Objective To examine the effect of early and late pregnancy on the microarchitecture of maternal cancellous bone. Sample Transilial bone biopsies were obtained from two groups of pregnant women one group (n = 15) in t...
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Objective To examine the effect of early and late pregnancy on the microarchitecture of maternal cancellous bone. Sample Transilial bone biopsies were obtained from two groups of pregnant women one group (n = 15) in the first trimester and the other (n = 13) at term. Comparison was made with biopsy and autopsy samples from a group (n = 25) of normal premenopausal nonpregnant women. Methods Undecalcified sections were analysed under a low power optical microscope using an automated trabecular analysis system which measures a comprehensive range of structural variables including the bone volume, trabecular number, width, separation and connectivity. Results In early pregnancy the quantity of cancellous bone fell from a mean relative bone volume of 23.07% (SD 5.49) in nonpregnant controls to 16.72% (SD 3.91) (P < 0.001). This was primarily due to a decline in trabecular thickness from 122.9 mu m (SD 10.5) to 97.2 mu m (SD 21.8) (P < 0.01) and was accompanied by a loss of trabecular connectivity expressed as a reduction in the trabecular node: terminus ratio from 0.90 (SD 0.71) to 0.38 (SD 0.26) (P < 0.001). By late pregnancy the bone volume had been entirely restored to 23.41% (SD 9.76). This was primarily due to an increase in the number of trabeculae from 73.2 (SD 35.5)/field to 100.3 (SD 33.3)/field (P < 0.05) with an associated reduction in trabecular separation from 431 mu m (SD 150) to 315.8 mu m (SD 78.5) (P < 0.01). Conclusions Pregnancy affects the maternal skeleton by producing a fluctuation in the cancellous bone volume in which early temporary bone loss through trabecular thinning is restored in entirety through the addition of new trabeculae to produce a modestly more complex system of thinner more numerous bars by term.
To evaluate the effect of elcatonin on osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2), 5 mu g of rhBMP-2 was implanted into intramuscular sites of rats. For 14 days after the implantation, ...
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To evaluate the effect of elcatonin on osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2), 5 mu g of rhBMP-2 was implanted into intramuscular sites of rats. For 14 days after the implantation, elcatonin was administered intraperitoneally with total dosage of 80 U, 8 U, and 0.8 U, respectively. For the control group, only physiological saline was administered. At 21 days after implantation, the area of the oval shadow in the radiologic findings depended on the elcatonin dose and the amount of trabecular bone and the number of osteoblasts observed in the histologic findings depended on the dosage of elcatonin, The values of ALP activity and Ca content also showed an elcatonin dose dependency. These results suggested that elcatonin is effective in enhancing osteoinduction by rhBMP-2 within the dose range of this study, and that elcatonin has an anabolic effect on osteoblasts in addition to an antiresorptive effect. (C) 2000 Academic Press.
Wolff's Law describes the relationship between the structure and function of bane, Julius Wolff based his law on a comparison of the stress trajectories in Culmann's crane with the pattern of trabecular bone i...
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Wolff's Law describes the relationship between the structure and function of bane, Julius Wolff based his law on a comparison of the stress trajectories in Culmann's crane with the pattern of trabecular bone in the femoral neck. However, his analysis was based on a misinterpretation of mechanical data and a rejection of bone resorption. Wilhelm Roux was the first to accurately describe the adaptation of bone to altered load, so Roux's Law would be a more accurate eponym.
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