Aminopeptidase B (EC 3.4.11.6).

Aminopeptidase B (EC 3.4.11.6) is a Zn(2+)-dependent exopeptidase which selectively removes arginine and/or lysine residues from the NH2-terminus of several peptide substrates including Arg0-Leu-enkephalin, Arg0-Met-enkephalin and Arg-1-Lys0-somatostatin-14. Analysis of its primary structure showed that aminopeptidase-B is structurally related to leukotriene A4 hydrolase, an important enzyme of the arachidonic acid pathway. This structural relationship is further supported by the capacity of aminopeptidase-B to hydrolyse leukotriene A4. Aminopeptidase-B is widely distributed in a number of tissues, including endocrine and non-endocrine cells. Moreover, in rat PC12 pheochromocytoma cells, the enzyme is secreted and associated with the external face of the plasma membrane. Together these data strongly argue in favour of a role of this bi-functional enzyme in the final stages of precursor processing mechanisms occurring either in the secretory pathway, at the plasma membrane, or at both locations.     

Lysosomal storage diseases presenting as transient or persistent hydrops fetalis.

Two cases of beta-glucuronidase deficiency (mucopolysaccharidosis VII), presented with fetal hydrops at 20 and 26 weeks of gestation. The enzyme deficiency was observed in cultured amniotic fluid cells and in fetal plasma from cord-blood and was confirmed after termination of pregnancy. A third case presented with transient ascites at 6.5 months of gestation. Mild dysmorphic features at birth and gradual neurological deterioration were observed. Deficiency of beta-galactosidase was documented confirming a GM1 gangliosidosis. Evidence has accumulated that fetuses affected by lysosomal diseases, may present with transient or persistent hydrops fetalis. The exact frequency is however not known. Further diagnostic studies in persistent or transient hydrops fetalis, looking for lysosomal and other metabolic diseases, whenever major causes of hydrops fetalis have been excluded, are therefore indicated. Amniocentesis and cordocentesis should always be performed.     

A new case of partial trisomy 15q-

Summary Partial trisomy 15 was observed in a newborn with malformations of the head and extremities. A t(5;15) translocation was found in the mother and maternal grandfather.Recipients of a Nato-grant (No. 1428)