Difference in label length between demethylchlortetracycline and oxytetracycline: Implications for the interpretation of bone histomorphometric data

Summary We measured the individual lengths of fluorescent labels on the three subdivisions of the endosteal envelope in iliac bone biopsy specimens produced by the administration of both oxytetracycline and demethylchlortetracycline. Fifty-one healthy subjects and 53 patients with postmenopausal osteoporosis were labeled in the stated order, and 8 osteopenic patients were labeled in the reverse order. Whatever the order of administration, the demethylchlortetracycline label was longer than the oxytetracycline label. We conclude: (1) the difference in label lengths reflects a difference between the two compounds in some intrinsic property, whether physical, chemical, or pharmacokinetic. (2) If the calculation of extent of mineralizing surface is based on the mean length of the two labels, a suitable correction should be applied to the shorter label; alternatively, the length of the longer label alone should be used. (3) Unlabeled osteoid not due to label escape probably results from slow terminal mineralization after cessation of matrix synthesis during which too few tetracycline molecules are incorporated to exceed the threshold for visible fluorescence, rather than from the temporary interruption of mineralization followed by its resumption.     

Human fetal bone development: histomorphometric evaluation of the proximal femoral metaphysis

Quantitative data on metaphyseal bone histology during early human development are scarce. In the present study the proximal femoral metaphysis of 35 fetuses and newborns (gestational age 16–35 weeks) was analyzed by histomorphometry. Averaged over the entire metaphyseal area, the relative amount of bone and cartilage was higher in the third compared to the second trimester. Osteoid thickness increased with gestational age, whereas indices of bone resorption decreased. The relative amount of cartilage decreased with increasing distance from the growth plate, whereas the relative amount of bone increased. This was due to trabecular thickening, which occurred at an estimated rate of 3 μm/day in areas close to the growth plate. Despite this rapid rate of net bone gain, osteoid indices were relatively low, indicating that mineralization occurred very rapidly after bone deposition. These observations suggest that modeling, not remodeling, is the predominant mechanism responsible for the development of femoral metaphyseal cancellous bone in utero.     

The bone histomorphometric study of the bone growth as revealed by scanning electron microscopy

The present study was made with a view to examining the availability of the SEM observation method for bone histomorphometry. On Wistar strain newborn rats, 3 segments for measurement, i.e. temporal segment, middle segment and sagittal segment were prepared in the central part of the parietal bone endocranial aspects, and the bone surfaces were observed by SEM up to the fifteenth day at intervals of five days from after birth to measure areal volumes of the resorbing bone surface, forming bone surface and intermediate surface and change in the number of osteocyte lacunae in the forming bone surface, using Zeiss IBAS 2000. The results revealed that the resorption process preceded the forming process for the temporal segment from about the tenth day, the forming process preceded the resorbing process from the fifth day for the middle segment and the forming process preceded from the beginning for the sagittal segment. These findings directly reflect an aspect of the growing process of parietal bone, making it possible to regard this SEM observation method as one of the effective approaches to the bone histomorphometry.     

Effects of immobilization on fetal bone development. A morphometric study in newborns with congenital neuromuscular diseases with intrauterine onset

Summary The effects of immobilization on fetal bone development were studied through postmortem radiographs in 11 newborns with congenital neuromuscular diseases (CNMD) of intrauterine onset. Quantitative parameters were determined in the following bones: tibia, femur, humerus, radius, 3rd lumbar vertebra, and 5th rib. Thirty stillborns or newborns of similar gestational age and deceased from causes other than neuromuscular or related diseases were used as controls. No significant differences in bone lengths were observed between both groups. However, external diameters, cortex thicknesses, and cortical areas values were significantly lower in newborns with CNMD than in the control group. In newborns with CNMD, the medullary diameter of long bones showed good correlation with gestational age. However, this diameter was greater than that expected according to the reduced external diameter. These results suggest that intrauterine immobilization induces a decrease in mechanical usage of bone, mainly influencing bone modeling and probably bone remodeling. No changes were observed in longitudinal bone growth. Bones showed osteopenia and mechanical defects and were prone to fractures. In summary, reduced immobilizationin utero produces bone osteoporosis of the fetus.     

