The effects of prepubertal ovariectomy on connective tissue generation

Polyvinyl sponges were implanted subcutaneously in 84-day-old female rats and in prepubertally ovariectomized rats of the same age. Animals from both groups were killed 72 ± 1 hours later. The mean hexosamine concentrations in sponge tissue were, in the intact animals and ovariectomized rats respectively, 340 ± 28 and 258 ± 19 μg hexosamine per 100 mg dry lipid-free tissue. The confidence intervals were derived from the Student's t test (5%). Prepubertal ovariectomy decreases the hexosamine concentration of the sponge tissue during the early stages of connective tissue generation in young adult rats and may have a similar effect on serum hexosamine. The mean hydroxyproline concentrations in the sponge tissue of the remaining animals, which were killed 10 days after implantation, were 1027 ± 77 and 777 ± 130 μg hydroxyproline per 100 mg dry lipid-free tissue for the ovariectomized and intact animals respectively (5% confidence interval). Prepubertal ovariectomy increases the rate of connective tissue generation in young adult rats. The ovariectomized rats were heavier at death than the intact animals and no apparent histologic differences were noted in the sponge tissue recovered from the two groups.

A comparison of connective tissue lining aortic grafts with extravascular connective tissue

Knitted Dacron arterial prostheses were occluded by Perspex rods and allowed to become organized by connective tissue while embedded in the tissues of rabbits and dogs. In dogs one organized prosthesis was grafted into the aorta with its blood supply intact while another was left undisturbed as a control. Later the linings of these tubes were examined by light microscopy and electron microscopy. During their sojourn in large arteries the connective tissue linings of the grafts developed a superficial layer of smooth muscle and elastic tissue and a surface of endothelium. These developments had no parallel in the control tubes. The first recognizable stages of elastic tissue formation took place in the intercellular space close to smooth muscle cells. The young elastin was intimately associated with fine banded fibres and with amorphous material. Though the prostheses functioned successfully mural thrombi were found in the distal part of three grafts out of five. There was no evidence from these experiments that prostheses already organized by connective tissue would make more satisfactory arterial grafts than the usual unorganized prostheses.