Growth of human skin fibroblast lines with sex chromosome aneuploidy was studied in cell culture. Two lines were derived from individuals with 45,X and two from individuals with 47,XYY chromosome constitution. The aneuploid cell lines were compared with normal skin fibroblasts derived from age-matched same-sex siblings. To ensure similar conditions in culture, each study-control pair was treated simultaneously and equally in all steps. Growth in both 45,X cell cultures slowed down earlier than in control cultures. One of the 47,XYY cultures grew faster and the other at a similar speed to the control culture. Thus, the 45,X cell lines seemed to have lesser, and one of the 47,XYY cell lines greater, growth potential than the 46,XX and 46,XY cells, respectively. These differences in the final cell numbers may relate to changes in the rate of cell division of the aneuploid cell lines. However, the results do not support the hypothesis that an increasing number of sex chromosomes decreases the rate of cell division.

Adolescent↗

PubMedDate not supplied

Healing of experimental fractures in the denervated limbs of the rat.

The effects of denervation on healing of experimental fractures of the tibia after sciatic nerve section or spinal cord transsection or both were studied in rats. In addition to normal weight-bearing controls, non-weight-bearing controls were prepared by means of experimental hip luxations. The healing of fractures was monitored by tensile strength measurements, and by X-ray studies up to two months. The tensile strengths of the fractures with peripheral nerve lesion or with spinal cord trauma were significantly higher than those of the respective weight-bearing or non-weight-bearing control fractures at the early phase of healing. Osseous union of denervated fractures was radiographically evident earlier or at least at the same time as in the controls. Denervation, however, caused irregularities in the radiopacity and increased the length of fracture callus. These results confirm the clinical observations on enhanced healing of fractures in extremities of patients with spinal cord trauma.

Animals↗