Elevated soluble platelet glycoprotein VI is a useful marker for DVT in postoperative patients treated with edoxaban.

Prevention of deep vein thrombosis (DVT) is important in patients undergoing major orthopedic surgery. Although the detection of an elevated D-dimer level is useful for predicting DVT, it is not efficacious in postoperative patients being treated with anti-Xa agents. The soluble platelet glycoprotein VI (sGPVI) level is a marker of activated platelets, but not bleeding. Therefore, sGPVI levels are usually examined as a predictor of DVT in such patients. In the present study, 83 orthopedic patients were treated with 30 mg of edoxaban for prophylaxis of DVT. Fourteen patients developed DVT and 17 patients discontinued the prophylaxis due to decreased hemoglobin levels. Plasma levels of sGPVI in the patients were significantly higher after surgery than before surgery. On day 1, the sGPVI levels increased, while the platelet counts decreased. There were no significant differences in D-dimer, soluble fibrin, or FDP levels in orthopedic patients with and without DVT before surgery and on days 1, 4, and 8. Plasma sGPVI levels were significantly higher in the patients with DVT than in those without DVT on days 1 and 4. Plasma levels of D-dimer were significantly higher in patients with withdrawal than in those without. However, there were no significant differences in sGPVI levels between those with and without withdrawal. As D-dimer levels are known to increase in patients with withdrawal, this parameter is not useful for evaluating the risk of DVT in these patients. In contrast, the sGPVI level is not increased in those with withdrawal and may therefore be useful for evaluating the risk of DVT in postoperative patients treated with an anticoagulant.

Longitudinal magnetic resonance imaging of pseudotumors following metal-on-metal total hip arthroplasty.

The purpose of the study was to determine the natural history of pseudotumors following metal-on-metal total hip arthroplasty (THA) using magnetic resonance imaging (MRI). Initial MRI was conducted at a mean of 36months postoperatively. Follow-up MRI was performed at a mean of 20months after the detection of 24 asymptomatic pseudotumors. Pseudotumor size was determined on MRI. The mean pseudotumor size changed from 729mm(2) to 877mm(2). Pseudotumors increased in size in eight and decreased in six. Ten hips showed no changes. The bigger the pseudotumor size, the more likely the size would increase. In conclusion, pseudotumors frequently change in size. A single MRI study in the clinical decision-making process should be avoided and a longitudinal study should be performed.

The relationships among hemostatic markers, the withdrawal of fondaparinux due to a reduction in hemoglobin and deep vein thrombosis in Japanese patients undergoing major orthopedic surgery.

BACKGROUND: The relationships among the hemostatic markers, the development of deep vein thrombosis (DVT) and the withdrawal of fondaparinux due to a reduction in the hemoglobin levels were examined. METHODS: Two-hundred twenty-one Japanese patients who underwent major orthopedic surgery and were treated with 1.5mg of fondaparinux instead of 2.5mg of fondaparinux were studied. Forty-seven of 221 patients discontinued fondaparinux treatment (withdrawal group) and 37 patients developed DVT. RESULTS: The age, frequency of total knee arthroplasty (TKA), withdrawal of fondaparinux, reduction of hemoglobin and the plasma levels of soluble fibrin (SF), D-dimer and fibrinogen and fibrin degradation product (FDP) on day 1 after the operation were significantly higher in the patients with DVT. Elevated SF, D-dimer or FDP levels were associated with the risk for DVT. The age, frequency of TKA or DVT, anti-Xa activity and the creatinine, FDP and D-dimer levels were significantly higher in the withdrawal group. An anti-Xa level >0.33 mg/l and an elevated D-dimer or FDP level were associated with the risk of withdrawal. CONCLUSION: The age and SF levels, TKA and withdrawal of fondaparinux were related to the risk of DVT, and the anti-Xa activity, creatinine level and DVT were related to the risk of withdrawal of fondaparinux due to a reduction in hemoglobin.

Prevalence and risk factors for knee osteoarthritis in elderly Japanese men and women.

