Electron microscopy of developing calvaria reveals images that suggest that osteoclasts engulf and destroy osteocytes during bone resorption

Summary It is generally accepted that osteoclasts are responsible for the breakdown and removal of bone matrix constituents. However, very little is known about the fate of osteocytes during bone resorption. In the present study we have examined sites of bone destruction in calvaria of young rats aged 4–9 days in the hope of obtaining information on the fate of osteocytes. Decalcified glutaraldehyde-formaldehyde-fixed specimens were prepared for ultrathin section electron microscopy. When sequentially arranged, the images obtained suggest that osteoclasts engulf and destroy osteocytes during bone degradation. We propose that the following sequence of events takes place when a lacuna is opened up by an osteoclast: (1) When the osteoclast comes in contact with an osteocyte, the villi of the ruffled border become flat and broad. (2) Long osteoclastic extensions surround the osteocyte. (3) The osteocyte is subsequently internalized with apparent degradation.     

Osteoporosis and Coronary Atherosclerosis in Asymptomatic Postmenopausal Women

Estrogen deficiency is a risk factor for osteoporosis and coronary artery disease. Osteoporosis can be evaluated by measuring bone mineral density (BMD). Coronary atherosclerotic burden can be evaluated by measuring coronary calcium using electron beam computed tomography (EBT) of the heart. We compared coronary calcium scores in 45 asymptomatic postmenopausal women with normal and low BMD. BMD of the lumbar spine and proximal femur was measured by dual X-ray absorptiometry (DXA), and coronary calcium was measured quantitatively by EBT. Women were divided into control, osteopenia, and osteoporosis groups based on the T score of the lumbar spine. Women were similar in age, years since menopause, height, weight, and body mass index (BMI). BMD ± SD (g/cm²) of L1–L4 was 0.96 ± 0.11, 0.83 ± 0.03, and 0.73 ± 0.05, in control, osteopenia, and osteoporosis group, respectively. The total coronary calcium score ± SD (relative units) was 41.9 ± 83.1, 115.1 ± 181.9, and 221.7 ± 355.4 for control, osteopenia, and osteoporosis group, respectively; the score was significantly higher in the osteoporosis than in the control group. This study provides initial data suggesting that women with osteoporosis may have a higher risk of developing coronary atherosclerosis.     

小儿先天性髋关节脱位近年来应用术式的演变及其评估

本文介绍本院近４年来小儿先天性髋脱位治疗应用术式的演变。由２０多年来一直喜欢用骨盆截骨术演变为近１年来用得最多的是造盖术。近４年共手术４６３例，５６５髋。实践证明：比起骨盆截骨术，造盖术显得更简便，侵袭小，不需二次手术拔除内固定针。因在我国大龄髋脱位偏多，造盖术更适合我国国情。经过一些改进，可以克服造盖折断和吸收问题。     

Utilisation des implants biodégradables dans le traitement chirurgical des fractures et au cours des ostéotomies

Résumé L'utilisation de matériaux d'ostéosynthèse biodégradables a l'avantage d'éviter la réintervention pour extraire le matériel. Les biomatériaux de polymères polyglycolides ont été expérimentés sur plus de 3 600 animaux de laboratoire avant leur introduction en pratique clinique. Depuis 1984 nous les avons utilisés comme matériau d'ostéosynthèse dans près de 1 700 cas parmi lesquels 880 cas de fracture malléolaire, 226 cas d'ostéotomie en chevron pour hallux valgus, 65 cas de fracture de la tête radiale et 54 cas de fracture de l'olécrane. Parmi les 800 premiers cas traités par broches biodégradables nous avons obtenu des résultats favorables et sans incidents dans 91 pour cent des cas. Il y eut 7 cas de fixation défaillante nécessitant une réintervention. Il y a eu 7 cas d'infection superficielle et 3 cas d'infection profonde. Nous avons observé la formation d'une collection séreuse sous-cutanée sans influence sur le résultat radiologique ou clinique dans 52 cas (6,5 %). Au vue de ces résultats et compte tenu des avantages économiques et psychologiques des matériaux biodégradables (pas de réintervention), on peut penser que l'usage de biomatériaux rivalise favorablement avec l'usage de matériaux conventionnels dans certains types d'ostéosynthèse.

