Presence of double minutes and monosomy 17p in xenografted human osteosarcomas.

Cytogenetic analysis of 8 cases of xenografted human osteosarcomas are reported, including six newly diagnosed and two recurrent tumors. Histologically five were osteoblastic, two were chondroblastic, and one was the microcellular type. All tumors were studied in short-term primary cultures between two and six days. Clonal and nonclonal abnormalities were present in the eight cases; four had a chromosome number in the hypotriploid range, two in the hyperdiploid, one in the hypodiploid, and one in the hypertetraploid range. All cases had complex karyotypes and the recognizable structural rearrangements clustered to chromosome arms 1p, 1q, 3p, 5p, 6q, 11p, 13p, 14p, 15q, 16p, 16q, 20q, 21p, and 22q. Seven cases presented double monosomy 17 and six tumors showed double minutes (dmin) or a homogeneously staining region (hsr). This fact has been described recently and its relation with the amplification of the MDM2 gene observed in osteosarcomas is as yet unknown.

[Incidence of congenital cytomegalovirus infection in newborn infants of different socioeconomic strata]. / Incidencia de infección congénita por citomegalovirus en recién nacidos de distinta condición socioeconómica.

Cytomegalovirus is the main agent of congenital viral infections. The aim of this study was to compare the incidence of congenital cytomegalovirus infections of two groups of newborns of differing socioeconomic status. Cytomegalovirus was isolated from urine or oropharingeal secretions in 218 children born in a private clinic and 471 born in a public hospital. Positive viral isolates were confirmed with indirect immunofluorescence using monoclonal antibodies. Infection was detected in 12 children (1.82%), four coming from the private clinic (1.86%) and 8 coming from the public hospital (1.81%). Ninety two percent of infected children were asymptomatic. Urine and oropharingeal secretion samples had the same yield for viral isolation. It is concluded that the incidence of congenital cytomegalovirus infection is similar to that described in developed countries.