Angelo Serra

Dosage effect of SOD-A gene in 21-trisomic cells.

SummarySOD-A activity was measured by the polarographic method of catalytic currents in 30 subjects 10–24 years of age with a karyotype 47, +21, and 30 age matched normal subjects. The ratio of the average amount of SOD-A in 21-trisomic cells to the average amount in normal cells is 1.4495. Statistical analysis confirms that this ratio does not differ significantly from the ratio 1.5 expected in the case of a simple gene dosage effect.

Catalase and glutathione peroxidase activity in cells with trisomy 21.

CuZnSOD is produced in overdose in cells with trisomy 21.

A simple method for fusing human lymphocytes with rodent cells in monolayer by polyethylene glycol

Human lymphocytes were efficiently hybridized with three rodent cell lines growing attached to a substrate, by a procedure similar to the monolayer fusion technique. Lymphocytes in suspension were directly added to the monolayer and cocultured for a few hours. Treatment with polyethylene glycol (PEG) induced close contact between the two cell types, and extensive cell fusion occurred. The rate of hybridization differed markedly for the different cell lines used.

Long-term cytogenetic effects of antineoplastic treatment in relation to secondary leukemia☆

Chromosome translocations are consistently present in leukemias and lymphomas and are likely to represent primary events in the development of these neoplasias. A study of conditions that predispose to leukemia could shed some light on the origin of these translocations and therefore help in clarifying their exact role in the process of neoplastic transformation. Based on this assumption, we studied a group of individuals treated with radiochemotherapy for previous lymphoma and who were at increased risk of developing a secondary leukemia. The group comprised 14 Hodgkins disease patients, 11 non-Hodgkins lymphoma patients, and 13 controls. The patients were in remission and had been off therapy for at least 6 months. Chromosomes were studied from phytohemagglutinin (PHA)-stimulated peripheral lymphocytes and from bone marrow cells by the direct method and after short-term cultures (72 hours). The latter were also exposed to 5-bromodeoxyuridine (BrdU). Metaphases were scored for chromosome breaks, gaps, and other rearrangements. The percentage of gaps and breaks was significantly higher in patients than in controls. The difference was induced by BrdU and was apparent in bone marrow cells, but not in peripheral lymphocytes. We conclude that individuals exposed to the action of mutagenic agents (radiochemotherapy) have an increased chromosome instability that could be related to their increased risk of developing a secondary leukemia.

Lack of position effect on the activity of SODCu/Zn gene in subjects with 21/D and 21/G robertsonian translocations

SummaryThe activity of the SODCu/Zn gene in balanced and unbalanced carriers of the 21/D and 21/G translocations is compared to that of subjects with free trisomy 21 and with normal karyotype. The results show that the translocation of the 21 chromosome has no effect on the activity of the SODCu/Zn gene.

Properties and significance of a small marker chromosome in amniotic fluid cells

We report the presence of a small supernumerary metacentric chromosome in an amniotic fluid cell culture. The extra chromosome was inherited from the mosaic mother, and was characterized by the presence of four satellite regions, two on each side of the centromere. The pregnancy proceeded to term, and our findings were confirmed in the clinically normal offspring. The problems posed by the presence of the marker chromosome, in terms of both cytogenetic diagnosis and genetic counseling, are discussed in the light of similar cases from the literature.

Chromosomal alterations in the course of viral leukemogenesis in the rat

Abstract A cytogenetic study of 35 primary thymic lymphomas induced in rats by the Gross leukemia virus revealed the presence of widespread aneuploidies, ranging from cells with 35 chromosomes or less to triploid and tetraploid cells. Analysis by G banding revealed that chromosomes No. 1, 2, 9, 12, 18–20, X in females, and Y in males were lost preferentially; unidentified marker chromosomes of various morphology and length were present in a high percentage of aneuploid mitoses. Similar alterations were observed in preleukemic thymi from rats sacrificed 30 days after virus injection, when clinical or histologic signs of the disease had not yet appeared. In rats that were sacrificed 7 or 15 days after virus injection, chromosomal anomalies were much more limited, although significantly more abundant than in the controls. Rats that were free of tumor at 130–160 days after virus injection showed a regression of the chromosomal anomalies, suggesting that these are not irreversible and are not necessarily followed by the development of a lymphoma.

A balanced translocation t(4;9) (q35;q12) with a breakpoint within the heterochromatic region of chromosome 9 in a woman with recurrent abortion

A case of recurrent abortion was found to be associated with the presence in the mother of a balanced translocation between chromosomes 4 and 9. The karyotype of the proposita was: 46, XX, t(4;9)(q35;q12). The effects of this translocation are discussed in the light of other cases reported in the literature.

Partial 9p monosomy in a girl with a tdic(9p23;13p11) translocation, minor anomalies, obesity, and mental retardation.

We report on a case with a partial monosomy for the regions 9p23 --> pter and 13p11 --> pter as a result of a de novo translocation (9p23;13p11). The patient, a 16-year-old girl, has mental deficiency, obesity, and minor anomalies, including trigonocephaly, hypertelorism and a short, broad neck. Cytogenetic and microsatellite marker analysis allowed us to assign the breakpoint to the chromosomal region 9p23, flanked by the markers D9S144 and D9S157. In an attempt to establish a phenotype-genotype correlation, the clinical manifestations present in our patient are compared to those with partial 9p monosomy and breakpoint in p23, referred to in the literature.

A phenotypically Turner-like female with karyotype 45,X/46,XY gonadoblastoma and fluorescent Y

SummaryA case of a phenotypically Turner-like female with 45,X/46,XY karyotype is presented; attention is drawn particularly to the apparently normal structure of the Y chromosome and the gonadoblastoma developed in the left streak-like gonad.