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Utilization of biodegradable implants in the surgical treatment of fractures and osteotomies

Summary The utilization of biodegradable implants instead of metals in orthopaedic surgery abolishes the need to remove the fixation material. For this study biodegradable rods and screws of self-reinforced polyglycolide, polylactide and lactide-glycolide copolymer were developed and manufactured. The clinical introduction of these implants was preceded by thorough experimental studies with 3 600 animals. From November 1984 the developed biodegradable method of osteofixation was used in 1 700 operations. These included 880 displaced malleolar fractures, 226 chevron-osteotomy for hallux valgus, 65 displaced fracture of the radial head, 54 displaced frature of the olecranon and other fresh fractures or orthopaedic operations. In the first 800 cases operated on using self-reinforced polyglycolide rods the postoperative course was uneventful (91%). Because of failure in the fixation reoperation was needed in 7 cases. A superficial wound infection was observed in 7 cases, deep infection in 3 and transient fluid accumulation in 52 cases (6,5%). Fluid accumulation did not influence the radiological or clinical end-result. The advantages of biodegradable fixation are many-sided. There is a costbenefit and clinical capacity is free for other use, and psychological advantages must be emphasised because removal of implants is not needed. The over all results of this study were considered favourable.

     

Expression of gelatinases within the trabecular bone compartment of ovariectomized and parathyroidectomized adult female rats

Ovariectomized (ovx) and parathyroidectomized (ptx) rat models of disturbed bone metabolism have been widely used in evaluating bone changes resulting from hormonal depletion, and are characterized by elevated and depressed bone turnover, respectively. We report here the expression of gelatinases extracted from native trabecular bone in these models. Nine-month-old female Sprague-Dawley rats were sacrificed after 3 weeks following ovx or 10 days post ptx to determine the influence of these procedures on the levels of proximal tibial bone tissue gelatinases. Identification and quantitation of these enzymes were performed via gelatin gel zymography of native tissue extracts and laser densitometry of developed gels, respectively. In the ptx model, a reduction in tissue levels of pro- and active-MMP-2 and 45 kDa activated fragment was seen, whereas ovx exhibited significant increases in these enzymes. The MMPs are therefore clearly under the influence of factors known to modulate bone remodeling in vivo. The study of MMP levels directly extracted from bone using these experimental models may assist in developing management regimes for metabolic bone diseases through the use of drugs aimed at controlling turnover.     

Effect of calcitonin on total body bone mineral contents of experimental osteoporotic rats determined by dual photon absorptiometry

Summary Total body bone mineral (TBBM) content in rats was measured by dual photon absorptiometry (DPA). TBBM showed significant increases over 4 weeks in control groups with significant bone loss over the same time in prednisolone-injected rats on low calcium feed. Daily injections of calcitonin significantly reduced loss of bone mass. Both prednisolone- and prednisolone-calcitonin-injected groups showed significantly elevated serum alkaline phosphatase with the prednisolone-calcitonin group also exhibiting elevated serum calcium and phosphate levels, confirming the impact of the experimental protocol. TBBM measured by DPA in all groups correlated well (r=0.928,P<0.001 n=20) with the total ash weight suggesting that the method reflects total skeletal mineral content in the small animal. TBBM measurement by DPA proves well-suited to monitoring bone mineral in a small animal experimental setting.     

Precision of dual-photon absorptiometry

Summary Precision of dual-photon absorptiometry (DPA) measurements was determined in a lumbar spine phantom and in humans. Approximately half of the measurements were made before and half after a¹⁵³gadolinium source change. The phantom was measured with different amounts of acrylic, which simulates human soft tissue, in order to evaluate the influence of body thickness on bone mineral density (BMD). Results of scans analyzed with two software versions from Lunar Radiation Corp., the widely used 08B and a prototype 08C, are compared. DPA with a cold source significantly overestimated BMD in the phantom in the presence of large amounts (more than 25 cm) of soft tissue equivalent with version 08B but not with the newer version 08C. Similiarly, in nine subjects, there was a significant decrease in spine BMD after a source change when scans were analyzed with version 08B (mean difference 0.026 g/cm²,P=0.002) but not with 08C (0.01 g/cm²,P=0.234). No systematic effect of source change on femoral BMD measurements was observed. The SD of the mean difference of two measurements of the nine subjects was 0.019 g/cm² (1.6% of the mean value) for the spine with software version 08B and 0.024 g/cm² (2.0%) with version 08C, 0.03 g/cm² (3.3%) for the femur neck, 0.03 g/cm² (4.0%) for the greater trochanter, and 0.04 g/cm² (4.9%) for Ward's triangle region of the proximal femur. The spine phanton was scanned on two other commercial bone densitometers in order to assess inter-instrument variation. Phantom measurements of L2-4 BMD made on two Lunar Radiation Corp model DP3 scanners which differed by 2% were 10 and 12% higher than those with a Norland Corp. model 2600 scanner.     

