摘要:

AbstractThe model of Norden was used to induce osteomyelitis in the left tibia of New Zealand White rabbits. Twenty‐one days following inoculation, the animals had primary debridement and then were randomized into one of three treatment groups. Group I received no additional treatment; in Group II, plain hydroxyapatite beads were packed into the defect; and in Group III, gentamicin crobefat‐loaded hydroxyapatite beads were packed into the defect. The animals were observed for 40 days after the primary debridement and then were killed. The intensity of infection was determined by swab cultures and quantitative bacterial cultures of the debrided material. At primary debridement, all of the animals in each group were equally infected. At the time of secondary debridement, only the animals in Group III had a statistically significant reduction in infection (p<0.001). In this study, we demonstrated that an antibiotic‐loaded osteoinductive ceramic bead can effectively eliminate bacteria from an osteomyelitic c

ISSN:0736-0266    

DOI:10.1002/jor.1100110502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractLocal deposition of antibiotics has became increasingly popular in the management of open fractures or osteomyelitis, and several substances have been employed as the vehicle for delivery. Although the elution characteristics of some substances have been documented, a comparative study of the characteristics of the commonly used substances could establish the clinical indications for particular vehicles. Cylindrical pellets of uniform size (6 × 4 mm) were prepared from bone graft (BG), demineralized bone matrix (DBM), plaster of Paris (POP), or polymethylmethacrylate (PMMA), with 25 mg of tobramycin/g of substance in each pellet. The pellets were suspended in phosphate buffered saline, and the antibiotic concentration in the buffer was determined at various time intervals by an enzyme immunoassay. BG and DBM eluted 70 and 45% of their antibiotic load by 24 h, and negligible amounts were detected at 1 week; POP released 17% of its load by 24 h, with trace amounts detected at 3 weeks; and PMMA eluted 7% at 24 h, with trace amounts detected for as long as 14 days. These findings suggest that the optimal vehicle for local deposition of antibiotic depends on the clinical setting. BG and DBM may be best employed when brief antibiotic coverage is required (as for acute contaminated open fractures), whereas POP and PMMA may be better suited for long‐term coverage (such as for established osteomyeliti

ISSN:0736-0266    

DOI:10.1002/jor.1100110503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractPhotodynamic therapy is a tumoricidal modality that utilizes an inactive pharmacologic agent that becomes activated on exposure to visible light. Neoplasms selectively retain and accumulate photosensitizers at levels generally higher than surrounding non‐neoplastic tissues. The purpose of this study was to establish a testing method for in vitro investigation of the effects of photodynamic therapy on human musculoskeletal neoplasms by examination of the sensitivity of these tumors to photoactivation. Three human musculoskeletal neoplasms were cultured, exposed to the photosensitizer Photofrin, and then studied for their response to photodynamic therapy after laser activation. Giant‐cell tumor, dedifferentiated chondrosarcoma, and osteosarcoma were examined with use of strict experimental controls. The photoradiation conditions during photodynamic therapy were kept constant. Cell viability was determined as a function of energy dose. We concluded that the three musculoskeletal tumors were susceptible to in vitro photodynamic therapy and the test system was reproducible. The optimal in vitro nontoxic incubation concentration of Photofrin was 3 μg/ml. A differential cytotoxic response to photodynamic therapy was exhibited by the musculoskeletal neoplasms as a function of increased dosages of en

