Synthesis of glycosaminoglycans in fibroblasts from abortuses with trisomy, triploidy, and from children with Down's syndrome.

A comparative study has been made of glycosaminoglycan (GAG) accumulation in human fibroblasts with trisomy 7 and triploidy from spontaneous abortuses, fibroblasts with triploidy from induced abortuses, fibroblasts from patients with Down's syndrome and diploid fibroblasts from age-matched controls. The study demonstrated that the incorporation of [3H] glucosamine into hyaluronic acid by fibroblasts with trisomy 7 and triploidy, established from spontaneous abortuses, and from two out of three induced abortuses with triploidy, was 2.6-5.3 times lower than control incorporation. One strain of fibroblasts from an induced abortus with triploidy (IMG-1062) did not show any differences in GAG production when compared with diploid fibroblasts. However, the strains from children with Down's syndrome revealed normal or even increased levels of hyaluronic acid production. The data support the contention that the decreased hyaluronic acid synthesis in fibroblasts with an abnormal karyotype is related to spontaneous abortion.

[The ratio of collagens type I and III in cultures of human fibroblasts with diploid and aberrant chromosome complement]. / Sootnoshenie kollagena tipov I i III v shtammakh fibroblastnykh kletok cheloveka s diploidnym i anomal'nym naborom khromosom.

The ratio of collagens I/III was studied in human diploid, trisomic and triploid fibroblast strains. The following material was used in experiments: 5 strains obtained from human spontaneous abortuses (trisomy 7, trisomy 9, triploidy), 6 diploid embryonic strains, 4 strains from patients with Down syndrome, 3 strains from healthy children, 4 strains from healthy adult donors and 3 strains from very old persons (81-107 years old). Various types of collagen were separated by means of electrophoresis. Distinct ontogenetic alterations were not observed in content of collagen III in diploid and aneuploid human cultivated fibroblasts. However, considerable alterations in the ratio of collagens I/III correlated with genetic pathologies only in the patients examined.

[Characteristics of intracellular metabolism of procollagen and other proteins in human embryo fibroblasts in trisomy for chromosome 7]. / Osobennosti vnutrikletochnogo metabolizma prokollagena i drugikh belkov v fibroblastakh émbrionov cheloveka s trisomiei po khromosome 7.

A comparative study of the relative rates of intracellular total protein metabolism in diploid and aneuploid (with trisomy for chromosome 7) human embryo fibroblasts in the logarithmic and stationary growth phases was carried out. Using double labeling with [14C]proline (24 hrs) and [3H]proline (3 hrs), it was found that: the rates of intracellular protein metabolism during transition to the stationary phase of growth are increased in diploid cells and decreased in cells with trisomy for chromosome 7; the relative rate of protein metabolism in the logarithmic phase is higher in trisomic cells than in diploid ones. The intracellular degradation of procollagen in trisomic cells is increased approximately by 17% as compared to normal fibroblasts. Treatment of cell lysates with bacterial collagenase revealed the presence of procollagen incomplete degradation products in anomalous fibroblasts. The observed differences in the rates and mode of protein metabolism during transition of diploid and trisomic fibroblasts to the stationary phase of growth suggest that the odd autosome interferes with the normal coordinated activity of genes in chromosomes.

[Detection of homozygotes and heterozygote carriers of GM2-gangliosidosis]. / Vyiavlenie gomozigot i geterozigotnykh nositelei GM2-gangliozidozov.

11 patients with Tay-Sachs disease (TSD) and 4 patients with Sandhoff disease were identified using the methods of heat inactivation of hexosaminidase at 50 degrees C (3 and 4 hours) and electrofocusing on PAG-plates in the pH range 3.5-9.5. Ion exchange chromatography on DEAE cellulose DE-52 proved to be reliable for identification of heterozygotes in cases when the proband was not available. The incidence of TSD gene was estimated in 2 population samples--from the cities of Gomel and Kostroma. It was about 0.004 in the Gomel sample. No heterozygotes were detected in Kostroma.

[Comparative characteristics of protein-synthesizing apparatus of diploid and aneuploid human embryo fibroblasts]. / Sravnitel'naia kharakteristika beloksinteziruiushchego apparata diploidnykh i aneuploidnykh fibroblastov émbrionov cheloveka.

The time of average polypeptide chain synthesis (tc), distribution of synthesized polypeptides according to their molecular masses, the ratio of translating and nontranslating ribosomes and polyribosomes of different size have been analyzed for diploid and aneuploid strains of fibroblasts. The magnitude of tc as well as the size of polypeptide chains synthesized were found to be similar for both kinds of fibroblasts. The relative cellular content of the translating ribosomes has been shown to decrease during the transition of cells from both strains to the stationary growth phase. The relative content of heavy polyribosomes is lower in aneuploid cells as compared with that in diploid cells. The process of translation in aneuploid fibroblasts is concluded to have no essential deviations from normal.

[Simultaneous activity of nucleolus organizer regions of human and Chinese hamster chromosomes in somatic cell hybrids]. / Odnovremennaia aktivnost' iadryshkoobrazuiushchikh raionov khromosom cheloveka i kitaiskogo khomiachka v gibridakh somaticheskikh kletok.

In an interspecific human-Chinese hamster hybrid that retains 13 and 85.6% of the chromosomes of each parental complement, activity of nucleolus-organizing regions (NOR) of both type chromosomes is observed in 18.9% of the cells. Interspecific chromosomal associations are also noted. Unlike the parental lines of Chinese hamster cells, the hybrids show the associations of the NOR of Chinese hamster chromosomes. In hybrid cells, there occurs partial suppression of NOR activity in human and Chinese hamster chromosomes, while the NOR of the 3d chromosome of the Chinese hamster is completely suppressed.

[Activity of nucleolar organizer regions of Chinese hamster chromosomes in clones of different ploidies]. / Izuchenie aktivnosti iadryshkoobrazuiushchikh raionov khromosom kitaiskogo khomiachka v klonakh razlichnoi ploidnosti.

Activity of nucleolar organizer regions was analyzed in hypodiploid and hypotetraploid clones of Chinese hamster cells. The quantity of the nucleolar organizers was directly proportional to ploidy. It is evidence of autonomous activity of the nucleolar organizers in Chinese hamster chromosomes.

[Isolation of hybrid clones of human-rodent somatic cells]. / Poluchenie gibridnykh klonov somaticheskikh kletok chelovek-gryzun.

Mutant cells of Chinese hamster or mouse were fused with normal embryonic human cells. The fusion was induced by polyethylene glycol. The Eagle medium containing hypoxanthine, aminopterine, thymidine, glycine, and ouabain served as a selective medium. The parent cells were completely destroyed in the selective medium. The hybrid cells formed colonies which were isolated and reproduced for cytogenetic analysis. The cytogenetic analysis has confirmed the hybrid origin of the isolated clones.