Effect of heat in increasing the range of knee motion after the development of a joint contracture: an experiment with an animal model

OBJECTIVE: To compare the effects of 2 different heat modalities, infrared and ultrasonic therapy, on a knee flexion contracture. DESIGN: In vivo, experimental, controlled study involving a rat knee joint contracture model that was immobilized using a ligature in flexion for 40 days. SETTING: Collegiate research laboratory. ANIMALS: Ninety-three adult male Wistar rats. INTERVENTIONS: After remobilization, rats were assigned to 3 treatment groups: stretching only (S), stretching with infrared therapy (S+IR), and stretching with ultrasonic therapy (S+US). Six treatment sessions were given in 2 weeks. MAIN OUTCOME MEASURES: The angle of maximum knee extension, wet-weight of triceps surae muscles, phase lag, and dynamic stiffness as mechanical responses were measured, and histologic study was conducted. RESULTS: Compared with the S group, both the S+IR and S+US groups exhibited a significant increase in range of motion (ROM) (P=.021, P=.008, respectively) and a tendency to decrease the phase lag, but there was no significant difference between the 2 heat-combined groups. There were no differences in the weights of the triceps surae muscles and in dynamic stiffness among the groups. CONCLUSIONS: Six treatment sessions of stretching with infrared or ultrasound were more effective than stretching without heat at increasing the ROM and decreasing the phase lag of a moderately severe joint contracture. The clinical implementation of heat is advocated to regain a normal ROM and mechanical property when experiencing a joint contracture.     

Mechanical effects of immobilization on the Achilles' tendon

OBJECTIVE: To measure the biomechanical effects of immobilization on the Achilles' tendon. DESIGN: Experimental, controlled study. SETTING: Physiatry research laboratory. ANIMALS: Twenty adult rabbits. INTERVENTION: One hindlimb immobilized in a cast for 4 weeks (n=10) or 8 weeks (n=10). The contralateral legs (n=20) served as controls. MAIN OUTCOME MEASURES: Cross-sectional Achilles' tendon area, mode of failure, mean failure load, and tendon stiffness. RESULTS: The Achilles' tendon cross-sectional area did not change. Achilles' tendon-calcaneus units failed at insertion at 4 weeks and in controls. Calcaneus fracture was the most prevalent mode of failure at 8 weeks. The mean load to failure of both immobilized groups (4wk: 187.5+/-45.7N; 8wk: 162.6+/-39.3N) was significantly smaller than that of the control group (549.2+/-93.7N, both P<.005). The mean tendon stiffness of both immobilized groups (4wk: 64.6+/-24.8N/mm; 8wk: 53.9+/-19.9N/mm) was significantly lower than that of the control group (125.1+/-26.5N/mm, both P<.005). CONCLUSIONS: Immobility for up to 8 weeks caused decreased stiffness but no atrophy or rupture of the Achilles' tendon, suggesting that immobility does not constitute a risk factor for Achilles' tendon midsubstance rupture. Clinically, graded reloading is required after immobilization to restore the tendon insertion and to reverse calcaneal disuse osteoporosis.     

Immobilization-related bone loss in the rat is increased by calcium deficiency

Summary The object of this study was to investigate whether a calcium-deficient diet increases the bone loss produced by mechanical hypofunction (disuse) in the rat. Male Sprague-Dawley rats of approximately 150 g were placed on either a normal diet or a calcium-deficient diet. After 7 days, all rats underwent unilateral hind-limb immobilization by sciatic neurectomy and were sacrificed 30 hours, 72 hours, or 10 days postsurgery. Femora were ashed and the total mineral content (ash weight) was determined. Tibiae were embedded, sectioned, and stained. The metaphyseal secondary spongiosa and the diaphyseal cortical bone were subjected to histomorphometric analysis. Femoral length and serum calcium were not affected by calcium intake or immobilization. Serum parathyroid hormone levels were elevated in rats on the calcium-deficient diet compared to those on the normal diet. Calcium deficiency caused a significant reduction in femoral ash weight (20–35%), tibial cortical thickness (16–20%), and trabecular bone volume (TBV) (33–39%) at 72 hours and 10 days postsurgery. Additional loss of bone mass occurred in the immobilized limb compared to the contralateral intact limb of both dietary groups. This loss occurred earlier (30 hours postsurgery versus 72 hours) in the animals on a calcium-deficient diet and was larger compared to animals on a normal diet (10.6% versus 4.8% at 72 hours and 17.9% versus 12.45% at 10 days). The total bone loss induced by the combination of a calcium-deficient diet and immobilization in this experiment was estimated to equal 46% of femoral ash weight and 79% of tibial TBV. Calcium deficiency increased the number of osteoclasts/mm bone surface in the secondary spongiosa by 25–45%. Immobilization caused a further increase of 50–60% by 72 hours postsurgery. Endosteal mineral apposition rate was significantly decreased (27–44%) by immobilization but was not altered by the low-calcium diet. These data suggest that dietary calcium deficiency augments immobilization-related osteopenia by increasing bone resorption.     

