein at times -30, 0, and 30 min and at 30 min intervals up to 240 min. Glucose was administered intravenously (0.5 ml 50%/kg body weight) during the first 3 min of the test, and blood samples were collected from an unconstricted, contralateral, antecubital vein at times -30, 0, 3, 5, 10, 20, 30, 45, 60, and 90 min. The results showed that urinary zinc excretion, and renal zinc clearance were significantly higher during the zinc and glucose tolerance tests than in the control condition. On the other hand, renal zinc clearance was more elevated during tile glucose tolerance test than during the zinc tolerance test. Variations in zinc tubular reabsorption and glomerular filtration rate were not detected. The results suggest that urinary excretion and renal clearance of zinc in healthy subjects increase during acute zinc ingestion and glucose infusion...

Relative bioavailability of zinc in supplemental inorganic and organic sources for Nile tilapia Oreochromis niloticus fingerlings

Do Carmo E Sá, M. V.; Pezzato, L. E.; Barros, M. M.; De Magalhães Padilha, P.
Tipo: Artigo de Revista Científica Formato: 273-281
Português
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A 90-day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg -1, as zinc sulphate monohydrate (ZnSO 4), zinc oxide (ZnO) or zinc amino acid complex (Zn-AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO 4 and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn-AA (171 ± 3.62 ?g g -1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 ?g g -1) or with ZnSO 4 (204 ± 19.9 ?g g -1). Assuming the concentration of zinc in bones as the response criterion...

Apparent absorption of zinc from supplemental inorganic and organic sources to Nile tilapia Oreochromis niloticus juveniles

Do Carmo e Sá, Marcelo Vinícius; Pezzato, Luiz Edivaldo; Barros, Margarida Maria; De Magalhães Padilha, Pedro
Tipo: Artigo de Revista Científica Formato: 375-383
Português
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Nile tilapia Oreochromis niloticus fingerlings were fed with purified or practical diets, supplemented with 150 Ing Zn/kg, from different sources. Dry matter (DM), crude protein (CP), ether extract (EE), and gross energy (GE) apparent digestibility coefficients (ADC), as well as zinc, copper, calcium, and phosphorus apparent absorption coefficients (AAC) were determined by the addition of 0.1% chromic oxide to the diets. The supplemental zinc sources utilized were commercial grade zinc sulfate monohydrate (ZnSO 4), zinc oxide (ZnO) and a zinc amino acid complex (Zn-AA). Analytical grade zinc sulfate heptahydrate was also utilized as a standard reference zinc source. There was a significant difference between purified (74.9%) and practical (41.3%) zinc AAC for the ZnO supplemented diets (P < 0.05). The supplemental zinc sources presented similar AAC when purified diets were utilized. However, ZnSO 4 was the best supplemental zinc source when practical type diets were used. There were no significant differences between supplemental zinc AAC from ZnS0 4 (68.9%), and supplemental zinc AAC from Zn-AA (61.3%) in practical diets, but Zn-AA diet showed a statistically lower zinc AAC when compared with the standard zinc source diet (75.6%). The practical diet supplemented with ZnO had the worst supplemental zinc AAC (41.3%). Dietary copper (74.21%)...

Efeito da remoção da fonte de zinco da mistura salina da dieta sobre o ganho de peso de ratos wistar e o valor nutritivo da caseina : influencia de adições crescentes de acido fitico; Effect of the removing zinc source of the saline mixture of the diet on profit of weight of Wistar rats and the nutritional value of the casein: influence of increasing additions of phytic acid

Karina Ribeiro Rios
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 20/08/2003 Português
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O zinco é um mineral que desempenha inúmeras funções biológicas, como catalisador para a atividade de mais de 300 enzimas, constituinte estrutural de muitas proteínas e como regulador na prevenção da formação de radicais livres. Dado a esta multiplicidade funcional, a deficiência de zinco é especialmente crítica em estádios de rápido crescimento e desenvolvimento onde seu requerimento é aumentado, na ingestão alimentar deficiente ou quando ocorre baixa biodisponibilidade do zinco. Com a descoberta da deficiência do mineral em humanos na década de 60 devido ao elevado consumo de ácido fítico por populações do Oriente Médio, os estudiosos acreditavam ser este um fato isolado, até que na década de 90 foi reconhecido como um problema de carência nutricional de ocorrência freqüente em países desenvolvidos. Com vistas a determinar a influência da fonte de zinco da mistura mineral da dieta AIN-93G e de adições de ácido fítico no crescimento e estado nutricional de zinco em ratos Wistar, estudou-se o efeito da suplementação com carbonato de zinco (56 % Zn) e ácido fítico na forma de hexafosfato de mioinositol (IP6), utilizando-se adições crescentes na dieta de caseína. Os resultados mostraram que apesar de o carbonato de zinco (56 % Zn) ter sido removido por 32 dias...

