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1.
Biochim Biophys Acta ; 1419(2): 173-85, 1999 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-10407069

RESUMO

The white, brown and scarlet genes of Drosophila melanogaster encode proteins which transport guanine or tryptophan (precursors of the red and brown eye colour pigments) and belong to the ABC transporter superfamily. Current models envisage that the white and brown gene products interact to form a guanine specific transporter, while white and scarlet gene products interact to form a tryptophan transporter. In this study, we report the nucleotide sequence of the coding regions of five white alleles isolated from flies with partially pigmented eyes. In all cases, single amino acid changes were identified, highlighting residues with roles in structure and/or function of the transporters. Mutations in w(cf) (G589E) and w(sat) (F590G) occur at the extracellular end of predicted transmembrane helix 5 and correlate with a major decrease in red pigments in the eyes, while brown pigments are near wild-type levels. Therefore, those residues have a more significant role in the guanine transporter than the tryptophan transporter. Mutations identified in w(crr) (H298N) and w(101) (G243S) affect amino acids which are highly conserved among the ABC transporter superfamily within the nucleotide binding domain. Both cause substantial and similar decreases of red and brown pigments indicating that both tryptophan and guanine transport are impaired. The mutation identified in w(Et87) alters an amino acid within an intracellular loop between transmembrane helices 2 and 3 of the predicted structure. Red and brown pigments are reduced to very low levels by this mutation indicating this loop region is important for the function of both guanine and tryptophan transporters.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Proteínas de Drosophila , Drosophila melanogaster/genética , Proteínas do Olho/genética , Proteínas de Insetos/genética , Alelos , Sequência de Aminoácidos , Animais , Resistência a Múltiplos Medicamentos/genética , Dados de Sequência Molecular , Mutação Puntual , Reação em Cadeia da Polimerase , Alinhamento de Sequência
2.
Lancet ; 2(8569): 1200-3, 1987 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-2890820

RESUMO

Sleeping with the bed-head raised is commonly recommended as treatment for patients with troublesome oesophagitis, but its effect has not been objectively tested. Ranitidine therapy is useful in oesophagitis, but it does not often produce complete relief of symptoms. The effects of each of these treatments alone and in combination have been studied in 71 patients with severe (grade III) peptic oesophagitis. Each treatment improved both symptoms and endoscopic appearances significantly more than placebo did. However, the combination of the two treatments was much better than either alone; the reduction in pain score and the area of ulceration healed were about twice those with either treatment alone. Smoking more than five cigarettes per day or drinking more than 30 g alcohol per day significantly reduced the effectiveness of ranitidine therapy, but age, sex, body weight, or the presence of a hiatus hernia had no detectable effect.


Assuntos
Esofagite Péptica/terapia , Postura , Ranitidina/uso terapêutico , Sono/fisiologia , Adulto , Idoso , Consumo de Bebidas Alcoólicas , Antiácidos/uso terapêutico , Ensaios Clínicos como Assunto , Terapia Combinada , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória , Fumar/efeitos adversos
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