HPLC study on the stability of bendamustine hydrochloride immobilized onto polyphosphoesters

Novel water soluble polymer complexes of bendamustine hydrochloride, a bifunctional alkylating agent with antimetabolic and cytotoxic activity, were developed using biodegradable polymer carriers-poly(oxyethylene H-phosphonate), poly(methyloxyethylene phosphate) and poly(hydroxyoxyethylene phosphate). Bendamustine hydrochloride was immobilized onto polyphosphoesters via covalent, ionic and hydrogen bonding. The structure of the complexes formed was elucidated by (1)H, (13)C, (31)P NMR and FT-IR spectroscopy. The chemical stability of bendamustine hydrochloride in the novel complexes was studied by HPLC analysis based on a validated method with appointed analytical parameters such as specificity, repeatability, limit of quantitation, limit of detection and linearity. The results from the HPLC indicate that in neutral (pH 7) and alkaline (pH 9) media bendamustine hydrochloride in the polymer complexes is more stable than the pure bendamustine hydrochloride. The enhanced stability of the immobilized drug is explained with the drug interaction with the polymer carriers or their degradation products.     

Analysis of fracture healing in osteopenic bone caused by disuse: experimental study

Osteoporosis has become a serious global public health issue. Hence, osteoporotic fracture healing has been investigated in several previous studies because there is still controversy over the effect osteoporosis has on the healing process. The current study aimed to analyze two different periods of bone healing in normal and osteopenic rats. Sixty, 7-week-old female Wistar rats were randomly divided into four groups: unrestricted and immobilized for 2 weeks after osteotomy (OU2), suspended and immobilized for 2 weeks after osteotomy (OS2), unrestricted and immobilized for 6 weeks after osteotomy (OU6), and suspended and immobilized for 6 weeks after osteotomy (OS6). Osteotomy was performed in the middle third of the right tibia 21 days after tail suspension, when the osteopenic condition was already set. The fractured limb was then immobilized by orthosis. Tibias were collected 2 and 6 weeks after osteotomy, and were analyzed by bone densitometry, mechanical testing, and histomorphometry. Bone mineral density values from bony calluses were significantly lower in the 2-week post-osteotomy groups compared with the 6-week post-osteotomy groups (multivariate general linear model analysis, P<0.000). Similarly, the mechanical properties showed that animals had stronger bones 6 weeks after osteotomy compared with 2 weeks after osteotomy (multivariate general linear model analysis, P<0.000). Histomorphometry indicated gradual bone healing. Results showed that osteopenia did not influence the bone healing process, and that time was an independent determinant factor regardless of whether the fracture was osteopenic. This suggests that the body is able to compensate for the negative effects of suspension.     

基于螺旋断层治疗的全身皮肤照射体位固定新技术初步观察

目的 初步观察不同体位固定技术在螺旋断层治疗技术下进行全身皮肤照射(TSI)的可行性。方法 对中山大学肿瘤防治中心接受TSI治疗的 3例蕈样霉菌病患者分别采用低温热塑高分子材料俯卧位固定、潜水衣结合负压真空袋仰卧位固定、低温热塑高分子材料结合真空袋仰卧位固定方法,观察固定效果并计算平均摆位误差、靶区适形指数(CI)、靶区均匀性指数(HI)和靶区 Dmean。结果 3种体位固定方式均起到良好固定效果,设计的放疗计划各参数均能达到临床要求。3例患者平均摆位误差在左右、头脚、腹背方向分别为(0.26±3.40)、(-2.63±4.63)、(6.13±4.86)mm,靶区CI为 0.56±0.09、HI为 1.186±0.059、Dmean为(2586.56±63.28)cGy。结论 低温热塑高分子材料或潜水衣都可以联合真空袋进行TSI治疗的体位固定。通过补偿膜剂量建成效应提高表皮剂量达临床要求,为螺旋断层治疗技术进行TSI提供了安全可靠的体位固定方法。     