Avaliação dos efeitos da suplementação de zinco durante a gestação de camundongos infectados com as cepas Y e Bolivia de Trypanosoma Cruzi; Evaluation of effects the zinc supplementation during pregnancy in infected mice with Y and Bolivia strain of Trypanosoma cruzi

Janaina Fernanda Gonçalves Neto
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/06/2006 Português
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36.73%
Dados da literatura relataram a importância da suplementação ou da ausência de determinados micronutrientes no comportamento de uma infecção. Assim como, durante a gestação, a concentração de Zinco (Zn) no plasma materno diminui devido a diversas alterações fisiológicas, aumento da absorção e transferência fetal. Entretanto, a avaliação da suplementação de micronutrientes durante a infecção chagásica pouco tem sido discutida. Diante dos benefícios proporcionados por meio da suplementação de Zn sobre algumas doenças infecciosas e durante a gestação, foram objetivos do presente trabalho: determinar as concentrações plasmáticas e teciduais de Zn, avaliar os efeitos da suplementação desse micronutriente durante a gestação de camundongos infectados por Trypanosoma cruzi e os efeitos in vitro em cultura de células. Foram utilizados camundongos Swiss prenhas e não prenhas, infectadas com duas cepas distintas de T. cruzi. Esses animais foram suplementados com 20mg/Kg de sulfato de zinco durante 7 dias (cepa Y) e 14 dias (cepa Bolívia). Após a suplementação diversos parâmetros foram avaliados: parasitemia, peso materno, peso e tamanho dos fetos, desenvolvimento dos filhotes após o nascimento, as concentrações plasmáticas e teciduais de Zn...

Propriedades ópticas e estruturais de óxido de zinco contendo enxofre; Structural and optical properties of sulfur-containing zinc oxide

Gabriela Zanotto Bosshard
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 25/07/2012 Português
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O objetivo deste projeto foi investigar a síntese de óxido de zinco contendo enxofre obtido a partir de sulfeto de zinco nas fases wurtzita (hexagonal) e blenda de zinco (cúbica), assim como fazer a caracterização e estudar as alterações estruturais e ópticas dos materiais sintetizados e compará-las às propriedades do óxido de zinco sintetizado a partir de hidroxicarbonato de zinco. O método de síntese utilizado permite a obtenção de sulfeto de zinco hexagonal ou cúbico a baixa temperatura, permitindo um estudo comparativo da influência da estrutura cristalina do sulfeto de zinco na formação do óxido de zinco. Os estudos por difração de raios X mostram que há leve variação nos parâmetros de rede do material obtido, principalmente quando a síntese parte da fase hexagonal do ZnS. Somado a isso, a análise da luminescência dos materiais obtidos mostra emissão em torno de 520 nm, que pode ser atribuída a transição eletrônica entre defeitos de Frenkel (Zni e VZn") que foram formados a temperaturas inferiores à requerida para a formação deste tipo de defeito, indicando, portanto alterações na rede do óxido de zinco contendo enxofre.; This project aimed to investigate the synthesis of sulfur-containing zinc oxide obtained from zinc sulfide in the wurtzite (hexagonal) or zinc blende (cubic) phases...

