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Biomedical subjects

M de Marchi

Publications and source records attributed to M de Marchi.

5 recordsLinked to original sources
PubMed1989

Pulsed-field gel analysis of human immunoglobulin heavy-chain constant region gene deletions reveals the extent of unmapped regions within the locus.

The human immunoglobulin heavy-chain constant region gene locus is organized in three main gene groups, the physical distances of which are unknown. Different types of gene deletions, originated by unequal crossingover, have been found to encompass one or more genes in the locus. We have analyzed some of these deletions by means of pulsed-field gel electrophoresis, which allows resolution of large DNA fragments. By identifying a fragment containing two of the main gene groups and by observing the size reduction of this fragment in subjects with deletions, we were able to estimate the distance between the two groups and better locate the pseudogene in-between.

Chromosome Deletion↗
PubMed1989

Gene deletions within the human immunoglobulin heavy chain constant region gene cluster.

Gene deletions due to unequal crossing-over events represent a not uncommon cause of immunoglobulin isotype deficiency. A variety of deleted haplotypes has been ascertained in the Italian population by means of screening for different Ig isotypes followed by Southern blot analysis of the deficient probands. The total frequency of gene deletions involving the gamma 2 and/or gamma 4 genes amounts to about 1/60; among these, a higher frequency was observed for multigene compared with single gene deletions. Carriers of multiple deficiencies due to gene deletions are able to activate compensation mechanisms, avoiding the usual pathological consequences of the deficiency.

Chromosome Deletion↗
PubMed1978

Central core disease: histochemical and ultrastructural study of muscle biopsies of father and daughter.

Two cases of central core disease, father and daughter, of a family with dominant autosomal inheritance, are presented, one with bilateral congenital dislocation of the hip. Muscle biopsy was performed in both cases. Oxidative enzymes evidenced only type I fibers, most of them presenting a central core and not uncommonly more than one. On electron microscopy the cores generally appeared well demarcated from the surrounding fibrils and were characterized by lack of mitochondria and abnormalities of the Z line. Transitional aspects from normal fibers to completely unstructured cores were observed, as well as from well structured and unstructured cores. These findings are discussed in the light of the previous literature and particular attention is paid to the problem of differentiation between central core and multicore disease. The pathogenesis of the muscular alteration is also discussed in relation with the possibility of their neurogenic origin. Eventually, the histochemical and ultrastructural similarities between central cores and target fibers are focused.

Biopsy↗