Effect of estrogen on the activity and growth of human osteoclasts in vitro.

OBJECTIVE: Estrogen deficiency results in postmenopausal osteoporosis by increasing the rate of bone loss. The mechanism responsible for the effects of estrogen on osteoclasts is still unclear. MATERIALS AND METHODS: The potential of mononuclear cells from cord blood or bone marrow to differentiate into mature osteoclasts when co-cultured with human osteoblast cells was investigated. The effects of estrogen on osteoclastogenesis and osteoclast activity were also examined. RESULTS: Macrophage markers CD11b and CD14 were downregulated and vitronectin receptor was upregulated during 28 days' co-culture of mononuclear cells and human osteoblasts. Long-term co-culture resulted in the formation of numerous large tartrate-resistant acid phosphatase-positive multinucleated cells capable of resorption of bone slices. After incubation for 28 days, the addition of 17beta-estradiol caused a significant decrease in the expression of vitronectin receptor and tartrate-resistant acid phosphatase-positive multinucleated cells in cultures derived from both bone marrow and cord blood. A significant decrease in bone resorption was also noted in the presence of estrogen. CONCLUSION: Estrogen not only suppresses osteoclastogenesis but also inhibits the activity of osteoclasts.

Expression of estrogen receptors alfa and beta mRNA and alkaline phosphatase in the differentiation of osteoblasts from elderly postmenopausal women: comparison with osteoblasts from osteosarcoma cell lines.

OBJECTIVE: To evaluate the expression of estrogen receptors (ER) alpha and beta, and activity of alkaline phosphatase during differentiation of primary osteoblast cells (hOB) from aged postmenopausal women and human osteosarcoma cell lines (HOS, MG63). MATERIALS AND METHODS: Osteoblast cultures were prepared from the upper femur of postmenopausal patients (age, 60-74 years) and HOS. At the indicated times (days 5, 10, 15, 20, and 25), alkaline phosphatase activity and expression of ERalpha and ERbeta mRNA were evaluated. RESULTS: In both cultures of primary hOB and HOS, alkaline phosphatase activity decreased at the osteoblast proliferation stage, whereas it subsequently increased at the matrix maturation stage. ER beta mRNA was strongly expressed in HOS on day 15 and remained at high levels of transcription through to day 25 (matrix maturation phase), whereas ERalpha mRNA was barely detectable during osteoblast differentiation. In hOB, transcription of ERalpha mRNA was much stronger than that of ERbeta mRNA. CONCLUSION: The presence of ERalpha and ERbeta mRNA in osteoblasts supports the involvement of estrogen in human bone formation. The developmental expression of alkaline phosphatase was not correlated to ER mRNA expression during osteoblast differentiation. ER isoforms may have different functions or interact with each other during osteoblast differentiation. Since the expression of ER isoforms is different between postmenopausal women and osteosarcoma cell lines, characteristics of osteosarcoma cell lines may not be suitable as a model for the evaluation of estrogen effects on postmenopausal osteoporosis.

Arthroscopic posterior cruciate ligament reconstruction with hamstring tendon autograft: results with a minimum 4-year follow-up.

This study prospectively evaluates the outcomes at a minimum 4-year follow-up after PCL reconstruction using quadruple hamstring tendon autograft with an arthroscopic double fixation technique. During 1996-1999, hamstring tendon autograft graft has been used in 57 patients. Data from 52 patients who had been followed up completely were analyzed. All patients suffered from a grade 3 or higher grade of posterior drawer test and posterior sag sign with MRI image confirmation. Twelve knees had combined posterior and posterolateral instability, which were simultaneously reconstructed. Clinical assessments included Lysholm knee score, International Knee Documentation Committee (IKDC) scores, KT-1000 instrumented test, thigh muscle assessment, and radiographic evaluation. The mean Lysholm score was 54 (40-65) and 91 (65-100) points (P<0.01) before and after surgery. Thirty (58%) patients could return to moderate or strenuous activity. The evaluation of AP translation has been performed with KT-1000. The average posterior displacement measured with KT-1000 was 11.69+/-2.01 mm preoperatively and 3.45+/-2.04 mm postoperatively. Forty-two (81%) patients demonstrated ligament laxity of less than 5 mm. Forty-two (81%) patients were rated as normal or nearly normal based on IKDC scores. Forty-six (88%) patients achieved a minimum of 80% recovery of extensor strength and 44 (85%) patients achieved a minimum of 80% recovery of flexor strength. Statistically significant differences existed in thigh girth, extensor strength, and flexor strength before and after reconstruction. Arthroscopic reconstruction for PCL with four-strand hamstring tendon graft produced satisfactory results. The semitendinosus and gracilis tendon graft is adequate in graft size, technically easier to perform and more reproducible, and had a satisfactory result.

Arthroscopic anterior cruciate ligament reconstruction with quadriceps tendon autograft: clinical outcome in 4-7 years.