Effect of zinc supplementation in pregnant mice during experimental Trypanosoma cruzi infection

GONCALVES-NETO, Janaina Fernanda; TOLDO, Miriam Paula Alonso; SANTOS, Carla Domingues; PRADO JR., Jose Clovis do; FONSECA, Colete; ALBUQUERQUE, Sergio
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.74%
Zinc is an essential micronutrient and has significant effects on human growth, development, and immune function. Zinc supplementation or deficiency may affect the course of infection. Zinc enhances immune response against a wide range of viral, bacterial, and parasitic pathogens. In the present study, we investigated the effects of zinc sulphate (ZnSO(4)) supplementation (20 mg/kg/day) during pregnancy in mice, Swiss Webster strain infected by the Y strain of Trypanosoma cruzi. Oral supplementation of zinc sulphate in pregnant and non-pregnant infected animals did not affect the count of blood parasites as well as tissue parasitism in the heart, liver, and spleen. Zinc supplementation did not alter female body weight, the length of fetuses and neonates, placental size/weight and mortality rate. Among zinc supplied animals, no significant plasmatic zinc concentrations were observed. Concerning to tissue zinc concentrations, only the liver displayed enhanced values as compared to other organs. For placental parasitism, zinc supplied group displayed a significant decrease in amastigote burdens (P < 0.05). However due to the reduced number of parasite burdens in placenta of animals supplied with zinc, these data suggest that zinc was partially effective in up-regulating the host`s immune response against parasite...

Effect of nickel and magnesium on zinc electrowinning using sulfate solutions

Lins,V. F. C; Castro,M. M. R; Araújo,C. R; Oliveira,D. B
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 Português
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Zinc electrowinning is performed with the application of a current through insoluble electrodes (Pb - Ag), causing the electrolysis of zinc sulfate, with or without impurities, and zinc deposition on the cathode of aluminum. The impurities can reduce the current efficiency and increase the energy consumption in zinc electrolysis. In this work, the effect of nickel and magnesium on zinc electrodeposition was studied using the electrochemical techniques of galvanostatic deposition and cyclic voltammetry. Additions of nickel, magnesium or both cations in zinc sulfate electrolyte resulted in a marginal increase in current efficiency. Addition of nickel or magnesium polarizes the cathode; however, the extent of polarization in the presence of magnesium is more than that of nickel. Addition of magnesium to the zinc electrolyte caused zinc reduction at a more negative potential. The addition of nickel to the zinc electrolyte increased the current density of the anodic peaks, thus increasing the dissolution of zinc and hydrogenated phases. The addition of nickel to the zinc and magnesium solutions decreased the nucleation loop, facilitating zinc deposition.

Plasma zinc and hair zinc levels, anthropometric status and food intake of children in a rural area of Brazil

Beinner,Mark Anthony; Menezes,Maria Ângela de Barros Correia; Silva,Jose Bento Borba da; Amorim,Flavia Regina de; Jansen,Ann Kristine; Lamounier,Joel Alves
Fonte: Pontifícia Universidade Católica de Campinas Publicador: Pontifícia Universidade Católica de Campinas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2010 Português
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OBJECTIVE: The objective of this study was to investigate the levels of plasma zinc, hair zinc, growth and food consumption in children aged 6 to 24 months in a rural area of Diamantina (MG), Brazil. METHODS: Plasma and hair zinc concentrations were analyzed using flame atomic absorption spectrometry and neutron activation analysis, respectively. Weight-for-age, weight-for-height and height-for-age, expressed as Z-scores, were measured according to the World Health Organization reference curves. Dietary zinc intake was determined by a 3-day dietary recall filled out by the mother or guardian. RESULTS: Zinc deficiency was found in 11.2% and 16.8% of the children according to plasma zinc e hair zinc levels, respectively. Mean plasma zinc and hair zinc for children 11 (127) months of age were 15.4 (SD=4.2) µmol L-1 and 139.5 (SD=72.1) µg g-1 and 16.0 (SD=4.5) µmol L-1 and 134.3 (SD=110.3) µg g-1, respectively. Anthropometric measurements showed that 8.0%, 6.8% and 3.4% of the children were underweight, stunted and wasted, respectively. The mean dietary intake of zinc was 3.2 (SD=2.3) mg/day. One-third of the children did not eat enough foods that contain zinc. There were no correlations among plasma zinc level, hair zinc level, anthropometric parameters and zinc intake. CONCLUION: The results demonstrate that zinc deficiency is a problem in the studied population...

