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A method that involves analysis of bovine liver by slurry nebulization and ICP-OES has been developed. This method permits rapid and accurate determination of Cu, Fe, Mg, Mn and Zn in bovine liver. Aliquots of freeze-dried and powdered bovine liver sample were dispersed in 2.0 M HNO3 and sonicated to homogenize the resulting slurries. Bovine liver samples were also microwave digested or subjected to aqueous extraction for comparison of analytical results. Concentrations of Cu, Fe, Mg, Mn and Zn in aqueous slurries, the digests, and aqueous extracts were determined by the ICP-OES using external calibration curves. A student’s ttest showed that the results obtained using the slurry method were in good agreement at 95 % confidence level (CL) with those of microwave digestion or aqueous extraction techniques, except for Fe. To check the accuracy and precision of the slurry method, a bovine liver CRM was analyzed and good agreement was achieved with the certified values at 95 % CL. The results demonstrate inefficiency of aqueous extraction technique for complete removal of Fe in bovine liver sample.

Master of Science / Department of Electrical and Computer Engineering / Punit Prakash / Microwave ablation is clinically used to thermally ablate cancerous tissue in the liver and other organs. When treating large tumor volumes, physicians may use multiple antennas simultaneously. Multiple antennas can ablate a larger tissue volume while using the same total power as a single antenna. Pre-clinical simulation and experimental studies most often presume parallel insertion of antennas. However, due to anatomical constraints, such as the presence of ribs and the diaphragm, it is often challenging to insert antennas in a parallel fashion in practice. Previous studies have attempted to analyze the effect of non-parallel antenna insertion on ablation outcome using computational and experimental approaches; however, they were limited because they did not account for dynamic temperature-dependent changes in tissue electrical properties in simulations and employed limited experimental validation. In this thesis, we have developed improved models of multiple-antenna microwave ablation, including accounting for the effects of temperature-dependent changes in tissue properties. We have also developed a system for experimental assessment of ablation zone profiles in ex vivo tissues. By utilizing 3D printing, we have constructed a device to precisely position antennas within experimental tissue samples and allows for accurate sectioning of the ablation zone relative to the plane of antenna insertion. Furthermore, we implemented image processing techniques for quantifying the size and shape of experimental ablation zones. This enables more accurate and repeatable comparisons of ablation profiles between simulations and experiments. We found that for an inter-antenna spacing in the range of 10 – 20 mm, simulations and experiments indicated that the ablation zone volumes may change by up to 30% due to non-parallel antenna insertion.

The flavin-containing monooxygenases (FMO / E.C.1.14.13.8) are microsomal NADPH and oxygen-dependent flavoprotein enzymes that catalyze the oxidation of a wide variety of xenobiotics, including drugs and environmental toxicants. Nucleophiles containing nitrogen, sulfur, phosphorus and selenium heteroatoms are the substrates of FMO. Bovine liver microsomal FMO enzyme activity was characterized using methimazole as substrate, which is a highly specific substrate for FMO. From 12 different bovine liver samples, microsomes were prepared and the average specific activity of bovine liver microsomal FMO was found to be 2.37 &amp / #61617 / 0.30 nmol/min/mg (Mean &amp / #61617 / SE, n=12). The rate of reaction was linear up to 0.5 mg of bovine liver microsomal protein. The maximum FMO enzyme activity was detected at 37 &amp / #61616 / C and at pH 8.0. Effects of detergents / Triton X-100 and Emulgen 913, on FMO activity were determined and found that enzyme activity increased by the addition of either detergent at all concentrations (0.1%-1.0%). The apparent Vmax and Km values of bovine liver microsomal FMO for methimazole substrate were found as 1.23 nmol/min/mg and 0.11 mM, respectively. Thermostability of bovine liver microsomal FMO was studied at four different temperatures / 24 &amp / #61616 / C, 37 &amp / #61616 / C, 50 &amp / #61616 / C and 65 &amp / #61616 / C. The incubation time required for the complete loss of enzyme activity was 5 minutes at 65 &amp / #61616 / C, 10 minutes at 50 &amp / #61616 / C and 6.5 hours at 37 &amp / #61616 / C. 68 % of the activity was still detectable at the end of 53 hours at 24 &amp / #61616 / C. Bovine liver microsomal activity towards two drug substrates, imipramine and chlorpromazine, was also determined and found to be 3.73 and 3.75 nmol NADPH oxidized/min/mg, respectively. Effects of two drug substrates, imipramine and chlorpromazine, on bovine liver microsomal FMO-catalyzed methimazole oxidation activity was also studied and found that they inhibit FMO activity at all concentrations studied. Modulation of bovine liver microsomal FMO activity was studied using three different heavy metal ions / Ni+2, Cd+2 and Hg+2. At all other concentrations studied for each heavy metal ion and at all substrate methimazole concentrations (0.1, 0.2, 0.5, 1.0 mM), FMO-catalyzed methimazole oxidation activity decreased compared to control activity. KI values for Ni+2, Cd+2 and Hg+2 were found to be 0.5 mM, 0.085 mM, 4.6 &amp / #61549 / M, respectively. From the Dixon plot, the pattern of inhibition for three heavy metal ions was observed to be noncompetitive.