双侧卵巢切除大鼠不同时间段骨形态计量学参数的观察

目的观察去卵巢大鼠骨质疏松模型复制情况并动态观察去卵巢后不同时间段骨丢失情况，为抗骨质疏松药物研究提供对照依据。方法4．5月龄SD雌性大鼠，按体重随机分组，大鼠摘除双侧卵巢；在实验的第0d（4．5月龄）、4w（5．5月龄）、12w（7、5月龄）、18w（9．5月龄）杀死大鼠取材；采用体内双荧光标记法，胫骨上段硬组织包埋切片及松质骨形态计量学分析处理，观察去卵巢后不同时间段骨丢失情况。结果大鼠去卵巢4w后骨量显著降低，骨结构变差，骨形成有增加，骨吸收增加，骨吸收大于骨形成，骨转换增加。去卵巢12w后，大鼠骨量进一步降低，骨小梁宽度先变窄（4w）后变宽（8、12、18w），骨形成和骨吸收均增加，去卵巢后大鼠在前一个月内（4w）骨量（Tb．Ar％）降低64．18％，差异有显著性（P〈0．05）。结论大鼠去卵巢4w后骨量降低，骨结构变差，骨形成和骨吸收增加，骨转换增加，去卵巢12w到18w骨量持续丢失，但较缓和，提示去卵巢后骨丢失在前4。最快更明显。因此，用于药物研究可选择去卵巢后4w时间进行。     

Reduced bone formation in patients with osteoporosis associated with inflammatory bowel disease

The pathophysiology of bone loss associated with inflammatory bowel disease has not been clearly defined. In this study we have performed a detailed histomorphometric analysis of iliac crest bone obtained from 19 patients with inflammatory bowel disease in whom a diagnosis of osteoporosis had been made. Eleven subjects were receiving prednisolone at the time of their biopsy. Comparison with control values demonstrated a highly significant reduction in trabecular bone area in the patient group (p<0.001). Wall width, adjusted appositional rate and bone formation rate were all significantly reduced in the patient group (p<0.001) and the formation period was significantly increased (p<0.001). Resorption cavities were slightly smaller in the patient group, differences in maximum cavity depth and cavity length achieving statistical significance (p<0.005 andp<0.05 respectively). The mineral appositional rate was significantly reduced in the patients with inflammatory bowel disease (p<0.001) and the mineralization lag time significantly increased (p<0.001); however, osteoid area, perimeter and seam width were not significantly different from controls. These results demonstrate that osteoporosis associated with inflammatory bowel disease is characterized by reduced bone formation at the cellular and tissue level; the proportionately greater change in wall width than in resorption cavity depth is consistent with a negative remodelling balance. Although none of the patients had osteomalacia as defined by the criteria of increased osteoid seam width and mineralization lag time, the higher mineralization lag time in the patient group indicates a mild mineralization defect.     

染料木黄酮对去势大鼠骨组织形态计量学参数的影响

目的　研究染料木黄酮对去势大鼠股骨远端形态计量学参数的影响 ,为染料木黄酮防治骨质疏松提供理论依据。方法　雌性Wistar大鼠 4 7只 ,按体重随机分为 6组 :假手术组、去势对照组、去势 雌激素组 (2 0 μg/kg体重 )、去势 染料木黄酮组 (染料木黄桐剂量分别为 2 5、5 0、10 0mg/kg体重 )。饲养 3个月后处死 ,测定股骨形态计量学参数。结果　去势组与假手术组比较 ,骨小梁体积、平均骨小梁板密度和厚度减少 ,平均骨小梁板间隙和类骨质宽度增加 ,矿化延迟时间和类骨质成熟时间延长 ,且差异均具有显著性 (P <0. 0 5 )。染料木黄酮各组与去势组比较 ,骨小梁体积和平均骨小梁板厚度增加 ,平均骨小梁板间隙变窄 ,矿化延迟时间和类骨质成熟时间缩短 ,且差异均有显著性 (P <0 . 0 5 )。结论　染料木黄酮有促进骨形成 ,减少切除卵巢后骨量丢失的作用。     

Bone tissue response to four-month antiorthostatic bedrest: A bone histomorphometric study

Summary A histomorphometric analysis were made on iliac crest biopsies from eight healthy male volunteers submitted to a 4-month antiorthostatic bedrest. Bone mass and bone cell parameters, reflecting resorption and formation activities, were measured before and after the bedrest period. Trabecular bone volume and mean cortical thickness were not modified despite a decreased number of trabeculae and nonsignificant increase of the trabecular thickness; total and active resorption surfaces and the number of osteollast per mm² of trabecular surfaces do not vary significantly. Osteoid thickness does not vary but we found a reduced osteoid surface and a nonsignificant decreased osteoid volume. Our results suggest that bone architecture may be more affected by the reduction of mechanical forces than the bone mass. These modifications were supposed to be the result of an accelerated bone turnover in the early stage of immobilization. In this study, we failed to find disuse osteoporosis; however, we must point out that the new organization of the trabecutae could affect the bone mechanical properties.     