The effect of high-dose salmon calcitonin on bone mineral metabolism in the normal rat

Summary The paucity of information on the effect of long-term high-dose salmon calcitonin administration on normal bone mineral metabolism and histology prompted an investigation of the influence of high-dose synthetic calcitonin in the rat. Serum ionized calcium, osteocalcin or BGP (bone gla protein), and immunoreactive PTH were measured serially during calcitonin administration and bone histomorphometry analyzed at 6 weeks (after sacrifice). Daily injections of salmon calcitonin, 0.4 IU/100 g (group B) and 2 IU/100 g (group C), resulted in significant hypocalcemia at 4 hours for both experimental groups (P<0.004). Serium iPTH was significantly higher over the study period for both groups administered calcitonin. Serum BGP levels were significantly lower than controls during the study in group C (P<0.002) and to a lesser extent in group B (P<0.05). In group C, bone histomorphometry revealed increased resorption (onteoclast count), decreased trabecular bone volume, and decreased double-labeled tetracycline surface (bone formation). In group B an increase in osteoclast count but no alteration in bone formation was observed. To assess the role of PTH in the above findings, high-dose calcitonin was administered to parathyroidectomized rats. All of the above changes in bone histomorphometry were not observed in this group of animals. In conclusion, high doses of calcitonin promote hypocalcemia, secondary hyperparathyroidism, and osteoclastosis in the normal rat in a dose-dependent manner with very high-dose calcitonin impairing bone formation.     

国产 89SrCl2治疗肿瘤骨转移灶所致骨痛临床多中心研究

目的　验证上海科兴药业公司提供的89SrCl2 注射液治疗转移性骨肿瘤所致骨痛的疗效。方法　试验采用随机、双盲、阳性药物 (英国Amersham公司生产的Metastron)对照 ,5个中心参加验证。对 90例原发病灶诊断明确的恶性肿瘤骨转移患者进行骨痛镇痛治疗 ,其中资料完整的Ⅰ组(验证组 ) 5 9例 ,Ⅱ组 (对照组 ) 2 9例 ,余 2例患者剔除。Ⅰ组中男 30例 ,女 2 9例 ,年龄 2 5～ 80 (5 9 95±13 80 )岁 ;原发性恶性肿瘤肺癌 2 1例 ,乳腺癌 2 4例 ,前列腺癌 12例 ,胃癌、肝癌各 1例 ;治疗前骨痛评分为 6～ 12 (7 5 9± 1 5 9)。Ⅱ组中男 11例 ,女 18例 ,年龄 35～ 91(5 8 93± 14 6 0 )岁 ;原发性恶性肿瘤肺癌 10例 ,乳腺癌 12例 ,前列腺癌 6例 ,胃癌 1例 ;治疗前骨痛评分为 6～ 9(7 14± 1 4 6 )。入选患者均以 14 8MBq静脉注射给药 ,疼痛得分大于 6 ,体力状况评分平均≤ 70分 ,患者预期生存期至少大于3个月。全身99Tcm 亚甲基二膦酸盐 (MDP)骨显像示多发骨骼放射性浓聚灶 ,并经实验室及其他影像学检查证实。治疗后观察 3个月。结果　Ⅰ组镇痛有效率为 6 2 71% (37 5 9例 ) ;其中无效占 15 2 4 %(9 5 9例 ) ,好转占 2 2 0 3% (13 5 9例 ) ,显效占 5 5 93% (33 5 9例 ) ,完全缓解占 6 78% (4 5 9例 )。Ⅱ组镇     

抗感染重组合异种骨对犬污染性桡骨缺损的一期植骨修复作用

目的探讨抗感染重组合异种骨(anti-infective reconstituted bone xenograft,ARBX)对犬污染性桡骨缺损的一期植骨修复的效果. 方法在重组合异种骨(reconstituted bone xenograft,RBX)基础上,结合抗生素局部缓释技术,制备具有较强抗感染能力和较高成骨作用的ARBX.取成年杂种犬8只,于双侧桡骨中上段制成15 mm节段性骨缺损,在缺损处注入5×106 CFU/ml金黄色葡萄球菌1 ml,静置15分钟后,于双侧缺损区分别植入ARBX、RBX,并用钢板固定.术后6个月对存活的6只犬进行取材,通过解剖学、X线片、组织学及细菌学检查,比较ARBX和RBX一期植骨修复犬污染性桡骨缺损的效果. 结果术后6个月,ARBX侧有5只完全修复,1只中央部3 mm缺损未修复,均无骨髓炎表现,标本细菌培养均为阴性.RBX侧有1只部分修复,5只未能修复,残留8～13 mm缺损,均有明显骨髓炎表现,标本细菌培养均为阳性. 结论 ARBX具有较高成骨活性和较强的抗菌能力,能够一期植骨修复细菌污染性骨缺损.