The high resolution structure of protein molecules and protein-protein complexes is important to investigate their functions. Today, large 3D or 2D crystals are required to obtain protein structures by X-ray crystallography or conventional Electron Microscopy, respectively. However, production of such crystals of good quality is a solely empirical procedure, which relies on screening numerous crystallization conditions. At the same time, multilayered protein crystals are often a by-product of attempts to grow 3D or 2D crystals and could be obtained more easily. So far, multilayered protein crystals have not been used in electron microscopy for structure determination, as the interpretation of an electron diffraction pattern is rather complicated. In this thesis we present the first protein structure bovine liver catalase at 4 Å resolution solved using electron diffraction data from multilayered crystals. 55 diffraction patterns (17 tilt series) were recorded and used for the reconstruction. The tilt geometry of each individual diffraction pattern was determined by a least-squares algorithm or Laue zone analysis to perform spot indexing. The phase problem was solved by molecular replacement. The influence of the missing data cone on the self-rotation function and interpretation of reconstructed map is discussed.

Made available in DSpace on 2014-12-17T14:03:26Z (GMT). No. of bitstreams: 1 RoseCPA.pdf: 565962 bytes, checksum: 1a689250021861f92b149a94b8da62bb (MD5) Previous issue date: 2005-03-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The vitamin A is essential to animals because of its participation in a great number of biological functions. The investigation of this vitamin s concentrations is important to serve as reference to normality parameters. This study had as aim to analyse the serics and hepatics concentrations of vitamin A in two groups of bovines and to compare the hepatics concentrations to the present requeriments of vitamin A for pregnant women. It was also appraised the consume habit of bovine liver by pregnant women through of the alimentary frequency quest. Two groups of bovine were studied and the first was formad by Nelore bovine breed and the second by bovine without defined breed (WDB). It was analysed 120 samples: 60 of liver and 60 of serum. The method used to dose retinol was High Performance Liquid Cromatography (HPLC). The average (+ sd) of retinol concentrations in Nelore breed bovine and WDB liver were 16947,8 + 6866,9 and 5213,1 + 2517,2 ?g of retinol/100g and at serum 39,6 + 17,9 e 28,6 + 9,4 ?g of retinol/dL, respectively. No statistically significant correlation was found between hepatic and the serum retinol. The bovines in this study had adequate vitamin A levels. Independently of animal breed, the daily ingestion of bovine liver is not advised for pregnant women who show adequate support of vitamin A. The consume of bovine liver by pregnant women consulted on school maternity hospital Janu?rio Cicco, UFRN, Natal RN, was considered high / A vitamina A ? essencial aos animais devido sua participa??o em uma s?rie de fun??es biol?gicas. A investiga??o das concentra??es desta vitamina ? importante para servir como refer?ncia para par?metros de normalidade. O objetivo do presente estudo foi analisar as concentra??es s?ricas e hep?ticas de vitamina A em dois grupos de bovinos e comparar as concentra??es hep?ticas com os atuais requerimentos desta vitamina para gestantes. Avaliou-se tamb?m o h?bito de consumo de f?gado bovino por mulheres gestantes atrav?s do question?rio de freq??ncia alimentar. Dois grupos de bovinos foram estudados sendo o primeiro formado por bovinos da ra?a Nelore e o segundo por bovinos sem ra?a definida (SRD). Analisou-se 120 amostras: 60 de f?gado e 60 de soro. O m?todo utilizado para dosar retinol foi a Cromatografia L?quida de Alta Efici?ncia (CLAE). As m?dias (+ dp) das concentra??es de retinol no f?gado dos bovinos da ra?a Nelore e SRD foram 16947,8 + 6866,9 e 5213,1 + 2517,2 ?g de retinol/100g e no soro 39,6 + 17,9 e 28,6 + 9,4 ?g de retinol/dL, respectivamente. N?o foi encontrada correla??o estatisticamente significativa entre o retinol hep?tico e o s?rico. Os bovinos do presente estudo se encontravam com aportes adequados de vitamina A. Independentemente da ra?a do animal, a ingest?o di?ria de f?gado bovino ? desaconselhada para mulheres gr?vidas que apresentam aportes adequados de vitamina A. O consumo de f?gado bovino por mulheres gestantes atendidas na Maternidade Escola Janu?rio Cicco, UFRN, Natal RN, foi considerado alto