CD44, an adhesion molecule that binds to the extracellular matrix, primarily to hyaluronan (HA), has been implicated in cancer cell migration, invasion, and metastasis. CD44 has also recently been ...recognized as a marker for stem cells of several types of cancer. However, the roles of CD44 in the development of bone metastasis are unclear. Here, we addressed this issue by using bone metastatic cancer cell lines, in which CD44 was stably knocked down. Tumor sphere formation and cell migration and invasion were significantly inhibited by CD44 knockdown. Furthermore, the downregulation of CD44 markedly suppressed tumorigenicity and bone metastases in nude mice. Of note, the number of osteoclasts decreased in the bone metastases. Microarray analysis revealed that the expression of HA synthase 2 was downregulated in CD44-knockdown cells. The localization of HA in the bone metastatic tumors was also markedly reduced. We then examined the roles of CD44-HA interaction in bone metastasis using 4-methylumbelliferone (4-MU), an inhibitor of HA synthesis. 4-MU decreased tumor sphere and osteoclast-like cell formation in vitro. Moreover, 4-MU inhibited bone metastases in vivo with reduced number of osteoclasts. These results collectively suggest that CD44 expression in cancer cells promotes bone metastases by enhancing tumorigenicity, cell migration and invasion, and HA production. Our results also suggest the possible involvement of CD44-expressing cancer stem cells in the development of bone metastases through interaction with HA. CD44-HA interaction could be a potential target for therapeutic intervention for bone metastases.
Mucopolysaccharidoses (MPS) are a group of inherited, multisystem, lysosomal storage disorders involving specific lysosomal enzyme deficiencies that result in the accumulation of glycosaminoglycans ...(GAG) secondary to insufficient degradation within cell lysosomes. GAG accumulation affects both primary bone formation and secondary bone growth, resulting in growth impairment. Typical spinal manifestations in MPS are atlantoaxial instability, thoracolumbar kyphosis/scoliosis, and cervical/lumbar spinal canal stenosis. Spinal disorders and their severity depend on the MPS type and may be related to disease activity. Enzyme replacement therapy or hematopoietic stem cell transplantation has advantages regarding soft tissues; however, these therapeutic modalities are not effective for bone or cartilage and MPS-related bone deformity including the spine. Because spinal disorders show the most serious deterioration among patients with MPS, spinal surgeries are required although they are challenging and associated with high anesthesia-related risks. The aim of this review article is to provide the current comprehensive knowledge of representative spinal disease in MPS and its surgical management, including the related pathology, symptoms, and examinations.
This letter discusses the characteristics of orbital angular momentum (OAM) of hybrid mode in the cylindrical corrugated waveguide. The well-known discussion of the OAM in Laguerre-Gaussian (L-G) ...laser fields is applied to the hybrid mode of the corrugated waveguide. The analytical discussions of the OAM are also investigated by numerical simulations of the finite-difference time-domain (FDTD) method. It is found that the hybrid modes in the corrugated waveguide carry well-defined OAM.
In this paper we determine the automorphism groups of the profinite braid groups with four or more strings in terms of the profinite Grothendieck-Teichm\"uller group.
The negative impact of cigarette smoking on bone union has been well documented. However, the impact of heated tobacco product (HTP) use on bone fracture-healing remains unclear. The present study ...investigated the effect of HTPs on preosteoblast viability, osteoblastic differentiation, and fracture-healing and compared the effects with those of conventional combustible cigarettes.
Cigarette smoke extracts (CSEs) were generated from combustible cigarettes (cCSE) and HTPs (hCSE). CSE concentrations were standardized by assessing optical density. Preosteoblast (MC3T3-E1) cells were incubated with normal medium, cCSE, or hCSE. The cell viability was assessed via MTT assay. After osteoblastic differentiation of CSE-exposed cells, alkaline phosphatase (ALP) activity was assessed. To assess the in vivo effects of CSEs, a femoral midshaft osteotomy was performed in a rat model; thereafter, saline solution, cCSE, or hCSE was injected intraperitoneally, and bone union was assessed on the basis of micro-computed tomography (μCT) and biomechanical analysis 4 weeks later.