Assessing in vitro solubilization potential of different zinc solubilizing bacterial (zsb) isolates

Saravanan,Venkatakrishnan Sivaraj; Subramoniam,Sudalayandy Rama; Raj,Savariappan Anthoni
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2004 Português
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Zinc solubilizing ability of Bacillus sp. and Pseudomonas sp. was assessed using zinc oxide, zinc sulphide (sphalerite) and zinc carbonate in both plate and broth assays. ZSB-O-1 (Bacillus sp.) showed highest dissolution in the zinc sulphide (Sphalerite ore), with 2.80 cm of dissolution zone and 14.50 cm² of area in the plate assay and 13.60 mg kg-1 of zinc in the broth assay on the 15th day after inoculation. The ZSB-S-2 (Pseudomonas sp.) showed more solubilizing ability in the zinc oxide, with 3.30 cm clearing zone and 20.43 cm² area in the plate assay and 16.40 mg kg-1 of zinc in the broth assay over the same inoculation period. The isolate ZSB-S-4 (Pseudomonas sp.) has highest solubilizing potential in zinc carbonate with 6.20 cm of dissolution zone and 13.40 cm² area in the plate assay and 13.40 mg kg-1 of zinc in the broth assay. Thus, the solubilization potential varies among different cultures. The solubilization might be due to production of acids by the culture, since the pH of the culture broth has been shifted form 7.0-7.3 to 4.8-6.5 after 15 days of inoculation. The zinc tolerance limit for two cultures (ZSB-O-1 and ZSB-S-2) was studied and determined to be upto 100 mg kg-1 of zinc in the in vitro broth assay.

Improving reproductive efficiency of chickpea by foliar application of zinc

Pathak,Girish Chandra; Gupta,Bhavana; Pandey,Nalini
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 Português
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Zinc deficiency is not only the cause of low productivity of crops, but it also results in low zinc content in seeds, which leads to poor dietary zinc intake. To study the effect of zinc foliar application on improving plant yield and seed zinc content for human consumption, chickpea plants were raised in refined sand culture with deficient (0.2 µM) and sufficient (1µM) supply of zinc under glass-house conditions. Prior to initiation of the reproductive phase, zinc was applied as 0.1% ZnSO4 foliar spray to both zinc sufficient and deficient plants. The plants exposed to different zinc treatments were studied for pollen and stigma structure and their involvement in fertilization and seed yield. Zinc deficiency induces flower abortion, pollen, and ovule infertility leading to low seed set and ultimately its yield. Foliar application of ZnSO4 to zinc deficient plants at the time of initiation of flowering partially reverses the adverse effect of zinc deficiency on pollen-stigma morphology, pollen fertility, and greatly enhanced seed yield of plants. Zinc foliar application improved not only the boldness and vigor of seeds in zinc-deficient plants, but also the seed zinc content in zinc-deficient seeds as well as the sufficient ones.

The Role of Particulate Matter-Associated Zinc in Cardiac Injury in Rats

Kodavanti, Urmila P.; Schladweiler, Mette C.; Gilmour, Peter S.; Wallenborn, J. Grace; Mandavilli, Bhaskar S.; Ledbetter, Allen D.; Runge, Marschall S.; Karoly, Edward D.; Peddada, Shyamal; Jaskot, Richard; Richards, Judy H.; Thomas, Ronald; Madamanchi, N
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
Português
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Background: Exposure to particulate matter (PM) has been associated with increased cardiovascular morbidity; however, causative components are unknown. Zinc is a major element detected at high levels in urban air.Objective We investigated the role of PM-associated zinc in cardiac injury. Methods: We repeatedly exposed 12- to 14-week-old male Wistar Kyoto rats intratracheally (1×/week for 8 or16 weeks) to a) saline (control); b) PM having no soluble zinc (Mount St. Helens ash, MSH); or c) whole-combustion PM suspension containing 14.5 ?g/mg of water-soluble zinc at high dose (PM-HD) and d ) low dose (PM-LD), e) the aqueous fraction of this suspension (14.5 ?g/mg of soluble zinc) (PM-L), or f ) zinc sulfate (rats exposed for 8 weeks received double the concentration of all PM components of rats exposed for 16 weeks). Results: Pulmonary inflammation was apparent in all exposure groups when compared with saline (8 weeks greater than 16 weeks). PM with or without zinc, or with zinc alone caused small increases in focal subepicardial inflammation, degeneration, and fibrosis. Lesions were not detected in controls at 8 weeks but were noted at 16 weeks. We analyzed mitochondrial DNA damage using quantitative polymerase chain reaction and found that all groups except MSH caused varying degrees of damage relative to control. Total cardiac aconitase activity was inhibited in rats receiving soluble zinc. Expression array analysis of heart tissue revealed modest changes in mRNA for genes involved in signaling...