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M Piantanida

Publications and source records attributed to M Piantanida.

9 recordsLinked to original sources
PubMed1992

Prenatal diagnosis of metabolic diseases on chorionic villi obtained before the ninth week of pregnancy.

Nine pregnancies at risk for various metabolic disorders were monitored by prenatal diagnosis on chorionic villi obtained between the sixth and ninth weeks of pregnancy. A diagnosis of an affected fetus was made in five cases (Sandhoff, Tay-Sachs (2), Pompe's, GM1), while metachromatic leukodystrophy, GM1 (2), and Pompe's were excluded in four cases. It is concluded that chorionic villi are a reliable tissue for prenatal diagnosis of metabolic disorders also when obtained before the ninth week.

Cerebroside-Sulfatase↗
PubMed1992

A homozygous missense arginine to histidine substitution at position 482 of the beta-galactosidase in an Italian infantile GM1-gangliosidosis patient.

We have studied, by the polymerase chain reaction, the beta-galactosidase cDNA from several Italian patients with infantile GM1-gangliosidosis. One homozygote for a previously undiscovered G > A mutation at position 1479, causing an arginine to histidine change, was detected. The same mutation, in heterozygosis, was identified in 6 unrelated patients, but not in 100 normal chromosomes.

Arginine↗
PubMed1992

Cyclophosphamide increases the frequency of sister chromatid exchange in direct preparations of human chorionic villi in the absence of supplementary enzymatic activation systems.

A study was performed to evaluate the effect on the frequency of sister chromatid exchange in first trimester chorionic villi of two chemical compounds, mitomycin C and cyclophosphamide. Mitomycin C is generally known to induce an increase in sister chromatid exchange both in vivo and in vitro standard conditions. Cyclophosphamide is a compound requiring additional enzymatic enrichment of the culture medium to express its mutagenic activity under in vitro conditions. We exposed chorionic villi samples to these chemicals without the use of conventional cell cultures and without adding enzymatic extracts to the medium. The results indicate a statistically significant increase in the frequency of sister chromatid exchange after exposure to both compounds and also at lower dosages.

Biotransformation↗
PubMed1990

Gene dosage effect in acquired monosomy 7: distinct behaviour of beta-glucuronidase and phosphoserine phosphatase.

Evidence for gene dosage effect for beta-glucuronidase (GUSB) and phosphoserine phosphatase (PSP), whose genes are mapped on chromosome 7, was searched in a group of 13 patients with myeloproliferative disorders and acquired monosomy 7. The monosomy 7 was the sole anomaly in nine patients and was associated with other chromosome changes in four. A group of 19 patients with similar diseases but with normal karyotype or with anomalies not involving chromosome 7 served as control. beta-galactosidase and arylsulphatase A, whose genes are not on chromosome 7, were tested as control enzymes. We obtained evidence for a gene dosage effect for GUSB, but not for PSP. When all cases with monosomy 7 were compared with controls, no dosage effect was observed for PSP, but when this group was split into two, according to the presence of anomalies additional to the monosomy 7, the values of activity in the group with additional anomalies were significantly lower than in the controls. Thus, in the case of PSP, the loss of one allele is not followed immediately by reduction in activity, and this could be due to the specific importance of PSP in nucleic acid metabolism. We postulate that some regulatory mechanisms are able to keep normal levels of PSP even in the presence of only one allele, and that they are overwhelmed only when additional chromosome changes are present. These changes tend to involve chromosomes carrying genes for enzymes involved in a metabolic pathway closely related to PSP functions, and only then is a gene dosage effect for PSP detectable.

Alleles↗
PubMed1990

Deletion of specific sequences or modification of centromeric chromatin are responsible for Y chromosome centromere inactivation.

Stable dicentric chromosomes behave as monocentrics because one of the centromeres is inactive. The cause of centromere inactivation is unknown; changes in centromere chromatin conformation and loss of centromeric DNA elements have been proposed as possible mechanisms. We studied the phenomenon of inactivation in two Y centromeres, having as a control genetically identical active Y centromeres. The two cases have the following karyotypes: 45, X/46,X,i(Y)(q12) and 46,XY/47,XY,+t(X;Y) (p22.3;p11.3). The analysis of the behavior of the active and inactive Y chromosome centromeres after Da-Dapi staining, CREST immunofluorescence, and in situ hybridization with centromeric probes leads us to conclude that, in the case of the isochromosome, a true deletion of centromeric chromatin is responsible for its stability, whereas in the second case, stability for its stability, whereas in the second case, stability of the dicentric (X;Y) is the result of centromere chromatin modification.

Adolescent↗
PubMed1989

Cytogenetic and molecular analysis of an unbalanced translocation (X;7) (q28;p15) in a dysmorphic girl.

A severely retarded and dysmorphic girl, carrying an unbalanced X/7 translocation with breakpoints at Xq28 and 7p14, was analyzed by cytogenetic, biochemical and molecular techniques. The X/7 translocated chromosome was found to replicate consistently late in the 105 metaphases analyzed. In 83 of these cells, late replication was limited to the X portion of the abnormal chromosome, whereas in 22 cells incomplete spreading into the autosomal fragment was observed. Southern blot and in situ hybridization experiments with probe G80 (locus D7S373) (previously localized to 7p13-15) and G98 (localized to 7p14-15) assigns the former to 7p15 and the latter to 7p14, thus suggesting the order 7ter-G80-G98-cen. The activity of the enzyme phosphoserine phosphatase localized to 7pter-p14 was increased. Southern blotting experiments with 19 probes spanning the entire X chromosome demonstrated that the translocated chromosome had lost a portion of Xq28 (locus DXS51) but still retained part of Xq27 (F9 locus). The results confirm that the proband is trisomic for the region 7p15-pter and monosomic for the region Xq28-qter. Comparing her phenotype with those of other cases of partial trisomy or monosomy 7p, we confirm that band 7q21 is probably involved in skull development.

Abnormalities, Multiple↗
PubMed1989

Differential expression of the ICF (immunodeficiency, centromeric heterochromatin, facial anomalies) mutation in lymphocytes and fibroblasts.

Fibroblasts from a patient with ICF syndrome were grown in the presence of excess of nucleotides, in media with different amounts of folic acid, and with caffeine in an attempt to induce the chromosomal anomalies observed in lymphocytes. We induced despiralisation and breakages in the centromeric heterochromatin of chromosomes 1 and 16 but not associations and multibranching. We suggest that the absence of the major chromosomal anomalies in fibroblasts from patients with ICF might be the result of both a longer G2 in these cells and differential patterns of interphase heterochromatin associations in the two tissues.

Adenosine↗