MC3T3-E1 cell viability was reduced in a time and concentration-dependent manner when treated with either cCSE or hCSE. ALP activity after osteoblastic differentiation of cCSE-treated cells was significantly lower than that of both untreated and hCSE-treated cells (mean and standard deviation, 452.4 ± 48.8 untreated, 326.2 ± 26.2 cCSE-treated, and 389.9 ± 26.6 hCSE-treated mol/L/min; p = 0.002). Moreover, the levels of osteoblastic differentiation in untreated and hCSE-treated cells differed significantly (p < 0.05). In vivo assessment of the femoral midshaft cortical region revealed that both cCSE and hCSE administration significantly decreased bone mineral content 4 weeks after surgery compared with levels observed in untreated animals (107.0 ± 11.9 untreated, 94.5 ± 13.0 cCSE-treated, and 89.0 ± 10.1 mg/cm3 hCSE-treated; p = 0.049). Additionally, cCSE and hCSE-exposed femora had significantly lower bone volumes than unexposed femora. Biomechanical analyses showed that both cCSE and hCSE administration significantly decreased femoral maximum load and elastic modulus (p = 0.015 and 0.019).
HTP use impairs cell viability, osteoblastic differentiation, and bone fracture-healing at levels comparable with those associated with combustible cigarette use.
HTP use negatively affects bone fracture-healing to a degree similar to that of combustible cigarettes. Orthopaedic surgeons should recommend HTP smoking cessation to improve bone union.
Lumbar spinal stenosis (LSS) is a common disease in the elderly, mostly due to degenerative changes in the lumbar spinal complex. Decompression surgery is the standard surgical treatment for LSS. ...Classically, total laminectomy-which involves resection of the spinous process, entire laminae and medial facet-has been the standard decompression technique; however, it can cause post-surgical instability. To overcome this disadvantage, various minimally invasive techniques that preserve the stabilization structures of the spine have been developed, and surgeons have begun to re-evaluate decompression surgery from the standpoint of reduced invasiveness and cost. More than two decades have passed since the introduction of microendoscopic spine surgery, and studies continue to shed light on its advantages and limitations as new knowledge becomes available. This article is a narrative review of the available literature, along with authors' experience, regarding the indications, surgical techniques, clinical outcomes, and limitations/complications of microendoscopic decompression for LSS.
Background:
The optimal graft choice between the bone–patellar tendon–bone (BPTB) and the quadriceps tendon remains controversial. Studies evaluating the microscopic anatomy of the quadriceps ...tendon–patellar bone (QTB) and BPTB grafts for anterior cruciate ligament (ACL) reconstruction are currently lacking.
Hypothesis:
The relationship between post–ACL reconstruction graft bending angle (GBA) and the angle corresponding to the GBA (cGBA) would indicate that the BPTB can bend more than the QTB at the femoral tunnel aperture.
Study Design:
Controlled laboratory study.
Methods:
Twenty paired human cadaveric knees fixed at <10° of knee joint flexion (mean age, 82.5 years) underwent histological sectioning and staining with Masson trichrome and toluidine blue. The femoral ACL insertion, QTB graft, and BPTB graft were microscopically analyzed. The width of the direct insertion, thickness of the uncalcified fibrocartilage and calcified fibrocartilage, ligament attachment angle, and cGBA for each group were measured. Eighteen patients who underwent ACL reconstruction with QTB or BPTB autograft were included for the evaluation of GBA using computed tomography images at 1 week postoperatively.
Results:
The mean insertion widths of the femoral ACL, QTB, and BPTB were 7.81, 9.07, and 6.54 mm, respectively. The QTB was 16% wider than the ACL, while the BPTB was 16% narrower than the ACL. The mean insertion thicknesses of the femoral ACL, QTB, and BPTB were 0.53, 0.94, and 0.38 mm, respectively. The QTB was 77% thicker than the ACL (P < .001), while the BPTB was 28% thinner than the ACL (P = .017). The mean ligament attachment angles of the femoral ACL, QTB, and BPTB were 20.3°, 30.2°, and 33.3°, respectively, and the QTB and the BPTB were 49% and 64% larger, respectively, than the ACL. The mean cGBAs of the femoral ACL, QTB, and BPTB were 33.9°, 35.1°, and 12.3°, respectively. The BPTB was 64% smaller than the ACL, while there was no significant difference between the QTB and the ACL. The mean GBA was 57.7°.
Conclusion:
The insertion width and thickness were significantly greater and smaller in the QTB and BPTB grafts, respectively, than in the ACL. The relationship between GBA after ACL reconstruction and cGBA in knee extension indicates that at the femoral tunnel aperture, the BPTB can bend more than the QTB.
Clinical Relevance:
QTB graft may allow more anatomic ACL reconstruction to be performed.