ISSN:0736-0266    

DOI:10.1002/jor.1100110504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe responses of the immortalized rat preosteoblast UMR‐201‐10B to ascorbic acid (AA), 1,25(OH)2D3(calcitriol), and retinoic acid (RA) were examined. UMR‐201‐10B cells have an undetectable basal alkaline phosphatase (ALP) activity that is induced after 24 h of treatment with 10−6MRA (4.64 ± 0.06 μmol/h/mg of protein). The addition of 10−8Mcalcitriol resulted in a slight induction of ALP activity after 72 h (0.43 ± 0.07 μmol/h/mg of protein). When calcitriol was added to RA, however, over the same period ALP activity was enhanced significantly compared with treatment with RA alone (RA and calcitriol, 12.29 ± 0.86 μmol/h/mg of protein). Treatment with AA (50 μg/ml) alone had no effect on ALP activity but increased RA‐induced ALP activity to 6.78 ± 0.28 μmol/h/mg of protein at 24 h. In contrast, AA inhibited calcitriol‐induced ALP activity after 7 days of combined treatment with calcitriol (calcitriol, 7.73 ± 0.16 μmol/h/mg of protein; AA and calcitriol, 1.44 ± 0.06 μmol/h/mg of protein). Individually, RA and calcitriol induced mRNA expression for ALP, matrix‐gla protein (MGP), and osteopontin (OP). The steady state level of pro‐α1(I) collagen mRNA also was increased significantly by treatment with RA and AA individually. The combination of RA and calcitriol had a synergistic effect on ALP, OP, and especially MGP mRNA expression but significantly reduced the expression of pro‐α1(I) collagen mRNA. AA enhanced the effect of RA on the expression of pro‐α1(I) collagen, MGP, and ALP mRNAs as well as the effect of calcitriol on OP and MGP. The addition of AA to RA resulted in a decrease in the steady state level of OP, whereas its cotreatment with calcitriol caused a decrease in pro‐α1(I) collagen and ALP mRNA. In conclusion, these studies identify RA, calcitriol, and AA as regula

ISSN:0736-0266    

DOI:10.1002/jor.1100110505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe limits of room temperature (24°C) and hypothermic (4°C) storage for preservation of endothelial eccrine function were investigated with use of an ex vivo perfusion apparatus model of the cannulated canine tibia. Norepinephrine‐induced contraction of smooth muscles in both the presence and absence of acetylcholine was compared, with and without selective blockade of endothelial‐derived relaxing factor (EDRF). At room temperature, release of EDRF deteriorated after 24 h and was absent after 48 h of storage. At 4°C, endothelial eccrine activity appeared unimpaired for as long as 72 h of storage. From 96–192 h of storage at 4°C, release of EDRF was suggested, but with an attenuation of its effect on smooth muscle. At 216 and 504 h of storage at 4°C, no endothelial eccrine activity was de

ISSN:0736-0266    

DOI:10.1002/jor.1100110506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe kinetics of growth of bone into control (nontreated) and heat‐treated screws made of stainless steel (type 316L) and Ti‐6Al‐4V, implanted in the medullary canal of the femur in rats, were studied by mechanical, histological, and biochemical methods. A progressive and significant increase in the ingrowth of bone, as reflected by interfacial shear strengths of the screws, was measured with time after implantation. At all time intervals for as long as 35 days after implantation, the shear strength of the heat‐treated Ti‐6Al‐4V and stainless‐steel screws was significantly higher than (1.6–3.4 times) that of the control screws. The specific activity of alkaline phosphatase in extracts of tissue from around the implanted screws peaked 6 days after insertion, with significantly higher values at 5, 6, and 7 days postoperatively for the heat‐treated screws than for the controls. The extent of calcification also was higher at all time intervals for the heat‐treated screws than for the controls. The histological evaluation of formation of bone between the ridges of the implanted screw corroborated the mechanical and biochemical measurements. At each time interval, a more mature bone was noted around the heat‐treated screws than around the controls. It was concluded that the heat treatment of metal implants before insertion can result in augmentation of osseous ingrowth 1.6–5.3 times that into control implants in an in