Prostaglandin E2 enhances alveolar bone formation in the rat mandible

Prostaglandin E₂ (PGE₂) induces bone formation in stress-bearing bones. The mandible, a stress-bearing bone, is loaded daily during mastication. The aim of this study was to determine if PGE₂ delivered locally to the mandible over 20 days enhances alveolar bone deposition. In 18 Lewis rats, controlled-release pellets containing PGE₂ were implanted on the buccal aspect on the left-hand side of the mandible, mesial to the root of the first molar. Controlled-release pellets locally delivered 0.1, 0.05, or 0.025 mg/day of PGE₂. The right side of the mandible was used as a matched control for each animal. Six sham-treated animals were implanted with a placebo pellet. On days 7 and 19, animals were injected with the bone markers tetracycline and calcein, respectively. On day 21, animals were sacrificed and undecalcified tissues obtained for morphometrical analysis. Morphometrical measurements were analyzed by paired t test to determine differences between the matched samples and one-way ANOVA to compare the different treatment groups. A significant increase in alveolar bone area was observed in mandibles treated with 0.1 and 0.05 mg/day when compared with matched controls and the placebo group. This was accompanied by a significant increase in alveolar bone height and width. The proportions of double-labeled surface (dLS), the mineral apposition rate (MAR), and bone formation rate (BFR) were significantly increased in mandibles treated with the two higher doses of PGE₂. The proportion of resorptive surface (RS) was significantly reduced in these two groups. It is concluded that PGE₂ induces alveolar bone formation in the mandible when locally delivered at a dose of 0.1 or 0.05 mg/day for 20 days.     

Effect of a five-week swimming program on rat bone: A histomorphometric study

Summary To specify the exercise-induced changes on different skeletal sites, the effect of a 5-week endurance swin training was studied in rats. Eighteen Lyon strain (Sprague-Dawley) 5-week old female rats were divided into nine sedentary and nine swimming rats. Each swim training session was increased by 15 minutes from 2–6 hours per day. A histomorphometric study was performed at the primary and secondary spongiosa of the distal femur and at the secondary spongiosa of lumbar and thoracic vertebral bodies. After training, bone loss was observed in the secondary spongiosa of lumbar vertebral bodies (24.7%) and in the primary spongiosa of distal femur (15.2%). A tendency to bone loss was also detected in the secondary spongiosa of distal femur (10.8%), whereas no change was detected in thoracic vertebral bodies. In secondary spongiosa, bone loss was accompanied with a thinning of trabeculae. Total eroded surfaces and osteoid surfaces were significantly decreased in the three studied skeletal sites, suggesting a decreased bone turnover. The decreased thickness of osteoid seams in both lumbar vertebrae and distal femur could mean that the osteoblastic activity has also been altered at the cell level, leading to thinning of trabeculae. Five-week swim training with such duration and intensity of exercise appears unable to increase bone volume in rats and, therefore, causes adverse effects. The three studied bones seemed to adapt differently to experimental conditions. The lack of ground reaction forces induced by water immersion might have contributed to the observed bone loss. Normal gravity would be an important cofactor in the osteogenic effects of exercise.     

Effect of heparin on bone formation in cultured fetal rat calvaria

Summary To assess the effects of heparin on bone formation we measured [³H]proline incorporation into collagenase-digestible (CDP) and noncollagen protein (NCP), [³H]thymidine (TdR) incorporation into DNA, and DNA content in 21-day-old fetal rat calvaria cultured in BGJ medium with bovine serum albumin for 24–96 hours. Heparin at 5–125 μg/ml decreased TdR incorporation by 26–51% at 24 and 96 hours. At 96 hours, heparin 5, 25, and 125 μg/ml decreased [³H]proline incorporation into CDP by 41, 48, and 32%, respectively, with no significant change in NCP. To evaluate the possible role of PGE₂ in these inhibitory responses, media PGE₂ concentration was measured and the effects of heparin on CDP labeling and DNA synthesis were tested in the presence of indomethacin, piroxicam, and flurbiprofen to inhibit endogenous prostaglandin E₂ (PGE₂) production and in the presence of a high concentration (10⁻⁷ M) of exogenous PGE₂. Heparin did not alter PGE₂ production at 24 hours but at 48 hours there was a significant reduction. At 96 hours, indomethacin (10⁻⁶ M) inhibited [³H]proline incorporation into CDP by 38% but had no effect on the labeling of NCP. Heparin had no further significant inhibitory effect in the presence of indomethacin. Piroxicam and flurbiprofen did not alter DNA content and had a smaller inhibitory effect than indomethacin on the labeling of CDP. Moreover, addition of heparin produced a further inhibition of CDP and DNA content and finally, heparin decreased CDP labeling by 71% in the presence of PGE₂. We conclude that heparin has direct inhibitory effects on DNA and collagen synthesis, which could play a role in heparin-induced osteoporosis. The mechanism by which heparin decreases collagen and DNA synthesis appears to be largely unrelated to its effect to decrease PGE₂ production.     

Effects of raloxifene,hormone replacement therapy,and placebo on bone turnover in postmenopausal women

Raloxifene, a nonsteroidal selective estrogen receptor modulator (SERM), increases bone mineral density (BMD), decreases biochemical markers of bone turnover, and prevents incident vertebral fractures in postmenopausal women, while sparing the breast and endometrium from the undesirable stimulation caused by estrogen. How the long-term beneficial effects of raloxifene on bone turnover, as assessed by bone histomorphometry, compare with hormone replacement therapy (HRT) and placebo are not known. We studied 66 healthy postmenopausal women (age 55 to 75 years, mean 63 years) who were randomized to either raloxifene 150 mg/day, HRT (Premarin 0.625 mg/day, and Provera 2.5 mg/day), or placebo for 1 year. All women received 1–1.5 g of calcium/day. Following double tetracycline labeling, transiliac bone biopsies were obtained at baseline and 1 year and analyzed for changes in histologic indexes of bone remodeling on the cancellous surface as well as at the endocortical subdivision of the endosteal envelope, the location of the greatest fraction of postmenopausal bone loss. BMD and biochemical markers of bone turnover were also determined at baseline and 1 year. Four paired biopsies were obtained in the HRT group, six in the raloxifene group, and five in the placebo group. The frequency of remodeling events on cancellous bone and rate of bone formation in both cancellous and endocortical bone increased in the placebo group, while these measurements decreased in both drug treatment groups. Using analysis of mean percentage changes, when compared with the placebo group, these changes were significantly different for both raloxifene and HRT treatment groups (p<0.02). In all subjects, the bone was lamellar with discrete tetracycline labels and there was no evidence of marrow fibrosis or abnormal bone cells. BMD increased from baseline at the lumbar spine (p<0.05 in the HRT group) and in the total body (p<0.05 for both raloxifene and HRT). Compared with that of the raloxifene group, the increase in BMD was greater in the HRT group at the lumbar spine but not in the total body. Serum bone alkaline phosphatase, serum osteocalcin, and urine C-terminal cross-linking telopeptide of type I collagen significantly decreased (p<0.05) in both active treatment groups, changes significantly different from those seen with placebo. Overall, these results support the hypothesis that raloxifene preserves bone mass by reducing the elevated bone turnover found in postmenopausal women receiving placebo, by mechanisms similar to those operative in postmenopausal women receiving HRT.     

Glucocorticoid-induced inhibition of osteoblastic bone formation in ewes: A biochemical and histomorphometric study

The mechanisms underlying glucocorticoid-induced osteoporosis in humans are a defect in bone formation associated with increased bone resorption. The latter may be due to elevated parathyroid hormone (PTH) levels induced by the impairment of intestinal calcium absorption caused by corticosteroids. In this study we analysed the effects of corticosteroids in old ewes, a potential model for the study of human bone turnover. Two groups of seven 9-year-old female sheep were selected. The first group was injected intramuscularly with a daily dose of 30 mg methylprednisone (MP) during the first 2 months and 15 mg during the last month. After 2 and 3 months of treatment, blood samples were taken. At the end of the experiment the animals were slaughtered and the iliac crest kept for bone histomorphometry. Serum osteocalcin (sOC) rapidly and markedly decreased in the MP-treated group compared with controls (–77%;p<0.01). In contrast, at the end of the experiment serum calcium and PTH levels were similar in both groups. Histomorphometric analysis showed a significant reduction in the wall width of trabecular packets. Dynamic parameters reflecting bone formation at the tissue and cell levels were significantly lower in the MP-treated group than in controls, with a highly significant decrease in the mineralization rate (MAR: –63%,p<0.05) and double-labeled perimeter (dLPm/B.Pm: –92%p<0.05). The bone formation rate (BFR/B.Pm) also decreased by 84% and the adjusted apposition rate (Aj.AR) by 80%. The increase in the total formation period was mainly due to an increase in the inactive period. Significant correlations were found between sOC and MAR, dLPm/B.Pm and BFR/B.Pm (withr respectively 0.67, 0.76 and 0.51). In conclusion, the effects of corticosteroid on ewe bone remodeling are essentially characterized by a major bone formation defect without evidence of secondary hyperparathyroidism, although this cannot be totally excluded by our results. Ewes treated with glucocorticoids could represent a good model for evaluating the effects of drugs candidates for all bone conditions characterized by reduced bone formation resulting from osteoblastic depression.     

