Low-adhesion and low-swelling hydrogel based on alginate and carbonated water to prevent temporary dilation of wound sites.

Hydrogel-based wound dressings have been developed for rapid wound healing; however, their adhesive properties have not been adequately investigated. Excessive adhesion to the skin causes wound expansion and pain when hydrogels absorb exudates and swell at wound sites. Herein, we developed a low-adhesion and low-swelling hydrogel dressing using alginate, which is non-adhesive to cells and skin tissue, CaCO3, and carbonated water. The alginate/CaCO3 solution rapidly formed a hydrogel upon the addition of carbonated water, and the CO2 in the hydrogel diffused into the atmosphere, preventing acidification and obtaining a pH value suitable for wound healing. Remarkably, the skin adhesion and swelling of the hydrogel were 11.9- to 16.5-fold and 1.9-fold lower, respectively, than those of clinical low-adhesion hydrogel dressings. In vivo wound-healing tests in mice demonstrated its therapeutic efficacy, and the prepared hydrogel prevented temporary wound dilation during early healing. These results illustrate the importance of controlling skin adhesion and swelling in wound dressings and demonstrate the potential clinical applications of this wound-friendly hydrogel dressing.

A physician-staffed ground emergency medical service does not significantly shorten door-to-balloon time in patients with STEMI: an observational study in a single emergency center in Japan.

AIM: Current guidelines recommend a door-to-balloon time (DTBT) of <90 min for reperfusion treatment of patients with ST-segment elevation myocardial infarction (STEMI). A physician-staffed ground emergency medical service (GEMS) using a rapid response car (RRC) system was implemented at our hospital in April 2015. The medical team, including a physician and nurse, is dispatched to assess the patient and expedite the start of treatment by emergency physicians and cardiologists after arrival at the hospital. The study aimed to determine whether the RRC system shortened the DTBT. METHODS: This retrospective observational study was carried out in a tertiary emergency center in Japan. Those STEMI patients with primary percutaneous intervention between January 2016 and December 2018 were evaluated. The DTBTs of patients transported by the RRC system, the emergency medical service (EMS), and transferred from other hospitals after STEMI diagnosis (TRANS group) were compared. RESULTS: A total of 121 patients were included, 33 in the RCC, 20 in the EMS, and 68 in the TRANS groups. The median DTBT was 51 min (interquartile range [IQR], 43-67) in the RRC, 61 min (IQR, 52-85) in the EMS, and 59 min (IQR, 48-72) in the TRANS groups (P = 0.13). The DTBT was not significantly shorter in the RRC than in the other groups. CONCLUSION: An RRC physician-staffed GEMS did not significantly shorten the DTBT of patients with STEMI compared with other transport systems.

Utility of CD64 on Neutrophils in Orthopedic Infection.

BACKGROUND: Musculoskeletal infections are often seen in the daily practice of orthopedics. Several markers [white blood cell (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT)] have been used for diagnosing these infections. However, these markers may be elevated due to surgery or trauma, and may not be infection-related. These markers also show drug-dependent dynamics during infection that differ from its usual dynamics. Such situations make diagnosis of infections difficult, and Cluster of Differentiation 64 (CD64) has been brought to attention. This study aimed to clarify the utility of CD64 on neutrophils by comparing it with conventional infection markers (CRP, PCT) in musculoskeletal infection. METHODS: Forty-four patients who were suspected of having musculoskeletal infection between May 2010 and November 2013 in our hospital were enrolled in this study. Patients were divided into subgroups according to their culture results, antibiotics administration, measurement timing, and if they were immunocompromised. The measurements of the infection markers were compared between each group. In addition, the positive rates of each infection marker were compared between groups. RESULTS: There was no difference in the infection marker measurements between several groups. There was no statistically significant difference between groups for the positive rates of CD64, CRP, and PCT. CONCLUSION: We evaluated the utility of CD64 on neutrophils in musculoskeletal infection. CD64 showed the utility that was equivalent to conventional infection markers in diagnoses of various musculoskeletal infections.

Cytoplasmic maspin expression predicts poor prognosis of patients with soft tissue sarcomas.

