Extraction of hemoglobin with calixarenes and biocatalysis in organic media of the complex with pseudoactivity of peroxidase

The present work involves the use of p-tert-butylcalix[4,6,8]arene carboxylic acid derivatives ((t)Butyl[4,6,8]CH2COOH) for selective extraction of hemoglobin. All three calixarenes extracted hemoglobin into the organic phase, exhibiting extraction parameters higher than 0.90. Evaluation of the solvent accessible positively charged amino acid side chains of hemoglobin (PDB entry 1XZ2) revealed that there are 8 arginine, 44 lysine and 30 histidine residues on the protein surface which may be involved in the interactions with the calixarene molecules. The hemoglobin-(t)Butyl[6]CH2COOH complex had pseudoperoxidase activity which catalysed the oxidation of syringaldazine in the presence of hydrogen peroxide in organic medium containing chloroform. The effect of pH, protein and substrate concentrations on biocatalysis was investigated using the hemoglobin-(t)Butyl[6]CH2COOH complex. This complex exhibited the highest specific activity of 9.92 x 10(-2) U mg protein(-1) at an initial pH of 7.5 in organic medium. Apparent kinetic parameters (V'(max), K'(m), k'(cat) and k'(cat)/K'(m)) for the pseudoperoxidase activity were determined in organic media for different pH values from a Michaelis-Menten plot. Furthermore, the stability of the protein-calixarene complex was investigated for different initial pH values and half-life (t(1/2)) values were obtained in the range of 1.96 and 2.64 days. Hemoglobin-calixarene complex present in organic medium was recovered in fresh aqueous solutions at alkaline pH, with a recovery of pseudoperoxidase activity of over 100%. These results strongly suggest that the use of calixarene derivatives is an alternative technique for protein extraction and solubilisation in organic media for biocatalysis.

O metacinema norte-americano e o storytelling : de Orson Welles a David Lynch

ABSTRACT: The American metacinema which, by tradition, is narrative but extremely formulaic favours the story above the telling. No man contributed more to alter this state of affairs than Orson Welles, whose cinematic practice exalted the filmic enunciation and linked it more explicitly to the narrative intentions of the creator, making it obvious that metanarrative is synonymous with metacinema. With Citizen Kane (1941), in particular, the cinema was made more disnarrative, as meant by French writer/director Alain Robbe–Grillet, well ahead of Modernism. The fragmented narration, the temporal convolutions, a tendency for paradox and the interpretative obstacles all come together to anticipate the serial practice of David Lynch in his last four features. Structuring the films in segments which constitute different but complementary versions of the same events, Lynch manages to express the director’s enunciation along with the narration of the characters, reinforcing the role of the telling in the midst of the story. In INLAND EMPIRE (2006) the use of mise-en-abyme as a way of duplicating stories and tellers further increases the objective and complicates what is clearly the reign of the puzzle or mind-game film. In the footsteps of Welles, Lynch contributed for an outbreak of metanarrative / metacinematic crossover indie films closer to the European aesthetic practice but still very much within the American narrative tradition.

Glucose-6-Phosphate dehydrogenase deficiency in children from 0 to 14 years hospitalized at the Pediatric Hospital David Bernardino, Luanda, Angola

The Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymatic defect in the world. The most common clinical manifestations are acute hemolytic anemia associated with drugs, infections, neonatal jaundice and hemolytic non-spherocytic chronic anemia. The main aim of this study was to determine the frequency of major genetic variants of G6PD leading to enzyme deficiency in children from 0 to 14 years at a Pediatric Hospital in Luanda, Angola. A cross-sectional and descriptive analytical study covered a total of 194 children aged from 0 to 14 years, of both genders and hospitalized at the Pediatric Hospital David Bernardino, Luanda between November and December, 2011. The G202A, A376G and C563T mutations of the G6PD gene were determined by real-time PCR with Taqman probes. The disabled A-/A- genotype was detected in 10 girls (10.9%). Among the boys, 21 (20.6%) presented the genotype A-. Considering all the samples, the A- variant was observed in 22.4% of cases. The Mediterranean mutation was not detected in the Angolan sample. Furthermore, no association was found between genotype and anemia, nutritional state and mucosa color. A significant association, however, was observed with jaundice. Based on the results obtained, there is a clear need to identify those with the disabled genotype in the Angolan population in order to avoid cases of drug-induced anemia, particularly in the treatment of malaria, so prevalent in Angola.

O espectador (in)visível: reflexividade na óptica do espectador em Inland empire de David Lynch

Com INLAND EMPIRE (2006) David Lynch realiza uma obra inteiramente metacinematográfica, provando que este género transversal à História do cinema é passível de coexistir com uma poética arrojada, de pendor moderno, segundo a divisão que Gilles Deleuze faz da Sétima Arte. A produção teórica sobre esta vertente fílmica de Lynch é em termos internacionais muito escassa e em Portugal virtualmente inexistente, justificando que se proceda um trabalho de investigação nestes moldes. Ademais, INLAND EMPIRE não é um exemplo isolado na obra do cineasta, mas sim o ponto culminante de uma carreira que tem vindo a prestar cada vez mais atenção à temática meta-espectatorial. A abordagem de Lynch tem a particularidade de congregar num único trabalho o desejo de manifestar o vidente espelhando igualmente o filme, o que permite abordar INLAND EMPIRE como reflexividade na óptica do espectador. Trata-se de encenar uma alegoria do vidente, mas equacionando produção com recepção. Deste modo, o presente livro adopta o mecanismo da enunciação como base da reflexividade institucional e narrativa em duas secções teóricas distintas versando, respectivamente, a (re)duplicação especular e a mise en abyme. A cada um destes capítulos corresponde uma análise prática directamente relacionada com os factores teóricos apontados. A obra culmina com um areflexão sobre as implicações do cinema digital para a execução de alegorias cinematográficas e a sua influência em INLAND EMPIRE, que já foi inteiramente produzido com esta tecnologia.