Surgical reconstruction of the anterior cruciate ligament (ACL) is indicated in the ACL-deficient knee with symptomatic instability and multiple ligaments injuries. In the present study, we describe the clinical results of quadriceps tendon-patellar bone autograft for ACL reconstruction. From 1996 to 1998, the graft has been used in 38 patients. Thirty-four patients with complete final follow-up for 4-7 years were analyzed. The average follow-up time was 62 (48-84) months. Thirty-two patients (94%) achieved good or excellent results by Lysholm knee rating. Twenty-six patients (76%) could return to moderate or strenuous activity after reconstruction. Twenty-eight patients (82%) had ligament laxity of less than 2 mm. Finally; 31 patients (91%) were assessed as normal or nearly normal rating by IKDC guideline. Twenty-five patients (73%) had less than 10 mm difference in thigh girth between their reconstructed and normal limbs. Thirty-two (94%) and 31 (91%) patients could achieve recovery of the extensor and flexor muscle strength in the reconstructed knee to 80% or more of normal knee strength, respectively. A statistically significant difference exists in thigh girth difference, extensor strength ratio, and flexor strength ratio before and after reconstruction. Tunnel expansion with more than 1 mm was identified in 2 (6%) tibial tunnels. Our study revealed satisfactory clinical subjective and objective results at 4-7 years follow-up. Quadriceps tendon autograft has the advantage of being self-available, relatively easier arthroscopic technique, and having a suitable size, making it an acceptable graft choice for ACL reconstruction. There is little quadriceps muscle strength loss after quadriceps harvest. A quadriceps tendon-patellar autograft is an adequate graft choice to ACL reconstruction.

Expression of estrogen receptors alpha and beta in human osteoblasts: identification of exon-2 deletion variant of estrogen receptor beta in postmenopausal women.

BACKGROUND: Postmenopausal osteoporosis is associated with estrogen deficiency. Estrogens have effects on bone metabolism, which are mediated by estrogen receptors (ERs). If estrogen responsiveness is related to the ER expression level, ER expression in postmenopausal women should be different from previous studies using osteoblast lineage. We investigated the expression of variant isoforms of ER messenger ribonucleic acid (mRNA) in osteoblasts (OB) from postmenopausal women and a human osteosarcoma cell line, MG 63. METHODS: Osteoblast cultures were prepared from the upper femur of postmenopausal patients or MG 63. For OB cultures at 5, 10, 15, 20, and 25 days, the expressions of ERalpha and beta mRNA were examined using reverse transcriptase-polymerase chain reaction. RESULTS: In MG 63, ERbeta mRNA was constantly and highly expressed during the 25-day culture, whereas ERalpha mRNA was barely detected. In the primary OB cells, both ERalpha and beta mRNA were transcribed during the 25-day culture, but expression of ERalpha mRNA was much stronger than that of ERbeta mRNA. A splice variant form of ERbeta mRNA that was missing the entire exon 2 (ERbeta delta 2) was detected and heterogeneously expressed in OB cultures from 16 postmenopausal women. CONCLUSION: Differential expressions of these ER isoforms suggest that they may have different functions or that they interact with each other during bone metabolism. The different ratio of ERbeta to ERbeta delta 2 mRNA or ERalpha to ERbeta mRNA expressions in osteoblast cultures may be related to different bone conditions. Whether the presence of ERbeta delta 2 in postmenopausal women influences the biological properties of bone needs to be determined.

Talar body fracture combined with traumatic rupture of anterior talofibular ligament and peroneal longus tendon.

A rare case of talar body fracture combined with traumatic rupture of the anterior talofibular ligament and peroneal longus tendon is presented and reports in the literature are reviewed. We suggest that the mechanism of the injury was initial plantar flexion and inversion with rupture of anterior talofibular ligament and peroneal longus tendon, followed by forced dorsiflexion with talar body fracture. The treatment consisted of open reduction with internal fixation of the talar body fracture and primary repairs of the ruptured anterior talofibular ligament and peroneal longus tendon.

Effect of estrogen and 1alpha,25(OH)2- vitamin D3 on the activity and growth of human primary osteoblast-like cells in vitro.

OBJECTIVE: To evaluate effects of 17beta-E(2) and 1alpha,25(OH)(2)-vitamin D(3) on human osteoblast-like (hOB) cells. DESIGN: Controlled, experimental study. SETTING: University hospital. PATIENT(S): hOB cell cultures were prepared from the upper femur of postmenopausal patients undergoing bipolar endoprosthesis arthroplasty for a fractured femoral neck. INTERVENTION(S): hOB cells were subcultured with either 17beta-E(2) or 1alpha,25(OH)(2)-vitamin D(3), or both. MAIN OUTCOME MEASURE(S): Cell proliferation and activity of alkaline phosphatase, osteocalcin, and interleukin-6. RESULT(S): 17beta-E(2) significantly reduced interleukin-6 and osteocalcin to 34% and 60% of control value but induced alkaline phosphatase and cell proliferation to 183% and 150% of control value. 1alpha,25(OH)(2)-vitamin D(3) significantly decreased cell proliferation to 88% of that of control group, but 1alpha,25(OH)(2)-vitamin D(3) plus 17beta-E(2) showed no difference from the control group. Alkaline phosphatase and osteocalcin were significantly increased by 1alpha,25(OH)(2)-vitamin D(3) alone or combined with 17beta-E(2), to 169% and 198% and to 144% and 144% of control value, respectively. 1alpha,25(OH)(2)-vitamin D(3), with or without 17beta-E(2), decreased interleukin-6 levels to 27% and 38% of control group, respectively. CONCLUSION(S): 17beta-E(2) and 1alpha,25(OH)(2)-vitamin D(3) have effects on osteoblasts. The prevention of osteoporosis by estrogen may be related not only to direct effects on osteoblastic activity and proliferation but also to indirect effects on osteoclasts by the decrease of interleukin-6 secretion.