Bone mineral density and bone histomorphometric assessments of postpregnancy osteoporosis: A report of five patients

Reports of five young women who developed vertebral fractures associated with pregnancy and lactation are presented (Fig. 1). Ages ranged from 24 to 37 (mean 30) years. All five patients have osteoporosis with two to nine vertebral fractures at presentation postpartum. Bone mineral density (BMD) was measured by single-photon absorptiometry, quantitative computer tomography, and dual-energy X-ray absorptiometry. BMD of the trabecular bone was less than normal values and it remained apparently low even several years after pregnancy. Histological findings of bone biopsy identified the bone loss with increasing bone resorption. Our present findings suggest that postpregnancy osteoporosis affects mainly the trabecular bone site, and the patients might have low peak bone mass and poor reversibility probably due to a low rate of remodeling.     

小鼠骨组织形态学特征及泼尼松对骨量及骨钙的影响

目的探讨小鼠骨组织形态学和小鼠骨钙含量的研究方法,并观察不同剂量的泼尼松对小鼠骨形态学及骨钙含量的影响.方法 24只昆明种♀小鼠,随机分为4组正常对照组,泼尼松低、中、高剂量组,对照组给予生理盐水,其余3组分别按泼尼松0.75、1.5、6.3 mg.kg-1@d-1灌胃给药,实验21 d后,眼眶放血,取右胫骨进行硬组织包埋切片,作骨组织形态计量学检测,取右股骨测骨钙含量.结果小鼠骨形态学与大鼠相似,但松质骨骨量个体差异大.形态学中骨量与骨钙含量有正相关(P＜0.05).对不同剂量泼尼松作用的检测表明低、高两剂量泼尼松对骨钙含量无明显影响,中剂量可增加骨钙含量(P＜0.05);骨形态计量学观察可见低、中剂量的泼尼松有增加骨量的趋势,中剂量差异有显著性(P＜0.05),高剂量泼尼松有减少骨量的趋势.中剂量增加松质骨表面双荧光强度(P＜0.05).结论小鼠骨形态学特征和骨钙含量有低的相关关系,泼尼松低的剂量可增加小鼠的骨钙含量、骨量和骨小梁表面荧光,当剂量增加时却有减少骨量和骨表面荧光的作用.提示测定药物对骨钙含量影响在一定程度上反映形态学中骨量的变化,提示若用高剂量泼尼松可致小鼠骨量减少模型.     

Relationships between bone structure in the iliac crest and bone structure and strength in the lumbar spine

The purpose of this study was to examine the relationship between histomorphometric variables of cancellous bone structure and ultimate compressive strength (UCS) in the second lumbar vertebra (L2) and to determine whether structural variables in the iliac crest are predictive of the same variables and of UCS in L2. At autopsy, 7.5 mm diameter cores were removed from the iliac crest and from L2 of 29 subjects who had died suddenly without bone disease. Cancellous bone volume (BV/TV, %) was significantly lower in L2 than in iliac crest due to lower trabecular number (Tb.N, per mm) and thickness (Tb.Th, µm). There were significant correlations between iliac crest and L2 for BV/TV, Tb.N and trabecular separation (Tb.Sp, µm), but not for Tb.Th. BV/TV was negatively correlated, and Tb.Sp was positively correlated with age at both sites. Tb.Th was not significantly correlated with age in the iliac crest, but a significant negative correlation was observed in L2. The UCS of vertebral cores was negatively correlated with age. BV/TV and Tb.Th in L2 were positively correlated with UCS in L2. Cortical width and BV/TV in iliac crest were positively correlated with UCS in L2. We conclude that: (1) cancellous bone volume in the iliac crest is higher than in the lumbar spine due to thicker, more closely spaced trabecular plates, (2) the changes in structural variables with age are generally similar in the iliac crest and lumbar vertebra, but trabecular thinning with age is more evident in the spine than in the ilium, and (3) the compressive strength of cancellous bone in the lumbar spine is correlated with histomorphometric variables of bone structure, as measured both in the lumbar spine and in the iliac crest.     

