RESUMO
Chaperone-like activity and structural changes of lens alpha-crystallin from rats fed with galactose at various time intervals have been studied using high-performance liquid chromatograph (HPLC), circular dichroism (CD), and 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence emission. It was found that chaperone-like activity of alpha-crystallin from galactose-fed rats toward dithiothreitol (DTT)-induced insulin B aggregation started to decrease after 3 weeks and decreased significantly after 5 weeks. Consistent results were observed in lens morphology, and lens opacity slightly developed after 3 weeks and became obvious after 5 weeks. HPLC analysis for chaperone function showed that the formation of high molecular weight aggregates (HMWA) of alpha-/gamma-crystallins decreases with the increase of galactose-feeding time, revealing that chaperone-like activity is concomitant with the formation of HMWA. Circular dichroism results showed the reduction of beta-sheet structure and loss of microenvironment of aromatic-type amino acids for opaque lenses, indicating alpha-crystallin's secondary and tertiary structure changed with the development of the lens opacity. ANS binding site estimated by Klotz equation showed it is 1.5 times higher at room temperature and is 2.4 times higher at 58 degrees C for age-matched normal alpha-crystallin than for 5-week galactose-fed lens alpha-crystallin, indicating opaque lens alpha-crystallin loses the ability to assemble into an appropriately placed hydrophobic regions. The overall results accordingly indicated that galactose-induced cataractous alpha-crystallin has disordered structure, leading to the loss of its chaperone-like activity.
Assuntos
Cristalinas/química , Cristalinas/metabolismo , Galactosemias/metabolismo , Galactosemias/patologia , Cristalino/química , Cristalino/patologia , Naftalenossulfonato de Anilina/metabolismo , Animais , Sítios de Ligação , Catarata/induzido quimicamente , Catarata/metabolismo , Catarata/patologia , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Ditiotreitol/farmacologia , Feminino , Galactose/administração & dosagem , Galactose/metabolismo , Galactose/farmacologia , Galactosemias/induzido quimicamente , Insulina/metabolismo , Cristalino/metabolismo , Chaperonas Moleculares/química , Chaperonas Moleculares/metabolismo , Peso Molecular , Ligação Proteica/efeitos dos fármacos , Conformação Proteica/efeitos dos fármacos , Desnaturação Proteica , Ratos , Ratos Sprague-Dawley , Espectrometria de Fluorescência , Relação Estrutura-Atividade , Temperatura , Fatores de TempoRESUMO
Results from a one year prospective study of a relationship between major and minor life events (all other events), and relapse in twenty-two schizophrenic (DSM III-R) patients are reported. Seven (33%) patients relapsed during the one year of follow-up. Relapsed patients had experienced significantly more independent major and minor life events during the one year compared to non-relapsed patients. The independent events experienced by the relapsed patients occurred twice as often in the three month period prior to the relapse as compared to any other period among the relapsed, or the non-relapsed patients. These findings are discussed in the context of the prospective design of this study and the inclusion of minor as well as major events.