Comparison of long bones and vertebrae in growing male rats: rate of growth, mineralization, and uptake of 3H-tetracycline at the organ level.

Two vertebral and two long bones of the growing male rat were separated as an intact anatomical unit (at the organ level) and analyzed for mass of dry weight, calcium, and collagen. The rate of growth (mass) and mineralization (uptake of 3H-tetracycline) was determined in rats from 3 to 36 weeks of age. Groups of rats age 3, 6, 8, 10, 14, 20, and 36 weeks were given a single dose of 3H-tetracycline 4 days before sacrifice. Whole bones were assayed for calcium, collagen, and 3H-tetracycline radioactivity. Growth of vertebrae and long bones is similar from 3 to 6 weeks of age. From age 6 to 20 weeks vertebrae grow at a faster rate than long bones. While long bones reach a peak dry mass at 20 weeks of age, the dry mass of vertebrae continues to increase. At ages 3 and 4 weeks, mineralization is significantly higher in vertebrae than in long bones. Peak calcification occurs at 8 weeks for long bones and at 10 weeks for vertebrae. These differences appear to be associated with the difference in age at which closing of growth plates occur as well as differences in formation rates between vertebrae and long bones.

Canine cortical bone autograft remodeling in two simultaneous skeletal sites.

The morphological and physical aspects of cortical bone autografts implanted in dogs for 1-9 months in two differently located skeletal defects are reported with a twofold aim: to provide a reference system for further comparison with various allografts and to delineate a general pattern of cortical bone graft healing. A 3-cm osteoperiosteal gap was created in the diaphyseal segment of the ulna and fibula of mature dogs. The grafts, freed from periosteum and bone marrow, were then inverted and replaced for the autografts in the left limb bone without internal fixation or external splints. On the right side, different allografts were tested. A group of three animals also had an unfilled segmental resection on the right as control. Dogs were observed for 1, 2, 3, 6, and 9 months and were able to bear weight within 3 days. Twenty-eight ulnae and 27 fibulae were available for this autograft study. Fluorochromes were injected at mid-term and at the end of the observation. All the grafts were assessed morphologically by cross-section microradiographs and ultraviolet light microscopy, and a morphometric analysis for porosity and fluorescence was done. To evaluate the physical aspects of graft healing, the recovered ulnar autografts, when available, were submitted to photon absorptiometry and to torsional loading. Morphologically, resorption was found to invade the cortical bone graft transversely through radial tunnels, and in addition to the host-bone-graft junction, the entire transplant surface provided another way for revascularization. The highest porosity level was achieved 2 months after surgery for both ulna and fibula, while new bone formation, as assessed by fluorochromes, was most important at 3 months. At 9 months, porosity remained above the normal range as determined in a set of five nongrafted dogs. While the lack of correlation for porosity between the two grafts suggests that local factors are more important in graft resorption, the observed correlation for fluorescence indicates that new bone deposition is more dependent upon skeletal metabolic activity. Within each graft, porosity and new bone formation were not well correlated. In the ulna, the bone mineral content (BMC) reflected the graft volumetric variations during the remodeling, with the lowest mean value at 3 months. For each graft, BMC was well correlated with the torsional stiffness. When torsionally loaded, the maximal tangential shear stress at failure of the graft was negatively related to its cortical porosity.(ABSTRACT TRUNCATED AT 400 WORDS)

[Radiologic studies of the correlation between the mineral content of the peripheral and axial skeleton]. / Radiologische Untersuchungen zur Korrelation des Mineralgehaltes zwischen peripherem und Stammskelett.

Estimations of mineral content of normal human skeletons using three radiological methods have led to the following conclusions: 1. Bone density of vertebral bodies increases from T.6 to L.5. Average values for thoracic and lumbar vertebrae are 0.71 and 0.88 g./cm2. 2. There is no linear correlation between the mineral content of an easily accessible peripheral bone and of the vertebrae. 3. The method for bone mineral estimation, using thulium170, which was developed in Dresden, can be used for the peripheral and central skeleton. 4. 125-photon absorption us useful for measurements on the peripheral skeleton, where it is the most elegant and accurate method. It is, however, useless for measurements of the central skeleton.

Changes in bone mineral content following ligamentous knee injuries.

In 44 patients with clinical signs of ligamentous injuries to the knee-joint without fracture, the bone mineral content was measured by gamma absorptiometry in the proximal end of the tibia and the fibula. The injuries caused a loss of an average 10% in those patients who had no signs of complete tears of knee ligaments and were therefore treated only with an ace-bandage and for a shortime, whereas the loss was 18% in those who were operated on with repair of ligamental injuries followed by plaster immobilization. Repeated injuries did not seem to cause further loss of mineral. There were no signs of restoration within the first year. The pre-injury bone mineral content was in these patients above that of an unselected control population, however, the post-traumatic loss of mineral brought the values down into a normal range.

[Distribution of mineral salts in structures of the compact substance of human bone]. / Raspredelenie mineral'nykh solei v strukturakh kompaktnogo veshchestva kosti cheloveka.

Mineral distribution has been studied in osteoni and intermediate spaces of the compact substance in fibular and occipital human bones. The material has been taken from 34 corpses. Total mineral content was estimated by the contact microroentgenography technique. Calcium, phosphorus and magnium content and distribution were studied by means of X-ray spectral microanalysis. The results obtained characterized bone morphological structure depending on the degree of their miniralization. Peculiarities in calcium and phosphorus distribution along radius osteoni were studied. Quantitative data were obtained on their content in the bone morphological structures. In spite of uneven distribution of some elements in the bone samples, constant molar Ca/P ratio was noted.

[Use of x-ray spectral microanalysis for studying mineralized tissues]. / Primenenie rentgenospektral'nogo mikroanaliza dlia izucheniia mineralizovannykh tkanei

In microanalysis of mineralized tissues an x-ray spectral method possessed an absolute limit of sensitivity about 5-10 minus 15 g. A relative limit of the method sensitivity constituted hundredth parts of a per cent and locality of the analysis--several cubic microns. The x-ray spectral microanalysis permitted to carry out qualitative and quantitative estimations of content of elements in different structures of biological tissues. The data were obtained on content of calcium and phosphorus in compact part of human tubular bone.