Electromagnetic stimulation of bone repair: a histomorphometric study

The effect of pulsing electromagnetic fields (PEMFs) on bone repair was studied in principal metacarpal bones of eight adult male horses: Six horses were treated with PEMFs, and two horses were untreated. In treated horses, Helmholtz coils were applied during a 60-day period to the left metacarpal bones, bored with eight holes of equal diameter and depth, from the middiaphysis toward the distal metaphysis. Eight equal holes bored in the right metacarpal, surrounded by unactivated Helmholtz coils, were taken as controls. The two untreated horses were taken as additional control. The results of computer-assisted histomorphometric analysis indicate that (a) in diaphyseal levels, the amount of bone formed during 60 days is significantly greater (p less than 0.01) in PEMF-treated holes than in contralateral ones and those in control horses; (b) in metaphyseal levels, PEMF-treated holes are sometimes more closed, sometimes less, as compared with contralateral holes and those in control horses; in any case the statistical analysis indicates that the symmetry in the rate of hole repair, found between the two antimeres of control horses, is not appreciable at metaphyseal levels also; (c) there was no statistically significant difference between untreated holes in PEMF-treated horses and holes in control horses, neither at diaphyseal nor at metaphyseal levels. These preliminary findings indicate that PEMFs at low frequency influence the process of bone repair on both diaphysis and metaphysis, and seem to improve the process of bone repair in skeletal regions normally having a lower osteogenetic activity, i.e., in diaphyses as against metaphyses.     

Bone histomorphometric analysis for the cause of osteopenia in vitamin C-deficient rat (ODS rat)

Summary A particular strain of rat, the osteogenic disorder rat (ODS rat), was established in 1973. Phenotypic expression of od/od in ODS rat develops signs characteristic of a vitamin C-deficient animal, with bleeding tendencies and limb fractures. We investigated the bone histomorphometry to clarify the pathogenesis of osteopathy found in ODS rat. Bone histomorphometry revealed that static parameters reflecting bone formation were found to be remarkably decreased in od/od rats. These observations were more prominent in the metaphysis of distal femurs of od/od rats than those in the tail vertebrae. Parameters reflecting bone resorption in od/od rats were reduced in the distal femoral metaphysis, but were similar to those of controls in the tail vertebrae. These parameters were restored to control levels after ascorbic acid supplementation to pair-fed od/od rats. The mineral appositional rate in od/od rats was not significantly different from that in controls. Although body weight gain in pair-fed controls was significantly reduced compared to those fedad libitum, histomorphometric parameters, on the contrary, were unaltered between these groups. Our present study provides evidence that the cause of osteopenia found in od/od rat is attributable to an imbalance between the total amounts of resorption and formation, and the pathogenesis of osteopathy could be due to ascorbic acid deficiency itself rather than malnutrition.     

Computerized three-dimensional histomorphometric study of iliac bone in patients with femoral neck fracture

To elucidate the pathology of osteoporosis, we used a computer, to investigate three-dimensional tissue morphometry in biopsied iliac bone specimens from 20 female patients with femoral neck fractures. The 20 fracture patients were divided into two groups according to age: group I, patients below 70 years of age (n=10) and group II, patient 70 years of age or more (n=10). Five patients who also underwent iliac bone biopsy but who did not have fractures served as the control group. We found that the ilium in group I patients was composed of many small thin trabecular structures, while the ilium in group II was composed of only a few broad trabecular structures. The three-dimensional Euler number was small in osteoporosis, suggesting that trabecular connectivity was also diminished and the fractal dimension decreased. This indicated that the trabecular structure had become irregular. These findings indicate that the number of trabeculae appeared to decrease with trabecular blocking due to osteoporotic changes, and, simultaneously with this phenomenon, the which of the individual trabeculae seemed to become thicker in accordance with bone adaptation to mechanical stress.A summary of this paper was reported at the 9th Annual Orthopaedic Research Meeting of the Japanese Orthopaedics Association (October, 1994), and the 3rd Study Meeting of the Japanese Society of Osteoporosis (October, 1994).