Abstract There are few reports of the Oxford unicompartmental knee arthroplasty (UKA) survival rate in Asia. This study describes outcomes of 1279 Oxford UKAs for Japanese patients. The mean ...follow-up was 5.2 years. We divided patients into two groups based on preoperative indications (extended indications group and strict indications group). The Oxford knee score improved from 22.3 to 40.8 ( P = 0.041). The 10-year survival rate using revision was 95%. A total of 25 UKAs (2.0%) required revision. The most common reason was subsidence of tibial component. The 5-year cumulative survival rate of the strict indications group was significantly higher than that of the extended indications group (99.1% vs. 93.8%, P < 0.001). When we followed inclusion criteria strictly, good clinical results were achieved in Asia.
Background:
Arthroscopic reshaping surgery is the first treatment option for a symptomatic discoid lateral meniscus (DLM) to preserve the peripheral rim. However, the degree of postoperative ...morphological change in the residual meniscus is unclear.
Purpose/Hypothesis:
The purpose of this study was to measure the meniscus after reshaping surgery for a DLM, to verify when the morphological change occurred, and to examine the related risk factors. The hypothesis was that the residual meniscal width would decrease throughout the postoperative course.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
We retrospectively reviewed the medical records of patients who underwent reshaping surgery for a symptomatic DLM and had undergone follow-up for ≥2 years. Magnetic resonance imaging (MRI) was routinely performed preoperatively and at 3, 6, 12, and 24 months postoperatively, and the width, height, and extrusion of the residual meniscus were measured. According to the width of the midbody on final MRI scans, we compared the preoperative and postoperative data for the preserved group (≥5 mm) and decreased group (<5 mm). The associated risk factors for a decreased meniscal width (<5 mm) of the midbody were analyzed on final MRI scans.
Results:
We included 61 knees of 54 patients in this study. The mean age at the time of surgery was 11.7 years. The intraobserver and interobserver reliabilities of the midbody width were 0.937 and 0.921, respectively. The width of the anterior horn, midbody, and posterior horn decreased significantly from 3 to 24 months after surgery (from 9.1 to 8.6 mm P < .001, from 7.5 to 6.1 mm P < .001, and from 9.5 to 8.9 mm P = .001, respectively). Meniscal extrusion of the midbody did not change significantly (from 1.2 to 1.5 mm; P = .062). Overall, 46 knees (n = 20/32 in the preserved group and n = 26/29 in the decreased group) had longitudinal tears that required meniscal repair. Clinical outcomes did not differ significantly between the 2 groups. Multivariate logistic analysis showed that intrameniscal degeneration (odds ratio, 4.36; P = .023) significantly increased the risk of a decreased meniscal width.
Conclusion:
The width of the anterior horn, midbody, and posterior horn decreased significantly from 3 to 24 months after surgery. In particular, the average decrease rate of the midbody was 19%. No clinical difference was seen in patients with a decreased width and height or with peripheral extrusion. Increased intrameniscal signals on preoperative MRI scans were associated with an increased risk of a decreased meniscal width. Surgeons should consider this result to determine the amount of resection.
To quantitatively evaluate degeneration of articular cartilage using magnetic resonance imaging (MRI) T2 mapping before and after arthroscopic surgery for discoid lateral meniscus (DLM).
We ...retrospectively reviewed the medical records of patients who underwent arthroscopic reshaping surgery for symptomatic DLM from September 2013 to October 2017 and who had undergone follow-up for ≥2 years. MRI T2 relaxation examinations had been performed preoperatively and at 3, 6, 12, and 24 months postoperatively. The T2 relaxation times of the whole lateral femoral condyle and the tibial plateau were assessed. In addition, the lateral femoral condyle was divided into 3 subcompartmental areas: anterior, middle, and posterior.
In total, 30 knees of 27 patients were included in this study. The patients’ mean age at operation was 13.3 years (range 6-23 years), and the mean follow-up period was 31.6 months. Saucerization alone was performed in 3 knees and saucerization with repair in 27 knees. The T2 relaxation time of the whole lateral femoral condyle was significantly increased at 3 and 6 months postoperatively and significantly decreased at 12 and 24 months. The T2 relaxation time of the whole lateral tibial plateau was significantly increased at 3 months postoperatively and significantly decreased at 24 months. The T2 relaxation time of the posterior subcompartment of the lateral femoral condyle was significantly increased at 3 months and significantly decreased at 12 and 24 months.
The T2 relaxation time of the lateral femorotibial joint cartilage increased at 3 and 6 months postoperatively and then had decreased at 12 and 24 months. Quantitative MRI allowed us to monitor the substantial changes in the cartilage during the early postoperative period and the recovery at the distant time point after reshaping surgery for DLM.
Level IV, case series
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