BACKGROUND: Maspin is a 42 kDa protein known to act as a tumor suppressor. Although its function has not been fully elucidated, numerous reports have investigated the prognostic impact of maspin in patients with several types of cancer. However, there have been no reports on the association between maspin expression and the prognosis of patients with soft tissue sarcomas (STS). The aim of this study was thus to explore the association of maspin expression with the prognosis of patients with STS. METHODS: One-hundred and eight paraffin-embedded STS tissue samples were immunohistochemically analyzed using antibodies for maspin and Ki-67 antigen. The patients were followed up for 1 to 300 months (median: 33 months) and the prognostic value was evaluated by log-rank test and Cox's regression hazard model. RESULTS: Cytoplasmic maspin expression was observed in 48.1% of specimens, and was significantly correlated with a higher FNCLCC grade (P = 0.002) and the presence of distant metastases (P = 0.001), and those with cytoplasmic maspin expression had both shorter disease-free survival (DFS) and overall survival (OS) by log-rank test (P <0.001, P = 0.001, respectively). By Cox's multivariate analysis, the presence of distant metastases was the only prognostic factor for DFS and OS. CONCLUSIONS: This is the first report to reveal an association between maspin expression and the prognosis of patients with STS. Although further studies with a larger series of patients and a longer follow-up period will be needed, cytoplasmic maspin expression could be an indicator of unfavorable prognosis in patients with STS. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_205.

Sacral chordoma in an adult showing an aggressive clinical course: A case report.

The current report presents a case of a 78-year-old male with sacral chordoma, showing an aggressive clinical course. The patient underwent sacral resection, however, nine months later, multiple metastases were detected by magnetic resonance imaging. The metastases progressed rapidly and 15 months following surgery the patient succumbed to respiratory dysfunction. An autopsy revealed multiple metastases of the lung, liver, heart, kidneys and vertebrae. Pathologically, the tumors did not show proliferation of anaplastic cells or dedifferentiation; however, the metastatic tumor cells were smaller than the primary tumor cells. The Ki-67 labeling indices were <5% in all of the patient's tumors, therefore, the capacity for cellular proliferation of the tumors was considered to be low. Chordoma in adults are generally slow-growing tumors and are associated with a relatively prolonged course and frequent local recurrences. Therefore, it must be recognized that chordoma may grow rapidly and show an aggressive clinical course, even when the Ki-67 labeling index is low.

Proliferative fasciitis mimicking a sarcoma in a child: a case report.

Proliferative fasciitis (PF) is a benign, discrete proliferation of fibroblasts or myofibroblasts in soft tissue. Proliferative fasciitis mostly occurs in adults and is often confused with a sarcoma because of its rapid growth and peculiar histological features. We report a case of PF mimicking a sarcoma which developed in a 13-year-old boy, who noticed a painful tumor, with gradual enlargement, in his right lower leg. Magnetic resonance imaging revealed that the tumor measured 34 mm × 20 mm × 41 mm and was located in the subcutaneous tissue. The tumor was surgically resected. Pathologically, the tumor was composed of a proliferation of atypical spindle cells, admixed with larger ganglion-like cells. Immunohistochemically, the tumor cells were positive for vimentin, cytokeratin, smooth muscle actin, HHF-35 and Fli-1. The tumor was subsequently diagnosed as a PF, although it was difficult to differentiate from a sarcoma. Five years after surgery, the postoperative course has been uneventful with no recurrence or metastasis.

Clinical features and surgical outcomes of lumbar spinal stenosis in patients aged 80 years or older: a multi-center retrospective study.

INTRODUCTION: With increased aging of the population, spine surgeons have more opportunity to treat elderly patients for lumbar spinal stenosis (LSS). The purpose of this study was to clarify the clinical features and surgical outcomes for LSS in the elderly aged 80 years or older. MATERIALS AND METHODS: We retrospectively reviewed 702 consecutive patients with LSS who underwent decompression surgery without fusion between 2006 and 2010. Patients with other conditions that could affect functional status were excluded from this study. Of the remaining 304 patients, 241 with LSS whose condition could be evaluated 6 months at least after surgery were analyzed. The mean follow-up period was 14.4 months (range 6-60 months). There were 144 males and 97 females aged 45-93 years old (average: 72.2 years old). Patients were divided into two age groups: 80 years or older (Group A, 46 patients) and under 80 years of age (Group B, 195 patients). We evaluated differences in the clinical features and surgical outcomes between the two groups. RESULTS: There were no significant differences in surgical levels, the number of operation levels, operation times, or the amount of intraoperative bleeding between Groups A and B. The percentages of patients with comorbidities were 73.9 % in Group A and 60.0 % in Group B, which were not significantly different. There were no significant differences in Japanese Orthopaedic Association scores preoperatively, 6 months postoperatively, and at the final follow-up between the two groups. Furthermore, recovery ratios 6 months postoperatively and at final follow-up were similar between the two groups. The percentages of patients with postoperative complications were 19.6 % in Group A and 13.3 % in Group B, which were not significantly different. CONCLUSIONS: This multi-center retrospective study demonstrated that the benefits and risks of decompression surgery for LSS were similar between patients aged over 80 years and those under 80 years. Therefore, decompression surgery is a reasonable treatment even for elderly patients aged over 80 years.