ISSN:0736-0266    

DOI:10.1002/jor.1100110507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe influence of pulsed low‐frequency electromagnetic fields (PEMFs) on bone formation was investigated in studies of the healing process of transcortical holes, bored at the diaphyseal region of metacarpal bones of six adult horses, exposed for 30 days to PEMFs (28 G peak amplitude, 1.3 ms rise time, and 75 Hz repetition rate). A pair of Helmholtz coils, continuously powered by a pulse generator, was applied for 30 days to the left metacarpal bone, through which two holes, of equal diameter and depth, had been bored at the diaphyseal region. Two equal holes, bored at the same level in the right metacarpal and surrounded by an inactive pair of Helmholtz coils, were used as controls. All horses were given an intravenous injection of 25–30 mg/kg of tetracyline chloride on the 15th and again on the 25th day after the operation and were killed 5 days later. The histomorphometric analysis indicated that both the amount of bone formed during 30 days and the mineral apposition rate during 10 days (deduced from the interval between the two tetracycline labels) were significantly greater (p<0.01 and p<0.0001, respectively) in the PEMF‐treated holes than in the controls. As did a previous investigation, these preliminary findings indicate that PEMFs at low frequency not only stimulate bone repair but also seem to improve the osteogenic phase of the healing process, at least in our experimental condi

ISSN:0736-0266    

DOI:10.1002/jor.1100110508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractSerum bone Gla protein (BGP) and alkaline phosphatase (AP) activity were compared for the assessment of skeletal status in 11 normal pregnant women, 12 normal women on days 3 and 13 of the menstrual cycle, five postmenopasual women before and after 1 month of treatment with ethinyl estradiol (20 μg/day), five patients with cancer and hypercalcemia during treatment with calcitonin, and one patient with Paget disease during treatment with Plicamycin. BGP and AP correlated with each other only in the pregnant women. In all other circumstances, there was no correlation between these two serum osteoblast products. Furthermore, there were condisitions in which the two measurements became discordant. These studies demonstrate that BGP and AP commonly are dissociated when used as measurements of skeletal status. Although both are osteoblast products, BGP and AP probably reflect different aspects of osteoblast differentiation and function

ISSN:0736-0266    

DOI:10.1002/jor.1100110509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractImmunological methods were used to determine the identity of the major components comprising a network of electron‐dense seams (described by the authors in a previous work) within the extracellular matrix of medial collateral ligament (MCL) from humans and rabbits. Tissue obtained from MCL midsubstance was subjected to pre‐embedding labelling with colloidal gold at the electron microscopic level with monoclonal antibodies (MAbs) against type‐VI collagen and chondroitin sulphate (CS), before and after digestion with chondroitinase ABC and testicular hyaluronidase. Tissue labelled with anti‐type‐VI MAbs showed gold conjugates attached to the microfilamentous component of the seams both before and after enzyme digestion, which confirmed the identity of the beaded microfilaments as type‐VI collagen. Treatment of the tissue with anti‐CS MAbs resulted in labelling of undigested tissue only. In these treatments, gold particles were found attached to granules that were interspersed throughout the network of type‐VI microfilaments. Both the granules and gold labels were absent from the network following enzyme digestion. Thin nonbeaded microfilaments that did not label with anti‐type‐VI MAbs also were present within the seams. The loss of these nonbeaded microfilaments following enzyme digestion suggested that they might represent strands of hyaluronan. The codistribution and seqestering of type‐VI collagen and CS within discrete seams or channels suggests that these regions of the MCL midsubstance may contain higher concentrations of water than the surrounding d

ISSN:0736-0266    

DOI:10.1002/jor.1100110510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractA noncontact, kinematic method was used to determine the lengths and in situ loads borne by portions of the human anterior cruciate ligament (ACL) by the combination of kinematic data from the intact knee and load‐length curves of the isolated ACL. Specimens from knees of cadavers of young people were tested in passive flexion and extension as well as with 100 N of anterior tibial drawer at 0, 30, 45, and 90° of flexion. The results showed that the in situ load on the whole ACL (as much as 129 N) can exceed the magnitude of the applied anterior tibial drawer. The load distribution within the ligament changes with flexion of the knee. The anterior and posterior portions share the anterior drawer force equally toward full extension. However, at flexion>45°, the anterior portion supports 90–95% of the load. This information is important for the determination of the function of the entire ACL and of its subportions in response to external loading of the intact knee. In particular, the preferential loading found for one of the portions of the ACL demonstrates that successful operative reconstruction of this ligament may not be achieved simply by reproduction of its gross anatomy; consideration of the role of the ligament in the overall kinematics of the knee is nece

ISSN:0736-0266    

DOI:10.1002/jor.1100110511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY