Cytogenetic studies in spontaneous abortion: the Calgary experience.

In a series of 493 apparently consecutive products of spontaneous abortions obtained for cytogenetic studies, tissue culture was attempted in 428 cases; chromosome analysis using the Q-banding technique was completed in 215 cases (50.2%). Abnormal karyotypes were identified in 80 cases (37.2%). Maternal tissue contamination was apparent and the actual frequency of karyotypic abnormal abortuses could be as high as 50%. Comparison of the frequency of a specific type of chromosome abnormalities with nine other series of studies showed the lowest frequency of autosomal trisomies and the highest frequency of triploidies and structural aberrations in the Calgary series. In addition, a significantly lower gestational age was observed for triploidies 69, XXX as compared to the 69, XXY.

Preparation of high resolution chromosomes from amniotic fluid cells.

A relatively simple method of obtaining high resolution chromosomes from amniotic fluid cells is described. The elongated chromosomes are achieved by adding ethidium bromide (5 micrograms/ml) to the culture 4 1/2 hours before harvesting and the high resolution banding can be produced by usual banding procedures.

Additional evidence for fragile X activity in heterozygous carriers.

The result of a previous study showing an association between mental development and fragile X activity in heterozygous females is given further support by similar investigations of three additional kindreds. The increased frequency of demonstrable fragile X chromosomes in mentally retarded females appears to be due to an increase in the active fragile X while the inactive marker X remains at a similar low frequency in all heterozygotes whether retarded or not. The frequencies of the active fragile X separated the normal and abnormal subjects into two distinct populations. The suggested inverse correlation between the number of lymphocytes with detectable fragile X chromosomes and advancing age can be attributed to ascertainment biases.

Adaptation of human long-term B lymphoblastoid cell lines to chemically defined, serum-free media.

Attempts were made to adapt human long-term B lymphoblastoid cell lines to prolonged growth in serum-free, chemically defined media. A newly described medium, which is an enriched modification of Dulbecco's modified Eagle's medium containing additional amino acids and vitamins, was used. The serum is totally replaced by albumin, transferrin, and soybean lipid. The cell lines were all adaptable from RPMI 1640 over a period of time during which the 10% fetal bovine serum (FBS) concentration was reduced and then eliminated in successive steps. After 3 to 6 wk minor alterations in cell shape and adhesion were noted without significant histological changes. Growth characteristics were comparable in the new medium provided a double initial inoculum was used. A panel of cell surface markers, including surface immunoglobulins, Ia antigens, Fc and complement receptors, and T and B erythrocyte rosettes, all showed no altered expression. Molecular genotyping of Ia antigens was carried out by 3-D gel electrophoresis. The antigens showed their full polymorphism without change and were shed into the new culture medium without alteration. Chromosome analysis was performed on Q-banded karyotypes from one of the lines and showed no alteration resulting from the change to serum-free conditions. Thus long-term B lymphoblastoid cell lines can be adapted to prolonged growth in serum-free medium. This will facilitate the assay and isolation of cell products regulating lymphocyte function and the identification and characterization of cell surface molecules free of interference from undefined serum components.

Porcine (Sus scrofa domestica) chromosome identification and suggested nomenclature.

Various banding techniques have been used for chromosome analysis in domestic pigs (Sus scrofa domestica). The techniques used in karyotype analysis were Q-banding by (CMA)2S, trypsin-G-banding, BrdU-Acridine-Orange R-Banding and C-banding. Sequential staining techniques of quinacrine-Giemsa were used to record the length of each chromosome and determine arm ratios. Sequential Quinacrine-Giemsa-Ag-AS treatment was used to locate the nucleolar organizer (NOR) on specific chromosomes. A G-C specific fluorochrome was used for reverse fluorescent banding and to differentiate certain chromosome regions which may contain G + C rich DNA. Unequivocal identification of all individual autosomes and sex-chromosomes in the porcine complement is now possible. The X-chromosome of the species has a banding pattern similar to the human X-chromosome. A nomenclature system similar to that used for human chromosomes is proposed for the G-banded and Q-banded karyotype of the domestic pig. The results of C-banding and olivomycin fluorescent banding suggest that at least three types of heterochromatin are contained in the porcine genome.