Intramuscular myxoma of the buttock mimicking low-grade fibromyxoid sarcoma: diagnostic usefulness of MUC4 expression.

Intramuscular myxoma (IM) is a benign intramuscular neoplasm composed of fibroblasts and abundant myxoid stroma. Some malignant soft tissue tumors can undergo myxomatous degeneration, which makes it difficult to distinguish them from IM. We describe a case of IM of the buttock region mimicking low-grade fibromyxoid sarcoma. The tumor appeared as a well-defined ovoid mass with a cystic lesion on MRI images, and mild uptake on PET images was seen. This was originally misdiagnosed as low-grade fibromyxoid sarcoma (LGFMS) after core-needle biopsy. The mass was excised en bloc and sent for histology. The surgical specimen showed the features of LGFMS with the same characteristics as those mentioned in the previous biopsy report. After surgery, MUC4 expression, a highly sensitive and specific immunohistochemical marker for LGFMS, and FUS gene rearrangement by FISH was not detected upon re-examination; therefore, a conclusive diagnosis of IM was made. The patient had no local recurrence at the 3-year follow-up. Our case suggests that IM with mild FDG uptake is frequently confused with other low-grade malignant myxoid tumors. In addition, absence of MUC4 expression is the definitive key to distinguish IM from LGFMS.

Influence of spinous process spacers on surgical outcome of laminoplasty for OPLL.

Expansive laminoplasty for ossification of the posterior longitudinal ligament (OPLL) has had favorable outcomes. Many modifications of expansive laminoplasty have been developed, including expansive laminoplasty with and without spinous process spacers (SPS). The purpose of this study was to determine whether surgical outcomes were similar between expansive laminoplasty surgeries with and without SPS.Of 109 consecutive patients undergoing surgery for OPLL, 68 patients undergoing expansive laminoplasty were included in the study after excluding patients with other conditions affecting their functional status. The patients were divided into 2 groups based on their K-line, which connects the midpoints of the spinal canal at C2 and C7. Patients were further divided into 2 subgroups: those undergoing expansive laminoplasty without SPS (without SPS group) and those undergoing expansive laminoplasty with SPS (with SPS group). Surgical outcomes were evaluated between K-line (+) and K-line (-) groups. After dividing those groups further into the with SPS and without SPS groups, the differences in surgical outcomes were evaluated again.No significant difference existed in the recovery rate between the with SPS and without SPS groups and between the K-line (+) and K-line (-) groups. When the surgical outcome was only evaluated in the K-line (+) group, the recovery rate 1 year postoperatively was higher in patients without SPS than in those with SPS. Therefore, for patients with K-line (+), the possibility exists that SPS can restrict the posterior shift of the spinal cord and affect the surgical outcome.

Early surgical intervention for spinal infection in patients with malignancy requiring chemotherapy: report of two cases and review of the literature.

Advances in chemotherapy for various malignancies have contributed to the increased life expectancy of patients. If such a patient has a concurrent infection, his/her oncologist would hesitate to perform prompt chemotherapy owing to the risk of inducing sepsis. Therefore, the treatment of infection would have priority over initiating chemotherapy for the malignancy. We present a 69-year-old female with malignant lymphoma requiring prompt chemotherapy who also demonstrated spinal infection with Mycobacterium tuberculosis and a 66-year-old male with esophageal cancer who also demonstrated spinal infection with Staphylococcus aureus. Anterior debridement and interbody fusion were performed for both patients. One patient died of malignant lymphoma 4 years after surgery, and the other is still alive and has remained disease-free 4 years after surgery. Saving the life of a patient with malignancy would be difficult without prompt chemotherapy. Conservative treatment for spinal infection requires prolonged antibiotic treatment, and there is no guarantee that the spinal infection would be controlled only with antibiotics. Therefore, early surgical intervention would be an alternative option under such a condition.

Multifocal localized pigmented villonodular synovitis arising separately from intra- and extra-articular knee joint: case report and literature review.