BACKGROUND: The aims of the present study were to examine the prevalence and risk factors for knee osteoarthritis in elderly Japanese men and women. METHODS: We examined 598 of the 1513 inhabitants of Miyagawa village aged > or = 65 years (393 women, 205 men). Baseline data, obtained with standard questionnaires, included information on age, past history, sports activity, working, knee pain, smoking, and intakes of alcohol and milk. Bone mineral density of the forearm was measured using dual energy X-ray absorptiometry. Anteroposterior radiographs of both knees were graded for osteoarthritis using the Kellgren-Lawrence grading system. Definite osteoarthritis was defined as a grade of 2 or higher. We used logistic regression analysis by the stepwise method to determine the risk factors for radiographic knee osteoarthritis. RESULTS: The prevalence of definite radiographic knee osteoarthritis was 30.0% overall: 17.7% in men and 36.5% in women. The prevalence of symptomatic knee osteoarthritis was 21.2% overall: 10.7% in men and 26.7% in women. There were significant differences in the risk of radiographic knee osteoarthritis with body mass index (BMI), sex, age, and bone mineral density (BMD). CONCLUSIONS: The prevalence of definite radiographic knee osteoarthritis was 30.0% and that of symptomatic knee osteoarthritis was 21.2%. We found that higher BMI, female sex, older age, and higher BMD were significantly associated with an increased risk for radiographic knee osteoarthritis.

Cytological properties of stromal cells derived from giant cell tumor of bone (GCTSC) which can induce osteoclast formation of human blood monocytes without cell to cell contact.

When human blood monocytes were cocultured with stromal cells derived from human giant cell tumor of bone (GCTSC) and a Millipore filter (0.4 microm) was interposed between monocytes and GCTSC, multinucleated giant cell formation of monocytes was induced. The multinucleated giant cells have characters as osteoclast-like cells, indicating that a soluble osteoclast-inducing factor(s) is secreted from GCTSC expressing RANK, RANKL/ODF/OPGL and TACE mRNA. Furthermore, OCIF/OPG inhibited GCTSC-induced osteoclastogenesis, showing that the RANK-RANKL system is involved in GCTSC-induced osteoclastogenesis and that soluble form of ODF/RANKL induces osteoclasts from monocytes. GCTSC expressed the cytokine mRNAs such as M-CSF, GM-CSF, IL-3, IL-4, IL-6, and IFN-gamma mRNAs. None of IL-1ralpha, IL-1alpha, IL-1beta, IL-2, IL-4, IL-10, IL-18, TNF-alpha, G-CSF and IFN-gamma could be detected in all culture media. A significant amount of IL-6 could be detected in the culture media of all GCTSC. IL-8 was found in the culture media of two GCTSC and two osteosarcoma-derived cells. M-CSF was detected in all culture media. GCTSC express CaSR, and stimulation of GCTSC with either extracellular Ca(2+) or neomycin, agonist of CaSR, augmented the expression of RANKL. Some lines of GCTSC expressed alkaline phosphatase, osteocalcin and Cbfa1, suggesting that GCTSC are intimately related to osteoblastic lineage.

Human osteosarcoma-derived cell lines produce soluble factor(s) that induces differentiation of blood monocytes to osteoclast-like cells.

When monocytes were cocultured with human osteosarcoma-derived cells (HOS cells), multinucleated giant cell formation of monocytes was induced. Intriguingly, even when a filter was interposed between monocytes and HOS cells, polykaryocytes also appeared. The multinucleated giant cells have characters similar to osteoclast-like cells. These findings indicate that soluble factor(s) secreted from HOS cells play an important role in polykaryocyte formation from monocytes. Twelve cloned cells were established from HSOS-1 cells and their capacities of inducing osteoclasts were investigated. Three cloned cells inducing nos. 4 and 9 had an ability of inducing osteoclasts (multinucleated giant cells, TRAP, calcitonin receptor and c-src mRNAs, osteoresorbing activity), and three cells, including nos. 1 and 5, did not show the ability. HOS cells and the cloned cells expressed several cytokine mRNAs. M-CSF was detected in the culture fluids of HOS cells, which also expressed RANK and RANK/ODF/OPGL mRNAs. Intriguingly, HOS cells secreting a soluble osteoclast inducing factors(s) expressed TNF-alpha converting enzyme mRNA. Furthermore, OCIF/OPG inhibited HOS cell-induced osteoclastogenesis and soluble RANKL could be detected in the culture fluids of HOS cells expressing TACE, suggesting that one of soluble osteoclast-inducing factor(s) is soluble RANKL. When blood monocytes were indirectly cocultured with HSOS-1 cells or cloned no. 9 cells in the presence of OCIF for 14 days, HOS cell-mediated osteoclastogenesis was suppressed, indicating that RANK-RANKL system is involved in the HOS cell-mediated osteoclastogenesis.