Functional and structural studies of alpha-crystallin from galactosemic rat lenses.

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.

Joubert syndrome with congenital hepatic fibrosis: an entity in the spectrum of oculo-encephalo-hepato-renal disorders.

Joubert syndrome is an autosomal recessive inherited condition characterized by agenesis or hypoplasia of the cerebellar vermis, retinal dystrophy, chorioretinal colobomata, oculomotor abnormalities, episodic hyperpnea, ataxia, and mental retardation. Congenital hepatic fibrosis has not previously been described in Joubert syndrome. We report two unrelated children with Joubert syndrome and hepatosplenomegaly. On histopathological examination, both had congenital hepatic fibrosis. Both were also found to have congenital medullary cystic disease of the kidneys. Joubert syndrome appears to be one of a spectrum of congenital malformation syndromes involving the central nervous system, eye, liver and kidneys.

Multiple sulfatase deficiency with early severe retinal degeneration.

We report an unusual case of multiple sulfatase deficiency in which neurodegeneration was accompanied by early, severe visual impairment associated with prominent pigmentary retinopathy, suggesting a diagnosis of neuronal ceroid-lipofuscinosis. The levels of arylsulfatases A, B, and C, heparan N-sulfatase, N-acetylgalactosamine-6-sulfate sulfatase, and iduronate-2-sulfate sulfatase were all markedly decreased in cultured skin fibroblasts. Screening tests for mucopolysacchariduria were consistently negative; however, thin-layer chromatographic analysis of isolated urinary glycosaminoglycans showed increased amounts of heparan sulfate.