We present a case of intra- and extra-articular localized pigmented villonodular synovitis (PVNS) of the right knee joint separately. A 14-year-old girl presented with a painful mass over the medial aspect of the right knee. MRI demonstrated nodular masses located in the anteromedial area of the knee joint and on the surface of the deep medial collateral ligament outside the joint. Arthroscopic and open synovectomy were performed for both lesions. Histopathology confirmed diagnosis of localized PVNS and pigmented villonodular bursitis, respectively. Our case highlights that localized PVNS are likely to occur in intra- and extra-articular regions separately.

Angiosarcoma of the proximal humerus: a case report and review of the literature.

INTRODUCTION: Angiosarcoma of bone is an uncommon primary bone neoplasm that is composed of tumor cells that show endothelial differentiation. This is an aggressive malignancy characterized by frequent local recurrence and distant metastases. The majority of patients die within one year of diagnosis, and this shows that angiosarcoma of bone is an aggressive high-grade tumor. CASE PRESENTATION: We present the case of a 65-year-old Japanese woman who had primary angiosarcoma of the proximal humerus with a pathological fracture. An open biopsy confirmed a diagnosis of primary angiosarcoma of bone. Our patient was treated with neoadjuvant chemotherapy and wide resection. One month after surgery, she developed multifocal distant metastasis to her liver and spleen. CONCLUSIONS: Angiosarcoma of the humerus is extremely rare. Radiographically, there is no specific finding associated with angiosarcoma of bone as opposed to other malignant bone tumors. The cornerstone of treatment is en bloc resection followed by as much adjuvant radiation therapy as possible. However, the role of chemotherapy remains undefined, and better systemic agents are clearly needed.

Surgical outcomes and prognostic factors of cervical spondylotic myelopathy in diabetic patients.

BACKGROUND: There have been a few reports on the surgical outcomes of cervical myelopathy in diabetic patients; however, those studies included ossification of the posterior longitudinal ligament. This study investigated whether surgical outcome of expansive laminoplasty (ELAP) for diabetic patients with cervical spondylotic myelopathy (CSM) differs from that for non-diabetic patients and determined prognostic factors in diabetic patients. METHODS: We retrospectively reviewed 78 patients with CSM after excluding the cases with other medical conditions, which could affect surgical outcome from 222 consecutive patients who had undergone ELAP between 2000 and 2008 in our hospital. The patients were divided into two groups: diabetic patients (Group 1) and non-diabetic patients (Group 2). We evaluated differences in age, gender, pre- and postoperative Japanese Orthopaedic Association (JOA) score, recovery rate (RR), symptom duration, and postoperative complications between the two groups. In Group 1, the correlation between RR and factors indicating the severity of diabetes mellitus was assessed. RESULTS: There were 13 patients in Group 1 and 65 in Group 2. There was no significant difference in age, gender, JOA score before or after surgery, or symptom duration between the two groups. Group 1 showed poorer recovery of sensory and motor function in the lower extremities. A negative correlation was observed between RR and the preoperative hemoglobin A(1c) (HbA(1c)) level in Group 1. CONCLUSIONS: Diabetic patients experienced benefits from ELAP similar to non-diabetic patients. A negative correlation between RR and preoperative HbA(1c) level suggests that strict blood sugar control is recommended before surgery.

Clinical features and surgical outcomes of cervical spondylotic myelopathy in patients aged 80 years or older: a multi-center retrospective study.

With the aging of the population in developed countries, spine surgeons have recently been more likely to encounter elderly patients in need of treatment. This study investigated whether decompression surgery for cervical spondylotic myelopathy (CSM) in elderly patients aged 80 years or older would likely be a reasonable treatment. We retrospectively reviewed 605 consecutive patients with cervical myelopathy who underwent decompression surgery between 2004 and 2008. Patients with other conditions that could affect functional status or compression factors other than spondylosis were excluded from this study. Of the remaining 189 patients, 161 with CSM whose condition could be evaluated 6 months after surgery were analyzed. The patients were divided into two age groups: 80 years or older (Group A, 37 patients) and younger than 80 years of age (Group B, 124 patients). We evaluated the differences in symptom duration, clinical data, involved levels, surgical outcome, comorbidities, and postoperative complications between the two groups. The symptom duration was significantly shorter in Group A. The average JOA scores preoperatively and 6 months postoperatively were significantly lower in Group A; however, there was no significant difference in the recovery ratio. There were no significant differences in the percentages of patients with comorbidities or those with postoperative complications. Elderly patients aged 80 years or older regained approximately 40% of their function postoperatively, and the incidence of postoperative complication was similar to that in younger patients. Since this age group shows a rapid deterioration after onset, prompt decompression surgery is required.

