Biomedical subjects

R Gatti

Publications and source records attributed to R Gatti.

283 records · Page 16Linked to original sources

PubMedDate not supplied

An Asn > Lys substitution in saposin B involving a conserved amino acidic residue and leading to the loss of the single N-glycosylation site in a patient with metachromatic leukodystrophy and normal arylsulphatase A activity.

Sphingolipid activator proteins are small glycoproteins required for the degradation of sphingolipids by specific lysosomal hydrolases. Four of them, called saposins, are encoded by the prosaposin gene, the product of which is proteolytically cleaved into the four mature saposin proteins (saposins A, B, C, D). One of these, saposin B, is necessary in the hydrolysis of sulphatide by arylsulphatase A where it presents the solubilised substrate to the enzyme. As an alternative to arylsulphatase A deficiency, deficiency of saposin B causes metachromatic leukodystrophy. We identified a previously undescribed mutation (N215K) in the prosaposin gene of a patient with metachromatic leukodystrophy but with normal arylsulphatase A activity and elevated sulphatide in urine. The mutation involves a highly conserved amino acidic residue and abolishes the only N-glycosylation site of saposin B.

Amino Acid Sequence↗

PubMedDate not supplied

Congenital bilateral juvenile granulosa cell tumor of the ovary in leprechaunism: a case report.

We report on a case of leprechaunism. In addition to the typical clinical and biochemical features, a bilateral juvenile granulosa cell tumor of the ovaries and cytomegalovirus hepatitis were found. The granulosa cell tumor may result from the mitogenic effect of insulin at high concentration, which acts via a mechanism mediated by insulin-like growth factor I receptors.

Cytomegalovirus Infections↗

PubMedDate not supplied

[Mucolipidosis. biologic characteristics (author's transl)].

Mucolipidosis II is a severe inherited lysosomal storage disease characterized by profound psychomotor retardation, severe Hurler-like skeletal changes and normal urinary mucopolysaccharide excretion. Mucolipidosis II is a related disorder distinguished by its milder course, milder to absent mental retardation and survival to adult life. Cultivated fibroblasts from patients with both of these disorders display large inclusions on phase microscopy and reduced levels of many acid hydrolases. However, culture medium fibroblasts out the body fluids of affected patients show enormously elevated levels of these hydrolases. The lysosomal enzyme activities in serum, leukocytes, fibroblasts extracts and culture medium from seven patients with mucolipidosis II are similar to those found in four cases of mucolipidosis III. The findings of excessive excretion of sialyl-oligosaccharide in urine and of increased level of sialic acid compounds in cultured fibroblasts associated with a sialidase deficiency in leukocytes, fibroblasts and serum are discussed.

Child, Preschool↗

PubMedDate not supplied

Ataxia-telangiectasia (group A): localization of ATA gene to chromosome 11q22-23 and pathogenetic implications.

Ataxia-telangiectasia (AT) is an autosomal recessive disorder resulting from a single defective gene in each family. Complementation studies suggest that the same syndrome is associated with defects of at least four AT genes (ATA, ATC, ATD and ATE). The syndrome is multifaceted and involves the cerebellum, skin, immunological system, chromosomes, cancer susceptibility, radiosensitivity, premature ageing and serum alphafetoprotein levels. In order to further develop understanding of how these seemingly unrelated physiological systems interact in this disease, we attempted to localize the gene by linkage analysis, using a single large Group A AT family to screen 171 genetic markers and 30 additional AT families to confirm any positive linkages. We found a linkage to AT (Group A) with genetic markers on chromosome 11q22-23. This region of the human genome is syntenic with a large region of the mouse genome on chromosome 9 and includes such "candidate" genes as THY1, NCAM, CD3G-D-3, ets-1, and APOA1-C3-A4. In addition, studies of human chromosomes identify fragile sites in this region as well as breakpoints associated with translocation 4: 11 and 9; 11 in acute non- lymphocytic leukemias. The pathogenetic implications of this localization to 11q22-23 are considered.

Animals↗

PubMedDate not supplied

Seasonal changes of parafollicular and follicular cells of the dormouse thyroid (Myoxus glis): an ultrastructural and immunocytochemical study.

The follicular epithelium of dormouse thyroid consists of two distinct cellular types, follicular and parafollicular cells. Parafollicular cells can be easily identified by their high cytoplasmic dye-affinity for phloxine, round to ovoid shape, basal arrangement and lack of contact with follicular colloid. The wide cytoplasmic matrix is clear and contains many secretory granules of variable electron density whose contents histochemically appears to be proteic with a lean glucidic component. Furthermore immunocytochemical reactions with antibodies against calcitonin and somatostatin showed that both hormones are co-stored in the secretory granules of all parafollicular cells. Both follicular and parafollicular cells show seasonal morphological variations in their secretory activity. Follicular cell activity is high in summer, reaches a peak in late fall or prehibernation and progressively slows down throughout hibernation. Parafollicular cells exhibit a fair synthetic activity in summer, in fall, and in the animals captured during winter hibernating sleep and killed after 12 days stay in laboratory. In winter sleep, granules with interrupted membrane and cottony contents are prevalent and the ultrastructural aspects suggest an intense discharge of secretion. The results are compared with those from other hibernating mammalians and discussed in the light of blood calcium values and seasonal balances of other metabolisms.

Animals↗

PubMedDate not supplied