Bone Tissue Development Research Articles

Biological evaluation of glass-ionomer cement (Ketac-0) as an interface material in total joint replacement. A screening test

In a screening test procedure diffusion chambers were used to evaluate a glass-ionomer Ketac-0 as a bone cement for orthopaedic use. The procedure offers a sensitive evaluation of a specific tissue response to an implant material. Ketac-0 has no inhibitory effect on bone tissue development; in fact, it appears to promote osteoblastic activity and the normal differentiation of haemopoetic tissue in the enclosed environment of the tissue chamber. The favourable results achieved in the screening test justify further bulk testing and clinical evaluation under functional stress situations.

Proto-oncogene c-fos expression in growth regions of fetal bone and mesodermal web tissue.

The phylogenic conservation of the proto-oncogene c-fos suggests that this gene product is required for normal metabolic processes. Investigations into the transcription pattern of c-fos in normal tissues and cells have revealed expression during development, differentiation and growth which is dependent to a large extent on external signals transferred by growth factors. The complex pattern of stage and tissue-specific expression has raised the hypothesis that the c-fos gene product might function in the control of either proliferation or differentiation. However, no detailed analysis is yet available concerning the normal expression of c-fos during embryonic and fetal development. Interestingly, recent data derived from studies in transgenic mice reveal that the biological effect of overexpression of exogenous fos is restricted to the developing bone tissue and T-cell development of the mice, perhaps signifying that these cells represent a physiological target tissue of the proto-oncogene fos. Thus, to gain deeper insight into the functional role of the c-fos gene product during physiological processes, it is a requirement to carry out a detailed analysis of the localization and cell-type specificity of c-fos expression in normal mouse embryos. Using the technique of in situ hybridization, we demonstrate here that stage-specific expression of the proto-oncogene c-fos in mouse embryos is restricted to the perichondrial growth regions of the cartilaginous skeleton. Moreover, we found strong c-fos transcription in web-forming mesodermal cells, which are also characterized by a stage-specific high growth capacity. Our results suggest a tissue-specific regulatory role of c-fos during differentiation-dependent growth processes of fetal bone and mesodermal web tissue.

Effect of peripheral nerve on limb development.

The effect of peripheral nerve on limb growth and maturation has received little attention after the limb differentiation stage. This study used an amphibian model (Rana pipiens) to examine the effect of temporary denervation on the development of limb muscle and bone tissues. Quantitative microscopic techniques were employed to evaluate bone and muscle size and cellularity between denervated and control limbs. A 15% decrease in tibial length and a 17% decrease in cross-sectional area were found in the temporarily denervated limbs as compared with the control limbs during the growing period studied. A 26% increase in tibial osteocyte density was found in the denervated limbs, although total osteocyte number was the same. The same differences were found on comparing less and more mature limbs from normal animals. Gastrocnemius muscle from temporarily denervated limbs had a 46% lesser cross-sectional surface area and a 66% greater muscle fiber density as compared with control limbs. Total muscle fiber number was the same. Similar findings were observed comparing limbs of different maturities from normal unoperated animals. This study suggests that the absence of peripheral nerves decreases the rate of bone maturation, which effect may be responsible for the diminished size of denervated limbs. This work demonstrates a model for regional growth disturbances that may aid in understanding such disorders as idiopathic leg length discrepancy, hemihypertrophy, clubfoot, and the limb deformities created by paralytic diseases.

Growth factors in bone matrix. Isolation of multiple types by affinity chromatography on heparin-Sepharose.

The mineralized matrix of osseous tissue harbors abundant mitogenic activity which is extractable by demineralizing solvents. In bovine bone powder free of blood and cartilage contamination, the volume concentration of mitogens is up to 20 times greater than in serum. Growth factor activity in bone extracts was quantitated on quiescent mouse BALB/c/3T3 fibroblasts, where [3H]thymidine incorporation for 48 h was stimulated up to 200-fold in a linear, dose-dependent manner. Six distinct bone-derived growth factors (BDGFs) have been resolved and partially purified (up to 44,000-fold) on heparin-Sepharose using NaCl gradient elution. Provisionally named by the NaCl molarity at which they elute, these BDGFs include BDGF-0.45 (25% of total activity). This factor is heat-stable and sensitive to dithiothreitol, and displaces 125I-labelled bovine platelet-derived growth factor in a radioreceptor assay. BDGF-0.45 (approximately 50 ng/g of bone) is closely related or identical to bovine platelet-derived growth factor. BDGF-1.1 (10%) has a pI of 5.2 and shows a 16,600-dalton doublet on sodium dodecyl sulfate-polyacrylamide gel electrophoresis Western blots stained with antiserum to bovine anionic fibroblast growth factor. Two activities with high heparin affinity resemble cationic forms of fibroblast growth factor. BDGF-1.5 is the dominant factor in fetal membranous bone (50%), but is less abundant in adult bone (20%). BDGF-1.7, a 17,500-18,400-dalton triplet, is virtually absent in fetal bone (7%) but abundant (30%) in adult bone and may be related to cartilage derived growth factor. Two minor activities, BDGF-0.1 (10%) and BDGF-2.0 (7%) have not been characterized. Proliferation of bovine capillary endothelial cells was strongly supported by BDGFs 1.1, 1.5, and 1.7, but not by 0.45. These four purified BDGFs and the crude bone extract were also strongly mitogenic for rat osteoblasts while depressing alkaline phosphatase specific activity by 2-3-fold. Bone exhibits the most complex spectrum of growth factor activities of any tissue yet described. Bone cells and other indigenous cell types must be considered as possible sources of the BDGFs, in addition to sequestration from blood. Mechanisms for unmasking or release of BDGFs from the mineralized matrix resulting in local action on target cells are undoubtedly important for the development and maintenance of bone tissue.

The effect of neurogenic stimulation on the development and growth of bony tissues.

In order to elucidate the mechanisms of neurogenic control of bone development and growth, the effects of traumatic and electric stimulation on the development, size, and shape of antler bone tissue were investigated. Unilateral growth of antler in a female deer was initiated after traumatic stimulation of the frontal bone. Electrical stimulation of antler nerves or antler periosteum resulted in an increase in more than 70% in antler length and over 40% in weight. Stimulation of antler nerves also resulted in abnormal shape of antlers. The role of periosteal nerves and the participation of the central nervous system in the responses to stimulation is discussed.

Nutritional aspects of the development of bone and connective tissue.

Nutritional aspects of the development of bone and connective tissue.

Inductive properties of transplanted transitional rat epithelium

In transplanting the mucous membrane of the urinary bladder to rats under the fascia of the anterior abdominal wall osteogenesis was induced not earlier than in 18–20 days, whereas in guinea pigs — in 10 days; the bone tissue development occurs in about 10% of the cases. Morphology and histochemistry of osteogenesis induction are very much alike in guinea pigs and rats. Low inducing activity of the rat transitional epithelium may be explained by the close contact of transitional epithelium and the vascular network in these animals. Such relationship is easily explained if to accept that the production of the inducing substance-factor from the epithelium is constant.

A case of bone formation in the lung

The development of bone tissue in the lung is quite rare, and branchy bone formation is especially rare. Most often, the bone of the stenosis of bronchial cartilage with bronchiectasis develops, then in the form of real bone tumors (osteoma, osteosarcoma, osteochondroma), then, finally, in the form of branched formations, to which the described case belongs.