色氨酸酶基因工程菌固定化及其培养条件的研究

对色氨酸酶基因工程菌 ＷＷ－ １１进行固定化及培养条件研究,为工业化生产 Ｌ－色氨酸奠定基础。方法;通过色氨酸酶活力测定,考察三种固定化材料及温度、 ｐＨ、单价阳离子和乙醇对固定化 ＷＷ－ １１色氨酸酶活力的影响。结果：以聚乙烯醇作为ＷＷ－１１的固定化载体,其活力回收为６０．９％。固定化ＷＷ－１１色氨酸酶降解反应最适ｐＨ为９．０、最适温度为５０℃;固定化ＷＷ－１１色氨酸酶合成反应最适ｐＨ为７．５、最适温度为４５℃。Ｋ＋、ＮＨ＋对固定化工程菌色氨酸酶有明显激活作用,而Ｎａ＋则有一定的抑制作用。结论：固定化工程菌色氨酸酶对温度、乙醇等的稳定性比游离菌有显著提高。     

固定化酵母细胞生产1，6－二磷酸果糖的动力学研究

筛选获得一株１,６－二磷酸果糖（ＦＤＰ）的高产酵母菌株,改变通透性后的酵母细胞,在发酵及固定化生产ＦＤＰ过程中发现Ｆｅ２＋和甘油能大量提高ＦＤＰ的积累。将戊二醛交联后的酵母细胞,用卡拉胶固定化后,装入酶反应柱,连续生产ＦＰＤ,柱反应可稳定在１０天以上,转化率维持在２０％以上。     

新型脊柱固定器械的研制与临床应用

自１９８９年以来，临床应用一种新型脊柱固定器械，共６８例，其中５２例为胸腰椎骨折，１６例为椎体滑脱。经临床观察和随访，治疗效果满意。这种新型固定器械，既可行胸腰椎骨折的固定，也可行椎体滑脱的复位。根据临床需要，该器械可行压缩、撑开、成角和中立位固定。作者强调，脊柱损伤只要有手术指征，手术时机甚为重要，应早期或立即手术，有利于脊柱骨折和椎管前方骨块的复位，早期也有利于神经功能的恢复。     

Comparative morphometric changes in rat cortical bone following ovariectomy and/or immobilization

Gonadal hormone deficiency following ovariectomy and skeletal unloading by limb immobilization are useful models of osteopenia. The purpose of this study was to compare changes in cortical bone after ovariectomy (OVX) or immobilization (IMM) for 6 and 12 weeks. Comparisons were also made when rats were ovariectomized or immobilized for 6 weeks and then immobilized (OVX/IMM) and ovariectomized (IMM/OVX), respectively, for 6 more weeks. Tibias and femurs were collected and static and dynamic cortical bone indices were determined by morphometric methods. Femurs from animals OVX or IMM for 12 weeks were tested for bone stiffness by torsional testing. Six and 12 weeks after OVX, there were increases in the periosteal perimeter, cortical area, and periosteal bone formation indices, indicating that ovariectomy increased modeling-dependent bone gain on the periosteal envelope, relative to controls. Contrarily, 6 and 12 weeks after IMM, there were decreases, compared with controls, in periosteal perimeter, cortical bone area, and periosteal bone formation indices. This indicates that immobilization decreased modeling-dependent bone gain on the periosteal envelope. These differences in modeling between the animals that were OVX and IMM resulted in a smaller cortical width and minimum cortical width in the IMM compared with the OVX animals. There were significant decreases in cortical bone stiffness and minimum cortical width at the fracture site following mechanical testing in the animals IMM for 12 weeks. Both ovariectomy and immobilization increased endocortical resorption surface, endocortical perimeter and expansion of the marrow cavity. Because of suppressed periosteal bone formation with increased endocortical resorption, immobilization had a greater effect on bone loss and decreased bone stiffness than did ovariectomy. In the OVX/IMM or IMM/OVX groups, there were changes that reflected both conditions. Immobilization mitigated the increase in periosteal bone formation but tended to augment endocortical resorption following ovariectomy. These results show that ovariectomy and immobilization have envelope-specific effects on rat cortical bone.