Effect of raloxifene on arthritis and bone mineral density in rats with collagen-induced arthritis.

We studied the effect of raloxifene (RAL) on arthritis and bone mineral density (BMD) in rats with collagen-induced arthritis (CIA). Seven-month-old female Sprague-Dawley rats were divided into five groups: rats without CIA (CNT), CIA rats that underwent ovariectomy (OVX) and were treated with RAL (CIA + OVX + RAL), CIA rats that underwent OVX and were treated with vehicle (CIA + OVX + Veh), CIA rats that had sham surgery and were treated with RAL (CIA + sham + RAL), and CIA rats that had sham surgery and were treated with vehicle (CIA + sham + Veh). RAL was orally administered at 10 mg/kg every day for 3 weeks, beginning 1 week after initial sensitization until death at 4 weeks. Every week until death, we evaluated hind paw thickness and arthritis score. BMD was measured by peripheral quantitative computed tomography at the distal metaphysis and the diaphysis of the femur; we also performed histomorphometry of the proximal tibia and histological evaluation of arthritis. RAL administration suppressed hind paw thickness and arthritis score and prevented decreases in BMD and cortical thickness. In the histomorphometric analysis, bone-resorption parameters were significantly lower in the RAL groups than in the Veh groups. RAL significantly inhibited synovial proliferation in CIA rats. RAL effects on arthritis and bone were apparent regardless of whether an animal had undergone OVX. RAL could suppress arthritis and bone loss in estrogen-replete or -depleted rats. These findings, using an animal model, indicate the potential usefulness of RAL as an effective treatment for premenopausal RA patients as well as postmenopausal ones.

Spinal subdural haematoma concurrent with cranial subdural haematoma: Report of two cases and review of literature.

Subdural haematomas co-existing in the cranium and spine are considered extremely rare. We report 2 cases demonstrating the condition described here with a review of literature. One of these 2 patients was the first case in which the spinal lesion was found before the cranial lesion. A 66-year-old man without trauma presented with paraparesis accompanied by severe leg pain. The patient was diagnosed as having spinal subdural haematoma extending from L1 to S1 vertebral levels with magnetic resonance images (MRI). Two days after admission, the patient developed disorientation and abnormal behavior; therefore, computed tomography (CT) of brain was performed, and chronic cranial subdural haematoma was observed. A 60-year-old man who developed headache showing gradually progressive was diagnosed as having cranial subdural haematoma on CT. Three days after admission, he became insomnolent due to severe low back pain radiating to ankle. On MRI, subdural haematoma was found extending from L3/4 to S2 vertebral levels. Only brain surgery was performed for all cases by the neurosurgeons. Paraparesis and severe leg pain, which were derived from spinal lesions, showed recovery approximately 2 weeks after onset and spinal subdural haematoma was completely resolved on MRI obtained 2 or 5 months after onset, respectively. There is a possibility that the incidence of spinal subdural haematoma concurrent with cranial subdural haematoma could be underestimated because the doctor had not obtained CT or MRI of the brain. Doctors should aware of such a condition and check patients with spinal subdural haematoma for neurological signs derived from brain lesions. Spontaneous resolution of spinal subdural haematoma was observed; therefore, surgery for this condition should be indicated only for patients with moderate or severe paraparesis or paraparesis deteriorated.

Prognostic significance of Minichromosome maintenance protein 7 and Geminin expression in patients with 109 soft tissue sarcomas.

Minichromosome maintenance complex (MCM2-7) and Geminin are important in the prevention of DNA re-replication in the cell cycle, and are also prognostic markers for numerous human malignancies. The present study examined Minichromosome maintenance protein 7 (MCM7) and Geminin expression in human soft tissue sarcomas (STSs) to clarify their correlation to the clinicopathological factors. Immunohistochemistry was performed to detect the expression of MCM7, Geminin and Ki-67 on paraffin-embedded sections of 109 STSs. Labeling indices (LIs) of the molecules were evaluated in the tumors. Higher LIs of MCM7, Geminin and Ki-67 were significantly correlated with distant metastasis (P<0.01), histological grade (P<0.01) and poor prognosis (P<0.01), respectively. LIs of MCM7 and Geminin were significantly correlated with Ki-67 LIs, (MCM7/Ki-67: rs=0.745, P<0.01 and Geminin/Ki-67: rs=0.604, P<0.01). Multivariate analyses showed that the higher LIs of Geminin, but not MCM7 and Ki-67, were shown to be an independent factor of poorer prognosis (relative risk 2.72, P=0.013). The immunohistochemical expression of MCM7 and Geminin may be novel and useful markers for evaluating the prognosis in patients with human STS.

Tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 in the cerebrospinal fluid of patients with cervical myelopathy and lumbar radiculopathy.

There have been few reports describing cytokines in the cerebrospinal fluid (CSF) of patients with spinal degenerative disorders. This study investigated whether interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) could be detected in CSF of patients with cervical myelopathy or lumbar radiculopathy and whether the concentrations of those cytokines correlated with the severity of disease conditions. CSF samples were obtained from 21 patients with cervical myelopathy (Group M) and 19 patients with lumbar radiculopathy (Group R), and six volunteers (control). The concentration of IL-6 was significantly higher in Groups M and R than in the control, possibly demonstrating spinal cord and nerve root damage, respectively. However, TNF-alpha was lower than the detection limit. IL-1beta was detected in only five samples from three patients in Group M and two volunteers in the control. The concentrations of IL-6 did not show any correlation with symptom duration, the scoring system by the Japanese Orthopaedic Association, or the duration of nerve root block. There is a possibility that the concentration of inflammatory cytokines in CSF can indicate certain pathological aspects of cervical myelopathy or lumbar radiculopathy.

Comparison of osteoclast precursors in peripheral blood mononuclear cells from rheumatoid arthritis and osteoporosis patients.

Osteolytic disorders cause serious problems for quality of life with aging. Osteolysis is performed by osteoclasts of the hematopoietic lineage that share some characteristics with monocytes and macrophages. As osteoclast precursors (pOCs) are present in peripheral blood, their characterization in osteolytic diseases may help us to understand risk factors. Although essential factors for osteoclastogenesis have been reported, the effective induction from pOCs in human peripheral blood mononuclear cells (PBMCs) to mature osteoclasts in culture requires further improvement. The aim of this study was development of an efficient culture system for human osteoclastogenesis and providing a simple system for the enrichment of pOCs from PBMCs. We employed coculturing of human PBMCs with a mouse stromal cell line. Significant numbers of tartrate-resistant acid phosphatase-positive (TRAP(+)) multinucleated osteoclasts (MNCs), which could resorb dentine slices, were efficiently induced in this culture condition. pOCs were enriched in an anti-CD16 antibody column-passed anti-CD14 antibody-bound cell population isolated by magnetic cell sorting. We compared the percentage of the CD14(high) CD16(dull) cell population, which mainly contained pOCs in PBMCs, from age-matched patients with rheumatoid arthritis (RA) and osteoporosis (OP), but it was comparable. However, the mean number of TRAP(+) MNCs generated in cultures from PBMCs of RA was higher. In contrast, the frequency of pOCs in PBMCs from OP was relatively higher. These results suggest the characteristics of pOCs from RA and OP may be different, because single pOCs from OP gave rise to lower numbers of osteoclasts than those from RA.

Effect of estrogen replacement therapy on arthritis and bone mineral density in estrogen-replete rats with collagen-induced arthritis.

The influence of estrogen therapy on changes in arthritis and bone mineral density (BMD) was evaluated using an estrogen-replete collagen-induced arthritis (CIA) rat model. Seven-month-old female Sprague-Dawley rats (n = 30) were divided into the three groups; control (CONT), collagen sensitization (CIA), and CIA + 17beta-estradiol administration for 7 weeks (CIA + E). BMD was measured by peripheral quantitative computed tomography in the proximal tibia every 2 weeks. Eight weeks after the initial sensitization the rats were killed and histomorphometry of tibia was performed. The hind paw thickness increased with time in CIA rats and there was a significant difference between CONT and CIA at 8 weeks after the initial sensitization. Estrogen tended to make the development of arthritis milder. In CIA, BMD at metaphyseal cancellous bone began to decrease with the onset of arthritis and became significantly lower than in CONT after 8 weeks. Compared with the CIA, the deterioration in BMD was inhibited in CIA + E. Histomorphometrical parameters of bone resorption were increased in CIA compared with CONT, and those elevations were reduced by estrogen treatment, but estrogen had no effect on bone formation parameters. In conclusion, estrogen could partially suppress arthritis and bone loss in estrogen-replete rats as well as estrogen-deplete ones.